Distal renal tubular acidosis Health Article

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.