Secondary Renal Hypertension
High blood pressure, or hypertension, occurs when blood pushes against the walls of the blood vessels with greater force than normal. Unlike primary high blood pressure, which has no known cause, secondary high blood pressure is caused by an underlying medical condition. In the case of secondary renal hypertension, it is caused by kidney disease.
Either type of high blood pressure is harmful because it increases the workload of both the heart and the blood vessels, forcing them to work harder and less efficiently.
Causes of Secondary Renal Hypertension
A relatively uncommon condition, secondary renal hypertension can result from renal artery stenosis, a narrowing of the arteries that supply blood to the kidneys. In response to the poor blood flow, the kidneys naturally produce a hormone (renin) to raise the blood pressure. However, because the poor blood flow is a result of renal artery stenosis—and not low blood pressure—the renin raises the blood pressure too high, leading to secondary renal hypertension.
Other possible causes of secondary renal hypertension include impaired kidney function due to polycystic kidney disease, glomerulonephritis or a complication of diabetes.
Symptoms of Secondary Renal Hypertension
In most cases, secondary renal hypertension does not have distinctive symptoms. Some signs that could point to kidney disease as the cause of high blood pressure include:
- High blood pressure that cannot be controlled with medication
- Previously controlled high blood pressure that stops responding to medication
- Sudden-onset high blood pressure before age 30 or after age 55
- High blood pressure that develops in a patient who maintains a healthy body weight and has no family history of cardiovascular disease
Diagnosis of Secondary Renal Hypertension
If secondary renal hypertension is suspected based on the symptoms, a physician may order one or more diagnostic tests, such as:
- Creatinine and blood urea nitrogen (BUN) tests to evaluate kidney function
- Bloodwork to measure the levels of calcium and potassium in the blood
- Thyroid function tests
- An ultrasound to assess the size of the kidneys
- A computed tomography (CT) scan or magnetic resonance imaging (MRI) scan to evaluate the kidneys and adrenals glands
- An arteriogram to track blood flow to the kidneys
Treatments for Secondary Renal Hypertension
In general, secondary high blood pressure will persist until the underlying condition is resolved. Therefore, a key aspect of treatment involves addressing the underlying kidney disease, often with lifestyle changes and medication. If the kidneys are failing or end-stage renal failure occurs, dialysis or a kidney transplant may be required.
Tampa General Hospital has earned a reputation as one of the best hospitals in the nation for nephrology. By treating a high volume of patients with kidney disease, our team has acquired unparalleled expertise, allowing us to achieve better outcomes and quality of life for our patients.