Читать книгу Pathy's Principles and Practice of Geriatric Medicine - Группа авторов - Страница 144

The term small‐vessel disease encompasses a wide range of pathological processes that affect the brain’s small vessels (i.e. small arteries, arterioles, capillaries and small veins).¹⁴ Small‐vessel disease has assumed special relevance since it has been recognized as a major cause of cognitive decline and other functional losses and disabilities in the older person (e.g. mood disorders, gait disturbances, sphincteric problems).¹⁵ The most common forms of cerebral small vessel diseases are related to (i) arteriolosclerosis and (ii) amyloid angiopathy.

Arteriolosclerosis is characterized by the loss of smooth muscle cells from the tunica media and deposits of fibro‐hyaline material that result in the narrowing of the vessel lumen and thickening of the wall. It is strongly associated with systemic vascular risk factors such as hypertension and diabetes and, consequently, affects not only the brain but also other organs and tissues (e.g. kidneys and retinas).¹⁴ Amyloid angiopathy is characterized by the accumulation of amyloid protein in the wall of leptomeningeal and cortical small‐to‐medium‐sized arteries, arterioles, and, to a lesser extent, capillaries and veins. This condition is frequently documented in clinicopathological studies enrolling older participants¹⁶ and is considered among the neuropathological hallmarks of AD.¹⁷ It represents a major cause of cerebral lobar haemorrhages (frequently showing a recurrent course) and microbleeds but has also been associated with ischemic changes such as white matter lesions and microinfarcts.^14,18

The effects of small‐vessel disease on the brain parenchyma are heterogeneous and include both ischemic and haemorrhagic manifestations. Accordingly, it is responsible for diverse MRI changes encompassing white matter lesions, lacunes, microinfarcts, and microbleeds¹³ (Table 6.1).