To best understand how to treat distal renal tubular acidosis (dRTA), it is important to understand what dRTA is. Primary dRTA is caused by a change in one of several genes and is inherited. Secondary dRTA is caused by another disease or medication.
The kidneys have many important jobs. One of them is to maintain a balance between acid and base (opposite of acid) by removing and filtering acids from the blood and through the urine. dRTA happens when the kidneys can’t effectively remove the buildup of circulating acids in the blood. The buildup of acids in the blood causes an imbalance known as “acidosis” or “metabolic acidosis”. Metabolic acidosis can lead to serious health problems and requires prompt medical attention. dRTA can also cause kidney stones, brittle bones, hearing loss, gastrointestinal problems, and other medical problems. Not all people living with dRTA will experience the same health problems.
The main treatment goals are to restore and maintain normal acid-base balance, while trying to help reduce and/or prevent problems with the heart, bones and kidneys.
The main treatment for dRTA involves alkali agents, which are used to reduce acid buildup in the blood. Alkali agents can include sodium bicarbonate, potassium bicarbonate, sodium citrate or potassium citrate.
Sodium bicarbonate plays an important role in the treatment of primary dRTA by helping to lower the acidity (pH) of the blood. As with any medication, you should not take sodium bicarbonate or other medications unless your healthcare provider recommends it. Sodium citrate can be used if sodium bicarbonate is not effective or not well tolerated.
Potassium bicarbonate or potassium citrate can be used when potassium levels in the blood are low (hypokalemia), or in some people with high blood and urine levels of calcium (hypercalciuria) or calcium kidney stones. Citrate is converted to bicarbonate in the body and helps to correct the acid buildup in the blood. In addition, citrate helps to prevent calcium deposits in the kidney. Sodium (found in sodium bicarbonate, sodium citrate or other sodium salts) can increase calcium levels in the blood and urine.
Reducing acid levels by alkali agents can also help correct imbalances of other electrolytes, such as potassium and phosphorus. Correcting these imbalances, may help reduce the risk of bone disease and help prevent kidney stones. However, not all patients respond the same way to these treatments. How well a treatment works can depend on different factors, such as a person’s age, stage of disease, overall health and if there are other diseases present. It also depends on how well someone stays with their treatment plan and takes their medication as prescribed.
These treatments might also have side effects. For example, sodium bicarbonate might be difficult on your stomach causing gastrointestinal upset. Also, the right balance of acid, potassium, phosphorus, and calcium is important to maintain health. For example, potassium levels that are too high (hyperkalemia) or blood acid levels that are too low (alkalosis) can be problematic and should be avoided. Your healthcare team will work with you and test periodically to make sure you are getting the right treatments.
You should speak to a doctor, pharmacist, or other member of your healthcare team if you have questions about your treatment. You can also let them know about any side effects. Any decision to change your treatment should be discussed with your healthcare team.
Treatment of conditions related to dRTA
Primary dRTA can have a genetic origin (inherited) and secondary dRTA can have an acquired origin from an autoimmune disorder or by certain medications you may be taking. Treatment of secondary dRTA can involve addressing the underlying autoimmune disease like Sjögren's syndrome and systemic lupus erythematosus (SLE). Secondary dRTA can also be caused by certain medications, such as amphotericin B (an antifungal), lithium (a psychiatric medication), and certain antibiotics (pentamidine). Nonsteroidal anti-inflammatory drugs (NSAIDs), including ibuprofen and naproxen, rarely cause dRTA but their overuse can be harmful to the kidneys. These medications should be avoided by people with dRTA, if possible. It is important to speak with a healthcare professional before taking any new medications and to review what medicines you are taking, including over-the-counter medications and herbal supplements.
Reducing acid levels with the use of alkali agents can also help manage some of the problems caused by dRTA, such as bone disease or kidney stones. Vitamin D and oral calcium supplements can be used to treat bone disorders, such as rickets (bowing of bones) in children or osteomalacia (softening of bones) in adults. In addition to medications and supplements, practicing a healthy lifestyle should be part of an overall treatment plan. Regular exercise and healthy diet can be important parts of managing dRTA.
If you have high acid levels (acidosis), you may also be asked to reduce or avoid consumption of too much animal protein, grains or other 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 alkaline (opposite of acid).
If you have a kidney stone, then you may be asked to increase your daily intake of water. You healthcare team may also try to let the stone pass without surgery. However, the stone may need to be removed with surgery if the stone is too large, blocks the flow of urine, or if there is a sign of infection. You may also be asked to take steps to help prevent future kidney stones, such as continuing to drink 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. This can address both the acid levels in your blood (acidosis) and kidney stones. Eating less salt (sodium) might also be needed, since sodium can increase calcium levels in the blood and urine.
Certain forms of inherited primary dRTA can cause hearing loss. While treatments aimed at preventing acidosis can help manage rickets, growth delays and calcium deposits in the kidney, treatment does not prevent or improve hearing loss.
If you have been diagnosed with chronic kidney disease, then it is important to manage related conditions, such as high blood pressure and diabetes. These conditions are not only linked to heart disease, but also kidney disease. A healthy lifestyle and kidney-friendly diet can help.
You should speak with a dietitian or other healthcare professional about your diet and nutritional needs based on your medical situation.
Clinical trials for new drugs
Research into dRTA has helped gain insight into the disease and how it can be treated. There are some promising treatments for acidosis and dRTA being tested in patients in clinical trials. If you are interested in participating in a clinical trial, or determine if a clinical trial is right for you, discuss the possibilities with your family and your healthcare team. For more information on if a clinical trial is right for you, visit www.clinicaltrials.gov.
It is important to realize over time, until an effective treatment or cure is found, some patients with dRTA, but not all, will advance to chronic kidney disease, and some of these people can slowly get worse until they reach kidney failure. If this happens, people will need a kidney transplant or dialysis.
Remember, dRTA can have a long-term impact so it is important for people living with the disease to keep up with their medical appointments, take their daily medications as prescribed, and stay with the treatment plan as recommended by their healthcare team. Like with other rare disorders, having a support system in place is also important to your overall well-being.