Health Encyclopedia

Distal renal tubular acidosis

Definition

Distal renal tubular acidosis is a disease that occurs when the kidneys don't remove acid properly into the urine, leaving the blood too acidic (called acidosis).

Alternative Names

Renal tubular acidosis - distal; Renal tubular acidosis type I; Type I RTA; RTA - distal; Classical RTA

Causes, incidence, and risk factors

Your kidneys normally regulate your body's pH by controlling acids.

Distal renal tubular acidosis (Type I RTA) is caused by a defect in the kidney tubes that causes acid to build up in the bloodstream.

Type I RTA is caused by a variety of conditions, including:

Autoimmune diseases
Drugs such as amphotericin B, lithium, and analgesics
Hereditary disorders

Symptoms

Confusion or decreased alertness
Fatigue
Impaired growth
Increased breathing rate
Kidney stones
Nephrocalcinosis
Osteomalacia
Rickets
Skeletal deformities
Muscle weakness

Other symptoms can include:

Bone pain
Bloody urine
Decreased urine output
Increased heart rate or irregular heartbeat
Muscle cramps
Pain in the back, flank, or abdomen

Signs and tests

Arterial blood gas (ABG) and blood chemistries may indicate metabolic acidosis and low blood potassium level.
Blood pH and urine pH may show poor hydrogen ion excretion. The urine pH is usually > 5.0.
Urinalysis may show abnormalities, including increased levels of calcium and potassium in the urine.

Treatment

The goal is to restore the normal pH (acid-base level) and electrolyte balance. This will indirectly correct bone disorders and reduce the risk of calcium build-up in the kidneys (nephrocalcinosis) and kidney stones. The underlying cause should be corrected if it can be identified.

Alkaline medications such as potassium citrate and sodium bicarbonate correct the acidic condition of the body. Sodium bicarbonate may correct the loss of potassium and calcium.

Vitamin D and calcium supplements are usually not given because there may be too much calcium in the kidneys, even after bicarbonate therapy.

Expectations (prognosis)

The disorder must be treated to reduce its effects and complications, which can be permanent or life-threatening. Most cases get better with treatment.

Complications

Osteomalacia
Rickets
Nephrocalcinosis
Kidney stones
Electrolyte imbalances, such as low blood potassium level

Calling your health care provider

Call your health care provider if you have symptoms of distal renal tubular acidosis.

Get help immediately if you develop emergency symptoms, such as:

Decreased consciousness
Seizures
Severe decrease in alertness or orientation

Prevention

There is no prevention for this disorder.

Review Date:11/12/2007
Reviewed By:Charles Silberberg, D.O., Private Practice specializing in Nephrology, Affiliated with NY Medical College, Division of Nephrology, Valhalla, NY. Review provided by VeriMed Healthcare Network.

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