Authors: Thomas MacMahon / Editor: Turlough Bolger / Reviewer: Thomas MacMahon / Codes: HC7, HP1, HP2, SLO5 / Published: 18/03/2022

A 14-year-old boy presents with a one week history of lethargy, shortness of breath on minimal exertion such as climbing stairs, palpitations, recurrent spontaneous epistaxis lasting 10-15 minutes and easy bruising. He has no bone pain, abdominal discomfort or distension. He has not lost weight.

He has had no recent illnesses, is usually fit and extremely healthy, and is a keen basketball player. He has no past medical history, no medications or allergies, and is fully vaccinated. Born in Lithuania and living in Ireland since infancy, he has not travelled recently.

His temperature, blood pressure, pulse rate, oxygen saturation and respiratory rate are all within normal limits.

When you see him, he looks pale, with pale sclerae. His ENT, cardiovascular, respiratory, abdominal and neurological examinations are all normal. He has no regional lymphadenopathy. He has several recent spontaneous bruises on his arms and legs.

An urgent full blood count shows a macrocytic anaemia (haemoglobin low at 6.0g/dl; MCV elevated at 98.3fl). His platelet count is markedly decreased at 14×109/l. He is leukopaenic (white cell count 2.4×109/l) and neutropaenic (0.5×109/l). His reticulocyte count is decreased. A blood film shows polychromasia but no blast cells.

His infectious mononucleosis screen is negative. His renal, liver and bone profiles are normal. His CRP, LDH, vitamin B12, folate and ferritin levels are all normal. His iron studies, prothrombin time, APTT and fibrinogen levels are also normal.

Chest x-ray, ECG and urinalysis are all normal.