Secondary Hypertension

What is Secondary Hypertension?

Hypertension, also known as high blood pressure, is a key risk factor for heart diseases. Currently, over 30% of adults have hypertension. Mostly, the cause of hypertension isn’t known, but in some cases (about 10%), it’s due to a specific reason, referred to as secondary hypertension.

Secondary hypertension is high blood pressure caused by a known issue. Although it doesn’t occur very often, identifying what triggers secondary hypertension in certain patients is crucial. Not only does this help decide on the right treatment, it could also completely cure their hypertension, and save them from having to take blood pressure-lowering medication. Medical professionals treating high blood pressure should look out for clues that might suggest a secondary cause.

Secondary hypertension might be suspected in certain situations. These include stubbornly high blood pressure that doesn’t respond to three different types of medication (including a water pill), a sudden spike in blood pressure in a patient who previously had stable readings, non-black patients under 30 years old with high blood pressure but no other risk factors (like obesity or family history), severely high blood pressure or signs of problems in other organs caused by high blood pressure (like sudden kidney problems, neurological signs, sudden heart failure, damage to the eyes, enlargement of the left side of the heart), high blood pressure alongside signs of certain chemical imbalances in the body, or high blood pressure starting before puberty.

Another potential sign of secondary hypertension is an abnormal pattern in the blood pressure readings throughout the day. Normally, blood pressure decreases, or ‘dips’, at night. If this dip is absent or happens during the day instead of at night, it could suggest a secondary cause of hypertension.

What Causes Secondary Hypertension?

There are many reasons that can cause secondary hypertension, which we can group into several main categories.

Renal Parenchymal Disease is the top cause of secondary hypertension. This refers to a collection of kidney issues which could include diabetic kidney disease, glomerulonephritis, degenerative kidney diseases, and polycystic kidney diseases. These conditions can lead to high blood pressure in more than half of the people suffering from them, and this rate only increases as the kidney problems get worse. The development of high blood pressure tends to speed up the decline of kidney function, which could lead to serious kidney disease.

Endocrine Disorders can also cause secondary hypertension due to an overproduction of certain hormones. Common disorders that cause this type of hypertension include primary aldosteronism, pheochromocytoma, and Cushing’s syndrome, with primary aldosteronism accounting for most of the cases. Acromegaly, primary hyperparathyroidism, and thyroid disorders can also lead to secondary hypertension, but these cases are very rare.

Renovascular Disorders can also cause hypertension, though this is not common. It may occur if there’s narrowing of one or both kidney arteries. It’s usually caused by hardening of the arteries in older people, while in younger people, especially women, it can be due to an overgrowth of muscle tissue in the artery wall.

Blood Vessel Disorders can result in secondary hypertension as well. In young adults, a common cause is a narrowing of the aorta, the main artery that carries blood from the heart to the rest of the body. Secondary hypertension could be rarely caused by inflammation of medium or large arteries, or abnormal connections between arteries and veins.

Other miscellaneous causes include sleep apnea, polycystic ovarian syndrome, preeclampsia, and even certain medications. With sleep apnea, the quality and amount of sleep are affected, which increases the risk of high blood pressure. Several drugs have been linked to high blood pressure, including common ones such as non-steroidal anti-inflammatory drugs, antacids, drugs used to treat ADHD, certain anti-depressants, and more. Even some herbal supplements and over-the-counter medicines can cause high blood pressure. Thus, it’s important to consider what medications a person is taking when looking into their high blood pressure issues. Lastly, certain substances like nicotine and alcohol, and some chemotherapy drugs can also lead to secondary hypertension.

Risk Factors and Frequency for Secondary Hypertension

Secondary hypertension, meaning high blood pressure caused by another medical condition, is found in up to 10% of adults with high blood pressure. The likelihood of having secondary hypertension varies with age, and is most common in the very young and very old. It causes high blood pressure in 70 to 85 percent of children under 12 and 17 percent of adults over 65.

Interestingly, the group of people with high blood pressure who are least likely to have secondary hypertension are those aged 19 to 39. However, adolescents between the ages of 12 and 18 have a 10 to 15% prevalence of secondary hypertension.

Disease in the tissue of the kidneys is behind secondary hypertension in 3-5% of those diagnosed with high blood pressure.
If kidney function worsens, the rate of secondary hypertension will also increase. In fact, over two thirds of patients with severe chronic kidney disease have high blood pressure.
Primary aldosteronism, a hormonal condition, is the leading cause of secondary hypertension, affecting up to 5% of those with high blood pressure. Luckily, this type of hypertension can usually be cured by treating the hormonal disorder.
Renovascular hypertension, which is high blood pressure caused by problems with the arteries supplying the kidneys, affects 1% of high blood pressure patients and can occur at any age.

Signs and Symptoms of Secondary Hypertension

Secondary hypertension is a type of high blood pressure that is caused by another health condition. To understand the cause of secondary hypertension, healthcare professionals need to thoroughly evaluate the medical history and physical conditions of the patient. Some signs that indicate the presence of secondary hypertension include sudden high blood pressure in patients who are already on medication, development of high blood pressure in very young or very old age or a rapid onset of complications due to hypertension.

The following are specific signs that could hint at the underlying causes of secondary hypertension:

Snoring, obesity, and daytime sleepiness may suggest obstructive sleep apnea.
History of kidney malfunction, heart disease, and swelling could be associated with chronic kidney disease.
Recurrent urinary infections, kidney stones, persistent abdominal pain, blood in urine, and progressing kidney failure could signal an inherited kidney disorder, such as polycystic kidney disease.
Occasional high blood pressure, headache, and racing heart, especially during times of stress, might be symptoms of pheochromocytoma or paragangliomas, both are rare tumors that produce a hormone causing high blood pressure.
Lower blood pressure in legs compared to arms, or unequal blood pressure between arms could indicate coarctation of the aorta, a congenital heart defect, or inflammations in blood vessels.
Weight gain, fatigue, weakness, excess body hair, missing menstrual periods, moon-shaped face, hump on the back, purple stretch marks, and central obesity occur in Cushing syndrome.
Tiredness, weight loss, hair loss, muscle weakness occur with low thyroid function, while sensitivity to heat, weight loss, palpitations, protruding eyes, tremors, and rapid heartbeat can reflect overactive thyroid.
Kidney stones, osteoporosis, depression, fatigue and muscle weakness are symptoms of hyperparathyroidism, a condition characterized by overactivity of the parathyroid glands.
Headaches, fatigue, visual problems, enlargement of the hands, feet, and tongue are found in acromegaly, a hormonal disorder.
Heartburn, Raynaud phenomenon (where some parts of the body like fingers and toes feel numb and cold in response to cold temperatures or stress), and pitted nails might suggest scleroderma, a group of disorders involving the abnormal growth of connective tissue.

Testing for Secondary Hypertension

If a doctor suspects that your high blood pressure (or hypertension) isn’t due to common causes but to an underlying condition, they might carry out investigations to identify the cause. This often starts with a screening test, and if the screening test indicates a particular condition might be to blame, you’ll receive a confirmatory test. Usually, people who have these conditions are often recommended to see a specialized doctor.

Investigations for renal diseases, which occur in the kidney, begin with screening tests like a blood test to check your creatinine level (which tells us how well your kidneys are functioning), a urine test, a kidney ultrasound and a kidney biopsy which examines your kidney’s tissue under a microscope. If these tests come out positive, you’ll be referred to a kidney specialist, or nephrologist, to manage the condition.

If a hormonal disorder is suspected as the cause of your hypertension, different tests will be performed based on the suspected condition. For instance, if primary aldosteronism is suspected (especially when you have low potassium levels and high blood pressure), you’ll undergo screening that measures the levels of different hormones in your blood. If pheochromocytoma (a rare tumor that often causes high blood pressure) is suspected, your doctor may ask for measurements of metanephrines in your urine or blood, and imaging tests to locate any tumor. For suspected thyroid disorders, hormone levels will be checked through blood tests, and further tests like ultrasound or biopsy may be done if there’s a suspicion of thyroid cancer. Lastly, if a condition like Cushing syndrome is suspected, the cortisol level in your body will be checked with different tests.

Additionally, when the arteries in the kidney narrow (a condition known as renal artery stenosis) it can lead to high blood pressure. The first step is to get an ultrasound, and you might undergo further imaging tests like a CT scan or MRI for clearer results.

Conditions related to the heart and blood vessels, like the narrowing of the aorta (coarctation of the aorta) or vasculitis (inflammation of the blood vessels), may also cause high blood pressure. For these, tests like an echocardiogram (an ultrasound of your heart), CT scan, and MRI may be necessary. If your doctor suspects the cause of your high blood pressure might be a sleep-related condition like sleep apnea, an in-laboratory sleep study might be suggested.

Treatment Options for Secondary Hypertension

Managing secondary (or high) blood pressure often means adopting a healthy lifestyle, taking medication, and addressing any underlying causes. Experts recommend referring patients to specialist doctors so they can treat the root cause of the high blood pressure. Also, identifying drugs which might be contributing to the high blood pressure is crucial for effective management.

Let’s discuss how to manage some common causes of secondary high blood pressure:

Kidney Disease: Diseases like diabetic kidney disease, chronic glomerulonephritis, glomerulosclerosis, and polycystic kidney disease can lead to secondary high blood pressure. High blood pressure is present in more than two-thirds of patients with kidney disease and can further damage the kidneys. Therefore, keeping blood pressure under control is a must. Although there isn’t a cure for chronic kidney disease, by controlling blood pressure and addressing reversible causes, the progression toward advanced kidney disease can be attenuated. Medicines which block the renin-angiotensin (a hormone system that regulates blood pressure) are often preferred since they not only control high blood pressure but also slow down kidney disease progression, particularly in patients with protein in their urine.

Renovascular Hypertension: For people suffering from renovascular high blood pressure due to narrowing of the arteries supplying the kidney (renal artery stenosis), medical treatment and revascularization are suggested. This includes using high blood pressure medication, antiplatelets, statins, diet, and lifestyle modifications. Drugs such as ACE inhibitors and ARBs are recommended, but should be avoided in certain situations like bilateral renal artery stenosis due to the risk of rapid kidney dysfunction. Restoration of blood flow in the kidney artery through minimal invasive techniques (percutaneous revascularization) can also be efficient in reducing blood pressure, especially in patients with fibromuscular dysplasia.

Endocrine Hypertension: Conditions like aldosteronism and Cushing Syndrome can cause high blood pressure due to hormonal imbalances. These conditions generally need surgical removal of the overactive gland. For example, pheochromocytoma, a hormone-producing tumor of the adrenal gland, is treated by surgical removal following administration of certain drugs to prevent a high blood pressure crisis. For thyroid disorders, the treatment may include thyroid hormone replacement or antithyroid drugs depending on whether the patient has an overactive (hyperthyroidism) or underactive (hypothyroidism) thyroid.

Vascular Hypertension: This form of high blood pressure is often the result of a narrowing of the aorta (aorta coarctation), especially in younger people. The ultimate treatment involves a surgical correction of the narrowing, but medication is also used based on the specific patient’s co-existing conditions. Some inflammatory conditions of the blood vessels (like Takayasu Arteritis) can also lead to high blood pressure and are treated with antihypertensive drugs along with corticosteroids or other drugs that suppress the immune system.

Obstructive Sleep Apnea: Continuous positive airway pressure (CPAP) therapy is the main treatment for this condition. Combining CPAP, lifestyle modifications, and weight loss can give better results. For patients with mild to moderate sleep apnea, oral appliances can be as effective as CPAP in reducing blood pressure.

Pregnancy-Related Hypertension: Management during pregnancy involves lifestyle changes and taking safe antihypertensive drugs like labetalol, nifedipine, and methyldopa. In cases of severe high blood pressure like severe preeclampsia or eclampsia, early delivery is usually recommended, especially after 37 weeks of gestation.

When considering possible causes of secondary hypertension (high blood pressure), doctors assess a variety of other illnesses. These may include:

Chronic kidney disease
Polycystic kidney disease
Narrowing of the renal arteries (renal artery stenosis)
Fibromuscular dysplasia
Primary aldosteronism
Cushing syndrome/disease
Overactive thyroid gland (hyperthyroidism) or underactive thyroid gland (hypothyroidism)
Increased activity of the parathyroid gland (hyperparathyroidism)
Pheochromocytoma
Excessive growth hormone production (acromegaly)
Congenital adrenal hyperplasia
Narrowing of the aorta (coarctation)
Obstructive sleep apnea
Drug-induced hypertension
Pregnancy
Scleroderma

By taking detailed patient history and conducting a thorough examination, doctors can screen and potentially diagnose the underlying cause of the high blood pressure early on.

What to expect with Secondary Hypertension

Secondary hypertension, a type of high blood pressure, can be hard to manage with medication if we don’t correctly identify and treat its root cause. This condition may lead to early organ damage, hypertension crisis (dangerously high blood pressure), and heart-related health problems at a younger age. However, if we catch and treat the underlying issue early, people with secondary hypertension often have a positive outlook.

Possible Complications When Diagnosed with Secondary Hypertension

High blood pressure, or hypertension, is the most common non-communicable disease worldwide, and it can increase the risk for several heart-related illnesses. This includes heart disease, stroke, and disease of the arteries in parts away from the heart. Hypertension can also harm the small blood vessels in our bodies, leading to kidney disease and issues with the retina in our eyes. It also makes conditions like irregular heartbeat (atrial fibrillation) and heart failure more likely, especially in older individuals.

Secondary hypertension, a type of high blood pressure that is caused by another medical condition, leads to the same complications as primary hypertension, but there are a few problems that are more common in individuals with secondary hypertension. For instance, it’s common for individuals with this type of high blood pressure to have ‘resistant hypertension’, which means their high blood pressure is not controlled, despite taking full doses of at least three medications for high blood pressure, including a diuretic. If secondary hypertension is not diagnosed and treated in time, it can cause harm to vital organs in the body faster and significantly increase the likelihood of premature cardiovascular events.

Common issues include:

Heart disease
Stroke
Peripheral arterial diseases
Chronic kidney disease
Retinopathy (damage to the retina in the eye)
Atrial fibrillation (irregular heartbeat)
Heart failure
Resistant hypertension
Premature cardiovascular events

Preventing Secondary Hypertension

Secondary hypertension, which is a potentially serious health condition that can speed up heart-related complications and damage to vital organs, is important to promptly identify and manage. It’s crucial for individuals to be aware of any specific symptoms linked to this condition and to discuss these symptoms with their doctor. This can help diagnose and treat the root cause of the problem at an early stage. All individuals treating hypertension should make sure to lead a healthy lifestyle, take their medications as directed, and keep a regular check on their blood pressure at home. If any new symptoms crop up or they notice changes in their blood, it’s advisable to inform their doctor. These changes could be signs that the underlying cause of the hypertension needs to be reassessed.

Frequently asked questions

Secondary hypertension is high blood pressure caused by a known issue. It is not very common, but identifying the triggers of secondary hypertension is crucial for determining the right treatment and potentially curing the hypertension.

Secondary hypertension is found in up to 10% of adults with high blood pressure.

Signs and symptoms of secondary hypertension include: - Sudden high blood pressure in patients who are already on medication - Development of high blood pressure in very young or very old age - Rapid onset of complications due to hypertension Specific signs that could hint at the underlying causes of secondary hypertension include: - Snoring, obesity, and daytime sleepiness may suggest obstructive sleep apnea. - History of kidney malfunction, heart disease, and swelling could be associated with chronic kidney disease. - Recurrent urinary infections, kidney stones, persistent abdominal pain, blood in urine, and progressing kidney failure could signal an inherited kidney disorder, such as polycystic kidney disease. - Occasional high blood pressure, headache, and racing heart, especially during times of stress, might be symptoms of pheochromocytoma or paragangliomas, both are rare tumors that produce a hormone causing high blood pressure. - Lower blood pressure in legs compared to arms, or unequal blood pressure between arms could indicate coarctation of the aorta, a congenital heart defect, or inflammations in blood vessels. - Weight gain, fatigue, weakness, excess body hair, missing menstrual periods, moon-shaped face, hump on the back, purple stretch marks, and central obesity occur in Cushing syndrome. - Tiredness, weight loss, hair loss, muscle weakness occur with low thyroid function, while sensitivity to heat, weight loss, palpitations, protruding eyes, tremors, and rapid heartbeat can reflect overactive thyroid. - Kidney stones, osteoporosis, depression, fatigue and muscle weakness are symptoms of hyperparathyroidism, a condition characterized by overactivity of the parathyroid glands. - Headaches, fatigue, visual problems, enlargement of the hands, feet, and tongue are found in acromegaly, a hormonal disorder. - Heartburn, Raynaud phenomenon (where some parts of the body like fingers and toes feel numb and cold in response to cold temperatures or stress), and pitted nails might suggest scleroderma, a group of disorders involving the abnormal growth of connective tissue.

There are several main categories of conditions that can cause secondary hypertension, including renal parenchymal disease, endocrine disorders, renovascular disorders, blood vessel disorders, sleep apnea, polycystic ovarian syndrome, preeclampsia, certain medications, nicotine and alcohol use, and certain chemotherapy drugs.

The doctor needs to rule out the following conditions when diagnosing Secondary Hypertension: - Chronic kidney disease - Polycystic kidney disease - Narrowing of the renal arteries (renal artery stenosis) - Fibromuscular dysplasia - Primary aldosteronism - Cushing syndrome/disease - Overactive thyroid gland (hyperthyroidism) or underactive thyroid gland (hypothyroidism) - Increased activity of the parathyroid gland (hyperparathyroidism) - Pheochromocytoma - Excessive growth hormone production (acromegaly) - Congenital adrenal hyperplasia - Narrowing of the aorta (coarctation) - Obstructive sleep apnea - Drug-induced hypertension - Pregnancy - Scleroderma

The types of tests that may be needed for secondary hypertension include: - Screening tests such as blood tests to check creatinine levels, urine tests, kidney ultrasounds, and kidney biopsies for renal diseases. - Hormone level measurements in the blood and imaging tests for suspected hormonal disorders. - Ultrasound, CT scan, and MRI for conditions related to the heart and blood vessels. - In-laboratory sleep study for sleep-related conditions like sleep apnea. - Echocardiogram, CT scan, and MRI for conditions like coarctation of the aorta and vasculitis. - Additional tests may be necessary based on the suspected underlying cause of secondary hypertension.

Secondary hypertension is treated by managing the underlying causes and adopting a healthy lifestyle. This may involve referring patients to specialist doctors to treat the root cause of high blood pressure and identifying any drugs that may be contributing to it. For specific causes of secondary hypertension, such as kidney disease, renovascular hypertension, endocrine hypertension, vascular hypertension, obstructive sleep apnea, and pregnancy-related hypertension, targeted treatments are recommended. These treatments may include medication, lifestyle modifications, surgical interventions, and other specialized therapies depending on the specific cause of secondary hypertension.

When treating secondary hypertension, there can be some side effects. These may include: - Rapid kidney dysfunction in certain situations when using ACE inhibitors and ARBs for renovascular hypertension with bilateral renal artery stenosis. - High blood pressure crisis during surgical removal of hormone-producing tumors like pheochromocytoma. - Potential side effects from antithyroid drugs or thyroid hormone replacement for thyroid disorders. - Medication side effects based on the specific patient's co-existing conditions when treating vascular hypertension. - Potential side effects from continuous positive airway pressure (CPAP) therapy for obstructive sleep apnea. - Side effects from antihypertensive drugs used during pregnancy for pregnancy-related hypertension. It's important to note that the specific side effects can vary depending on the individual and the medications or treatments being used. It's always best to consult with a healthcare professional for personalized advice and guidance.

People with secondary hypertension often have a positive outlook if the underlying issue is caught and treated early. However, if secondary hypertension is not correctly identified and treated, it can lead to early organ damage, hypertension crisis (dangerously high blood pressure), and heart-related health problems at a younger age.

A specialist doctor, such as a nephrologist, endocrinologist, or cardiologist, should be consulted for Secondary Hypertension.