Spontaneous Retroperitoneal Haematoma Unmasking Haemophilia a in a Young Adult

Abstract

We report a 33-year-old man who presented to the Emergency Department with two brief syncope episodes and abdominal pain radiating to the hip after a 20-km motorcycle ride. He was tachycardic (165/min) and hypotensive (90/60 mmHg) with pallor; airway and breathing were intact. Initial investigations showed alkalemia with elevated lactate (pH 7.508, HCO₃⁻ 17.7 mmol/L, lactate 10.21 mmol/L), severe anaemia (Hb 6.22 g/dL), mild hyponatremia (Na 133 mmol/L) and hypokalaemia (K 3.2 mmol/L). ECG revealed sinus tachycardia with a short PR interval, and chest radiography was unremarkable. Contrast-enhanced CT of the abdomen identified a spontaneous retroperitoneal hematoma. Resuscitation included intravenous fluids, analgesia, vitamin K (10 mg), and transfusion of uncrossmatched packed red cells. Post-CT labs showed leucocytosis (31,600/µL), platelet count 4.57 lakh/µL, and markedly prolonged aPTT (72.7 s) with INR 1.20; repeat venous gas demonstrated acidosis and rising lactate (pH 7.251, lactate 12.20 mmol/L). Thromboelastography showed prolonged R (42.2 min) and K (9.8 min) with reduced α-angle (22.1°) and borderline MA (53.9 mm), consistent with a coagulation-factor deficiency phenotype. He underwent digital subtraction angiography, which demonstrated no aorto-iliac leak, and received intra-procedural blood products (packed red cells, fresh frozen plasma, cryoprecipitate). Coagulation assays confirmed haemophilia A with factor VIII activity of 4%; recombinant factor VIII was initiated (tapered over 3–6 June 2024), alongside cryoprecipitate support. Serial monitoring showed clinical stabilization, ultrasound evidence of hematoma reduction, and a rise in factor VIII to 73.9% at discharge. This case highlights spontaneous retroperitoneal haemorrhage as a sentinel presentation of previously unrecognized haemophilia A and underscores the value of early CT imaging, viscoelastic testing, targeted factor replacement, and selective angiography in management.