Building prognostic models for adverse outcomes in a prospective cohort of hospitalised patients with acute leptospirosis infection in the Philippines

A 16-year-old man with leptospirosis and atypical disseminated intravascular coagulation: a case report

BACKGROUND

Leptospirosis is known for its pulmonary form characterized by intra-alveolar hemorrhage, exhibiting a high mortality rate. Management by venous-venous extracorporeal membrane oxygenation has been reported in a small number of cases.

CASE PRESENTATION

We report herein the case of a 16-year-old Caucasian male who was admitted with rapidly deteriorating respiratory and digestive complaints. He developed severe acute respiratory distress syndrome secondary to disseminated intravascular coagulation and intra-alveolar hemorrhage, requiring initiation of venous-venous extracorporeal membrane oxygenation. Initial infectious and immunological assessments were inconclusive, but repeat serology on the tenth day of admission confirmed a diagnosis of leptospirosis. The patient received multiple transfusions, and upon favorable response to treatment with corticosteroids and antibiotics, he was successfully weaned off venous-venous extracorporeal membrane oxygenation, which was discontinued after 12 days.

CONCLUSION

Leptospirosis is a rare cause of severe acute respiratory failure following pulmonary hemorrhage. It is typically diagnosed by serology, with detectable IgM antibodies 5-7 days after the onset of symptoms. We report that early support with respiratory extracorporeal membrane oxygenation favors timely clearance of endobronchial clotting, parenchymal recovery, and prevention of ventilator-induced lung injury. Major hypofibrinogenemia, which did not seem to worsen during extracorporeal membrane oxygenation application, was managed by repeated transfusions. Further studies investigating the pathogenesis of this coagulopathy are required to further optimize the management of this rare and severe complication.

Demographic and clinical risk factors associated with severity of lab-confirmed human leptospirosis in Colombia, 2015-2020

BACKGROUND

Leptospirosis is a common zoonoses and is a major global public health threat. Most cases are mild, typically presenting as a non-specific acute febrile illness. However, leptospirosis can have life-threatening manifestations, including pulmonary hemorrhage syndrome, and acute kidney injury. In Colombia, notification and lab-confirmation of suspected human cases are mandatory. However, little is known about the demographic and clinical factors associated with severe leptospirosis, which could help to reduce clinical complications and mortality. Our aim was to identify risk factors associated with severe leptospirosis, intensive care unit (ICU) admission, and mortality in lab-confirmed cases in Colombia, 2015-2020.

METHODS AND FINDINGS

We analyzed 201 lab-confirmed human leptospirosis cases by microagglutination test. We used a logistic regression to identify the demographic and clinical risk factors associated with severe leptospirosis, admission to ICU, and death. Most leptospirosis confirmed cases occurred in men (85.6%); the mean age was 36.7 years. We classified severe cases (43.3%) by clinical manifestations as renal (29.9%) and liver (27.4%) failure, multiple-organ failure (24.4%), septic shock (24.4%), Weil syndrome (18.4%), pulmonary hemorrhage (18.4%), and meningitis (2.5%), admitted to the ICU (30.3%), and fatal (8.5%). Clinical conditions associated with severe leptospirosis were dyspnea (OR: 5.54; 95% CI: 1.46 to 20.98), tachycardia (OR:9.69; 95% CI: 15.96 to 58.8), and rash (OR: 10.25; 95% CI: 25.01 to 42.08).

CONCLUSIONS

We identified demographic characteristics and clinical symptoms associated with severe leptospirosis in Colombia. We hope these results can support clinicians in providing timely treatment to leptospirosis patients to avoid preventable medical complications or deaths.

Prognostic Factors for Leptospirosis Infection Severity

BACKGROUND

Leptospirosis is an important health problem in Thailand. People infected with leptospirosis may not have any mild symptoms, whereas some people have acute and severe illnesses. It is crucial to strengthen critical patients' diagnosis and treatment to prevent severe complications and reduce mortality. This study was performed to explore a set of parameters for the prediction of severe leptospirosis illness under routine clinical practice.

METHODS

A case-control study was conducted in eight general hospitals in Thailand. Retrospective collection data were used, and key information was retrieved from inpatient medical files. Patients were grouped into two severity categories, severe and non-severe infection. Backward elimination was used to reach the final multivariate model.

RESULTS

The six significant predictors identified in the study were hemoptysis (OR = 25.80, 95% CI 5.69, 116.92), hypotension (blood pressure < 90/60 mmHg) (OR = 17.33, 95% CI 6.89, 43.58), platelet count < 100,000/µL (OR = 8.37, 95% CI 4.65, 15.09), white blood cell count (WBC) > 14,000/µL (OR = 5.12, 95% CI 2.75, 9.51), hematocrit ≤ 30% (OR = 3.49, 95% CI 1.61, 7.57), and jaundice (OR = 3.11, 95% CI 1.71, 5.65). These predictors could correctly predict the severity of leptospirosis infection in 91.31% of the area under the receiver operation curve (AuROC).

CONCLUSIONS

The results of this study showed that severe leptospirosis infections have identifiable predictors. The predictors may be used to develop a scoring system for predicting the level of severity.

C-reactive protein: An easy marker for early differentiation between leptospirosis and dengue fever in endemic area

In tropical regions, leptospirosis and dengue fever (DF) are infectious diseases of epidemiological importance and have overlapping symptomatic features. The objective of this study was to identify the factors associated to diagnosing leptospirosis that differentiate it to DF at the initial hospital evaluation. A multicenter retrospective study was conducted comparing confirmed leptospirosis to DF cases. Clinical/laboratory findings were compiled at hospital admission on Reunion Island between 2018 and 2019. Multivariable logistic regression was used to identify the predictors of leptospirosis. In total, 98 leptospirosis and 673 DF patients were included with a mean age of 47.8 (±17.1) and 48.9 (±23.3) years, respectively. In the multivariate analyses, the main parameters associated with leptospirosis were: i) increased neutrophil counts, ii) C-reactive protein values, iii) the absence of prolonged partial thromboplastin time, and iv) a decrease of platelets. The most discriminating parameter was C-reactive protein (CRP). With a threshold of 50mg/L, CRP taken alone had a sensitivity of 94% and a specificity of 93.5%. The positive and negative likelihood ratios were 14.5 and 0.06, respectively. In the setting of an early presumptive diagnosis, we found that an increased CRP value (>50 mg/L) could help diagnose leptospirosis and aid the decision process for hospital surveillance and/or a potential antibiotic treatment regimen.

An Observational Study of Human Leptospirosis in Seychelles

A 1-year population-based prospective study was launched in Seychelles, a country with one of the highest human incidence of leptospirosis worldwide, to describe the characteristic features of the epidemiology of the disease and highlight the most prominent risk factors. Diagnosis was based on the IgM enzyme-linked immunosorbent assay, microscopic agglutination test, and real-time PCR. A standardized questionnaire was administered to 219 patients aged ≥ 13 years consulting for acute febrile illness. The high incidence of leptospirosis in Seychelles was confirmed. The disease was particularly severe, as the case fatality rate was 11.8%. Leptospirosis was positively associated in univariate analysis with socio-professional and clinical variables including gardening/farming, oliguria, jaundice, conjunctivitis, history of hepatitis C virus infection, anemia, thrombocytopenia, and/or biological renal failure. Epidemiological analyses of the questionnaires highlighted a link of the disease with living in houses (versus apartment), the presence of animals around and in houses, gardening, and misuse of personal protective equipment. Multivariate analyses indicated that being a farmer/landscaper and having cattle and cats around the home are the most significant drivers of leptospirosis. Biological features most associated with leptospirosis were thrombocytopenia, leukocytosis, high values for renal function tests, and elevated total bilirubin. We report changes in behavior and exposure compared with data collected on leptospirosis 25 years ago, with indication that healthcare development has lowered case fatality. Continuous health education campaigns are recommended as well as further studies to clarify the epidemiology of human leptospirosis, especially the role of domestic animals.

Identifying factors associated with treatment delay in leptospirosis: A retrospective study of patients admitted to hospital in Reunion (Indian Ocean) between 2014 and 2015

BACKGROUND

Leptospirosis is a life-threatening zoonotic disease for which delayed treatment onset has been associated to poor prognosis. The purpose of the study was to identify the determinants of therapeutic delay in hospitalized leptospirosis cases.

PATIENTS AND METHODS

We carried out a retrospective multicenter study in the 4 public hospitals of Reunion Island, South Western Indian Ocean. Medical records of confirmed leptospirosis cases occurring in 2014-2015 were reviewed for socio-economic, demographic, geographic and medical data. The primary outcome measure was the therapeutic delay, defined as the time elapsed between the onset of symptoms and initiation of antibiotics.

RESULTS

Of the 117 patients included, 107 were men, with an average age of 44.9±15years. The median therapeutic delay was 4 days (interquartile: 2-5 days) and this delay was not found to be associated with severity. The following were found to be at increased risk of having a longer therapeutic delay: cases occurring outside the epidemic period, or rainy season (OR 2.8 [1.08-7.3], P=0.04) and cases with first medical evaluation in primary health care (OR 4.63 [1.43-14.93]; P=0.01) instead of emergency unit. No socio-economic or geographic characteristics were found to be linked to a longer therapeutic delay.

CONCLUSION

Although delayed treatment was not associated to disease severity, our results indicate that leptospirosis awareness is needed all year in the subtropical area of Reunion Island and particularly in primary care.

A simple score to predict severe leptospirosis

Background

The case-fatality rate of severe leptospirosis can exceed 50%. While prompt supportive care can improve survival, predicting those at risk of developing severe disease is challenging, particularly in settings with limited diagnostic support.

Methodology/Principal findings

We retrospectively identified all adults with laboratory-confirmed leptospirosis in Far North Queensland, Australia, between January 1998 and May 2016. Clinical, laboratory and radiological findings at presentation were correlated with the patients’ subsequent clinical course. Medical records were available in 402 patients; 50 (12%) had severe disease. The presence of oliguria (urine output ≤500 mL/24 hours, odds ratio (OR): 16.4, 95% confidence interval (CI): 6.9–38.8, p<0.001), abnormal auscultatory findings on respiratory examination (OR 11.2 (95% CI: 4.7–26.5, p<0.001) and hypotension (systolic blood pressure ≤100 mmHg, OR 4.3 (95% CI 1.7–10.7, p = 0.002) at presentation independently predicted severe disease. A three-point score (the SPiRO score) was devised using these three clinical variables, with one point awarded for each. A score could be calculated in 392 (98%) patients; the likelihood of severe disease rose incrementally: 8/287 (3%), 14/70 (20%), 18/26 (69%) and 9/9 (100%) for a score of 0, 1, 2 and 3 respectively (p = 0.0001). A SPiRO score <1 had a negative predictive value for severe disease of 97% (95% CI: 95–99%).

Conclusions/Significance

A simple, three-point clinical score can help clinicians rapidly identify patients at risk of developing severe leptospirosis, prompting early transfer to referral centres for advanced supportive care. This inexpensive, bedside assessment requires minimal training and may have significant utility in the resource-limited settings which bear the greatest burden of disease.

Leptospirosis, a neglected tropical disease with a global distribution, is estimated to kill 60,000 people every year. Predicting those at risk of developing severe disease is challenging, and a simple scoring system to quantify the risk of severe disease has proven elusive. Identifying the high-risk patient is important, as it might expedite the initiation of life-saving supportive care. This review of 402 adult patients with leptospirosis in tropical Australia determined that three clinical variables identified at presentation independently predicted severe disease (a subsequent requirement for Intensive Care Unit admission, intubation, vasopressor support, renal replacement therapy or the development of pulmonary haemorrhage). These three variables (abnormal auscultatory findings on respiratory examination, hypotension and oliguria) were used to generate a simple, three-point clinical score which can be determined rapidly and reliably at the bedside by health care workers with minimal training. This simple score may help the clinical management of patients with leptospirosis, particularly in lower and middle-income countries that bear the greatest burden of disease.

[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.