Spontaneous bacterial peritonitis in non-cirrhotic portal hypertension secondary to primary myelofibrosis: A rare case report

Spontaneous bacterial peritonitis (SBP) is a life-threatening infection of ascitic fluid, typically associated with cirrhosis and advanced portal hypertension, while its occurrence in non-cirrhotic portal hypertension (NCPH) is rare and often underrecognized. Primary myelofibrosis (PMF), a myeloproliferative neoplasm, may lead to NCPH through mechanisms such as hypercoagulability, extramedullary hematopoiesis, and splenomegaly-related hemodynamic changes; however, SBP in this setting is extremely uncommon. A 60-year-old woman who presented to Dr. Soetomo General Academic Hospital with progressive painful abdominal distension, fever, and bilateral lower limb edema. Laboratory evaluation revealed leukocytosis, anemia, and elevated inflammatory markers, with preserved renal and liver function. Ascitic fluid analysis demonstrated a polymorphonuclear leukocyte count of 1676 cells/mm³. Serologic tests for hepatitis B and C were negative, and the aspartate aminotransferase-to-platelet ratio index score was 0.4. Imaging studies showed splenomegaly and features of portal hypertension without evidence of cirrhosis or splanchnic thrombosis. PMF was confirmed by detection of the Janus kinase 2 mutation and bone marrow biopsy findings. The patient was diagnosed with SBP in the setting of NCPH secondary to PMF and was treated with intravenous cefotaxime, resulting in clinical improvement. This case highlights that SBP can occur in non-cirrhotic portal hypertension due to PMF and underscores the importance of early diagnostic paracentesis, prompt antibiotic therapy, and increased clinical vigilance in atypical presentations.