Q) When does one suspect RTA and how is it diagnosed?
A) It is suspected whenever an infant or a child fails to put on weight or loses weight due to no apparent cause, becomes dehydrated, has excessive urine output (polyuria), excessive thirst, weakness, poor appetite, vomiting, constipation and muscle weakness which may be severe enough to cause paralysis of respiratory muscles due to low serum potassium levels (hypokalemia). Breathlessness with air hunger type of breathing due to acidosis may be seen in severe cases. Rickets and bony deformities occur late in the disease. In clinically suspected cases, arterial blood gas estimation will reveal low serum HCO3/TCO2 level with low blood pH and normal anion gap. Urinary pH may be inappropriately high (>5.5) for the level of acidosis in distal RTA.

Q) What is the treatment for RTA?
A) Treatment of RTA is oral alkali therapy to correct acidosis and keep serum bicarbonate levels within the normal range continuously. If serum potassium is reduced, oral potassium supplements are required. Rarely, in severe cases intravenous potassium infusion is used to correct hypokalemia before starting alkali therapy.

Q) Will the treatment cure the skeletal deformities? If not, why is treatment required?
A) Treatment of RTA with alkali therapy does not correct the skeletal deformities but if started below the age of one –one and half years can prevent skeletal deformities.

Q) What are the complications of RTA?
A) Complications of RTA can be life threatening like hypokalemia or uncontrolled acidosis with dehydration and shock. Hypercalciuria with nephrocalcinosis in distal RTA can lead to chronic tubulointerstitial damage and CRF(Chronic renal failure).

Q) How are the skeletal deformities that have already occurred treated?
A) Skeletal deformities due to RTA occur because the calcium from the bones is mobilized to buffer excess of H+ ion and bones become demineralised, deformed, bowed and can sustain fractures. These deformities can be corrected by surgery after sustained correction of acidosis.

Q) Is it necessary to keep the acid level in the blood absolutely under control?
A) It is important to keep the acid level in the blood absolutely under control i.e. Serum NaHCO3 levels between 20-22 meq/L in infants and between 22-26 meq/L in children using Shohl’s solution (sodium citrate + citric acid + water) or oral soda bicarbonate.

Q) My son refuses to take Shohl’s solution. Can I give him soda-mint tablet instead?
A) Since Shohl’s solution contains Citric acid, it is sour and many children may refuse to take it. One can use oral Tablet soda-mint (325 mg= 3.4 meq of alkali) in equivalent doses.

Last updated on 14-03-2001