Coordinated Health

Definition

Distal renal tubular acidosis is a disease that occurs when the kidneys do not properly remove acids from the blood into the urine. As a result, too much acid remains in the blood (called acidosis).

Alternative Names

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

Causes

When the body performs its normal functions, it produces acid. If this acid is not removed or neutralized, the blood becomes too acidic. This can lead to electrolyte imbalances in the blood. It can also cause problems with normal function of some cells.

The kidneys help control the body’s acid level by removing acid from the blood and excreting it 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 blood.

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

• Amyloidosis
• Fabry disease (abnormal buildup in the body of a certain type of fatty substance)
• High blood calcium
• Sickle cell disease
• Sjogren syndrome
• Systemic lupus erythematosus
• Wilson disease
• Use of certain medicines, such as amphotericin B, lithium, and analgesics

Symptoms

Symptoms of distal renal tubular acidosis include any of the following:

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

Other symptoms can include:

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

Exams and Tests

The doctor will perform a physical exam and ask about your symptoms.

Tests that may be ordered include:

• Arterial blood gas
• Blood chemistry
• Urine pH
• Urinalysis

Treatment

The goal is to restore normal acid level and electrolyte balance in the body. This will help correct bone disorders and reduce calcium buildup in the kidneys (nephrocalcinosis) and kidney stones.

The underlying cause of distal renal tubular acidosis should be corrected if it can be identified.

Medicines that may be prescribed include potassium citrate and sodium bicarbonate. These are alkaline medicines that help correct the acidic condition of the body. Sodium bicarbonate may correct the loss of potassium and calcium.

Outlook (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.

Possible Complications

Untreated, distal renal tubular acidosis can lead to any of the following conditions:

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

When to Contact a Medical Professional

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

Get medical help right away if you develop emergency symptoms, such as:

• Decreased consciousness
• Seizures
• Severe decrease in alertness or orientation

Prevention

There is no prevention for this disorder.