Differentials
Autoimmune haemolytic anaemia, warm antibody type
SIGNS / SYMPTOMS
Splenomegaly is often present.
INVESTIGATIONS
The direct antiglobulin (Coombs) test is usually positive.
Spherocytes may be present on blood film.
Cells lacking GPI-anchored proteins are not present.
Microangiopathic haemolytic anaemia
SIGNS / SYMPTOMS
A reason for microangiopathy (cancer, hypertension, haemangioma, haemolytic uraemic syndrome, thrombotic thrombocytopenic purpura) is usually present.
INVESTIGATIONS
Blood film shows schistocytes.
Paroxysmal cold haemoglobinuria
SIGNS / SYMPTOMS
Haemoglobinuria follows exposure to cold. In children, often occurs 2 weeks after a viral infection or immunisation.
INVESTIGATIONS
Donath-Landsteiner (bithermic haemolysis) test may be positive.
Direct Coombs test may be positive with anti-C3d.
Cells lacking GPI-anchored proteins are not present.
Myoglobinuria
SIGNS / SYMPTOMS
Evidence of muscle breakdown (pain, history of trauma, relevant drug history, etc.) present.
INVESTIGATIONS
Urinary pigment is myoglobin.
Serum creatine kinase is increased, as is serum alanine aminotransferase and aspartate aminotransferase.
Cells lacking GPI-anchored proteins are not present.
Abdominal thrombosis (portal, hepatic veins, mesenteric veins or arteries, renal veins)
SIGNS / SYMPTOMS
From asymptomatic to bouts of abdominal pain, diminished bowel sounds, ascites/varices, bowel perforation, or renal failure. Signs and symptoms depend on the thrombosed vessel.
INVESTIGATIONS
Cells lacking GPI-anchored proteins are not present.
Testing for other sources of thrombosis may be positive
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