The changes in small arterioles include hyaline arteriolosclerosis (deposition of hyaline, collagenous material), which causes glomerular collapse (wrinkling and thickening of capillary basement membranes and collapse of capillary lumen) and solidification (glomeruli exhibit sclerosis and increase in mesangial matrix). The degree of scarring correlates with the degree of glomerular filtration deficit. Malignant nephrosclerosis is where hypertensive nephrosclerosis occurs in presence of malignant hypertension (when DBP > 130mmHg). Vessels feature intimal thickening, fibrinoid necrosis, red blood cell fragmentation, extravasation, thrombosis. These changes create an exaggerated layered appearance (onion skinning). Urine test
Microalbuminuria (moderate increase in the levels of urinary albumin) is a non-specific finding in patients with vascular disease that is associated with increased risk of cardiovascular events. The majority of patients with benign nephrosclerosis have proteinuria in the range from 0.5 to 1 g/ 24hr. In the case of glomerular damage occurring in HN, hematuria can occur as well. Definitive diagnosis
The definitive diagnosis of HN requires morphological examination. Common histological features can be identified in the renal and glomerular vasculature. Glomerulosclerosis is often present, either focally or globally, which is characterized by hardening of the vessel walls. Also, luminal narrowing of the arteries and arterioles of the kidney system. However, this type of procedure is likely to be preceded by a provisional diagnosis based on laboratory investigations. Future diagnostic approaches
Increasing access to, and use of, genome profiling may provide opportunity for diagnosis based on presentation and genetic risk factors, by identifying ApoL1 gene variants on chromosome 22.
The resulting inadequate blood flow produces tubular atrophy, interstitial fibrosis, and glomerular alterations (smaller glomeruli with different degrees of hyalinization – from mild to sclerosis of glomeruli) and scarring around the glomeruli (periglomerular fibrosis). In advanced stages, kidney failure will occur. Functional nephrons have dilated tubules, often with hyaline casts in the opening of the tubules. Additional complications often associated with hypertensive nephropathy include glomerular damage resulting in protein and blood in the urine.Hypertensive nephropathy refers to kidney failure that can be attributed to a history of hypertension It is a chronic condition and it is a serious risk factor for the development of end-stage kidney disease (ESKD). However, despite the well-known association between hypertension and chronic kidney disease, the underlying mechanism remains unclear. The two proposed mechanisms of HNs pathophysiology both centre around how the glomerulus, a network of dense capillaries that carries out the kidney filtration process, is affected; with one theory identifying glomerular ischemia as the main contributor to HN and the other  identifying glomerular hypertension and glomerular hyperfiltration at the centre of HNs pathogenesis. Glomerular ischemia
High blood pressure in the long term can damage the endothelium, commonly known as the blood vessel lining. This leads to a build-up of plaques and they can be deposited in the renal arteries causing stenosis and ischemic kidney disease. In this situation, the kidney supplied blood by the narrowed renal artery suffers from inadequate blood flow, which in turn causes the size of the kidneys to decrease.