microangiopathie

Microangiopathy, or microangiopathie in some languages, is a pathological process that affects the small blood vessels—arterioles, capillaries, and venules—leading to impaired tissue perfusion and organ dysfunction. It can arise as a primary vascular disorder or as a consequence of systemic diseases. The term encompasses several conditions, including diabetic microangiopathy, hypertensive arteriolosclerosis, and thrombotic microangiopathy (TMA), which includes thrombotic thrombocytopenic purpura (TTP) and hemolytic-uremic syndrome (HUS).

Pathophysiology commonly involves endothelial injury and remodeling of the microvasculature. In diabetes mellitus, chronic hyperglycemia promotes basement membrane thickening and hyaline arteriolosclerosis, causing capillary nonperfusion. In hypertension, elevated pressure induces arteriolar wall thickening and luminal narrowing. Thrombotic microangiopathy is driven by endothelial damage with formation of intravascular platelet-rich microthrombi, leading to red cell destruction and organ ischemia.

Clinical features depend on the underlying context. Diabetic microangiopathy contributes to retinopathy, nephropathy, and peripheral neuropathy. Hypertensive microangiopathy can underlie kidney disease and cerebrovascular changes. TMA presents with microangiopathic hemolytic anemia (schistocytes on blood smear), thrombocytopenia, and organ injury such as acute kidney failure or neurologic symptoms. Retinal microangiopathy may accompany several of these conditions.

Diagnosis relies on clinical context, laboratory findings (schistocytes, elevated LDH, low haptoglobin, thrombocytopenia), and disease-specific tests (eg, ADAMTS13 activity for TTP). Management targets the underlying cause and may include blood pressure and glycemic control, supportive care, and specific therapies such as plasma exchange for TTP or complement inhibition in select cases. Prognosis varies with etiology and prompt treatment.