Secondary Hypertension.. Causes, Diagnosis, and Treatment

Secondary hypertension is of particular importance because discovering and treating the underlying cause may, in some cases, lead to a clear improvement in blood pressure and may reduce the need for antihypertensive medications.

What is secondary hypertension?

Secondary hypertension is a persistent rise in blood pressure resulting from a specific, identifiable medical condition or factor. Although most cases of hypertension in adults are primary, secondary hypertension is relatively more common in children, adolescents, and some patients who exhibit certain clinical signs.

A secondary cause may be suspected when hypertension begins at an early age, appears suddenly, becomes severe within a short period, or does not respond to standard treatment despite the use of several appropriate medications.

The most important causes of secondary hypertension:

There is a wide range of causes that may lead to secondary hypertension, the most important of which are:

1 - Kidney diseases:

Kidney diseases are among the most common causes of secondary hypertension. The kidneys play a fundamental role in regulating fluid volume, salts, and blood pressure. Diseases such as chronic nephritis, chronic kidney disease, and certain renal vascular diseases can lead to hypertension.

Narrowing of the arteries that supply the kidneys, a condition known as renal artery stenosis, can also occur, leading to the activation of hormonal systems that raise blood pressure.

2 - Hormonal and endocrine disorders:

Some endocrine disorders can cause hypertension. Examples include hyperthyroidism or hypothyroidism, Cushing's syndrome, primary aldosteronism, and certain adrenal gland tumors.

An important condition is pheochromocytoma, a rare tumor of the adrenal gland that may lead to episodes of severe hypertension, sometimes accompanied by headaches, sweating, and heart palpitations.

3 - Obstructive sleep apnea:

Obstructive sleep apnea is an important cause of hypertension, especially in people who suffer from severe snoring, breathing pauses during sleep, or excessive daytime sleepiness.

Apnea episodes lead to decreased oxygen and activation of the sympathetic nervous system, which may contribute to persistent hypertension.

4 - Certain medications and substances:

Some medications and substances can raise blood pressure. Examples include certain non-steroidal anti-inflammatory drugs (NSAIDs), corticosteroids, some nasal decongestants, and certain hormonal contraceptives, in addition to other medications depending on the patient's condition and the dosage used.

Some stimulants and illicit drugs can also lead to a dangerous rise in blood pressure. Therefore, it is important for the patient to inform the doctor about all medications, supplements, and substances they use.

5 - Coarctation of the aorta:

Coarctation of the aorta is a congenital cause of hypertension and occurs as a result of a narrowing of a part of the aorta. It may be discovered in childhood or youth, and sometimes it is not diagnosed until a later stage.

When is secondary hypertension suspected?

A single high reading does not necessarily mean that the patient has secondary hypertension. However, there are signs that may prompt a doctor to look for a specific cause, including:

- The onset of hypertension at a very early age.

- Sudden or severe rise in blood pressure.

- Difficulty controlling blood pressure despite using multiple medications.

- Loss of blood pressure control after it had been stable.

- Presence of signs indicating kidney disease or a hormonal disorder.

- Low blood potassium levels without a clear cause.

- Presence of characteristic symptoms such as episodes of headache, sweating, and heart palpitations.

- Presence of symptoms or signs associated with sleep apnea.

How is it diagnosed?

Diagnosis of secondary hypertension begins with taking a detailed medical history and performing a comprehensive clinical examination. The doctor focuses on the time of onset of hypertension, medications used, family history, associated symptoms, sleep habits, and lifestyle.

Tests may include blood and urine analysis to evaluate kidney function, salt levels, and certain hormones. Imaging tests, such as a renal ultrasound, or a CT or MRI scan of the blood vessels, may also be used, depending on the suspected cause.

If sleep apnea is suspected, the doctor may recommend a sleep study. If a hormonal disorder is suspected, specialized hormonal tests may be performed.

It is important that the results of these tests be interpreted in the context of the patient's clinical condition; performing a large number of tests without a clear clinical reason may lead to inaccurate or unnecessary results.

Treatment of secondary hypertension:

Treatment depends on addressing the underlying cause, in addition to controlling blood pressure when necessary.

If the cause is kidney disease, treatment focuses on protecting kidney function and controlling blood pressure. If the cause is renal artery stenosis or coarctation of the aorta, the patient may need specialized procedures according to the severity and cause of the condition.

As for endocrine disorders, their treatment is directed at the hormonal disorder itself and may include medication or surgical intervention in some cases.

At the same time, the patient may need antihypertensive medications. The doctor determines the type of medication, the number of medications, and the dosages based on the underlying cause, kidney function, age, comorbidities, and response to treatment.

The role of lifestyle:

Even when hypertension is secondary, healthy habits remain an important part of treatment. This includes reducing salt intake, maintaining a healthy weight, engaging in appropriate physical activity, following a balanced diet, refraining from smoking, reducing alcohol consumption, and getting sufficient sleep.

However, improving lifestyle does not replace the need to treat the medical cause when hypertension is the result of a specific disease.