S LEIBOWITZ1, T SCOTT1
1Princess Alexandra Hospital, Brisbane, Australia
Background: Haemophagocytic lymphohistiocytosis (HLH) is a potentially life-threatening condition characterised by an overactive inflammatory response with dysregulated cytokine activity. Secondary HLH is commonly associated with Epstein-Barr virus (EBV), while tuberculosis is a rare cause and challenging to diagnose without pulmonary involvement. Although rates of tuberculosis in Australia are comparatively low, Mycobacterium tuberculosis remains a problem in Far North Queensland, with Aboriginal and Torres Strait Islander people five times more likely to be affected compared with non-Indigenous people.
Case Report: A 60-year-old Aboriginal male with diabetic nephropathy on chronic haemodialysis was admitted with shock, preceded by diarrhoea and constitutional symptoms. A PET/CT revealed FDG-avid lymphadenopathy in the mediastinum and retroperitoneum; splenomegaly; and numerous nodules suspicious for miliary tuberculosis. EBV DNA was also detected in serum. Bone marrow biopsy showed haemophagocytosis and granulomas. Lymph node biopsy also showed granulomas. The haemophagocytosis in combination with fever, splenomegaly, an elevated serum ferritin (14,900µg/L) and soluble CD25 titre (28,147U/mL) fulfilled diagnostic criteria for HLH. He was thus treated with steroids and five doses of intravenous immunoglobulin. He commenced empirical tuberculosis treatment with rifampicin, isoniazid (and supplemental pyridoxine) and dose-adjusted pyrazinamide. Mycobacterium tuberculosis was subsequently cultured from bone marrow. After discharge, he continued tuberculosis treatment, and the soluble CD25 titre (12,656U/mL) and ferritin (278µg/L) decreased. Due to this response to tuberculosis treatment, it was inferred as the likely cause of HLH.
Conclusions: Kidney failure and diabetes, as in this case, cause immunocompromise; therefore, vigilance is crucial to identify opportunistic infections. Rigorous investigation is required, as tuberculosis might have been missed if HLH had been solely attributed to EBV. Early indentification of the trigger is key, as treating infection can curb HLH.
Dr Saskia Leibowitz is a second-year basic physician trainee at the Princess Alexandra Hospital with a keen interest in nephrology. She completed her residency in Townsville, where she had ongoing involvement with Indigenous patients and observed the unique cultural, social and geographic challenges which hamper both their access to treatment and their recovery. She aspires to improve access to healthcare by Indigenous patients, a population vulnerable to kidney disease, and to devise means of providing high-level care to these patients in their remote locations, in order to improve health outcomes, thereby improving quality of life.