Typhus disease group

Japanese Spotted Fever and Irreversible Renal Dysfunction during Immunosuppressive Therapy after a Living-Donor Kidney Transplant

Ten years ago, a 56-year-old woman with a history of IgA nephropathy who received a living-donor kidney transplant across ABO barriers was managed with immunosuppressive drugs. The kidney transplant donor was her father who had poor kidney function. The patient’s renal function was stable for 10 years. The patient visited our department with a complaint of skin rash, occurring 2 days after an onset of fever. Although a skin rash is atypical for Japanese spotted fever (JSF), we suspected JSF and started treatment with minocycline because we found a scar suggestive of an eschar. Furthermore, the blood test results were similar to those associated with JSF, and the patient lived in a JSF-endemic area. The patient’s symptoms improved after 1 week. She was diagnosed with JSF by serological tests against Rickettsia japonica. JSF usually does not cause any complications after recovery. However, the patient’s renal function did not completely recover. JSF can cause an atypical rash in patients taking excessive immunosuppressive drugs. Early treatment is required for patients with suspected JSF to prevent complications of renal dysfunction after receiving a living-donor kidney transplant.

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)

OBJECTIVES

Renal involvement in scrub typhus ranges from simple urinary abnormalities to acute kidney injury (AKI) leading to death. This study evaluated the incidence, predictors and prognosis of AKI associated with scrub typhus according to the RIFLE (risk, injury, failure, loss, end-stage kidney disease) criteria.

METHODS

We retrospectively evaluated the medical records of patients diagnosed with scrub typhus from January 2001 to November 2013 in Gyeongsang National University Hospital.

RESULTS

During the study period, 510 patients were diagnosed with scrub typhus and the incidence of AKI was 35.9%. There were 132 (25.9%) patients at risk, 37 (7.3%) with injury and 14 (2.7%) with failure. In comparison with the non-AKI group, the AKI group was older (73.9 vs 63.4 years, p<0.001) and had more comorbidities such as hypertension, diabetes mellitus and chronic kidney disease (CKD). AKI frequently occurs in hypertensive patients taking angiotensin receptor blockers or ACE inhibitors (p=0.002), and in patients with diabetes with higher glycated haemoglobin levels (p=0.033). Haematuria and proteinuria were more frequent in the AKI group. There was no relationship between the severity of proteinuria and occurrence of AKI. Intensive care unit admission and death were more frequent in the AKI group. The renal function of most patients with AKI recovered without sequelae, except for 1 patient who had underlying CKD. Multivariate analysis showed that age, presence of CKD, serum albumin level and time to hospital presentation after symptom onset were independent predictors of AKI in patients with scrub typhus.

CONCLUSIONS

Our current results suggest that the presence of underlying CKD, older age, lower serum albumin level and time to hospital presentation after symptom onset were important risk factors to determine occurrence of AKI. Whether earlier diagnosis and treatment in patients with the above risk factors reduce the incidence and severity of AKI deserves to be investigated.

Immunohistochemistry in the diagnosis of cutaneous bacterial infections

The identification of pathogens is of vital importance for the adequate treatment of infections. During the past 2 decades, the approach to histopathologic diagnosis has been dramatically transformed by immunohistochemistry (IHC) specifically in the diagnosis and classification of tumors and more recently in the diagnosis of infectious diseases in tissue samples. The main goals of this article were to: (1) identify by IHC the cutaneous structures where bacterial pathogens are expressed in the course of infection, (2) identify the specific cells in which bacterial pathogens are expressed in positive cases, and (3) describe the pattern of distribution of the bacterial antigens within these cells (nuclear, cytoplasmatic, or membranous). This article is an up-to-date overview of the potential uses and limitations of IHC in the histopathologic diagnosis of cutaneous bacterial infections. In conclusion, IHC is especially useful in the identification of microorganisms that are present in low numbers, stain poorly, are fastidious to grow, culture is not possible, or exhibit an atypical morphology.

A case of scrub typhus requiring maintenance hemodialysis

Renal failure caused by scrub typhus is known to be reversible. In most cases, renal function is almost fully restored after appropriate antibiotic treatment. A 71-year-old man was diagnosed with scrub typhus complicated by renal failure. A renal biopsy revealed histopathologic findings consistent with acute tubulointerstitial nephritis. Renal function did not improve 18 months after discharge and the patient required continuous hemodialysis. Although severe renal failure requiring dialysis is a rare complication of scrub typhus, we describe a case of scrub typhus requiring maintenance hemodialysis. To the best of our knowledge, this is the first such report.

Scrub typhus: a frequently overlooked cause of acute renal failure

Acute renal failure associated with scrub typhus infection is not rare as previously thought. The possibility of scrub typhus should be borne in mind when patients present with fever and varying degrees of acute renal failure, particularly if an eschar exists, along with a history of environmental exposure in an area like Taiwan, where scrub typhus is endemic. Prompt diagnosis and the use of appropriate antibiotics can rapidly alter the clinical course of the disease and prevent the development of serious or fatal complications. To illustrate the above point, this study reports 3 cases of scrub typhus associated with acute renal failure. They were seen at Chang Gung Memorial Hospital in a 2-year interval. Case 1 was referred from district hospital with clinical features of multiple organ dysfunctions, including shock, fever, acute respiratory failure, acute renal failure, and acute hepatitis. Case 2 was admitted with the chief problems of shock, fever, acute renal failure, and DIC. Case 3 visited our outpatient clinic due to fever, maculopapular rash and acute renal failure. In all these patients, the diagnosis was confirmed using immunofluorescence techniques, which showed that Orientia tsutsugamushi had an IgM titer of 1:80 or greater. Notably, despite having varying degrees of acute renal deterioration, the patients responded very well to doxycycline therapy and recovered completely. Additionally, a total of 4 similar cases of scrub typhus associated with acute renal failure were reviewed from the past literature.

Rickettsialpox

Rickettsialpox is a member of the spotted-fever group of the rickettsioses and results from an infection with Rickettsia akari. This microbe is transmitted by the bite of the house-mouse mite Liponyssoides sanguineus. Patents experience fevers, sweats, headaches, and a vesicular eruption over the trunk and extremities. The palms and soles are spared. An eschar results at the spot of the mite bite. Tetracycline is the treatment of choice.