Thrombotic Thrombocytopenic Purpura (TTP)

TTP is a rare but life-threatening hematologic emergency characterized by the formation of microthrombi in small blood vessels, resulting in a sharp decrease in platelet count, hemolysis, and organ dysfunction.

The underlying mechanism is a deficiency of the enzyme ADAMTS13, which normally cleaves large von Willebrand factor (vWF) multimers. When ADAMTS13 is absent or nonfunctional, these vWF multimers remain active and bind platelets, forming microthrombi.

Forms of TTP:

Acquired (autoimmune) TTP: Autoantibodies inhibit ADAMTS13.

Hereditary TTP (Upshaw–Schulman syndrome): Genetic mutation in ADAMTS13.

Clinical manifestations (the classic pentad, which may not be fully expressed):

Thrombocytopenia: bruising, bleeding.

Microangiopathic hemolytic anemia: fatigue, jaundice.

Neurological symptoms: dizziness, confusion, and in severe cases, stroke or coma.

Renal dysfunction: elevated creatinine, urine abnormalities.

Fever.

Diagnostic methods:

Laboratory signs of acute hemolysis: elevated LDH, indirect bilirubin, and presence of schistocytes.

Thrombocytopenia without marked leukocytosis or infection.

ADAMTS13 activity <10% (confirms diagnosis).

Detection of anti-ADAMTS13 antibodies.