Renal Hypertension

Renal hypertension (also called renovascular hypertension) is a type of high blood pressure caused by narrowing or blockage of the arteries that supply blood to the kidneys (renal arteries). This condition reduces blood flow to the kidneys, triggering a cascade of hormonal responses that lead to elevated blood pressure.

Causes of Renal Hypertension

1.Renal Artery Stenosis (RAS)

Atherosclerosis (hardening of the arteries due to plaque buildup) – Most common in older adults.
Fibromuscular Dysplasia (FMD) – Abnormal cell growth in renal artery walls, often affecting younger women.

2.Chronic Kidney Disease (CKD)

Impaired kidney function leads to sodium retention and overactivation of the renin-angiotensin-aldosterone system (RAAS), raising blood pressure.

Symptoms of Renal Hypertension

Severe or resistant hypertension (high BP despite multiple medications)
Sudden worsening of previously controlled hypertension
Kidney dysfunction (elevated creatinine, proteinuria)
Headaches, blurred vision, or dizziness
Flank pain (if caused by a renal artery dissection)

Diagnosis of Renal Hypertension

1. Blood and Urine Tests

Serum creatinine & eGFR (to assess kidney function)
Urinalysis (checking for proteinuria)
Plasma renin activity & aldosterone levels (if RAAS overactivation is suspected)

2. Imaging Studies

Doppler Ultrasound – Checks blood flow velocity in renal arteries.
CT Angiography (CTA) or MR Angiography (MRA) – Provides detailed images of renal artery blockages.
Renal Arteriography (Gold Standard) – Invasive but most accurate for diagnosing stenosis.

3. Functional Tests

Captopril Renal Scintigraphy – Measures kidney blood flow before and after an ACE inhibitor.

Treatment Options for Renal Hypertension

1. Medications

ACE Inhibitors (e.g., Lisinopril) or ARBs (e.g., Losartan) – First-line for RAS but must be used cautiously in bilateral stenosis (risk of kidney failure).
Calcium Channel Blockers (e.g., Amlodipine) – Alternative if ACE/ARBs are contraindicated.
Diuretics (e.g., Hydrochlorothiazide) – Help reduce fluid retention.
Beta-blockers (e.g., Metoprolol) – Used if other medications are insufficient.

2. Revascularization Procedures

Renal Artery Angioplasty & Stenting – Opens narrowed arteries (effective for fibromuscular dysplasia).
Surgical Bypass – Rarely done, only for complex cases.

3. Lifestyle Modifications

Low-sodium diet (<2g/day)
Regular exercise & weight management
Smoking cessation & alcohol moderation

Complications if Untreated

Kidney failure (due to prolonged ischemia)
Heart disease & stroke (from uncontrolled hypertension)
Aortic dissection or aneurysm (in severe cases)

Prognosis

Early detection and treatment can reverse hypertension in some cases.
Fibromuscular dysplasia has a better prognosis than atherosclerosis-related RAS.
Without treatment, renal hypertension can lead to end-stage renal disease (ESRD).