Rare disorder (incidence ∼1 per 100,000 per year)

Idiopathic TTP most often seen in black women with obesity

TTP may be associated with autoimmune disorders (SLE, antiphospholipid antibody syndrome, scleroderma), pregnancy, and with drugs (e.g. quinine, clopidogrel, cancer chemotherapy)

Weakness

Nausea, vomiting, abdominal pain

Fever

Neurological abnormalities (fits, fluctuating focal deficits) (present in ∼50%)

Acute kidney injury (in ∼30%)

Full blood count

and film

Anaemia

Thrombocytopenia

No leucopenia

Fragmented red cells (schistocytes) characteristic

Increased reticulocyte count

Normal prothrombin and activated partial thromboplastin times

Increased LDH and unconjugated bilirubin (reflecting haemolysis)

Raised creatinine in ∼30%

Disseminated intravascular coagulation (Appendix 102.1)

In pregnant women, pre-eclampsia/eclampsia and HELLP syndrome (Table 100.8)

Evans syndrome

Autoimmune haemolysis

Immune thrombocytopenic purpura

Seek urgent advice from a haematologist

Do not transfuse platelets

Plasma exchange until platelet count normal

Add corticosteroid if no underlying cause found