Hereditary spherocytosis and membrane disorders — branching viva

Examiner opening (Examiner)

You are the general paediatric registrar in the outpatient clinic. A seven-year-old girl is referred for chronic fatigue, pallor and intermittent yellowing of the eyes. Her mother had a splenectomy at age twelve and a cholecystectomy at twenty-eight. On examination she has scleral icterus and a spleen palpable four centimetres below the costal margin. Talk me through your assessment and diagnostic plan. ^[1]

Exemplar opening (Candidate)

This child has a clinical picture strongly suggestive of hereditary spherocytosis, supported by the autosomal dominant family history of splenectomy and cholecystectomy and the triad of anaemia, jaundice and splenomegaly. I will confirm the diagnosis with a full blood count, reticulocyte count, unconjugated bilirubin, blood film, and a direct antiglobulin test to exclude autoimmune haemolysis. I expect to find a variable anaemia with a raised mean cell haemoglobin concentration, a raised reticulocyte count, unconjugated hyperbilirubinaemia, and spherocytes on the film with a negative direct antiglobulin test. I will then arrange the eosin-5-maleimide binding test as the first-line confirmatory investigation, and an abdominal ultrasound to document the spleen size and screen for gallstones. ^{[1] [2]}