microangiopathy

Microangiopathy is a pathological process affecting the small vessels of the circulatory system, including arterioles, capillaries, and venules. It is characterized by endothelial dysfunction, basement membrane thickening, hyaline changes, luminal narrowing, and increased permeability, which can lead to tissue ischemia and organ dysfunction. The condition may be localized to a single organ or part of a systemic process, and it occurs in several chronic diseases, most prominently diabetes mellitus and systemic hypertension.

In diabetes, chronic hyperglycemia promotes non-enzymatic glycation and formation of advanced glycation end products, contributing to capillary basement membrane thickening and rarefaction of small vessels. This underlies complications such as diabetic retinopathy, nephropathy, and neuropathy. Hypertensive microangiopathy typically presents with arteriolar hyalinosis and lipohyalinosis, especially in the brain and kidneys, and is linked to lacunar infarcts and chronic kidney disease. Other causes include age-related small vessel disease, cerebral amyloid angiopathy, and various vasculitides or immune-mediated conditions.

Diagnosis relies on clinical context and organ involvement. Retinal examination may reveal characteristic changes; renal impairment is assessed by proteinuria and estimated glomerular filtration rate; neuroimaging can show white matter changes and lacunar infarcts. Biopsy is rarely required but can confirm vessel-level pathology.

Management aims to treat the underlying condition and reduce vascular risk factors, including strict glycemic control in diabetes, blood pressure and lipid management, smoking cessation, and organ-specific interventions (for example, treatment of retinopathy). Prognosis depends on the extent and distribution of microvascular injury and the underlying disease.