Secondary Hypertension: Causes, Symptoms, and Treatment

What is Secondary Hypertension?

Secondary hypertension is a distinct form of high blood pressure with an identifiable underlying cause. It occurs when blood pressure rises due to disorders affecting the kidneys, renal arteries, heart, or endocrine system. This type of hypertension often manifests more suddenly than primary hypertension and may present with higher blood pressure readings that prove resistant to standard treatments.

When comparing primary and secondary hypertension, the key difference lies in their underlying causes. Primary hypertension, affecting about 90-95% of people with high blood pressure, develops over many years without a specific identifiable cause. In contrast, secondary hypertension results directly from another medical condition or factor affecting your body's blood pressure regulation.

Causes of Secondary Hypertension

Understanding the causes of secondary hypertension is vital for proper diagnosis and treatment. According to clinical studies and national health data, chronic kidney disease (CKD) is among the most common causes of secondary hypertension. Here are some other common health conditions that can cause secondary hypertension:

• Diabetic nephropathy
• Polycystic kidney disease
• Renal artery stenosis
• Endocrine disorders
• Obstructive sleep apnea (OSA)
• Certain medications
• Adrenal gland tumors
• Congenital blood vessel abnormalities
• Pregnancy-related conditions
• Excessive alcohol consumption

How Does Kidney Disease Contribute to Secondary Hypertension?

Kidney disease causes secondary hypertension by disrupting fluid balance and hormone regulation, leading to fluid retention and vessel constriction. High blood pressure then damages the kidney’s blood vessels, further reducing their function. This triggers excess renin release, raising blood pressure even more and creating a harmful cycle of worsening kidney and heart health.

Endocrine Disorders and Secondary Hypertension

Endocrine disorders contribute to secondary hypertension by disrupting normal hormonal balance and vascular regulation. Excess aldosterone in primary aldosteronism increases sodium retention and blood volume. Pheochromocytoma causes episodic surges of catecholamines (adrenaline and noradrenaline), causing blood pressure spikes accompanied by a rapid heartbeat, sweating, and severe headaches. Cushing’s syndrome raises cortisol levels, leading to sodium retention and increased vascular sensitivity, while thyroid disorders alter cardiac output and vascular resistance, both disrupting blood pressure regulation.

Symptoms of Secondary Hypertension

Recognizing secondary hypertension symptoms can be challenging because high blood pressure often develops silently. However, certain signs may indicate secondary rather than primary hypertension. The sudden onset of severe hypertension, especially in people younger than 30 or older than 55, often signals an underlying cause. Additionally, blood pressure that remains elevated despite taking three or more antihypertensive medications suggests secondary hypertension.

Secondary hypertension symptoms often relate to the underlying condition causing the blood pressure elevation. For instance, if kidney disease is the cause, you might experience fatigue, excessive thirst, frequent urination, or swelling in your legs and ankles. Those with endocrine disorders causing secondary hypertension may notice unexplained weight changes, muscle weakness, or mood swings. Sleep apnea–related hypertension typically presents with loud snoring, daytime fatigue, morning headaches, and difficulty concentrating.

How is Secondary Hypertension Diagnosed?

Diagnosing secondary hypertension requires a systematic approach to identify the underlying cause:

1. Comprehensive medical history: Your doctor will review your symptoms, medication use, and family history of hypertension or kidney disease
2. Physical examination: Includes blood pressure measurements in both arms and assessment for signs of underlying conditions
3. Basic laboratory tests: Blood and urine tests to check kidney function, electrolyte levels, and hormone markers
4. Medication review: Identifying any drugs that might contribute to elevated blood pressure
5. Screening for specific causes: Based on your age, symptoms, and initial test results
6. Specialist referral: When standard treatments fail or specific secondary causes are suspected

Imaging and Diagnostic Tests for Secondary Hypertension

Specific tests help identify the causes of secondary hypertension:

• Kidney Function Test (KFT) / Renal Function Test (RFT)
• Urine Routine Test
• ECG Test (Electrocardiogram)
• Electrolyte Test

In addition, doctors may recommend renal ultrasound, CT or MRI scans, renal Doppler studies, hormonal blood tests, sleep studies (polysomnography), and plasma or urinary metanephrines to evaluate for pheochromocytoma or related Adrenal tumors.

Treatment Options for Secondary Hypertension

Treatment for secondary hypertension focuses on correcting the underlying cause. When effectively treated—through surgery, medication adjustment, or hormone therapy—blood pressure may return to normal or significantly improve, sometimes reducing or eliminating the need for long-term antihypertensive medications.

The specific treatment approach depends entirely on what's causing your secondary hypertension. For instance, if renal artery stenosis is identified as the cause, procedures to open the narrowed artery can dramatically improve blood pressure. Similarly, removing a hormone-producing tumour or correcting a hormonal imbalance can resolve hypertension completely.

Managing Secondary Hypertension with Medication

While addressing the underlying cause, medications may be necessary to control blood pressure:

• ACE inhibitors: Help relax blood vessels and reduce kidney-related hypertension
• Angiotensin receptor blockers (ARBs): Alternative to ACE inhibitors with similar effects
• Calcium channel blockers: Prevent calcium from entering heart and blood vessel cells
• Beta-blockers: Reduce heart rate and cardiac output
• Diuretics: Help eliminate excess fluid and sodium
• Specific hormone antagonists: Target hormonal causes such as aldosterone excess

Surgical Options for Treating Secondary Hypertension

Surgical intervention can cure certain causes of secondary hypertension. Renal artery stenosis may require angioplasty with or without stenting to restore blood flow to the kidney. In selected patients, this procedure can improve or sometimes normalize blood pressure control. For Adrenal tumors causing hormone excess, surgical removal (adrenalectomy) often provides a complete cure.

Lifestyle Changes to Control Blood Pressure

Lifestyle modifications support medical treatment for secondary hypertension:

• Reduce salt intake to less than 5 grams daily
• Follow a balanced diet rich in fruits, vegetables, and whole grains
• Maintain healthy weight through portion control and regular meals
• Engage in regular physical activity—at least 150 minutes of moderate-intensity aerobic exercise per week, as recommended by WHO and AHA guidelines
• Limit alcohol consumption to recommended levels
• Quit smoking to improve overall cardiovascular health
• Manage stress through relaxation techniques or counseling
• Improve sleep quality, which is especially important for those with sleep apnea

Prevention and Long-Term Management

Prevention and long-term management of secondary hypertension require treating the underlying cause, adhering to therapy, and maintaining regular follow-ups with blood pressure and organ function monitoring. Consistent monitoring, medication adherence, and coordination between specialists help keep blood pressure controlled and prevent complications like heart attack, stroke, or kidney failure. Ongoing blood tests, imaging, and blood pressure monitoring ensure effective long-term management.

Can Secondary Hypertension be Prevented?

While not all cases of secondary hypertension can be prevented, you can reduce your risk by managing conditions that commonly cause it. Some causes of secondary hypertension, such as genetic kidney diseases or congenital blood vessel abnormalities, cannot be prevented. However, early recognition and treatment can minimize their impact on blood pressure and overall health.

Conclusion

Secondary hypertension is often reversible when its underlying cause is accurately identified and treated. Unlike primary hypertension, it requires a targeted approach that addresses root medical conditions such as kidney disease, endocrine disorders, or sleep apnea.

At Metropolis Healthcare, we understand the critical role that accurate diagnostics play in identifying and managing the causes of secondary hypertension. Our extensive portfolio of over 4,000 tests includes specialised panels for kidney function, hormone levels, and other markers crucial for diagnosing secondary hypertension. With our convenient home sample collection service covering more than 10,000 touchpoints across India, you can access these vital tests from the comfort of your home.

FAQs

What causes secondary hypertension?

Secondary hypertension arises from underlying conditions affecting blood pressure control. Common causes include kidney disease, renal artery stenosis, endocrine disorders (like adrenal or thyroid issues), Sleep apnea, certain medications, pregnancy complications, and blood vessel abnormalities.

Can secondary hypertension be cured?

Yes, secondary hypertension can often be cured or significantly improved when the underlying cause is effectively treated.

How is secondary hypertension diagnosed?

Secondary hypertension is diagnosed through medical history, physical exam, and blood pressure checks. Blood and urine tests identify causes, imaging (ultrasound, CT, MRI) reveals structural issues, hormone tests detect endocrine disorders, and sleep studies confirm Sleep apnea.

What are the symptoms of secondary hypertension?

• Sudden onset of high blood pressure, especially at unusual ages
• Fatigue and weakness
• Excessive thirst and frequent urination
• Unexplained weight changes
• Headaches, especially morning headaches
• Excessive sweating or hand tremors
• Loud snoring and daytime sleepiness
• Muscle cramps or Weakness
• Mood changes or anxiety

What is the best treatment for secondary hypertension?

The best treatment for secondary hypertension targets its cause—such as surgery, hormone therapy, or CPAP for Sleep apnea—while controlling blood pressure with medication. Combining cause-specific treatment, lifestyle changes, and regular monitoring ensures effective, lasting control by addressing the root problem, not just the symptoms.

References

• https://nhm.gov.in/images/pdf/guidelines/nrhm-guidelines/stg/Hypertension_full.pdf
• https://my.clevelandclinic.org/health/diseases/21128-secondary-hypertension
• https://www.mayoclinic.org/diseases-conditions/secondary-hypertension/symptoms-causes/syc-20350679