Introduction: Paroxysmal nocturnal haemoglobinuria (PNH) is an acquired disorder that leads to transient haemolysis following stress or infection, where haemoglobinuria (blood in the urine) is most noticeable in the morning. The haemolysis is driven by complement, leading to an autoimmune haemolytic anaemia. Most patients present with signs of anaemia (breathlessness, pallor, and fatigue), recurrent infections or thrombosis (which is the leading cause of mortality).
Case Study: A 32 year old female was referred to the haematology clinic with incidental findings of mild splenomegaly (13.4cm) during a recent hospitalisation. She has a complex medical history with previous admissions for bacteraemia with evidence of disseminated intravascular haemolysis (DIC). Increasing abdominal pain was the initial complaint that led to the incidental finding of splenomegaly.
Peripheral bloods showed signs of haemolysis with low haptoglobins (<0.08) and increased LDH (623U/L). Her reticulocyte count was slightly elevated at 109 x 10^9/L. Blood film evaluation showed spherocytosis, consistent with the haemolytic picture, however she was DAT negative and screening tests for Hereditary Spherocytosis and G6PD Deficiency were negative. Further haemolysis screening was ordered and the urinary hemosiderin was reported as detected.
Paroxysmal nocturnal haemoglobinuria was considered for the cause of her DAT negative haemolytic anaemia and flow cytometry was performed alongside a bone marrow biopsy. She was found to have a significant PNH clone of approximately 60% in her granulocytic/monocyte cells. Bone marrow results showed no dysplasia or evidence of aplastic anaemia to otherwise explain her episodes of anaemia.
A diagnosis of PNH was made, and her abdominal pain was considered to be consistent with smooth muscle dystonia associated with PNH. The patient was started on anti-complement therapy to help improve symptoms.
Conclusion: Presenting symptoms of splenomegaly and spherocytosis in unusual for PNH and highlights the importance of a full workup of cases of unexplained haemolysis markers