Dr ALEKSANDRA DJORDJEVIC1, Professor GERMAINE WONG1,2,3, Professor NATASHA ROGERS1,2,4, Dr JASVEEN RENTHAWA5, Professor JUSTIN BEARDSLEY6,7,8, Dr MELANIE WYLD1,2
1Department of Renal and Transplant Medicine, Westmead Hospital, Westmead, Australia, 2School of Public Health, Faculty of Medicine and Health, University of Sydney, Sydney, Australia, 3Centre for Kidney Research, Kids Research Institute, The Children's Hospital at Westmead, Westmead, Australia, 4Centre for Transplant and Renal Research, Westmead Institute for Medical Research, Westmead, Australia, 5Department of Tissue Pathology and Diagnostic Oncology, Institute of Clinical Pathology & Medical Research (ICPMR), Westmead Hospital, Westmead, Australia, 6Department of Infectious Diseases, Westmead Hospital, Westmead, Australia, 7Sydney Infectious Disease Institute, Faculty of Medicine and Health, University of Sydney, Sydney, Australia, 8Westmead Institute for Medical Research, Westmead, Australia
Biography:
Bio to come
Background:
Histoplasma capsulatum is a dimorphic soil fungus found globally, with cases best described in the United States. It can cause life-threatening disseminated disease in immunocompromised patients, including kidney transplant recipients, and is extremely rare in Australia. It poses a diagnostic challenge due to limited availability of antigen testing, prolonged incubation time for growth from tissue (4-6 weeks) and variable sensitivity of histopathological examination.
Case report:
A 53-year-old male, 20 years post kidney transplantation with good baseline graft function (creatinine 100-110umol/L, eGFR 65-70mL/min/1.73m2) presented with recurrent episodes of sepsis in the setting of over 12 months of chronic diarrhoea and significant weight loss. Despite extensive testing and radiological imaging to exclude infection, auto-immunity, malignancy and endocrinopathy, no definitive diagnoses were made. He was treated with multiple courses of broad-spectrum antibiotics and reduction in his immunosuppression to monotherapy hydrocortisone. Despite aggressive therapies his condition deteriorated.
Positron Emission Tomography (PET) revealed multiple hypermetabolic lesions in the bowel, adrenal glands and right tonsil raising suspicion of malignancy. Colonoscopy and biopsy with silver staining revealed numerous small, rounded fungal yeasts within macrophages. Polymerase chain reaction subsequently confirmed a diagnosis of Histoplasma capsulatum infection.
He was treated with induction liposomal amphotericin B, followed by maintenance therapy with itraconazole, resulting in marked clinical improvement.
Conclusion:
This case underscores the importance of maintaining a broad differential in kidney transplant recipients. It is likely that histoplasmosis is underdiagnosed in areas of low clinical suspicion, such as Australia, highlighting the need for increased availability of testing, as well as improved assays. Disseminated histoplasmosis should be considered in cases of persistent febrile illness with systemic features, especially when standard investigations and treatment fail.