Hypertensive Nephrosclerosis - Causes, Symptoms, and Treatment

Introduction:

Hypertensive nephrosclerosis is the hardening or thickening of the kidney associated with hypertension or high blood pressure. It is one of the common causes of end-stage kidney disease. Blood pressure is the force of the blood pressing against the walls of the blood vessels. Each time the heart beats, it fills blood into the blood vessels. High blood pressure or hypertension occurs when the force of the blood against the wall of the blood vessels is higher than 140/90 mm of Hg (millimeters of mercury).

Extra fluid in the blood and narrow or clogged blood vessels give rise to high blood pressure. High blood pressure can damage the kidney blood vessels, decreasing their ability to function properly. Thus, the kidneys cannot eliminate waste products and excess water from the body. This excess fluid in the blood vessels can further increase the blood pressure creating a cycle that could damage the kidneys.

The kidneys have an important role in blood pressure management. Kidney diseases deteriorate the function of the kidneys, causing an increase in blood pressure. Hypertension or high blood pressure can result in kidney failure or further aggravate the existing kidney disease. Uncontrolled hypertension can cause kidney failure in no time. Nephrosclerosis is the hardening of the walls of the blood vessels of the kidney. Hypertensive nephrosclerosis has been found to occur more in people of African origin.

What Is the Pathophysiology of Hypertensive Nephrosclerosis?

Hypertensive nephrosclerosis is multifactorial, and the exact cause is not known. However, it is caused by two mechanisms.

1. Glomerular Ischemia: It is a condition with reduced blood flow in the glomeruli. Glomeruli are tiny blood vessels in the kidneys where most filtration occurs. This happens due to chronic high blood pressure that results in thinning of the glomerular blood vessels, which further causes a reduction in glomerular blood flow. High blood pressure also causes some blood vessels to become sclerotic or hard.

This causes a decrease in kidney function. To compensate for this loss of kidney function, the remaining kidney cells or nephrons widen the glomerular blood vessels, which further causes an increase in the blood flow to the kidneys and glomerular filtration, leading to glomerular hypertension and hardening of the kidney blood vessels.

Some studies have suggested that hypertensive nephrosclerosis might not be a single disease occurring due to a single cause, such as high blood pressure or old age, but it is multifactorial. Hypertensive nephrosclerosis can also result due to fibroplasia(growth of fibrous tissue) in the smaller blood vessels causing reduced blood flow and damage to a few kidney cells. In due course of time, sclerosis or hardening of the kidney blood vessels causes a further reduction in the blood flow. Hypertension or high blood pressure precedes and increases changes in the kidney blood vessels.

2. Genetics: A genetic link between high blood pressure and kidney failure has been found in certain studies. Renal susceptibility genes regulate how much kidney damage is caused by high blood pressure.

What Are the Sign and Symptoms of Hypertensive Nephrosclerosis?

The symptoms of hypertensive nephrosclerosis include:

• Headache.

• Giddiness or dizziness.

• Lethargy.

• Discomfort in the neck.

• Nausea and vomiting.

• Loss of appetite.

• Itching.

• Confusion.

• Weight loss.

• Unpleasant taste in the mouth.

• Eyesight problems.

• Irregular heartbeat.

• Difficulty in passing urine.

• Hematuria (the presence of blood in the urine).

• Epistaxis (bleeding from the nose).

• Proteinuria (the presence of protein in the urine).

• Left ventricular hypertrophy (the thickening and enlargement of the wall of the heart's main pumping chamber, the left ventricle).

• Retinopathy (damage to the blood vessels supplying the back of the eye).

What Are the Risk Factors of Hypertensive Nephrosclerosis?

There are several risk factors associated with diabetic nephrosclerosis. They are:-

• Old age.

• Uncontrolled moderate to severe high blood pressure.

• Kidney disorders such as diabetic nephropathy (damage to kidney blood vessels that occur due to uncontrolled diabetes).

How Is Hypertensive Nephrosclerosis Diagnosed?

Hypertensive nephrosclerosis is diagnosed by certain tests:

• Family History- The physician enquires if similar conditions were experienced by family members.

• Medical History- The physician gathers details regarding medical history to rule out any underlying disease.

• Routine Eye Tests- Routine eye tests are performed to check if vision is normal.

• Routine Blood Tests- Routine blood tests are performed to check for the normal ranges of blood parameters.

• Urinalysis- Routine urine test is done to assess the presence of protein and uric acid in urine.

• Estimated Glomerular Filtration Rate- A test to check for the presence of creatinine is done. Creatinine is the waste product of normal muscle wear and tear.

• Electrocardiography (ECG)- This test is carried out to identify any abnormality related to the heart.

• Kidney Ultrasound- This is done to eliminate other causes of kidney injury.

• Kidney Biopsy- Biopsy is an invasive procedure where a part of the deceased tissue is removed and examined under a microscope. This test is done when no possible diagnosis is arrived at.

How Is Hypertensive Nephrosclerosis Treated?

Treatment of hypertensive nephrosclerosis depends upon the control of blood pressure with medications. The medications include,

ACE (Angiotensin-Converting Enzymes) inhibitors-

• These drugs relax the blood vessels to reduce high blood pressure.

• They reduce the presence of protein in the urine.

• They diminish the mortality rates in congestive heart failure.

• Reduce the increase in the size of heart cells- ventricular hypertrophy.

• Protect both diabetic and non-diabetic kidneys.

Angiotensin ll Receptor Antagonists-

• Lower the blood pressure.

• Reduce the presence of protein in the urine of patients who can not tolerate ACE inhibitors.

• Reduce left ventricular hypertrophy.

• Does not cause coughing.

Renin Inhibitors-

• It helps in reducing blood pressure.

• Reduces protein in the urine of diabetic patients.

Calcium Channel Blockers-

• These medications are used to lower blood pressure.

• They prevent calcium from entering the heart's blood vessels. Calcium causes the heart and its blood vessels to contract strongly, thus increasing blood pressure.

Beta Blockers-

• These medications decrease high blood pressure by blocking the effect of the hormone adrenaline.

Direct Vasodilators-

• Widens the blood vessels.

• Helpful in severe hypertension.

• Weight loss.

• Exercise.

• Limiting salt and water intake.

Dialysis- Dialysis is the procedure to remove excess water and waste from the blood when the kidneys stop working.

What Is the Prognosis of Hypertensive Nephrosclerosis?

The prognosis of hypertensive nephrosclerosis depends on how well the blood pressure is managed and the rate of kidney damage. Chronic kidney disease progresses slowly; thus, checking blood pressure and maintaining it might help avert nephrosclerosis and improve the prognosis.

Conclusion:

Hypertensive nephrosclerosis is a kidney syndrome marked by chronic high blood pressure, retinopathy (changes in the eyes), left ventricular hypertrophy, proteinuria, and kidney failure. Diagnosis of most cases is based on clinical features. Maintaining blood pressure within limits and treating kidney diseases properly can help avert the disease.