Related Subjects:
|Microangiopathic Haemolytic anaemia
|Haemolytic anaemia
|Immune(Idiopathic) Thrombocytopenic Purpura (ITP)
|Thrombotic Thrombocytopenic purpura (TTP)
|Haemolytic Uraemic syndrome (HUS)
|Thrombocytopenia
|Disseminated Intravascular Coagulation (DIC)
Thrombotic microangiopathies (TMA) are a group of related disorders that are characterized by thrombosis of the microvasculature and associated organ dysfunction
About
- A cause of red cell destruction
- RBC then live less than 100 days
- Schistocytes = helmet cells, small, irregular triangular
Types of MAHA
- Thrombotic thrombocytopenic purpura: Anaemia, Low ADAMTS13, Low Platelets, erythrocyte polychromasia and anisocytosis with prominent schistocytes
- Haemolytic-uraemic syndrome,
- Disseminated Intravascular Coagulation
- Heparin-induced thrombocytopenia (HIT): heparin exposure 5-14 days, large-vessel thrombosis and antiplatelet factor 4 antibodies
- Paroxysmal nocturnal hemoglobinuria: MAHA and low platelets
Aetiology
- Fibrin clots in small vessels.
- This leads to the destruction of red cells
Clinical
- Depends on clinical context
- Neurology with TTP
- Renal failure with HUS
Differential
- Disseminated intravascular coagulation
- Haemolytic uraemic syndrome: endothelial damage facilitated by Escherichia coli shiga toxin or complement dysregulation
- Malarial parasites
- Thrombotic thrombocytopenic purpura
- Malignant hypertension
- Severe Pre-eclampsia
- Mechanical heart valves
- Sicke cell anaemia
- Systemic sclerosis - scleroderma renal crisis with worsening renal function and microangiopathic features
Investigations
- Hb - Anaemia, Low platelets may be seen
- Increased reticulocytes, Unconjugated bilirubin
- Increased LDH, low Haptoglobin
- DAT Test Negative
- Blood film: schistocytes, helmet cells, fragmented cells, polychromasia.schistocytes suggest MAHA
- Urinary haemosiderin: positive in chronic intravascular haemolysis, such as paroxysmal nocturnal haemoglobinuria (PNH, very rare) and leaking mechanical heart valves
- Normal APTT and PT
- Flow cytometry with antibodies against CD55 and CD59 antigens for PNH
Management
- Manage cause which may include plasma exchange
- May require plasma infusion
References