What is dRTA?
Distal renal tubular acidosis is a rare and serious kidney disorder. Renal refers to the kidney, distal tubular refers to a specific portion of the kidney and acidosis means there is too much acid build up in the blood.
The job of the kidneys is to maintain a balance of acid and base (opposite of acid) in the body. dRTA happens when the kidneys are unable to maintain a balance between acid and base, leading to a buildup of circulating acids in the blood. This buildup of acids in the blood is known as metabolic acidosis.
Metabolic acidosis is a serious health problem and requires prompt medical attention, especially in infants. dRTA can lead to other health problems such as bone disease, muscle aches and pains, fatigue, gastrointestinal problems, kidney stones, and possibly hearing loss and kidney failure. Not all people living with dRTA will experience the same health problems.
Distal renal tubular acidosis can be inherited (primary dRTA) or be caused by another disorder or medication (secondary (acquired) dRTA). Primary dRTA can be seen as early as infancy and childhood and can cause growth to be impaired. Secondary dRTA can happen at any age, but usually happens later in life.
What are the symptoms of dRTA?
Symptoms can include the following:
- Confusion or decreased alertness
- Muscle weakness
- Breathing difficulties
- Increased heart rate or irregular heartbeat
- Muscle cramps and pain
- Severe pain in the back, sides or abdomen (known as flank pain) as this may indicate a kidney stone
- Bone pain
- Less urine output
- Difficulty hearing
- Hearing loss and deafness in some individuals
How is dRTA diagnosed?
Tests to diagnose dRTA can include a physical exam looking for signs and symptoms of the disease. If primary dRTA runs in the family, then a review of family history can help identify at-risk family members. Genetic testing may be offered to help confirm the diagnosis.
You may also be checked for other diseases that can cause secondary dRTA, such as Sjögren's syndrome or systemic lupus erythematosus (SLE). Your medications will be reviewed for drugs that can possibly cause secondary dRTA. This list should include all prescription medications, over-the-counter medications and herbal supplements you are taking.
Blood tests will be used to measure the acid levels in the blood, electrolytes, such as sodium, potassium and chloride. Urine tests will also be measure for electrolytes, acid levels and other factors to help check for possible signs of illness, or to help rule out other causes.
Occasionally, a challenge test is needed to make the diagnosis of dRTA. A patient is given an acid load test using ammonium chloride. The urine is then tested to see if the acid is excreted as it should be.
How is dRTA treated?
The main treatment for primary dRTA involves alkali agents, which are used to reduce excess acid in the blood. Alkali agents can include sodium bicarbonate, potassium bicarbonate, sodium citrate or potassium citrate. It is important to take your medications as prescribed by a healthcare professional.
If you have high acid levels (acidosis), you may also be asked to reduce or avoid foods that can increase acid levels. Generally, foods such as meat, eggs, cheese and grains can lead to more acids being produced in the body, compared to fruits and vegetables which can be more base or alkaline (opposite of acid).
You may also be asked to take steps to help prevent the formation of kidney stones by drinking enough water. Higher acid can increase the risk of kidney stones, so you may be asked to avoid consuming foods that can increase acid production in the body.