Analyses & Studies
Focus Healthcare : Primary Hypertension versus Secondary Hypertension – Detecting the Root Cause
Hypertension, or high blood pressure, is a significant health issue that affects millions of people worldwide. While most cases of high blood pressure are classified as primary (or essential) hypertension, secondary hypertension accounts for a smaller but crucial subset of cases. Secondary hypertension occurs as a result of an underlying medical condition or external factor. It is important to be vigilant for a root cause especially in young patients (< 40 years of age) or with those requiring multiple medications to control their blood pressure.
1. Kidney Diseases
One of the most common causes of secondary hypertension is kidney disease, particularly conditions such as chronic kidney disease (CKD), polycystic kidney disease, and glomerulonephritis. The kidneys play a vital role in regulating blood pressure through the balance of sodium and water in the body. When the kidneys are impaired, they may not function properly in filtering waste, leading to an imbalance in fluid levels and increased blood pressure. Conditions like renal artery stenosis, where there is a narrowing of the arteries supplying blood to the kidneys, can also reduce the kidney’s ability to detect blood flow and trigger mechanisms that increase blood pressure in response.
2. Endocrine Disorders
Endocrine disorders, which involve the glands that produce hormones, can also lead to secondary hypertension. Several hormonal imbalances are associated with high blood pressure, including:
- Hyperaldosteronism: This occurs when the adrenal glands produce too much aldosterone, a hormone that causes the body to retain sodium and water, raising blood pressure.
- Cushing’s Syndrome: Caused by excess cortisol production (often due to tumors in the adrenal glands or pituitary), Cushing's syndrome can lead to high blood pressure by promoting sodium retention and increasing fluid volume in the blood vessels.
- Pheochromocytoma: A rare tumor of the adrenal glands, pheochromocytoma leads to the overproduction of catecholamines (such as adrenaline), which can cause spikes in blood pressure.
Thyroid disorders, particularly hyperthyroidism, can also contribute to secondary hypertension. An overactive thyroid can increase heart rate and cause the blood vessels to constrict, raising blood pressure.
3. Obstructive Sleep Apnea (OSA)
Obstructive sleep apnea, a condition where the airway is intermittently blocked during sleep, is closely linked with hypertension. The repeated interruptions in breathing result in oxygen deprivation, which activates the body’s stress response. This leads to elevated levels of adrenaline and other stress hormones that can cause blood vessels to constrict, increasing blood pressure. Additionally, the lack of restorative sleep due to frequent awakenings can contribute to overall poor cardiovascular health. The tell tale sign of loud snoring is often described by the sleeping partners of patients.
4. Medications and Substances
Certain medications and substances can also cause secondary hypertension. Drugs such as nonsteroidal anti-inflammatory drugs (NSAIDs), decongestants, and stimulants (including drugs used to treat attention-deficit hyperactivity disorder) can increase blood pressure as a side effect. Other substances, such as alcohol and caffeine, can have temporary effects on blood pressure. Chronic alcohol consumption, for example, has been associated with sustained hypertension.
Moreover, some prescription medications, such as birth control pills, steroids, and antidepressants (particularly monoamine oxidase inhibitors), have been linked to increased blood pressure, particularly when used long-term.
Conclusion
Secondary hypertension is an important medical condition that can often be traced back to an underlying cause. Understanding the root causes of secondary hypertension is essential for proper diagnosis and treatment, as managing the underlying condition often leads to better control of blood pressure. For individuals diagnosed with hypertension, particularly when it arises unexpectedly, difficult to control or in the young, various additional investigations can be conducted in our clinic to rule of the possibility.
By recognizing and addressing the causes of secondary hypertension, individuals can reduce the risk of long-term cardiovascular complications and improve overall health outcomes.
by Dr. Pinakin V Parekh, Senior Consultant Cardiologist, The Harley Street Heart & Vascular Centre
