Distal renal tubular acidosis is a disease that occurs when the kidneys don't remove acid properly into the urine, leaving the too much acid in the blood (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
When your body performs its normal functions, it produces acid. If this acid is not removed or neutralized, your blood will become too acidic. This can lead to electrolyte imbalances in the blood.
Your kidneys normally help control the acid level in your body by removing acids from the blood and sending them into the urine.
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:
Amyloidosis
Fabry disease
High blood calcium
Sickle cell disease
Sjogren syndrome
Systemic lupus erythematosus
Wilson disease
Use of certain drugs such as amphotericin B, lithium, and analgesics
Arterial blood gas and blood chemistries may suggest metabolic acidosis or electrolyte imbalances, most often low levels of potassium or bicarbonate.
Other tests that may be done include:
Urine pH, usually greater than 5.3 in patients with this condition
Urinalysis may show increased levels of calcium and potassium
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 buildup 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 calcium deposits 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.
Review Date:
12/19/2011
Reviewed By:
David C. Dugdale, III, MD, Professor of Medicine, Division of General Medicine, Department of Medicine, University of Washington School of Medicine; Herbert Y. Lin, MD, PHD, Nephrologist, Massachusetts General Hospital; Associate Professor of Medicine, Harvard Medical School. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.
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