Classic paroxysmal nocturnal haemoglobinuria presenting with intestinal malabsorption syndrome, acute abdomen and acute kidney injury.

A male patient in his 30s presented with complaints of acute abdominal pain, black stools and red-coloured urine. CT revealed thrombi in the splenic and left renal veins, leading to infarctions. An endoscopy displayed scalloping of the duodenal folds, indicative of intestinal malabsorption syndrome (IMS). Histopathological examination confirmed IMS. Due to the presence of intravascular haemolysis, haemoglobinuria and thrombotic complications, paroxysmal nocturnal haemoglobinuria (PNH) was suspected and subsequently confirmed by flow cytometry. Thus, a diagnosis of classic PNH with IMS and thrombotic complications was established. This unique case highlights the coexistence of PNH and IMS, resembling the complement hyperactivation, angiopathic thrombosis and protein-losing enteropathy disease, suggesting potential shared pathophysiology.