Incidence, risk factors and clinical outcomes of acute kidney injury associated with scrub typhus: a retrospective study of 510 consecutive patients in South Korea (2001-2013)

Incidence of Scrub Typhus according to Changes in Geographic and Demographic Characteristic in the Chungcheong Region of Korea

To ascertain the incidence trends of scrub typhus in the Chungcheong region, we analyzed the epidemiological survey information of 14,379 cases of scrub typhus reported to the integrated disease health management system of the Korea Centers for Disease Control and Prevention between 2012 and 2022, along with demographic data from the Korean Statistics Information Service. Geographical analyses were performed to confirm the correlation between high-risk areas and the proportion of elderly people. The average age, proportion of elderly people, and changes in the agricultural population were statistically associated with incidence. The incidence of scrub typhus, and the agricultural population, in the Chungcheong region has decreased compared with that in 2012-2013. However, recent trends indicate a resurgence linked to increased outdoor activity, with higher risks observed in older age groups. Additionally, advancing age correlates with a heightened probability of reinfection and additional infections with other febrile diseases. The incidence of scrub typhus in the Chungcheong region (2012-2022) is changing according to age and route of infection, highlighting the need for revised prevention and promotion policies.

Scrub Typhus- An Underestimated Infectious Disease Attributable to Community Acquired Acute Kidney Injury

Acute Kidney Injury (AKI) associated with Scrub typhus is an emerging health problem which is more common in the tropics including India. This study intended to find out the occurrence of Scrub typhus among the Community Acquired Acute Kidney Injury patients in a tertiary care hospital in Assam, North East India. AKI patients with acute febrile illness admitted to Gauhati Medical College and Hospital, Guwahati, Assam were included in the study and demographic characteristics along with clinical features were recorded. The detection of Scrub typhus was done by IgM Enzyme Linked Immunosorbent Assay (ELISA) test (Optical Density > 0.5) and polymerase chain reaction (PCR) analysis. Routine haematological and biochemical tests were performed. Molecular characterization of Orientia tsutsugamushi was done followed by phylogenetic analysis. The Graph Pad Prism software 9 was used for statistical analysis. Out of 221 AKI patients admitted to hospital, 45 patients (20.4%) were confirmed to be Scrub typhus positive and among them, 4 cases were co-infected with leptospirosis. Majority of Scrub typhus positive AKI patients were in Stage I (82.2%) under KDIGO guideline. "Karp" was the predominant circulating serotype. The study showed cases of Scrub typhus associated Acute Kidney Injury was high and mortality was 11.1%. Hence, in this region, further studies need to be done with large number of population and more emphasis need to be given on differential diagnosis.

Supplementary Information

The online version contains supplementary material available at 10.1007/s12088-023-01137-x.

Mortality and complications of scrub typhus in the paediatric population: a systematic review and meta-analysis

Scrub typhus is a leading cause of treatable febrile illness. It can produce complications and dysfunction of multiple organs in children and is associated with considerable mortality. We attempted to perform a systematic review of original articles published between 1990 to 2020 based on certain selection criteria to estimate the case fatality risk of this disease in children. We addressed the pattern of complications of this disease with its impact on mortality We calculated pooled prevalence with a random effects model (restricted maximum likelihood method) that assumed varying effect sizes between studies using R statistical software. We reported the case fatality rate and its 95% confidence intervals (CIs) in the pooled analysis. Thirty-seven articles with a total of 3329 children were identified for inclusion. The case fatality rate was 1.1% (CI 0.05 to 2, I2=58% and prediction interval 0-6%). The mortality rate showed a declining trend over the last 5 y. Hepatitis (30.68% [95% CI 18.52 to 44.38]) remains the most common complication, followed by shock (14.45% [95% CI 7.71 to 22.85]), pneumonia (14.71% [95% CI 9.76 to 20.48]), acute kidney injury (13.72% [95% CI 8.49 to 19.97]) and meningitis/meningoencephalitis (11.57% [95% CI 7.83 to 15.92]). Multi-organ dysfunction syndrome was the main contributor to mortality.

Clinical significance of hypoalbuminemia in patients with scrub typhus complicated by acute kidney injury

Background

This study aimed to investigate the clinical significance of hypoalbuminemia (HA) in patients with scrub typhus complicated by acute kidney injury (AKI).

Methods

From 2009 to 2018, 611 patients were diagnosed with scrub typhus. We divided the patients into two groups [normoalbuminemia (NA) vs. HA] based on the serum albumin level of 3.0 g/dL and compared the incidence, clinical characteristics, and severity of AKI based on the RIFLE classification between the two groups.

Results

Of the total 611 patients, 78 (12.8%) were categorized into the HA group. Compared to patients in the NA group, patients in the HA group were older (73 ± 9 vs. 62 ± 14 years, P<0.001). The HA group had a significantly longer hospital stay (9.6 ± 6.2 vs 6.2 ± 3.1 days, p<0.001) and a higher incidence of complications in respiratory and cardiovascular systems. Furthermore, AKI developed significantly more in patients in the HA group (58% vs. 18%, p<0.001) as compared to the NA group. The overall incidence of AKI was 23.1%; of which, 14.9%, 7.0%, and 1.2% of cases were classified as Risk, Injury, and Failure, respectively. The serum albumin level correlated with AKI severity (3.4 ± 0.5 vs 3.0 ± 0.5 vs 2.6 ± 0.3, p<0.05). In a multivariate logistic regression analysis for predicting AKI, age, presence of co-morbidities such as chronic kidney disease, total bilirubin, leukocytosis, and hypoalbuminemia were significant predictors for AKI.

Conclusion

Serum albumin level is helpful to predict the development and severity of scrub typhus-associated AKI.

Community-Acquired AKI in Asia: An Update

Community-acquired acute kidney injury (CA-AKI) is the dominant form of AKI encountered in developing countries in Asia. Economic disparities, variations in access to health care services, geographic conditions, environmental risk factors, and sociocultural circumstances shape the causes and outcomes of CA-AKI. Infections, drugs, plant and chemical toxins, envenomations, and obstetric complications are common causes of CA-AKI. Previously healthy young individuals who often work outdoors in fields or farms are exposed to a wide variety of work-related or environmental risk factors for CA-AKI. Improving disease definitions, better data, and evolving host-pathogen interactions have changed disease descriptions and presentations over the past 20 years. Among infections, although the incidence of malaria has decreased, the number of cases with dengue and scrub typhus have increased sharply. The recognition of AKI in relation to Plasmodium knowlesi, Plasmodium vivax, scrub typhus, and leptospirosis in areas not traditionally considered at risk, association of infections with the future development of chronic kidney disease, and the role of complement dysregulation in infection-associated AKI are important new findings. Snake-bite-related toxic envenomation continues to be an important cause of AKI in some counties and is a neglected public health problem. On the other hand, significant decreases in the incidence of AKI related to acute diarrheal illness or obstetric causes are signs of hope. Coordinated efforts between administrative stakeholders, society, and health care delivery services at all levels have the potential to propel research and improve outcomes in CA-AKI.

Scrub typhus as a rare cause of acute pyelonephritis: case report

BACKGROUND

Scrub typhus can present with atypical signs and symptoms such as those of acute kidney injury, gastroenteritis, pneumonitis, and acute respiratory distress syndrome. Meningitis, encephalitis, and hepatic dysfunction have also been reported, particularly in severe cases with multisystem involvement. Scrub typhus has never been reported in the literature to cause urinary tract infections (UTIs) which includes cystitis and pyelonephritis.

CASE PRESENTATION

A 45-year old male presenting to the outpatient unit with fever, right flank pain, and burning micturition for three days was initially treated for UTI. However, he returned to the hospital on the fourth day of illness with persistent symptoms. He was hospitalized, with intravenous (IV) ceftriaxone. Computerized tomography scan of his abdomen-pelvis showed features of acute pyelonephritis, so his antibiotics were upgraded to meropenem and teicoplanin. Despite this, the patient's condition deteriorated. Laboratory investigations showed multisystem involvement: decreasing platelets, raised creatinine, and deranged liver panel. As Kathmandu was hit by dengue epidemic during the patient's hospitalization, on the seventh day of his illness, blood samples were sent for tropical fever investigation. All tests came out negative except for scrub typhus-IgM antibodies positive on rapid diagnostic test. The patient's symptoms subsided after 48 h of starting doxycycline and he became fully asymptomatic four days later. Fever did not recur even after discontinuing other IV antibiotics, favoring scrub typhus disease rather than systemic bacterial sepsis.

CONCLUSIONS

Scrub typhus is an emerging infectious disease of Nepal. Therefore, every unexplained fever cases (irrespective of clinical presentation) should be evaluated for potential Rickettsiosis. Moreover, for cases with acute pyelonephritis, atypical causative agents should be investigated, for example scrub typhus in this case.

Clinical significance of abnormal chest radiographic findings for acute kidney injury in patients with scrub typhus

Background

Abnormal chest radiographs are frequently encountered in patients with scrub typhus. This study aimed to investigate whether chest radiography on admission is significant as a predictive factor for acute kidney injury (AKI) in patients with scrub typhus.

Methods

From 2010 to 2016, 467 patients were diagnosed with scrub typhus in our hospital. We divided the patients into two groups: normal chest radiograph (NCR) and abnormal chest radiograph (AbNCR), based on chest radiography findings. The incidence, clinical characteristics, and severity of AKI were compared between AKI and non-AKI groups according to the RIFLE classification.

Results

Of the 467 patients, 96 (20.6%) constituted the AbNCR group. Compared with NCR patients, AbNCR patients were older (71 ± 11 vs. 62 ± 13 years, P < 0.001) and had higher total leukocyte counts (9.43 × 10³/mL vs. 6.98 × 10³/mL, P < 0.001). The AbNCR group had significantly longer duration of hospital stay (8.9 ± 5.5 vs. 6.3 ± 2.8 days, P < 0.001) and higher incidence of AKI (46.9% vs. 15.1%, P < 0.001). The common abnormal chest radiographic findings were pulmonary abnormalities, such as pulmonary congestion and pleural effusion. The overall AKI incidence was 21.6%, of which 12.4%, 7.9%, and 1.3% cases were classified as risk, injury, and failure, respectively. In a multivariable logistic regression analysis for association with AKI, old age, presence of chronic kidney disease or hypertension, leukocytosis, hypoalbuminemia, and chest radiographic abnormalities on admission were significant predictors of AKI.

Conclusion

Chest radiographic abnormalities on admission were independently associated with AKI in patients with scrub typhus.

Scrub typhus-associated acute kidney injury: A study from a South Indian Tertiary Care Hospital

Infections including scrub typhus contribute to a significant proportion of community-acquired acute kidney injury (AKI) in the tropics. Scrub typhus infection now requires global attention since disease outbreaks are being reported across continents. We intended to study the clinical profile, renal involvement, and parameters predicting renal involvement in scrub typhus infection. This is a retrospective study. The medical records of all patients who were admitted and treated for scrub typhus infection for a study period of two years (from September 2015 to August 2017) were analyzed, and salient clinical features and laboratory results were collected from the hospital data. Statistical analysis was done from the collected data. Our study had 272 patients including 81 children. Adults constituted 70.96% (n = 193) and the remaining 29.04% (n = 81) were pediatric population. Among adults, females constituted 62.7% (n = 121) and males 37.3% (n = 72). The mean age of the adult population was 45.7 ± 15 years and that of pediatric patients was 8.56 ±5.1 years. 18.7% of adult cases and 3.70% of pediatric cases had AKI. Renal replacement therapy was required in 3.67% of adult cases. Mortality was 4.14% in adults and 1.23% in children. Hypotension, pulmonary involvement, central nervous system involvement, multiorgan dysfunction syndrome, increased total counts, elevated aspartate transaminase levels, and hypoalbuminemia predicted AKI in our adult population. Scrub typhus should be considered as a differential in cases presenting with fever and AKI. Outcomes of scrub typhus infection in terms of mortality seem to be improving in this region.

Case Report: Acute pyelonephritis and hearing loss in scrub typhus

Acute pyelonephritis is a common renal manifestation in patients with diabetes. A 52-year-old diabetic lady presented with loin pain, dysuria, and fever and urinary incontinence that had begun seven and three days prior to presentation respectively. She was treated with escalating spectra of intravenous antibiotics without improvement. Urine and blood cultures were sterile, while radiological investigations were suggestive of pyelonephritis. Mild hepatic dysfunction prompted consideration of scrub typhus and she improved with empirical doxycycline. Scrub IgM was later confirmed to be positive. In conclusion, local prevalence of systemic infections such as rickettsioses should always be considered in diabetics with fever, even if symptoms and signs otherwise suggest typical diabetes-related infections. We, therefore report a case of acute pyelonephritis caused by scrub typhus which has not been previously described in English medical literature.

Incidence, risk factors, and clinical outcomes of acute kidney injury associated with acute pyelonephritis in patients attending a tertiary care referral center

Acute kidney injury (AKI) associated with acute pyelonephritis (APN) rarely has been reported. The aim of this study was to evaluate the incidence and risk factors of AKI associated with APN. We retrospectively reviewed the medical records of 403 patients over 18-year old age hospitalized for APN management from October 2009 to September 2014 in tertiary care referral center. Demographic data, clinical symptoms and signs, and laboratory findings were gathered from the medical records and analyzed. The mean age of patients was 57 years and APN commonly occurred in female (87.6%). AKI occurred in 253 patients (62.8%). As per the RIFLE classification, renal injury was graded as ‘Risk’ (62.1%), ‘Injury’ (26.5%), and ‘Failure’ (11.4%). AKI patients were more likely a male gender and had complicated APN. The AKI group had a significantly higher tendency to present with shock. The prevalence of underlying chronic kidney disease (CKD) was significantly higher in the AKI group. There was no difference in mortality between the AKI and non-AKI groups. Multivariate analysis revealed that age over 65 (OR 1.93, 95% CI 1.18–3.13, p= .008), complicated (OR 2.13, 95% CI 1.35–3.34, p= .001) and bilateral APN (OR 1.71, 95% CI 1.01–2.88, p= .045), and initial shock (OR 2.44, 95% CI 1.05–5.71, p= .039) were independent risk factors for the occurrence of AKI in patients with APN. Physicians should attempt to prevent, detect, and manage AKI associated with APN in patients with above conditions.

Awareness and Work-Related Factors Associated with Scrub Typhus: A Case-Control Study from South Korea

This study aimed to examine the awareness and the work-related factors associated with scrub typhus to provide data essential for evidence-based preventive strategies. A community-based case control study was carried out in the rural areas of Gyeongsangbuk-do, South Korea. Confirmed cases of scrub typhus (n = 57) were based on laboratory tests performed by the Korean Centers for Disease Control and Prevention (KCDC), 114 matched neighborhood controls, age (±6 years), gender and area of residence in the Gyeongsangbuk-do of South Korea. These cases were contracted over the 12-month period of January to December 2015. Overall, 61.4% cases and 79.8% of the control group had heard about scrub typhus. Cases were less aware about the fact that mites are mainly found in the bushes and that long sleeves and full-length pants and boots helped prevent scrub typhus. However, more were aware of the eschar lesion as a characteristic sign of scrub typhus. Work related risk factors such as having a wetland or puddles of water surrounding the house, dry field farming and working in the livestock industry were significantly associated with the scrub typhus. Health promotion strategies, such as creating general awareness, personal protection methods and improving personal hygiene and environmental sanitation in collaboration with relevant sectors, are recommended to reduce the burden of scrub typhus. Further intervention studies on awareness and behavioral and environmental modifications are required to investigate the effectiveness of such interventions.

Under-diagnosis of rickettsial disease in clinical practice: A systematic review

BACKGROUND

Rickettsial diseases present as acute febrile illnesses, sometimes with inoculation eschars.

METHODS

We performed a systematic review of studies published between 1997 and 2017 to assess the underestimation of non-eschar rickettsial disease (NERD) relative to eschar rickettsial disease (ERD), as a cause of acute fever in patients with rickettsial diseases that commonly present with eschar(s): scrub typhus (ST), Mediterranean spotted fever (MSF), and African tick-bite fever. We compared ERD/NERD ratios according to study design: 'complete approach' studies, with testing performed in all patients with 'unspecified febrile illness'; versus 'clinical judgement' studies, with testing performed if patients presented with specific symptoms.

RESULTS

In 'complete approach' studies, ERD/NERD ratios were significantly lower, suggesting a considerable under-diagnosis of NERD in 'clinical judgement' studies. Based on these results, we estimate that the diagnosis of rickettsial disease was missed in 66.5% of patients with ST, and in 57.9% of patients with MSF.

CONCLUSIONS

Study design influences the reported eschar rates in ST and MSF significantly. NERD is likely to be a vastly underdiagnosed entity, and clinicians should consider and test for the disease more often.

PROSPERO REGISTRATION NUMBER

CRD 42016053348.

Hemophagocytic Lymphohistiocytosis Associated with Scrub Typhus: Systematic Review and Comparison between Pediatric and Adult Cases

Background: Scrub typhus is a mite-borne bacterial infection caused by Orientia tsutsugamushi. Hemophagocytic lymphohistiocytosis (HLH) is a potential severe complication. Most reported cases of HLH associated with scrub typhus were single cases or case series with a small sample sizes. Thus, no clear consensus exists on clinical manifestations and differences between pediatric and adult cases of this condition. Methods: a systematic search of English and Japanese articles from PubMed, PubMed Central, and Directory of Open Access Journals databases was performed from 3 December 2016 to 28 December 2017. The primary outcome was mortality in patients with HLH associated with scrub typhus; secondary outcomes were differences in clinical symptoms, laboratory findings, and treatment between pediatric and adult patients with HLH associated with scrub typhus. Results: thirty cases of HLH associated with scrub typhus were identified (age range: 2 months to 75 years; median age: 21.5 years, male:female ratio, 1:1). Eschar was frequently observed in the pediatric group (p = 0.017), whereas acute kidney injury was more prevalent in the adult group (p = 0.010). Two patients died of intracranial hemorrhage complicated with multiple organ failure; overall mortality rate was 6.7%. Conclusions: HLH associated with scrub typhus could be cured with remarkable improvement using single antibiotic therapy in approximately half the cases, with the mortality rate being relatively lower than that of HLH associated with other secondary causes.