Renal Tubular Acidosis

Renal tubular acidosis (RTA) is a disease that occurs when the kidneys fail to remove the acids from the blood and excrete it through the urine, resulting in excess acid build-up in the blood. The acid, in the blood stream, is generated as a waste product of numerous chemical reactions that place in the body. RTA can cause stunted growth, kidney stones, chronic kidney disease, bone disease and even kidney failure. There are different types of RTA:

• Type 1 RTA or distal renal tubular acidosis. Distal means that the defect is at a distance from beginning of the tubules responsible for collecting fluids and waste from the blood to form urine. It is the most common type of RTA. Distal RTA can be inherited or caused by high blood calcium, sickle cell anaemia, autoimmune disorders (where the body’s immune system attacks its own organs), or use of certain medications

• Type 2 RTA or proximal renal tubular acidosis. Proximal means that the defect is near to the beginning of the tubule responsible for collecting fluids and waste from the blood to form urine. It is most prevalent in children as part of a disorder called Fanconi’s syndrome in which glucose, amino acids, uric acid, phosphate and bicarbonate are excreted with the urine instead of being reabsorbed. Other causes include vitamin D deficiency, fructose intolerance, use of certain medications or chronic rejection of transplanted kidney

• Type 3 is now thought to be a combination of type 1 and type 2 RTA and is rarely used as a classification

• Type 4 RTA or hyperkalemic renal tubular acidosis. This occurs due an abnormality in the transport of the distal tubule. Transport involves the movement of electrolytes such as sodium, chloride, and potassium between the blood and the body parts. This results in high levels of potassium in the blood (hyperkalemia). Hyperkalemia is can be dangerous for the heart as potassium is essential for regulating heart rate. Type 4 RTA can be caused by <urinary tract infection>, autoimmune disorders, sickle cell anaemia, rejection of kidney transplant, or the use of certain medications.

When to seek expert advise

It is most probable that RTA is discovered in your child during a urine or blood test carried out for another disease. Otherwise, if you notice a combination of urinary abnormalities and bone weaknesses/growth failure in your child, it is best to book a consultation with our highly skilled doctors at the Children's Hospital Service Line at The Aga Khan University Hospital the only internationally accredited hospital in Pakistan.

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