Bartter syndrome

Definition

Bartter syndrome refers to a rare group of conditions that affect the kidneys. People with Bartter syndrome have a loss of potassium (hypokalemic alkalosis) and a rise in the hormone aldosterone.

See also: Aldosterone test

Alternative Names

Causes

In some cases, Bartter syndrome may be genetic and the condition is present from before birth (congenital).

The condition is thought to be caused by a defect in the kidney's ability to reabsorb potassium. As a result, the kidneys remove too much potassium from the body. This is also known as potassium wasting. Unlike other forms of kidney disease, this condition does not cause high blood pressure.

Symptoms

This disease usually occurs in childhood. Symptoms include muscle cramping and weakness, constipation, increased frequency of urination, and growth failure.

Exams and Tests

The diagnosis of Bartter syndrome is usually made by finding low levels of potassium in the blood. The potassium level is usually less than 2.5 mEq/L. Other signs of this syndrome include:

• Normal blood pressure
• Low blood chloride
• Metabolic alkalosis
• High levels of the hormones renin and aldosterone in the blood
• High levels of potassium, calcium, and chloride in the urine

These same signs and symptoms can also occur in people who have taken too many diuretics or laxatives. Urine tests can be done to rule out these causes.

In Bartter syndrome, a biopsy of the kidney typically shows overgrowth of kidney cells called the juxtaglomerular apparatus. However, this is not found in all patients, especially in young children.

Treatment

Bartter syndrome is treated by keeping the blood potassium level above 3.5 mEq/L. This is done by following a diet rich in potassium. Many patients also need salt and magnesium supplements, as well as medicine that block the kidney's ability to get rid of potassium. High doses of non-steroidal anti-inflammatories (NSAIDs) may also be used.

Outlook (Prognosis)

The long term outlook for patients with Bartter syndrome is not certain. Infants who have severe growth failure may grow normally with treatment. While most patients remain well with ongoing treatment, some develop kidney failure.

Possible Complications

Kidney failure is a possible complication.

When to Contact a Medical Professional

Call your health care provider if your child is not growing well, is urinating frequently, and is having muscle cramps.

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