Thrombotic Microangiopathies: Differential Diagnosis

Thrombotic Microangiopathies (TMA) are a group of disorders characterized by thrombosis in small blood vessels, leading to hemolytic anemia, thrombocytopenia, and organ dysfunction.

Understanding TMA

TMA encompasses several conditions, including Thrombotic Thrombocytopenic Purpura (TTP), Hemolytic Uremic Syndrome (HUS), and atypical HUS (aHUS). Their differential diagnosis is crucial for proper treatment.

Clinical Features

• Microangiopathic Hemolytic Anemia: Fragmented RBCs (schistocytes) and elevated LDH.
• Thrombocytopenia: Low platelet count due to intravascular consumption.
• Organ Dysfunction: Most commonly affecting kidneys and brain.

Differential Diagnosis

Key conditions to consider include:

• TTP: ADAMTS13 deficiency, neurological symptoms.
• HUS: Often related to Shiga toxin-producing E. coli, severe renal involvement.
• aHUS: Genetic complement dysregulation, chronic renal disease.
• HELLP Syndrome: Pregnancy-related microangiopathy.
• DIC: Consumptive coagulopathy with extensive thrombosis and bleeding.

Diagnostic Approach

Diagnosis involves laboratory testing, including ADAMTS13 activity, stool cultures, complement assays, and coagulation studies.

Treatment Strategies

Management varies:

• TTP: Plasma exchange, corticosteroids.
• HUS: Supportive therapy, avoiding antibiotics.
• aHUS: Eculizumab for complement inhibition.