RESUMEN
We present the case of an adult man with cardiofaciocutaneous syndrome, who initially presented to the emergency department with severe abdominal pain and distension, but was diagnosed with cardiac tamponade on CT after distended neck veins and tachycardia were identified on examination. He had emergency pericardial drainage to relieve the haemopericardium and was treated with colchicine. He was further found to be deficient in factors II, VII and X despite not being on warfarin, and was therefore supplemented with vitamin K. This confirms a diagnosis of vitamin K deficiency, likely multifactorial from malabsorption due to chronic intestinal pseudo-obstruction, small bowel obstruction and possibly exacerbated by subsequent ciprofloxacin use for small intestine bacterial overgrowth. This is the first report of spontaneous haemopericardium secondary to vitamin K deficiency in an adult patient not on anticoagulation, and is an important learning point due to the life-threatening progression of the haemopericardium and cardiac tamponade.