Granulomatous interstitial nephritis secondary to histoplasmosis

Acute and Chronic Tubulointerstitial Nephritis of Rheumatic Causes

Tubulointerstitial nephritis (TIN) is the second most common cause of acute intrinsic kidney injury after acute tubular necrosis. Although drug-induced forms of TIN represent the vast majority, rheumatic disease is another common cause and often underdiagnosed. Early diagnosis of acute interstitial nephritis and prompt withdrawal of the culprit medication or a correct treatment can avoid chronic damage and progressive chronic kidney disease. This review highlights the recent updates, clinical features, and treatment in TIN in autoimmune rheumatic disease.

Etiological diagnosis of granulomatous tubulointerstitial nephritis in the tropics

Background

Granulomatous tubulointerstitial nephritis (GIN) is common due to infections, drugs or sarcoidosis. However, the cause is often difficult to establish and the studies are limited. We studied the etiology of GIN and compared the clinical and histological features and outcome in different etiologies at a tertiary care center in North India.

Methods

Renaö biopsies from GIN cases diagnosed from January 2004 to April 2014 were retrieved. Stain for acid fast bacilli was performed in all biopsies. Etiological diagnosis was based on clinical features, extra-renal manifestations, radiology, history of drug intake and demonstration of infective agent. Tissue PCR for tubercular DNA was performed in seven biopsies.

Results

Seventeen GIN patients [mean age 35 ± 15 years; males 11] were identified. Tuberculosis was the commonest etiology followed by idiopathic, sarcoidosis and fungal. Both tuberculosis and sarcoidosis patients presented with subnephrotic proteinuria and raised serum creatinine. Acid fast bacilli were demonstrated in 1/9 and necrosis was demonstrated in 3/9 granulomas in tuberculosis. Tissue PCR for tubercular DNA was positive in six TB patients and negative in one sarcoidosis patient. Patients responded well to appropriate therapy.

Conclusion

Etiological diagnosis of GIN is essential for timely and appropriate therapy. Tuberculosis is the commonest etiology (53%) in the tropics. Necrosis in granuloma, demonstration of acid fast bacilli, blood interferon gamma release assay and urine culture is not sensitive for the diagnosis of tuberculosis in GIN. Our findings suggest that tissue PCR for tuberculosis performed in an appropriate clinical setting is useful in the diagnostic evaluation of GIN.

Fungal granulomatous interstitial nephritis presenting as acute kidney injury diagnosed by renal histology including PCR assay

We describe two cases of fungal granulomatous interstitial nephritis (GIN) presenting as acute kidney injury (AKI). Increased serum creatinine was detected in Patient 1 after chemotherapy for pharyngeal cancer and in Patient 2 after steroid pulse therapy for bronchial asthma. Renal histology of both patients revealed GIN. Polymerase chain reaction (PCR)-based detection of fungal DNA sequences from kidney tissue demonstrated Trichosporon laibachii and Candida albicans, respectively. When AKI occurs in an immunocompromised host, differential diagnosis of fungal interstitial nephritis should be considered. Furthermore, PCR-based detection of fungal DNA sequences from renal specimens can be useful for rapid diagnosis.

Granulomatous interstitial nephritis associated with disseminated histoplasmosis in an immunocompetent patient

We present a case of a 64-year-old man with a prolonged history of fatigue, weight loss, fever, and kidney failure. Kidney biopsy showed severe granulomatous interstitial nephritis with numerous giant cells. Silver stains identified fungal micro-organisms consistent with Histoplasma species. Despite antifungal treatment, the patient died of overwhelming infection a few weeks later. This report emphasizes the importance of diagnosing histoplasmosis early. A high degree of suspicion is required to make the diagnosis of histoplasmosis in a case of granulomatous interstitial nephritis.

Renal disease in AIDS: it is not always HIVAN

Human immunodeficiency virus (HIV) infection can cause a broad spectrum of clinical manifestations, ranging from an asymptomatic carrier state to severe immunodeficiency. The most common renal lesion, HIV-associated nephropathy (HIVAN), is a sclerosing glomerulopathy. However, potentially reversible causes of renal disease in HIV-infected patients should also be considered. We describe two cases of patients with acquired immune-deficiency syndrome (AIDS) who presented with rapidly progressive renal failure but were found to have reversible etiologies. The first case was found to have syphilis and the second, disseminated histoplasmosis; their renal injury resolved after initiation of a third-generation cephalosporin antibiotic and amphotericin B, respectively.

Cryptococcal granulomatous interstitial nephritis and dissemination in a patient with untreated lupus nephritis

Infection is a significant cause of mortality and morbidity in systemic lupus erythematosus (SLE). There are many reports of cryptococcal infection in patients with SLE, on immunosuppression. However, untreated lupus with cryptococcal infection and dissemination is rare. CD4 lymphopaenia is not reported in such patients. We describe a patient with untreated SLE to be having cryptococcal granulomatous interstitial nephritis and dissemination with CD4 lymphopaenia.