What is distal renal tubular acidosis (dRTA)?

Distal renal tubular acidosis is a rare kidney disorder that occurs when the kidneys are unable to effectively remove the buildup of circulating acids in the blood—a condition called acidosis—which leads to a metabolic imbalance. dRTA is a serious disorder, especially for pediatric patients.

dRTA can be either genetically inherited or acquired. The inherited form of dRTA, also known as primary dRTA, is most common among infants and children, while the acquired form is more common in adults. Acquired dRTA can be due to autoimmune disorders, rheumatoid arthritis, or to certain medications.

An estimated 30,000 patients in Europe and 20,000 patients in the United States suffer from dRTA, which was first described in the 1930s.

What are the signs and symptoms of dRTA?

Severe manifestations of dRTA occur primarily in pediatric patients, especially infants. Early signs and symptoms in babies include nausea and vomiting, dehydration, extreme tiredness, feeding issues and problems with weight gain. Children can also develop rickets, and often experience impairment of growth.

Mineral imbalances caused by dRTA can lead to kidney stones and hypokalemia, or decreased levels of potassium in the blood. Hypokalemia can cause severe muscle weakness, shortness of breath and abnormal heart rhythm.

dRTA can also cause digestive disorders, such as anorexia, vomiting, diarrhea, and constipation, and can also lead to hearing loss.

How is dRTA treated?

Currently, the main treatment for dRTA involves alkali agents, which are used to neutralize excess acid in the blood. Pediatric patients are generally treated with higher doses because their bicarbonate needs are greater than adults. Potassium supplementation is required for patients with hypokalemia.

These products usually require multiple doses per day, are poorly tolerated and unpalatable to patients. Meeting the objective of maintaining therapeutic effect over 24 hours is challenging with these products due to, the need for overnight doses. Compliance with the required dosing regimen is low in pediatric patients, due to their increased sleep needs. As a result, patients may experience poor control of homeostasis over 24 hours, which is vital to preventing long-term complications. Side effects of these treatments can also include abdominal pain.