The causes and differential diagnosis of microangiopathic haemolytic anaemia in children

Abstract

Microangiopathic haemolytic anaemia (MHA) is generally easily differentiated from other causes of poikilocytosis, but may be difficult to separate from: (a) infantile pyknocytosis with associated thrombocytopenia (b) thrombocytopenia without prominent red cell changes. The condition finally diagnosed in children with MHA has included thrombotic microangiopathy ('haemolytic-uremic syndrome'), renal cortical necrosis, thrombotic thrombocytopenic purpura, chronic glomerulonephritis, giant haemangioma, Wilm's tumour, and pulmonary vascular disease. Prognosis is particularly poor in renal cortical necrosis and thrombotic thrombocytopenic purpura, the former running a fulminant course in which thrombocytopenia is more severe but red cell changes initially minimal. Sequential blood examinations require careful study under these circumstances. MHA usually indicates the presence of a microangiopathy associated with intravascular thrombosis; however, the latter is frequently unaccompanied by MHA, depending on the type of vessel involved and the presence or absence of blood flow through the involved vessel.