How does high blood pressure damage the kidneys? Understanding kidney damage and renal hypertension.

What damage does hypertension cause to the kidneys?

The long-term effect of hypertension on the kidneys is nephrosclerosis. Its development begins with arteriosclerosis of the renal arterioles, followed by sclerosis of the glomeruli, tubules, and interstitium. Because the renal tubules are highly sensitive to ischemia, the earliest clinical manifestation is often increased nocturia. If ischemic changes occur in the glomeruli, urinalysis will show positive protein in the urine. If the condition progresses further, the glomerular filtration rate decreases, gradually leading to renal insufficiency, until it reaches the stage of chronic renal failure—uremia.

Therefore, after being diagnosed with hypertension, it is essential to have the kidneys examined and evaluated to determine if there is any kidney damage.

Kidney disease is a major cause of secondary hypertension; the two are mutually causal. Regular urine tests can prevent many kidney diseases from being missed. If this is done, a significant number of people will not develop renal insufficiency or uremia.

What other kidney diseases can cause hypertension?

Because kidney disease is the most common secondary cause of hypertension. Renal hypertension should be diagnosed as early as possible, and it is important to differentiate it from kidney damage caused by hypertension. The following are some kidney diseases that can cause hypertension and their main characteristics:

(1) Renal parenchymal diseases: Early manifestations of renal parenchymal diseases such as glomerulonephritis and pyelonephritis are mainly changes in urine, such as proteinuria, casts, and red and white blood cells.

(2) Renal artery stenosis: Mild renal artery stenosis does not have a significant impact on the kidneys. Severe stenosis (70%–75% renal artery stenosis) can cause renovascular hypertension and ischemic nephropathy.

① Renovascular hypertension: Renovascular hypertension is characterized by a significant increase in diastolic blood pressure, which is difficult to lower to normal. When encountering such patients, renal vascular ultrasound, spiral CT, and other examinations should be performed as early as possible to confirm the diagnosis.

② Ischemic nephropathy: Characterized by a slow, progressive decline in renal function (decreased urine specific gravity, increased nocturia, etc.). Kidney function decline precedes changes in urine, which is a key distinction from parenchymal kidney disease.

③ Treatment of renal artery stenosis: The root causes of renal artery stenosis are hypertension and atherosclerosis. Therefore, antihypertensive, lipid-lowering, and antiplatelet therapies are essential. Percutaneous balloon dilation is a rapid and effective measure and should be performed as early as possible.