Door-to-dialysis time and daily hemodialysis in patients with leptospirosis: impact on mortality

Updated ACVIM consensus statement on leptospirosis in dogs

Since publication of the last consensus statement on leptospirosis in dogs, there has been revision of leptospiral taxonomy and advancements in typing methods, widespread use of new diagnostic tests and vaccines, and improved understanding of the epidemiology and pathophysiology of the disease. Leptospirosis continues to be prevalent in dogs, including in small breed dogs from urban areas, puppies as young as 11 weeks of age, geriatric dogs, dogs in rural areas, and dogs that have been inadequately vaccinated for leptospirosis (including dogs vaccinated with 2-serovar Leptospira vaccines in some regions). In 2021, the American College of Veterinary Internal Medicine (ACVIM) Board of Regents voted to approve the topic for a revised Consensus Statement. After identification of core panelists, a multidisciplinary group of 6 experts from the fields of veterinary medicine, human medicine, and public health was assembled to vote on the recommendations using the Delphi method. A draft was presented at the 2023 ACVIM Forum, and a written draft posted on the ACVIM website for comment by the membership before submission to the editors of the Journal of Veterinary Internal Medicine. This revised document provides guidance for veterinary practitioners on disease in dogs as well as cats. The level of agreement among the 12 voting members (including core panelists) is provided in association with each recommendation. A denominator lower than 12 reflects abstention of ≥1 panelists either because they considered the recommendation to be outside their scope of expertise or because there was a perceived conflict of interest.

Leptospirosis: A Potential Culprit for Chronic Kidney Disease of Uncertain Etiology

PURPOSE

Chronic kidney disease of uncertain etiology (CKDu) is an environmental nephropathy in which the etiological factors are yet uncertain. Leptospirosis, a spirochetal infection that is common among agricultural communities, has been identified as a potential etiology for CKDu beyond environmental nephropathy. Although CKDu is a chronic kidney disease, in endemic regions, an increasing number of cases are reported with features suggestive of acute interstitial nephritis without any known reason (AINu), with or without background CKD. The study hypothesizes that exposure to pathogenic leptospires is one of the causative factors for the occurrence of AINu.

METHOD

This study was carried out using 59 clinically diagnosed AINu patients, 72 healthy controls from CKDu endemic region (endemic controls [ECs]), and 71 healthy controls from CKDu non-endemic region (non-endemic controls [NECs]).

RESULTS

The seroprevalence of 18.6, 6.9, and 7.0% was observed in the AIN (or AINu), EC, and NEC groups, respectively, from the rapid IgM test. Among 19 serovars tested, the highest seroprevalence was observed at 72.9, 38.9, and 21.1% in the AIN (AINu), EC, and NEC groups, respectively, by microscopic agglutination test (MAT), particularly for serovar Leptospira santarosai serovar Shermani. This emphasizes the presence of infection in AINu patients, and this also suggests that Leptospira exposure might play an important role in AINu.

CONCLUSION

These data suggest that exposure to Leptospira infection could be one of the possible causative factors for the occurrence of AINu, which may lead to CKDu in Sri Lanka.

In silico prediction of molecular mechanisms of toxicity mediated by the leptospiral PF07598 gene family-encoded virulence-modifying proteins

Mechanisms of leptospirosis pathogenesis remain unclear despite the identification of a number of potential leptospiral virulence factors. We recently demonstrated potential mechanisms by which the virulence-modifying (VM) proteins-defined as containing a Domain of Unknown function (DUF1561), encoded by the PF07598 gene family-found only in group 1 pathogenic Leptospira-might mediate the clinical pathogenesis of leptospirosis. VM proteins belongs to classical AB toxin paradigm though have a unique AB domain architecture, unlike other AB toxins such as diphtheria toxin, pertussis toxin, shiga toxin, or ricin toxin which are typically encoded by two or more genes and self-assembled into a multi-domain holotoxin. Leptospiral VM proteins are secreted R-type lectin domain-containing exotoxins with discrete N-terminal ricin B-like domains involved in host cell surface binding, and a C-terminal DNase/toxin domain. Here we use the artificial intelligence-based AlphaFold algorithm and other computational tools to predict and elaborate on details of the VM protein structure-function relationship. Comparative AlphaFold and CD-spectroscopy defined the consistent secondary structure (Helix and ß-sheet) content, and the stability of the functional domains were further supported by molecular dynamics simulation. VM proteins comprises distinctive lectic family (QxW)₃ motifs, the Mycoplasma CARDS toxin (D3 domain, aromatic patches), C-terminal similarity with mammalian DNase I. In-silico study proposed that Gln412, Gln523, His533, Thr59 are the high binding energy or ligand binding residues plausibly anticipates in the functional activities. Divalent cation (Mg⁺²-Gln412) and phosphate ion (PO₄]^-3-Arg615) interaction further supports the functional activities driven by C-terminal domain. Computation-driven structure-function studies of VM proteins will guide experimentation towards mechanistic understandings of leptospirosis pathogenesis, which underlie development of new therapeutic and preventive measures for this devastating disease.

Workplace- and Residence-Associated Leptospirosis: A Case Report and Review of Current Literature

Leptospirosis is a zoonotic infection most commonly occurring in tropical regions through contact with water or soil contaminated with animal urine. In New York, approximately one to three cases occur annually, the majority occurring through workplace exposure to animal reservoirs. In cases of the more severe presentation of leptospirosis, Weil’s disease, it is important to identify the infection promptly to allow for early antibiotic initiation as well as early initiation of daily dialysis in cases in which it is necessary. We present a case of Weil’s disease in a 64-year-old male with presumed exposure through his combined workplace and residential environment. The resolution of symptoms occurred through a combination of hemodialysis, doxycycline, and meropenem antibiotic treatment. We also discuss the barriers to diagnosis, including the non-specific presentation of leptospirosis, the limitation of access to testing centers, and the limitations to antibody testing within the first week of symptom presentation due to low antibody levels.

Endothelial biomarkers as predictors for hemodialysis need in severe leptospirosis patients (Weil's disease)

OBJECTIVE

To investigate the prediction ability of vascular injury biomarkers for hemodialysis requirement in patients with severe leptospirosis.

METHODS

Prospective study with severe leptospirosis patients hospitalized in Fortaleza, Brazil. Blood samples were collected at hospital admission to quantify vascular injury biomarkers: syndecan-1, ICAM-1, VCAM-1, angiopoietin-2 and FGF-23. Two groups were evaluated according to hemodialysis requirement during hospital stay.

RESULTS

27 patients were included, with a mean age of 39 ± 18 years. 88.9% were males. 53.8% needed hemodialysis and presented higher levels of syndecan-1 (572 [300-811] vs. 263 [106-421] ng/mL; p = 0.03), angiopoietin-2 (1.52 [0.72-2.72] vs. 0.63 [0.4-1.38] ng/mL; p = 0.01), and FGF-23 (291 [56-2,031] vs. 10 [10-806] pg/mL; p = 0.021). Syndecan-1 showed significant correlation with creatinine (r = 0.546; p = 0.05) and total bilirubin levels (r = 0.534; p = 0.013) at hospital admission. Angiopoietin-2 showed significant correlation with creatinine levels (r = 0.513; p = 0.009) at hospital admission and the number of hemodialysis sessions (r = 0.406; p = 0.049). No significant correlation was found with FGF-23. Regarding prognostic performance, combined syndecan-1 and angiopoietin-2 levels had a better ability to predict hemodialysis need in patients with severe leptospirosis (AUC-ROC= 0.744 [CI 95%: 0.545 - 0.943] p=0.035).

CONCLUSION

Syndecan-1 and angiopoietin-2 were associated with hemodialysis need in patients with severe leptospirosis and may be useful to improve therapeutic approach and reduce mortality.

The epidemiology and outcomes of central nervous system infections in Far North Queensland, tropical Australia; 2000-2019

Background

The epidemiology of central nervous system (CNS) infections in tropical Australia is incompletely defined.

Methods

A retrospective study of all individuals in Far North Queensland, tropical Australia, who were diagnosed with a CNS infection between January 1, 2000, and December 31, 2019. The microbiological aetiology of the infection was correlated with patients’ demographic characteristics and their clinical course.

Results

There were 725 cases of CNS infection during the study period, meningitis (77.4%) was the most common, followed by brain abscess (11.6%), encephalitis (9.9%) and spinal infection (1.1%). Infants (24.3%, p<0.0001) and Aboriginal and Torres Strait Islander Australians (175/666 local residents, 26.3%, p<0.0001) were over-represented in the cohort.

A pathogen was identified in 513 cases (70.8%); this was viral in 299 (41.2%), bacterial in 175 (24.1%) and fungal in 35 (4.8%). Cryptococcal meningitis (24 cases) was diagnosed as frequently as pneumococcal meningitis (24 cases). There were only 2 CNS infections with a S. pneumoniae serotype in the 13-valent pneumococcal vaccine after its addition to the National Immunisation schedule in 2011. Tropical pathogens–including Cryptococcus species (9/84, 11%), Mycobacterium tuberculosis (7/84, 8%) and Burkholderia pseudomallei (5/84, 6%)–were among the most common causes of brain abscess. However, arboviral CNS infections were rare, with only one locally acquired case—a dengue infection in 2009—diagnosed in the entire study period. Intensive Care Unit admission was necessary in 14.3%; the overall case fatality rate was 4.4%.

Conclusion

Tropical pathogens cause CNS infections as commonly as traditional bacterial pathogens in this region of tropical Australia. However, despite being highlighted in the national consensus guidelines, arboviruses were identified very rarely. Prompt access to sophisticated diagnostic and supportive care in Australia’s well-resourced public health system is likely to have contributed to the cohort’s low case-fatality rate.

Pathogenic Leptospira Evolved a Unique Gene Family Comprised of Ricin B-Like Lectin Domain-Containing Cytotoxins

Leptospirosis is a globally important neglected zoonotic disease. Previous data suggest that a family of virulence-modifying (VM) proteins (PF07598) is a distinctive feature of group I pathogenic Leptospira that evolved as important virulence determinants. Here, we show that one such VM protein, LA3490 (also known as Q8F0K3), is expressed by Leptospira interrogans serovar Lai, as a secreted genotoxin that is potently cytotoxic to human cells. Structural homology searches using Phyre2 suggested that VM proteins are novel R-type lectins containing tandem N-terminal ricin B-chain-like β-trefoil domains. Recombinant LA3490 (rLA3490) and an N-terminal fragment, t3490, containing only the predicted ricin B domain, bound to the terminal galactose and N-acetyl-galactosamine residues, asialofetuin, and directly competed for asialofetuin-binding sites with recombinant ricin B chain. t3490 alone was sufficient for binding, both to immobilized asialofetuin and to the HeLa cell surface but was neither internalized nor cytotoxic. Treatment of HeLa cells with rLA3490 led to cytoskeleton disassembly, caspase-3 activation, and nuclear fragmentation, and was rapidly cytolethal. rLA3490 had DNase activity on mammalian and bacterial plasmid DNA. The combination of cell surface binding, internalization, nuclear translocation, and DNase functions indicate that LA3490 and other VM proteins evolved as novel forms of the bacterial AB domain-containing toxin paradigm.

Going Micro in Leptospirosis Kidney Disease

Leptospirosis is a zoonotic and waterborne disease worldwide. It is a neglected infectious disease caused by Leptospira spp., as well as a reemerging disease and global public health problem with respect to morbidity and mortality both in humans and animals. Leptospirosis emerges as a leading cause of acute febrile illness along with hepatorenal injury in many countries, including Thailand. While most affected persons are symptomatic in acute disease, which is always difficult to differentiate from other tropical diseases, there is growing evidence of subtle manifestations that cause unrecognized chronic symptoms. The kidney is one of the common organs affected by Leptospires. Although acute kidney injury in the spectrum of interstitial nephritis is a well-described characteristic in severe leptospirosis, chronic kidney disease from leptospirosis is widely discussed. Early recognition of severe leptospirosis leads to reduce morbidity and mortality. Thus, in this review, we highlight the spectrum of characteristics involved in leptospirosis kidney disease and the use of serologic and molecular methods, as well as the treatments of severe leptospirosis.

Leptospirosis in Intensive Care Unit

Tropical infections constitute 20 - 30% of intensive care unit (ICU) admissions in developing countries. Leptospirosis is a spectrum with mild form presenting as an acute febrile illness with jaundice, complicating in few as acute kidney injury (AKI), acute respiratory distress syndrome (ARDS), disseminated intravascular coagulation (DIC), and multi-organ dysfunction syndrome (MODS). The poor prognostic markers are hemorrhagic ARDS, acute renal failure, DIC, severe metabolic acidosis, older age, chronic alcohol abuse, high SOFA score, and septic shock. The confirmatory diagnosis relies on antibody testing, such as microscopic agglutination test (MAT) and IgM ELISA, while the reverse transcription-polymerase chain reaction test being reserved for clinically suspected antibody negative cases. The spectrum of multi-organ involvement necessitates a complete hematological, biochemical workup, including electrocardiogram (ECG), chest X-ray, and two-dimensional echocardiography. Specific antimicrobial therapy consists of the following-benzylpenicillin, ceftriaxone, cefotaxime, and doxycycline. The reported mortality ranges from 6% to as high as 44%. Various ICU scores like SPiRO, THAI LEPTO score, and Faine's criteria have been useful in risk stratification. Optimizing intensive care treatment with appropriate antibiotics, lung protection ventilation strategies, strict fluid management, and if need be timely initiation of renal replacement therapy (RRT) helps in reducing mortality. How to cite this article: Karnik ND, Patankar AS. Leptospirosis in Intensive Care Unit. Indian J Crit Care Med 2021;25(Suppl 2): S134-S137.

Predictors of Fatal Pulmonary Haemorrhage in Dogs Affected by Leptospirosis Approaching Haemodialysis

A retrospective case control study, which aimed to evaluate potential clinical, laboratory and imaging predictors of fatal pulmonary haemorrhage in dogs with Leptospirosis submitted to haemodialysis. The study population was divided in two groups according to the presence (PH) or absence (nPH) of pulmonary haemorrhage. A statistical comparison was performed at hospital admission for clinical (spontaneous bleeding, icterus, and respiratory distress), laboratory (serum creatinine, urea, phosphate, calcium, bicarbonate, bilirubin, AST, ALT, ALKP, GGT, total protein, albumin, glycaemia, sodium, potassium, CRP, RBC, HCT, HGB, WBC, PLT, PT, aPTT, fibrinogen), and pulmonary radiographic findings between the two groups of dogs. At hospital admission, dogs developing pulmonary haemorrhage were more likely to have respiratory distress (p = 0.002), severely elevated serum bilirubin (p = 0.002), AST (p = 0.04), ALT (p = 0.012), ALKP (p = 0.002), reduced serum glycaemia (p = 0.014), and thrombocytopenia (p = 0.04). Respiratory distress and elevated serum bilirubin (≥11.5 mg/dL) were independently associated with increased risk of pulmonary haemorrhage. In conclusion, the presence of respiratory distress at hospital admission is strongly associated (OR 40.9) with increased risk of pulmonary haemorrhage, even though no abnormalities are found at chest radiography.

Prevention and Therapy of AKI in Asia: A Big Challenge

Asia is the largest and most populous continent and has huge differences in socioeconomic status, development, and health care between the different countries and regions within each country. This manifests in the varied causes of acute kidney injury (AKI), particularly higher rates of community-acquired AKI and in the differential access to health care for the population. Because of resource limitations, prevention and treatment of AKI is a difficult challenge. This review highlights the differences in AKI in Asia compared with the developed world and discusses prevention and treatment of AKI within the context of resource limitations.

Renal Replacement Therapy in a Patient Diagnosed With Pancreatitis Secondary to Severe Leptospirosis

In areas where the zoonotic disease leptospirosis is endemic, reduced morbidity and mortality is strongly linked to quick initiation of renal replacement therapy.

Age-specific epidemiology of human leptospirosis in New Caledonia, 2006-2016

With over one million cases worldwide annually and a high fatality in symptomatic forms, human leptospirosis is a growing public health concern for the most vulnerable populations, especially in the context of global warming and unplanned urbanization. Although the Asia-Pacific region is particularly affected, accurate epidemiological data are often lacking. We conducted an eleven-year retrospective laboratory-based epidemiological survey of human leptospirosis in New Caledonia. From 2006 to 2016, 904 cases were laboratory-confirmed, including 29 fatalities, corresponding to an average annual incidence of 30.6/100,000 and a case fatality rate of 3.2%. Over the period, there was a major shift from indirect serological diagnosis by MAT to direct diagnosis by real-time PCR, a more specific and sensitive test when performed early in the course of the disease. The systematic implementation of genotyping informed on the variety of the infective strains involved, with a predominance of serogroups Icterohaemorrhagiae and Pyrogenes. The epidemiological pattern showed a marked seasonality with an annual peak in March-April. Interestingly, the seasonal peak in children of school age was significantly earlier and corresponded to school holidays, suggesting that attending school from February on could protect children from environment-borne leptospirosis.

Leptospirosis: Increasing importance in developing countries

Leptospirosis is a zoonotic disease caused by the pathogenic helical spirochetes, Leptospira. Symptoms include sudden-onset fever, severe headaches, muscle pain, nausea and chills. Leptospirosis is endemic in developing countries such as Malaysia, India, Sri Lanka, and Brazil where thousands of cases are reported annually. The disease risk factors include the high population of reservoirs, environmental factors, recreational factors, and occupational factors. To end the endemicity of leptospirosis, these factors need to be tackled. The management of leptospirosis needs to be refined. Early diagnosis remains a challenge due to a lack of clinical suspicion among physicians, its non-specific symptoms and a limited availability of rapid point-of-care diagnostic tests. The purpose of this review is to provide insight into the status of leptospirosis in developing countries focusing on the risk factors and to propose methods for the improved management of the disease.

Severe leptospirosis in tropical Australia: Optimising intensive care unit management to reduce mortality

Background

Severe leptospirosis can have a case-fatality rate of over 50%, even with intensive care unit (ICU) support. Multiple strategies–including protective ventilation and early renal replacement therapy (RRT)–have been recommended to improve outcomes. However, management guidelines vary widely around the world and there is no consensus on the optimal approach.

Methodology/Principal findings

All cases of leptospirosis admitted to the ICU of Cairns Hospital in tropical Australia between 1998 and 2018 were retrospectively reviewed. The patients’ demographics, presentation, management and clinical course were examined. The 55 patients’ median (interquartile range (IQR)) age was 47 (32–62) years and their median (IQR) APACHE III score was 67 (48–105). All 55 received appropriate antibiotic therapy, 45 (82%) within the first 6 hours. Acute kidney injury was present in 48/55 (87%), 18/55 (33%) required RRT, although this was usually not administered until traditional criteria for initiation were met. Moderate to severe acute respiratory distress syndrome developed in 37/55 (67%), 32/55 (58%) had pulmonary haemorrhage, and mechanical ventilation was required in 27/55 (49%). Vasopressor support was necessary in 34/55 (62%). Corticosteroids were prescribed in 20/55 (36%). The median (IQR) fluid balance in the initial three days of ICU care was +1493 (175–3567) ml. Only 2/55 (4%) died, both were elderly men with multiple comorbidities.

Conclusion

In patients with severe leptospirosis in tropical Australia, prompt ICU support that includes early antibiotics, protective ventilation strategies, conservative fluid resuscitation, traditional thresholds for RRT initiation and corticosteroid therapy is associated with a very low case-fatality rate. Prospective studies are required to establish the relative contributions of each of these interventions to optimal patient outcomes.

Severe leptospirosis continues to carry a high mortality. To improve outcomes, several countries have developed national guidelines for the management of severe disease. However, there is substantial variation in these guidelines despite the fact that severe leptospirosis has a very similar presentation around the world. In tropical Australia, the case-fatality rate of severe leptospirosis is only 4%. This retrospective study reviewed 55 patients with leptospirosis requiring support in an Australian Intensive Care Unit (ICU) in an effort to identify the management strategies that might explain these excellent outcomes. The low case-fatality rate was associated with prompt multimodal ICU support that included early antibiotics, protective ventilation strategies, conservative fluid resuscitation, traditional thresholds for renal replacement therapy initiation and corticosteroid therapy. However prospective, multinational studies–which include the resource-poor settings that bear the greatest burden of disease–are necessary to define which of these interventions have the greatest therapeutic value.

Infections tropicales graves dans les départements français d’Amérique, Antilles françaises et Guyane

Les Antilles-Guyane (AG) sont les départements français du continent américain, situés en zone intertropicale. La diversité des écosystèmes ainsi que le climat tropical à très forte pluviosité exposent à un vaste panel de pathologies infectieuses. Ces territoires sont de plus l’objet de mouvements importants de populations, voyageurs ou migrants, ce qui joue un rôle significatif dans le développement d’épidémies et/ou de pathologies émergentes. Ces pathologies infectieuses dites « tropicales » peuvent nécessiter une prise en charge en réanimation. Nous rapportons ici les principales données récentes concernant ces pathologies (hors infection liée au VIH) ainsi que les stratégies diagnostiques et thérapeutiques, à l’usage des réanimateurs amenés à exercer en zone tropicale AG ou recevant en métropole des patients issus de cette région.

A case of leptospirosis with acute respiratory failure and acute kidney injury treated with simultaneous extracorporeal membrane oxygenation and haemoperfusion

A 47-year-old man with a recent history of wading in floodwaters presented with a 1-week history of cough, myalgia, conjunctival suffusion and decreasing urine output. The patient had uraemia, hypotension, leukocytosis, thrombocytopenia, elevated liver enzymes and oliguria. His condition quickly worsened with haemoptysis, and respiratory distress which subsequently required intubation and mechanical ventilation. Continuous renal replacement therapy was started together with haemoperfusion (HP). The patient initially required norepinephrine and this was discontinued after the first session of HP. He was referred for veno-venous extracorporeal membrane oxygenation (ECMO) due to severe hypoxia and pulmonary haemorrhage. Oxygenation and lung compliance improved, and serum creatinine levels continued to normalise with improved urine output. He was placed off ECMO, extubated and eventually discharged. Patient was diagnosed with severe leptospirosis, acute respiratory failure and acute kidney injury successfully treated with simultaneous ECMO and HP. Blood samples were positive for Leptospira spp. DNA via PCR assay.

Leptospirosis in the elderly: the role of age as a predictor of poor outcomes in hospitalized patients

Background: The aim of this study was to investigate factors associated with poor outcomes among elderly hospitalized patients with leptospirosis. Methods: This is a retrospective cohort study with leptospirosis patients admitted to three tertiary hospitals in Fortaleza, Brazil, from January 1985 to July 2017. Patients were divided into two groups: elderly (age ≥60 years) and young (age <60 years). A comparison of demographical, clinical and laboratory data, treatment and outcomes was executed in order to investigate differences between groups. Results: A total of 507 hospitalized patients were included, with mean age 38 ± 15 years. Elderly group presented lower incidence of myalgia, vomiting, and dyspnea, as well as, higher medium systolic blood pressure. Elderly also manifested higher frequency of AKI (85.9 vs. 74.7%, p = 0.05), hemodialysis requirement (54.7 vs. 37.0%, p = 0.007) and death (32.8 vs. 12.2%, p < 0.001). In multivariate analysis, age ≥60 years was a predictor of hemodialysis requirement (p = 0.008, OR = 2.049, 95% CI = 1.207-3.477) and death (p < 0.001, OR = 3.520, 95% CI = 1.940-6.386). Conclusion: Leptospirosis in the elderly is associated with less hemodynamic impairment and higher frequency of AKI. Advanced age was also a predictor of poor outcomes, such as hemodialysis requirement and death, mostly due to kidney involvement.

Severe Leptospirosis Features in the Spleen Indicate Cellular Immunosuppression Similar to That Found in Septic Shock

Objectives: To compare microscopic and immunologic features in the spleens of patients who died of pulmonary hemorrhage and shock caused by leptospirosis (11 cases) or Gram-positive/-negative bacterial septic shock (10 cases) to those from control spleens (12 cases from splenectomy).

Methodology: Histological features in the red pulp and white pulp were analyzed using archived samples by a semi quantitative score. Immunohistochemistry was used for the recognition of immune cell markers, cytokines, caspase-3 and Leptospira antigens.

Results: The control group differed significantly from the leptospirosis and septic shock patients which demonstrate strong similarities: diffuse congestion in the red pulp with a moderate to intense infiltration of plasma cells and polymorphonuclear cells; follicles with marked atrophy; high density of CD20⁺ cells; low density of NK, TCD4⁺ and active caspase-3 positive cells and strong expression of IL-10; leptospirosis patients had higher S100 and TNF-α positive cells in the spleen than the other groups.

Conclusion: The results suggest that an immunosuppressive state develops at the terminal stage of severe leptospirosis with pulmonary hemorrhage and shock similar to that of patients with septic shock, with diffuse endothelial activation in the spleen, splenitis, and signs of disturbance in the innate and adaptive immunity in the spleen. The presence of leptospiral antigens in 73% of the spleens of the leptospirosis patients suggests the etiological agent contributes directly to the pathogenesis of the lesions. Our results support therapeutic approaches involving antibiotic and immunomodulatory treatments for leptospirosis patients and suggest that leptospirosis patients, which are usually young men with no co-morbidities, form a good group for studying sepsis and septic shock.

Acute kidney injury management using intermittent low efficiency haemodiafiltration in a critical care unit: 39 dogs (2012-2015)

BACKGROUND

Veterinary studies describing acute kidney injury (AKI) management using renal replacement therapy (RRT) are limited and have primarily focused on intermittent haemodialysis in North American populations. European data are lacking, although differences in populations, pathogen and toxin exposure and RRT modalities may exist between Europe and North America. The present study reviewed RRT-managed cases from the intensive care unit (ICU) of VetAgro Sup, Lyon, France, for the period 2012-2015. The aims were to describe a 4-h RRT protocol of intermittent low efficiency haemodiafiltration, population characteristics and outcomes in canine AKI cases requiring RRT and to identify prognostic variables. We defined DeltaCreat/h as the difference between the serum creatinine level after RRT treatment N and that before treatment N + 1 divided by the time between treatments (in hours).

RESULTS

Thirty-nine dogs were included, and 67% were males. The median (range) age, weight, hospitalization length and number of RRT treatments were 4.4 (0.25-15) years, 26.6 (6.7-69) kg, 8 (1-23) days and 3 (1-8) treatments, respectively. The main AKI causes were leptospirosis (74.4%) and nephrotoxins (15.4%). Age (4.0 vs 5.4 years; P = 0.04), admission urine output (0.5 mL/kg/h vs 0 mL/kg/h; P = 0.02) and hospitalization length (10 vs 4 days; P < 0.001) differed between survivors and non-survivors. Hospitalization length [odds ratio (OR) = 0.4], number of treatments (OR = 5.1), serum potassium level on day 2 (OR = 1.9), DeltaCreat/h between the first and second treatments (OR = 1.2), and UOP during hospitalization (OR = 0.2) were correlated with outcome. The main causes of death were euthanasia (44%) and haemorrhagic diatheses (33%). The overall survival rate was 54%, with 55% of survivors discharged with a median creatinine < 240 µmol/L.

CONCLUSIONS

This is the first description in the veterinary literature of a 4-h protocol of intermittent low efficiency haemodiafiltration to provide RRT in a veterinary critical care unit. While this protocol appears promising, the clinical application of this protocol requires further investigation. Among parameters associated with survival, UOP and DeltaCreat/h between the first and second RRT treatments may be prognostic indicators. The applicability of these parameters to other populations is unknown, and further international, multicentre prospective studies are warranted to confirm these preliminary observations.

[Update on leptospirosis]

Leptospirosis is a worldwide spirochetal zoonosis whose global incidence is increasing and is probably underestimated. Leptospirosis has long been associated with occupational contact with animals (rats and cattle) and has become in developed countries a pathology more related to recreational activities with exposure to fresh water (canoeing, swimming, canyoning) and to an environment contaminated by urine from leptospires excretory rodents. Leptospirosis should be one of the differential diagnoses to be considered when returning from travel to tropical areas, particularly Southeast Asia, and particularly during the rainy season. The clinical symptoms, particularly in the initial phase, are not specific and can limit to a flu-like syndrome or "dengue-like" making diagnosis often difficult. It is then necessary to look carefully for clinical (muscle pain, cough, conjunctival involvement, jaundice) and biological arguments (thrombocytopenia, cholestasis, rhabdomyolysis, frank elevation of CRP) that will help to diagnose leptospirosis and lead to quick antibiotic therapy before the progression to a severe icterohaemorrhagic (Weil's disease) or respiratory form associated with significant mortality. Treatment is based on injectable beta-lactams in severe forms (mainly cephalosporins) and amoxicillin, doxycycline or azithromycin in non-severe forms. Some atypical or delayed forms of leptospirosis occurring in the late immune phase of the disease are to know. Rapid diagnostic tools are currently being studied to improve diagnosis in remote areas and facilitate access to early treatment.

Early versus delayed initiation of renal replacement therapy for acute kidney injury: an updated systematic review, meta-analysis, meta-regression and trial sequential analysis of randomized controlled trials

Objective

To evaluate whether early initiation of renal replacement therapy is associated with lower mortality in patients with acute kidney injury compared to delayed initiation.

Methods

We performed a systematic review and meta-analysis of randomized controlled trials comparing early versus delayed initiation of renal replacement therapy in patients with acute kidney injury without the life-threatening acute kidney injury-related symptoms of fluid overload or metabolic disorders. Two investigators extracted the data from the selected studies. The Cochrane Risk of Bias Tool was used to assess the quality of the studies, and the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach was used to test the overall quality of the evidence.

Results

Six randomized controlled trials (1,292 patients) were included. There was no statistically significant difference between early and delayed initiation of renal replacement therapy regarding the primary outcome (OR 0.82; 95%CI, 0.48 - 1.42; p = 0.488), but there was an increased risk of catheter-related bloodstream infection when renal replacement therapy was initiated early (OR 1.77; 95%CI, 1.01 - 3.11; p = 0.047). The quality of evidence generated by our meta-analysis for the primary outcome was considered low due to the risk of bias of the included studies and the heterogeneity among them.

Conclusion

Early initiation of renal replacement therapy is not associated with improved survival. However, the quality of the current evidence is low, and the criteria used for -early- and -delayed- initiation of renal replacement therapy are too heterogeneous among studies.

Leptospirosis in ICU: A Retrospective Study of 134 Consecutive Admissions

OBJECTIVES

Leptospirosis causes reversible multiple organ failure, and its mortality remains high. The aim of this study was to determine the mortality rate of leptospirosis in an ICU offering all types of organ support available nowadays and to compare it with mortality in bacterial sepsis.

DESIGN

Retrospective, descriptive, and single-center cohort study.

SETTINGS

The largest ICU of Reunion Island (Indian Ocean) in a teaching hospital.

PATIENTS

Consecutive patients hospitalized in ICU for leptospirosis from January 2004 to January 2015.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

We report 134 cases of patients with leptospirosis hospitalized in ICU. The median age was 40 years (interquartile range, 30-52 yr), with a Simplified Acute Physiology Score II of 38 (27-50) and a Sequential Organ Failure Assessment score of 10 (8-12). Forty-one patients (31%) required mechanical ventilation and 76 (56%) required renal replacement therapy. The door-to-renal replacement therapy time was 0 (0-1) day after admission with a median urea of 25 mmol/L (17-32 mmol/L). Five patients required extracorporeal membrane oxygenation. The mortality rate was 6.0% (95% CI, 2.6-11.4). Among patients hospitalized for sepsis, the standardized mortality ratio of patients with leptospirosis with regards to Simplified Acute Physiology Score II was dramatically low: 0.40 (95% CI, 0.17 - 0.79).

CONCLUSIONS

The mortality of severe leptospirosis is lower than for other bacterial infection, provided modern resuscitation techniques are available. Prompt organ support ensures very low mortality rates despite high severity scores.

Leptospirosis: Report from the task force on tropical diseases by the World Federation of Societies of Intensive and Critical Care Medicine

Leptospirosis is a zoonosis caused by a gram negative aerobic spirochete of the genus Leptospira. It is acquired by contact with urine or reproductive fluids from infected animals, or by inoculation from contaminated water or soil. The disease has a global distribution, mainly in tropical and subtropical regions that have a humid, rainy climate and is also common in travelers returning from these regions. Clinical suspicion is critical for the diagnosis and it should be included in the differential diagnosis of any patient with a febrile hepatorenal syndrome in, or returning from endemic regions. The leptospiremic phase occurs early and thereafter there is an immunologic phase in which the most severe form, Weil's disease, occurs. In the latter, multiple organ dysfunction predominates. The appropriate diagnostic test depends on the stage of the disease and consists of direct and indirect detection methods and cultures. Severely ill patients need to be monitored in an ICU with appropriate anti-bacterial agents and early, aggressive and effective organ support. Antibiotic therapy consists of penicillins, macrolides or third generation cephalosporins.

Issues of Acute Kidney Injury Staging and Management in Sepsis and Critical Illness: A Narrative Review

Acute kidney injury (AKI) has a high incidence on intensive care units around the world and is a major complication in critically ill patients suffering from sepsis or septic shock. The short- and long-term complications are thereby devastating and impair the quality of life. Especially in terms of AKI staging, the determination of kidney function and the timing of dialytic AKI management outside of life-threatening indications are ongoing matters of debate. Despite several studies, a major problem remains in distinguishing between beneficial and unnecessary "early" or even harmful renal replacement therapy (RRT). The latter might prolong disease course and renal recovery. AKI scores, however, provide an insufficient outcome-predicting ability and the related estimation of kidney function via serum creatinine or blood urea nitrogen (BUN)/urea is not reliable in AKI and critical illness. Kidney independent alterations of creatinine- and BUN/urea-levels further complicate the situation. This review critically assesses the current AKI staging, issues and pitfalls of the determination of kidney function and RRT timing, as well as the potential harm reflected by unnecessary RRT. A better understanding is mandatory to improve future study designs and avoid unnecessary RRT for higher patient safety and lower health care costs.

The optimal time of initiation of renal replacement therapy in acute kidney injury: A meta-analysis

Background

The impact on the timing of renal replacement therapy (RRT) initiation on clinical outcomes for patients with acute kidney injury (AKI) remains controversial.

Materials and methods

We searched the Cochrane Library, EMBASE, Global Health, MEDLINE, PubMed, the International Clinical Trials Registry Platform, and Web of Science.

Results

We included 49 studies involving 9698 patients. Pooled analysis of 5408 critically ill patients with AKI showed that early RRT was significantly associated with reduced mortality compared to late RRT [odds ratio (OR), 0.40; 95% confidential intervals (CI), 0.32 - 0.48; I², 50.2%]. For 4290 non-critically ill patients with AKI, there was no statistically significant difference in the risk of mortality between early and late RRT (OR, 1.07; 95% CI, 0.79 - 1.45; I², 73.0%). Early RRT was markedly associated with shortened intensive care units (ICU) length of stay (LOS) and hospital LOS compared to late RRT in both critically ill and non-critically ill patients with AKI.

Conclusions

Early RRT probably reduce the mortality, ICU and hospital LOS in critically ill patients with AKI. Inversely, early RRT in non-critically ill patients with AKI did not decrease the mortality, but shortened the ICU and hospital LOS.

Changing patterns in leptospirosis: a three-decade study in Brazil

BACKGROUND

This study was conducted to investigate changes in the clinical pattern of leptospirosis over time, analyzing its clinical and laboratory presentations in a metropolitan city of Brazil.

METHOD

This was a retrospective study including all patients with leptospirosis admitted to tertiary care hospitals in Fortaleza in the northeast of Brazil, between 1985 and 2015. Patients were divided into three groups according to the year of hospital admission: group I for the years 1985-1995, group II for 1996-2005, and group III for 2006-2015. Demographic, clinical, and laboratory data were compared between the groups.

RESULTS

A total of 507 patients were included. Their mean age was 37.3±15.9years and 82.4% were male. The mean time between symptom onset and admission was 7±4 days. There was a linear decrease in the levels of serum urea (190.1±92.7, 135±79.5, and 95.6±73.3mg/dl, respectively, p <0.0001) and creatinine (5.8±2.9, 3.8±2.6, and 3.0±2.5mg/dl, respectively, p <0.0001) in each decade, while levels of hemoglobin (10.31±1.9, 10.8±2.0, and 11.5±2.1g/dl, respectively, p <0.0001) and platelets (57.900±52.650, 80.130±68.836, and 107.101±99.699×10⁹/l, respectively, p<0.0001) increased. There was a tendency towards a linear decrease in mortality (22%, 14%, and 11.6%, respectively, p=0.060).

CONCLUSIONS

Leptospirosis showed significant changes over time in this region. The main changes point to a decrease in disease severity and complications, such as acute kidney injury. Mortality has decreased, being close to 11%.

Initiation time of renal replacement therapy on patients with acute kidney injury: A systematic review and meta-analysis of 8179 participants

The early initiation of renal replacement therapy has been recommended for patients with acute renal failure by some studies, but its effects on mortality and renal recovery are unknown. We conducted an updated meta-analysis to provide quantitative evaluations of the association between the early initiation of renal replacement therapy and mortality for patients with acute kidney injury. After applying inclusion/exclusion criteria, 51 studies, including 10 randomized controlled trials, with a total of 8179 patients were analyzed. Analysis of the included trials showed that patients receiving early renal replacement therapy had a 25% reduction in all-cause mortality compared to those receiving late renal replacement therapy (risk ratio [RR] 0.75, 95% CI [0.69, 0.82]). We also noted a 30% increase in renal recovery (RR 1.30, 95% CI [1.07, 1.56]), a reduction in hospitalization of 5.84 days (mean difference [MD], 95% CI [-10.27, -1.41]) and a reduction in the duration of mechanical ventilation of 2.33 days (MD, 95% CI [-3.40, -1.26]) in patients assigned to early renal replacement therapy. The early initiation of renal replacement therapy was associated with a decreased risk of all-cause mortality compared with the late initiation of RRT in patients with acute kidney injury. These findings should be interpreted with caution given the heterogeneity between studies. Further studies are needed to identify the causes of mortality and to assess whether mortality differs by dialysis dose.

Acute kidney injury due to tropical infectious diseases and animal venoms: a tale of 2 continents

South and Southeast Asia and Latin American together comprise 46 countries and are home to approximately 40% of the world population. The sociopolitical and economic heterogeneity, tropical climate, and malady transitions characteristic of the region strongly influence disease behavior and health care delivery. Acute kidney injury epidemiology mirrors these inequalities. In addition to hospital-acquired acute kidney injury in tertiary care centers, these countries face a large preventable burden of community-acquired acute kidney injury secondary to tropical infectious diseases or animal venoms, affecting previously healthy young individuals. This article reviews the epidemiology, clinical picture, prevention, risk factors, and pathophysiology of acute kidney injury associated with tropical diseases (malaria, dengue, leptospirosis, scrub typhus, and yellow fever) and animal venom (snakes, bees, caterpillars, spiders, and scorpions) in tropical regions of Asia and Latin America, and discusses the potential future challenges due to emerging issues.

Determinants of mortality and impact of therapy in patients with leptospirosis admitted for intensive care in a Sri Lankan hospital--a three year retrospective study

INTRODUCTION

Leptospirosis is a disease of epidemic proportions in Sri Lanka. There is paucity of data on the determinants of mortality and impact of therapy in patients with leptospirosis admitted to critical care settings in endemic territories.

METHODOLOGY

This retrospective cross-sectional study was performed in patients with serologically confirmed leptospirosis admitted to the intensive care unit of the General Hospital, Kalutara from January 2011 to April 2014. Associations between socio-epidemiological, clinical and laboratory parameters and patient mortality were examined.

RESULTS

Forty-five patients were included. The mean age was 49.11(SD = 16.95) and majority (92%) were male. Percentage mortality was 44.4%. Patient mortality was associated with age > 40 (p = 0.012), symptoms of uremia (p = 0.017), evidence of CNS involvement (p = 0.039), presence of oliguria (p = 0.002) and anuria (p = 0.014), presence of multi-organ dysfunction syndrome (MODS) (p < 0.001), CRP > 96 (p = 0.036), platelet count < 20,000 (p = 0.045), Potassium > 5.0 (p = 0.05), metabolic acidosis with pH < 7.2 (p = 0.03), INR > 2 (p = 0.037) and requirement of mechanical ventilation (p < 0.001). Cox regression analysis revealed MODS and potassium > 5 to be independently associated with mortality.

CONCLUSIONS

A high mortality rate is noted. The presence of MODS and serum potassium concentration > 5.0 was independently associated with mortality in this retrospective study of patients with confirmed leptospirosis in a critical care setting.

Leptospirosis: risk factors and management challenges in developing countries

Leptospirosis is a widespread bacterial zoonosis with highest burden in low-income populations living in tropical and subtropical regions, both in urban and in rural environments. Rodents are known as the main reservoir animals, but other mammals may also significantly contribute to human infections in some settings. Clinical presentation of leptospirosis is nonspecific and variable, and most of the early signs and symptoms point to the so-called “acute fever of unknown origin”, a major diagnostic challenge in tropical and subtropical areas. However, leptospirosis can rapidly evolve to life-threatening complications, especially if left untreated. There is a need for good awareness of leptospirosis and rapid antibiotic treatment based on clinical and epidemiological suspicion. Severe leptospirosis cases include renal and/or respiratory failure and shock, necessitating intensive care, also seldom available or with limited capacity. Confirmation of leptospirosis relies on biological diagnosis, which unfortunately uses tricky methods seldom available. This biological confirmation, however, is essential for surveillance and public health purpose. A good knowledge of leptospirosis epidemiology (eg, the reservoir animals involved, the Leptospira strains circulating, the seasonal and geographical patterns, and specific populations at risk) can be achieved through adequate surveillance and diagnosis. This can pave the way to prevention and intervention strategies and in turn alleviate the toll leptospirosis takes on affected populations. Over the past few years, leptospirosis has been increasingly recognized, as the need for multidisciplinary approaches in a One-Health perspective has been acknowledged, raising hope to successfully tackle the challenges of this zoonosis.

Hemodiafiltration Decreases Serum Levels of Inflammatory Mediators in Severe Leptospirosis: A Prospective Study

BACKGROUND

Leptospirosis is a health problem worldwide. Its most severe form is a classic model of sepsis, provoking acute respiratory distress syndrome (ARDS) and acute kidney injury (AKI), with associated mortality that remains unacceptably high. We previously demonstrated that early initiation of sustained low-efficiency dialysis (SLED) followed by daily SLED significantly decreases mortality. However, the mode of clearance can also affect dialysis patient outcomes. Therefore, the objective of this study was to compare the effects of SLED with traditional (diffusive) clearance, via hemodialysis, and SLED with convective clearance, via hemodiafiltration (SLEDf), in patients with severe leptospirosis.

METHODS

In this prospective study, conducted in the intensive care unit (ICU) from 2009 through 2012, we compared two groups-SLED (n = 19) and SLEDf (n = 20)-evaluating demographic, clinical, and biochemical parameters, as well as serum levels of interleukins, up to the third day after admission. All patients received dialysis early and daily thereafter.

RESULTS

During the study period, 138 patients were admitted to our ICU with a diagnosis of leptospirosis; 39 (36 males/3 females) met the criteria for ARDS and AKI. All patients were on mechanical ventilation and were comparable in terms of respiratory parameters. Mortality did not differ between the SLEDf and SLED groups. However, post-admission decreases in the serum levels of interleukin (IL)-17, IL-7, and monocyte chemoattractant protein-1 were significantly greater in the SLEDf group. Direct bilirubin and the arterial oxygen tension/fraction of inspired oxygen ratio were significantly higher in the SLED group. We identified the following risk factors (sensitivities/specificities) for mortality in severe leptospirosis: age ≥ 55 years (67%/91%); serum urea ≥ 204 mg/dl (100%/70%); creatinine ≥ 5.2 mg/dl (100%/58%); Acute Physiology and Chronic Health Evaluation II score ≥ 39.5 (67%/88%); Sequential Organ Failure Assessment score ≥ 20.5 (67%/85%); and inspiratory pressure ≥ 31 mmHg (84%/85%).

CONCLUSIONS

The mode of dialysis clearance might not affect outcomes in severe leptospirosis.

The impact of "early" versus "late" initiation of renal replacement therapy in critical care patients with acute kidney injury: a systematic review and evidence synthesis

BACKGROUND

The optimal timing of initiating renal replacement therapy (RRT) in critical illness complicated by acute kidney injury (AKI) is not clearly established. Trials completed on this topic have been marked by contradictory findings as well as quality and heterogeneity issues. Our goal was to perform a synthesis of the evidence regarding the impact of "early" versus "late" RRT in critically ill patients with AKI, focusing on the highest-quality research on this topic.

METHODS

A literature search using the PubMed and Embase databases was completed to identify studies involving critically ill adult patients with AKI who received hemodialysis according to "early" versus "late"/"standard" criteria. The highest-quality studies were selected for meta-analysis. The primary outcome of interest was mortality at 1 month (composite of 28- and 30-day mortality). Secondary outcomes evaluated included intensive care unit (ICU) and hospital length of stay (LOS).

RESULTS

Thirty-six studies (seven randomized controlled trials, ten prospective cohorts, and nineteen retrospective cohorts) were identified for detailed evaluation. Nine studies involving 1042 patients were considered to be of high quality and were included for quantitative analysis. No survival advantage was found with "early" RRT among high-quality studies with an OR of 0.665 (95 % CI 0.384-1.153, p = 0.146). Subgroup analysis by reason for ICU admission (surgical/medical) or definition of "early" (time/biochemical) showed no evidence of survival advantage. No significant differences were observed in ICU or hospital LOS among high-quality studies.

CONCLUSIONS

Our conclusion based on this evidence synthesis is that "early" initiation of RRT in critical illness complicated by AKI does not improve patient survival or confer reductions in ICU or hospital LOS.

Risk factors for intensive care unit admission in patients with severe leptospirosis: a comparative study according to patients' severity

BACKGROUND

The aim of this study is to investigate predictive factors for intensive care unit (ICU) admission among patients with severe leptospirosis.

METHODS

This is a retrospective study with all patients with severe leptospirosis admitted to a tertiary hospital. Patients were divided in ICU and ward groups. Demographical, clinical and laboratory data of the groups were compared as well as acute kidney injury (AKI) severity, according to the RIFLE criteria (R = Risk, I = Injury, F = Failure, L = Loss, E = End-stage kidney disease).

RESULTS

A total of 206 patients were included, 83 admitted to ICU and 123 to ward. Mean age was 36 ± 15.8 years, with 85.9% males. Patients in ICU group were older (38.8 ± 15.7 vs. 34.16 ± 15.9 years, p = 0.037), had a shorter hospital stay (4.13 ± 3.1 vs. 9.5 ± 5.2 days, p = 0.0001), lower levels of hematocrit (29.6 ± 6.4 vs. 33.1 ± 8.6%, p = 0.003), hemoglobin (10.2 ± 2.4 vs. 11.6 ± 1.9 g/dL, p < 0.0001), and platelets (94,427 ± 86,743 vs. 128,896 ± 137,017/mm(3), p = 0.035), as well as higher levels of bilirubin (15.0 ± 12.2 vs. 8.6 ± 9.5 mg/dL, p = 0.001). ICU group also had a higher frequency of severe AKI (RIFLE-"Failure": 73.2% vs. 54.2%, p < 0.0001) and a higher prevalence of dialysis requirement (57.3% vs. 27.6%, p < 0.0001). Mortality was higher among ICU patients (23.5% vs. 5.7%, p < 0.0001). Independent predictors for ICU admission were tachypnea (p = 0.027, OR = 13, CI = 1.3-132), hypotension (p = 0.009, OR = 5.27, CI = 1.5-18) and AKI (p = 0.029, OR = 14, CI = 1.3-150). Ceftriaxone use was a protective factor (p = 0.001, OR = 0.13, CI = 0.04-0.4).

CONCLUSIONS

Independent risk factors for ICU admission in leptospirosis include tachypnea, hypotension and AKI. Ceftriaxone was a protective factor for ICU admission, suggesting that its use may prevent severe forms of the disease.

Renal replacement therapy in adult and pediatric intensive care : Recommendations by an expert panel from the French Intensive Care Society (SRLF) with the French Society of Anesthesia Intensive Care (SFAR) French Group for Pediatric Intensive Care Emergencies (GFRUP) the French Dialysis Society (SFD)

Acute renal failure (ARF) in critically ill patients is currently very frequent and requires renal replacement therapy (RRT) in many patients. During the last 15 years, several studies have considered important issues regarding the use of RRT in ARF, like the time to initiate the therapy, the dialysis dose, the types of catheter, the choice of technique, and anticoagulation. However, despite an abundant literature, conflicting results do not provide evidence on RRT implementation. We present herein recommendations for the use of RRT in adult and pediatric intensive care developed with the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) system by an expert group of French Intensive Care Society (SRLF), with the participation of the French Society of Anesthesia and Intensive Care (SFAR), the French Group for Pediatric Intensive Care and Emergencies (GFRUP), and the French Dialysis Society (SFD). The recommendations cover 4 fields: criteria for RRT initiation, technical aspects (access routes, membranes, anticoagulation, reverse osmosis water), practical aspects (choice of the method, peritoneal dialysis, dialysis dose, adjustments), and safety (procedures and training, dialysis catheter management, extracorporeal circuit set-up). These recommendations have been designed on a practical point of view to provide guidance for intensivists in their daily practice.

Leptospirosis in humans

Leptospirosis is a widespread and potentially fatal zoonosis that is endemic in many tropical regions and causes large epidemics after heavy rainfall and flooding. Infection results from direct or indirect exposure to infected reservoir host animals that carry the pathogen in their renal tubules and shed pathogenic leptospires in their urine. Although many wild and domestic animals can serve as reservoir hosts, the brown rat (Rattus norvegicus) is the most important source of human infections. Individuals living in urban slum environments characterized by inadequate sanitation and poor housing are at high risk of rat exposure and leptospirosis. The global burden of leptospirosis is expected to rise with demographic shifts that favor increases in the number of urban poor in tropical regions subject to worsening storms and urban flooding due to climate change. Data emerging from prospective surveillance studies suggest that most human leptospiral infections in endemic areas are mild or asymptomatic. Development of more severe outcomes likely depends on three factors: epidemiological conditions, host susceptibility, and pathogen virulence (Fig. 1). Mortality increases with age, particularly in patients older than 60 years of age. High levels of bacteremia are associated with poor clinical outcomes and, based on animal model and in vitro studies, are related in part to poor recognition of leptospiral LPS by human TLR4. Patients with severe leptospirosis experience a cytokine storm characterized by high levels of IL-6, TNF-alpha, and IL-10. Patients with the HLA DQ6 allele are at higher risk of disease, suggesting a role for lymphocyte stimulation by a leptospiral superantigen. Leptospirosis typically presents as a nonspecific, acute febrile illness characterized by fever, myalgia, and headache and may be confused with other entities such as influenza and dengue fever. Newer diagnostic methods facilitate early diagnosis and antibiotic treatment. Patients progressing to multisystem organ failure have widespread hematogenous dissemination of pathogens. Nonoliguric (high output) renal dysfunction should be supported with fluids and electrolytes. When oliguric renal failure occurs, prompt initiation of dialysis can be life saving. Elevated bilirubin levels are due to hepatocellular damage and disruption of intercellular junctions between hepatocytes, resulting in leaking of bilirubin out of bile caniliculi. Hemorrhagic complications are common and are associated with coagulation abnormalities. Severe pulmonary hemorrhage syndrome due to extensive alveolar hemorrhage has a fatality rate of >50 %. Readers are referred to earlier, excellent summaries related to this subject (Adler and de la Peña-Moctezuma 2010; Bharti et al. 2003; Hartskeerl et al. 2011; Ko et al. 2009; Levett 2001; McBride et al. 2005).

Pathophysiology of leptospirosis

Leptospirosis is an acute septicemic illness that affects humans in all parts of the world. Approximately 10% of patients with leptospirosis develop severe disease, the Weil syndrome, with jaundice, acute kidney injury (AKI), and pulmonary hemorrhage. Leptospirosis-induced AKI is typically nonoliguric with a high frequency of hypokalemia. Experimental and clinical studies demonstrated that tubular function alterations precede a drop in the glomerular filtration rate and are mainly in the proximal tubule. Studies in humans and animals have demonstrated a decrease in the expression of proximal sodium (NHE3) and water tubular transporter, aquaporin 1 (AQP1) together with higher renal expression of the Na-K-2Cl cotransporter NKCC2. In an experimental model, at the initial phase of the disease, the expression of AQP2, the water transport of the collecting duct, is decreased, which explains the higher incidence of nonoliguric AKI. During the recovery phase of AKI, AQP2 expression increased in human and animals as a compensatory mechanism. Alveolar hemorrhage, pulmonary edema, acute respiratory distress syndrome, or a combination of these features may accompany AKI and is associated with high mortality. Studies with hamsters demonstrated that in leptospirosis a noncardiogenic pulmonary edema occurs consequently to a decrease in the clearance of alveolar fluid, due to a decrease in sodium transporter in the luminal membrane (ENaC) and an increase in the NKCC1 basolateral membrane transporter. Antibiotic treatment is efficient in the early and late/severe phases and revert all kidney transporters. Early and daily hemodialysis, low daily net fluid intake, and lung-protective strategies are recommended for critically ill patients with leptospirosis.

Timing of renal replacement therapy initiation by AKIN classification system

INTRODUCTION

Previous studies using Acute Kidney Injury Network (AKIN)/RIFLE criteria to classify early initiation of renal replacement therapy (RRT) have defined it as the therapy started in less severe AKIN/RIFLE stages. Generally, these studies failed in demonstrating measurable benefits.

METHODS

We compared RRT initiation in critically ill patients and defined early or late RRT in reference to timing after stage 3 AKIN was met: patients beginning RRT within 24 hours after acute kidney injury (AKI) stage 3 were considered early starters. AKIN criteria were evaluated by both urine output (UO) and serum creatinine (sCr) and patients with acute-on-chronic kidney disease were excluded. A propensity score methodology was used to control variables.

RESULTS

A total of 358 critically ill patients were submitted to RRT. Only 150 patients with pure AKI at stage 3 were analyzed. Mortality was lower in the early RRT group (51.5 vs. 77.9%, P=0.001). After achieving balance between the groups using a propensity score, there was a significant 30.5 (95% confidence interval [CI] 14.4 to 45.2%, P=0.002) relative decrease of mortality in the early RRT group. Moreover, patients on the early RRT group had lower duration of mechanical ventilation, time on RRT and a trend to lower intensive care unit (ICU) length of stay.

CONCLUSIONS

For the first time, AKIN was used with UO criterion to evaluate early and late RRT. Using a time-based approach could be a better parameter to access the association between RRT initiation and outcomes in patients with AKI.

Impact of acute kidney injury exposure period among liver transplantation patients

Background

Acute kidney injury is a common complication of liver transplantation. In this single-centre retrospective observational study, we investigated the impact of acute kidney disease on liver recipient survival.

Methods

The study population consisted of patients who underwent a liver engraftment between January 2002 and November 2006, at a single transplantation centre in São Paulo, Brazil. Acute kidney injury diagnosis and staging were according to the recommendations of the Acute Kidney Injury Network and consisted of scanning the daily serum creatinine levels throughout the hospital stay. Patients requiring renal replacement therapy prior to transplantation, those who developed acute kidney injury before the procedure or those receiving their second liver graft were excluded from the study.

Results

A total of 444 liver transplantations were performed during the study period, and 129 procedures (29%) were excluded. The remaining 315 patients constituted the study population. In 207 procedures, the recipient was male (65%). The mean age of the population was 51 years. Cumulative incidence of acute kidney injury within 48 h, during the first week after transplantation, and throughout the hospital stay was 32, 81 and 93%, respectively. Renal replacement therapy was required within a week after the transplantation in 31 procedures (10%), and another 17 (5%) required replacement therapy after that period. Mean follow-up period was 2.3 years. Time in days from acute kidney injury diagnosis to initiation of replacement therapy or reaching serum creatinine peak was associated with lower overall survival even when adjusted for significant potential confounders (HR 1.03; 95% CI 1.01, 1.05; p=0.002). Overall, patients experiencing acute kidney injury lasting for a week or more before initiation of replacement therapy experienced a threefold increase in risk of death (HR 3.02; 95% CI 2.04, 4.46; p<0.001).

Conclusions

Acute kidney injury after liver transplantation is remarkably frequent and has a substantial impact on patient survival. Delaying the initiation of renal replacement therapy in such population may increase mortality by more than 20% per day.

Renal replacement therapy in acute kidney injury

Although the use of renal replacement therapy (RRT) to support critically ill patients with acute kidney injury (AKI) has become routine, many of the fundamental questions regarding optimal management of RRT remain. This review summarizes current evidence regarding the timing of initiation of RRT, the selection of the specific modality of RRT, and prescription of the intensity of therapy. Although absolute indications for initiating RRT-such as hyperkalemia and overt uremic symptoms-are well recognized, the optimal timing of therapy in patients without these indications continues to be a subject of debate. There does not appear to be a difference in either mortality or recovery of kidney function associated with the various modalities of RRT. Finally, providing higher doses of RRT is not associated with improved clinical outcomes.

Renal replacement therapy in ICU

Diagnosing and managing critically ill patients with renal dysfunction is a part of the daily routine of an intensivist. Acute kidney insufficiency substantially contributes to the morbidity and mortality of critically ill patients. Renal replacement therapy (RRT) not only does play a significant role in the treatment of patients with renal failure, acute as well as chronic, but also has spread its domains to the treatment of many other disease conditions such as myaesthenia gravis, septic shock and acute on chronic liver failure. This article briefly outlines the role of renal replacement therapy in ICU.

U-curve association between timing of renal replacement therapy initiation and in-hospital mortality in postoperative acute kidney injury

Background

Postoperative acute kidney injury (AKI) is associated with poor outcomes in surgical patients. This study aims to evaluate whether the timing of renal replacement therapy (RRT) initiation affects the in-hospital mortality of patients with postoperative AKI.

Methodology

This multicenter retrospective observational study, which was conducted in the intensive care units (ICUs) in a tertiary hospital (National Taiwan University Hospital) and its branch hospitals in Taiwan between January, 2002, and April, 2009, included adult patients with postoperative AKI who underwent RRT for predefined indications. The demographic data, comorbid diseases, types of surgery and RRT, and the indications for RRT were documented. Patients were categorized according to the period of time between the ICU admission and RRT initiation as the early (EG, ≦1 day), intermediate (IG, 2–3 days), and late (LG, ≧4 days) groups. The in-hospital mortality rate censored at 180 day was defined as the endpoint.

Results

Six hundred forty-eight patients (418 men, mean age 63.0±15.9 years) were enrolled, and 379 patients (58.5%) died during the hospitalization. Both the estimated probability of death and the in-hospital mortality rates of the three groups represented U-curves. According to the Cox proportional hazard method, LG (hazard ratio, 1.527; 95% confidence interval, 1.152–2.024; P = 0.003, compared with IG group), age (1.014; 1.006–1.021), diabetes (1.279; 1.022–1.601; P = 0.031), cirrhosis (2.147; 1.421–3.242), extracorporeal membrane oxygenation support (1.811; 1.391–2.359), initial neurological dysfunction (1.448; 1.107–1.894; P = 0.007), pre-RRT mean arterial pressure (0.988; 0.981–0.995), inotropic equivalent (1.006; 1.001–1.012; P = 0.013), APACHE II scores (1.055; 1.037–1.073), and sepsis (1.939; 1.536–2.449) were independent predictors of the in-hospital mortality (All P<0.001 except otherwise stated).

Conclusions

The current study found a U-curve association between the timing of the RRT initiation after the ICU admission and patients’ in-hospital mortalities, and alerts physicians of certain factors affecting the outcome after the RRT initiation.

Commonly used severity scores are not good predictors of mortality in sepsis from severe leptospirosis: a series of ten patients

Introduction. Severe leptospirosis, also known as Weil's disease, can cause multiorgan failure with high mortality. Scoring systems for disease severity have not been validated for leptospirosis, and there is no documented method to predict mortality. Methods. This is a case series on 10 patients admitted to ICU for multiorgan failure from severe leptospirosis. Data were collected retrospectively, with approval from the Institution Ethics Committee. Results. Ten patients with severe leptospirosis were admitted in the Patras University Hospital ICU in a four-year period. Although, based on SOFA scores, predicted mortality was over 80%, seven of 10 patients survived and were discharged from the hospital in good condition. There was no association between SAPS II or SOFA scores and mortality, but survivors had significantly lower APACHE II scores compared to nonsurvivors. Conclusion. Commonly used severity scores do not seem to be useful in predicting mortality in severe leptospirosis. Early ICU admission and resuscitation based on a goal-directed therapy protocol are recommended and may reduce mortality. However, this study is limited by retrospective data collection and small sample size. Data from large prospective studies are needed to validate our findings.

Timing of initiation of renal replacement therapy in acute kidney injury: a systematic review and meta-analysis

OBJECTIVE

The aim of the study is to summarize the effects of timing of initiation of renal replacement therapy (RRT) on mortality.

METHODS

A systematic search for randomized controlled trials (RCTs) and other clinical studies was performed without language restriction in PubMed, Web of Science, and Embase. We estimated pooled relative risk ratios (RRs) and 95% confidence intervals (CIs) using fixed effects model or random effects model as appropriate. Heterogeneity, publication bias, and subgroup analyses were conducted.

RESULTS

We analyzed the date extracted from 15 studies (3 RCTs, 2 prospective, and 10 retrospective comparative cohort studies) with a total of 2955 patients. Overall, 51.0% (772/1514) patients died in the "early" RRT group compared with 58.0% (836/1441) in the "late" RRT group. The pooled RR was 0.71 (95% CI: 0.59, 0.86), but the heterogeneity existed (p < 0.00001). Subgroup analysis based on modality did not record heterogeneity across trials. In continuous RRT (CRRT) group (n = 607), patients treated with "early" CRRT suggested a significant decrease in mortality compared with those in "late" CRRT group (27.8% vs. 43.0%) and the RR was 0.69 (95% CI: 0.56, 0.84) without evidence of heterogeneity (I2 = 33%, p = 0.18). In intermittent hemodialysis (IHD) group (n = 115), the RR was 0.26 (95% CI: 0.15, 0.45) without evidence of heterogeneity (I2 = 0%, p = 0.50). In the mixed group, heterogeneity existed.

CONCLUSION

"Early" CRRT and "early" IHD both could reduce the mortality of patients with acute kidney injury compared with "late" CRRT or IHD.

Different patterns in a cohort of patients with severe leptospirosis (Weil syndrome): effects of an educational program in an endemic area

The aim of this study is to investigate the changes in clinical pattern and therapeutic measures in leptospirosis-associated acute kidney injury; a retrospective study with 318 patients in Brazil. Patients were divided according to the time of admission: 1985-1996 (group I) and 1997-2010 (group II). Patients were younger in group I (36 ± 13 versus 41 ± 16 years, P = 0.005) and the numbers of oliguria increased (21% versus 41% in group II, P = 0.014). Higher frequency of lung manifestations was observed in group II (P < 0.0001). Although increased severity, there was a significant reduction in mortality (20% in group I versus 12% in group II, P = 0.03). Mortality was associated with advanced age, low diastolic blood pressure, oliguria, arrhythmia, and peritoneal dialysis, besides a trend to better mortality with penicillin administration. Leptospirosis is occurring in an older population, with a higher number of oliguria and lung manifestations. However, mortality is decreasing and can be the result of changes in treatment.

Leptospirosis-associated acute kidney injury: penicillin at the late stage is still controversial

WHAT IS KNOWN AND OBJECTIVE

Some antimicrobial agents are active in vitro against Leptospiras. The use of penicillins at the late stage of leptospirosis is still controversial. We aimed to evaluate the use of penicillin in patients with leptospirosis-associated acute kidney injury (AKI).

METHODS

A retrospective study was conducted of patients with leptospirosis admitted to two hospitals in Fortaleza city, Brazil, between 1985 and 2008. AKI was defined according to the RIFLE and AKIN classifications. Patients were divided in two groups according to whether they were treated with a penicillin or not.

RESULTS

Two hundred and eighty-seven patients were included, with an average age of 36·8±15·6 years and mostly male (80·8%). One hundred and twelve patients (39%) received a penicillin. Patients treated with a penicillin were younger (32±14 years vs. 39±16 years, P=0·0002) and had a shorter hospital stay (8·4±5·0 vs. 11±7·7 days, P<0·0001). There was no difference in the onset of symptoms before hospital admission between the two groups (6·5±3·0 vs. 7·7±4·7, P=0·33). Systolic blood pressure was lower in the penicillin group (111±21 vs. 119±22 mmHg, P=0·04). AKI, need of dialysis and renal recovery at the time of hospital discharge were more frequent in patients who did not use a penicillin (P<0·05). Mortality was similar in both groups (11·6% vs. 13·7%, P=0·60).

CONCLUSION

Treatment of leptospirosis with antibiotics, including the penicillin, remains controversial. The main benefit of using penicillin in the present study was a reduction in the length of hospital stay and fewer complications, such as AKI, but its use was not associated with a decrease in mortality. On balance of risks and benefits, we recommend the use of penicillin in late-stage leptospirosis.