008. A CASE OF HAEMOPHAGOCYTIC LYMPHOHISTIOCYTOSIS, THE GREAT MIMICKER OF RHEUMATIC ILLNESS

Abstract

Background: HLH is a rare and life-threatening condition characterized by persistent fever, hepatosplenomegaly, pancytopenia, lymphadenopathy and rash. It can be described as a syndrome of overwhelming auto-inflammatory response often driven by an underlying genetic predisposition, common infective triggers, haematological malignancies and rheumatological diseases (mainly AOSD and SLE). There are many similarities between HLH and ASOD. Given the significant morbidity and mortality attached to this diagnosis, it makes it an important differential diagnosis to consider when approaching a patient with pyrexia of unknown origin. Methods: A 57-year-old man presented via Accident and Emergency with a twelve-day history of fevers, night sweats and rigors. He reported symptoms of a dry non-productive cough. His past medical history included a history of hypertension, type 2 diabetes and recurrent episodes of pneumonia. He was originally from British Guyana, but had lived in the UK since the age of 4. There was no history of foreign travel or unwell contacts. Physical examination revealed widespread lymphadenopathy. Results: Blood tests revealed pancytopenia (Hb 126, MCV WC 0.8, Plt 139), abnormal liver function (Bilirubin 27, ALT 114, AST 373, GGT 401) and a CRP of 304. He was treated for neutropenic sepsis and further tests arranged. Immunoglobulin screen detected a pan-hypogammaglobulinaemia. LDH 2,000, Ferritin 30,000 and triglyceride of 7. Virology screen was negative. CT of the chest, abdomen and pelvis showed prominent lymphadenopathy in the axillae but no organomegaly. Urinalysis was normal. At this point, a bone marrow biopsy and lymph node examination were performed to exclude a haematological diagnosis which showed a grade 3 fibrosis with no features of malignancy. Multiple blood cultures were sent and one bottle isolated a fully sensitive Enterococcus. An echocardiogram showed suspicious vegetation on the mitral valve. The possibility of infective endocarditis was raised and broad spectrum antibiotics were started. Despite broad spectrum antibiotics, high-grade fevers persisted, with progressively worsening pancytopenia, rising inflammatory markers, ferritin and LDH as well as a progressive coagulopathy. The mitral vegetation's were felt to be marantic. In the absence of a diagnosis, a review of all histology was requested and a liver biopsy was scheduled. A soluble CD25 was also sent. Intravenous immunoglobulin was commenced for a suspected diagnosis of HLH and hypogammaglobulinaemia. Unfortunately the patient died soon after the liver biopsy. A review of the histology revealed a diagnosis of a high grade B Cell Lymphoma and the CD25 confirmed the diagnosis of HLH. Conclusion: HLH is an important cause to be considered when reviewing a patient with a PUO. If the clinical picture doesn't fit or the symptoms do not abate on standard treatment, it is important to review all previous information and continue the search for the underlying diagnosis.