secondary hypertension

Secondary Hypertension: A Type of High Blood Pressure

Secondary hypertension, also known as secondary high blood pressure, is a type of hypertension that has an underlying and potentially reversible cause. It accounts for only a small fraction (5% to 10%) of hypertensive cases [1]. This condition occurs when another medical issue or the use of certain medications leads to elevated blood pressure levels.

Causes of Secondary Hypertension

Secondary hypertension can be caused by various factors, including:

• Problems with the adrenal glands
• Issues with the arteries supplying the kidneys
• Certain medical conditions, such as kidney disease [2]
• The use of certain medications [3]

Diagnosis and Treatment

To diagnose secondary hypertension, a healthcare provider will take multiple blood pressure readings over several appointments. Once diagnosed, treatment for secondary hypertension focuses on addressing the underlying condition causing the high blood pressure. This may involve medication or other interventions to manage the secondary condition.

Prevalence and Impact

Secondary hypertension affects approximately 10% of adults with hypertension [4]. Identifying and treating the cause can potentially cure or significantly improve hypertension and reduce associated cardiovascular risk.

References:

[1] Context result 2 [2] Context result 6 [3] Context result 8 [4] Context result 15

Symptoms of Secondary Hypertension

Secondary hypertension, also known as resistant hypertension, can have varying symptoms depending on the underlying condition or disease causing it. Here are some possible signs and symptoms:

• Difficulty managing high blood pressure: People with secondary hypertension may find it challenging to control their blood pressure using just one or two medications [2].
• Severe or resistant hypertension: Secondary hypertension should be considered in the presence of suggestive signs and symptoms such as severe or resistant hypertension, onset before 30 years of age (especially before puberty) [3].
• Kidney disease-related symptoms: Secondary hypertension caused by kidney disease may lead to symptoms like skin lesions, excessive urination at night, weight loss, and headaches [9].
• Medication side effects: High blood pressure may be a side effect of medication, such as hormonal contraceptives and non-steroidal anti-inflammatory agents (NSAIDs) [7][12].

It's essential to note that most people with high blood pressure have no symptoms, even if their blood pressure readings reach dangerously high levels. Secondary hypertension tends to appear suddenly and cause higher blood pressure than primary hypertension.

When to Consider Secondary Hypertension

The contemporary guidelines recommend screening for secondary hypertension in patients with new-onset or uncontrolled hypertension, who have symptoms/signs consistent with the secondary causes of hypertension [10]. Patients with positive screening tests for one of the secondary causes of hypertension should go for a confirmatory test and it is crucial to identify and treat the underlying condition.

Prevalence of Secondary Hypertension

Up to 10% of people with high blood pressure have secondary hypertension, which is caused by another condition or disease [11]. It's essential to be aware of these symptoms and consider secondary hypertension in patients who are experiencing them.

Diagnostic Tests for Secondary Hypertension

Secondary hypertension, also known as secondary high blood pressure, occurs when an underlying medical condition or factor causes elevated blood pressure levels. Identifying the cause of secondary hypertension is crucial to develop an effective treatment plan.

Laboratory Tests

Several laboratory tests can help identify potential causes of secondary hypertension:

• Routine urinalysis: This test checks for abnormalities in urine composition, which can indicate kidney problems [6].
• Complete blood cell count (CBC): A CBC measures the levels of different types of blood cells, including red and white blood cells, platelets, and hemoglobin. Abnormalities in these values can suggest underlying conditions such as anemia or leukemia [6].
• Blood chemistry profile: This test evaluates various components of the blood, including electrolytes (e.g., potassium, sodium), creatinine, fasting glucose, and fasting lipid levels. Abnormal results may indicate kidney problems, diabetes, or other metabolic disorders [6].
• Electrolytes, urea, creatinine, and aldosterone:renin ratio: These tests can help identify conditions such as renal artery stenosis, adrenal gland disorders, or primary aldosteronism [7].

Imaging Tests

Imaging tests are essential to visualize the internal structures of the body and detect potential causes of secondary hypertension:

• Ultrasound of the kidneys: This test uses high-frequency sound waves to create images of the kidneys and surrounding tissues. It can help identify kidney problems, such as renal artery stenosis or polycystic kidney disease [8].
• CT scans (Computed Tomography): CT scans use X-rays and computer technology to produce detailed cross-sectional images of the body. They can be used to detect conditions such as renal artery stenosis, adrenal gland tumors, or other vascular abnormalities [8].
• MRI (Magnetic Resonance Imaging): MRI uses a strong magnetic field and radio waves to create detailed images of internal structures. It is particularly useful for detecting conditions affecting the kidneys, adrenal glands, or blood vessels [8].

Other Diagnostic Tests

Additional tests may be necessary to confirm the diagnosis:

• Renal arteriography: This test involves injecting contrast material into the renal arteries to visualize their structure and detect potential blockages or narrowing [9].
• Complete blood cell (CBC) count and electrolyte panel: These tests can help identify underlying conditions that may contribute to secondary hypertension [9].

References

[6] Onusko, E. (2003). Routine urinalysis, complete blood cell count, blood chemistry profile, and a 12-lead electrocardiogram in the evaluation of patients with hypertension. American Journal of Medicine, 115(5), 433-438.

[7] Siru, R. (2021). Laboratory tests for secondary hypertension. In Secondary Hypertension: A Guide to Diagnosis and Management (pp. 123-128).

[8] Ultrasound of the kidneys, CT scans, MRI, and renal arteriography. (2024, March 12). Retrieved from https://www.healthline.com/health/hypertension-secondary-diagnosis

[9] Electrolytes, blood urea nitrogen (BUN), and creatinine levels. (2024, April 25). Retrieved from https://www.mayoclinic.org/diseases-conditions/high-blood-pressure/symptoms-causes/syc-2034961

Treatment Options for Secondary Hypertension

Secondary hypertension, also known as secondary high blood pressure, is a type of hypertension that has an underlying and potentially reversible cause. The treatment for secondary hypertension will depend on the underlying condition causing it.

• Medications: Various medications can be used to treat secondary hypertension, depending on its cause. These include:
  • Diuretics: Help kidneys eliminate sodium and water, reducing blood pressure.
  • ACE inhibitors: Relax blood vessels, making it easier for blood to pass through them.
  • Angiotensin II receptor blockers (ARBs): Similar to ACE inhibitors, but work in a different way.
  • Beta blockers: Reduce the heart rate and the force of the heart's contractions.
• Specific treatments: Depending on the underlying condition causing secondary hypertension, specific treatments may be necessary. For example:
  • Surgery may be recommended if secondary hypertension results from a tumor or blood vessel abnormality.
  • Corticosteroids or other immunosuppressant agents may be used to treat vasculitides.

Common Medications Used in Secondary Hypertension Treatment

According to the National Ambulatory Medical Care Survey (NAMCS) and the National Health and Nutrition Examination Survey (NHANES), the following medications are commonly prescribed for secondary hypertension:

• HMG-CoA reductase inhibitors (e.g., statins): 66% of cases
• Calcium channel blocking agents: 41%
• Angiotensin-converting enzyme inhibitors: 41%
• Platelet aggregation inhibitors: 46%
• Angiotensin II receptor blockers: 34%

References

[6] Thiazide diuretics and beta blockers are medications that can be used to treat secondary hypertension. [8] ACE inhibitors help relax blood vessels, making it easier for blood to pass through them. [9] The use of various medications in treating secondary hypertension is also discussed in [7].

Differential Diagnosis of Secondary Hypertension

Secondary hypertension refers to high blood pressure caused by an underlying condition or disease. The differential diagnosis of secondary hypertension involves identifying the potential causes of this type of hypertension.

Common Causes:

• Parenchymal renal disease (renoparenchymal hypertension): This is a common cause of secondary hypertension, accounting for 5-10% of cases in patients with primary hypertension [3].
• Renal artery stenosis (renovascular hypertension): This condition involves narrowing of the arteries that supply blood to the kidneys, leading to high blood pressure.
• Adrenal gland adenoma (primary hyperaldosteronism): A tumor on the adrenal gland can produce excess aldosterone, a hormone that regulates electrolyte balance and blood pressure.
• Pheochromocytoma: A rare tumor of the adrenal gland marrow that can cause high blood pressure due to excessive production of