Proximal renal tubular acidosis is a disease that occurs when the kidneys don’t properly remove acids from the blood into the urine. As a result, too much acid remains in the blood (called
Renal tubular acidosis – proximal; Type II RTA; RTA – proximal; Renal tubular acidosis type II
When the body performs its normal functions, it produces acid. If this acid is not removed or neutralized, the blood will become 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. Acidic substances in the body are neutralized by alkaline substances, mainly bicarbonate.
Proximal renal tubular acidosis (Type II RTA) occurs when bicarbonate is not properly reabsorbed by the kidney’s filtering system.
Type II RTA is less common than Type I RTA. Type II most often occurs during infancy and may go away by itself.
Causes of type II RTA include:
- Cystinosis (body is unable to break down the substance cysteine)
- Drugs such as ifosfamide (a chemotherapy drug), certain antibiotics that are no longer used much (tetracycline), or acetazolamide
- Inherited fructose intolerance
Multiple myeloma Primary hyperparathyroidism Sjogren syndrome Wilson disease
- Vitamin D deficiency
Symptoms of distal renal tubular acidosis include any of the following:
Confusionor decreased alertness Dehydration Fatigue Increased breathing rate Osteomalacia Muscle pain Rickets Weakness
Other symptoms can include:
Decreased urine output
heart rateor irregular heartbeat
Pain in the bones, back, flank, or abdomen
Exams and Tests
The doctor will perform a physical exam and ask about the symptoms.
Tests that may be ordered include:
blood gas Blood chemistry
Other tests that may be done include:
- Blood pH level
Urine pH Urinalysis
The goal is to restore normal acid level and electrolyte balance in the body. This will help correct bone disorders and reduce the risk of osteomalacia and osteopenia in adults.
Some adults may need no treatment. All children need alkaline medicine such as potassium citrate and sodium bicarbonate. This is medicine that helps correct the acidic condition of the body. The medicine helps prevent bone disease caused by too much acid, such as rickets, and to allow normal growth.
The underlying cause of proximal renal tubular necrosis should be corrected if it can be found.
Although the underlying cause of proximal renal tubular acidosis may go away by itself, the effects and complications can be permanent or life-threatening. Treatment is usually successful.
Untreated, distal renal tubular acidosis can lead to any of the following conditions:
- Electrolyte imbalances, such as
When to Contact a Medical Professional
Call your health care provider if you have symptoms of proximal renal tubular acidosis.
Get medical help right away if any of the following emergency symptoms develop:
Decreased alertness or
Most of the disorders that cause proximal renal tubular acidosis are not preventable.