Growth failure associated with medullary sponge kidney, due to incomplete renal tubular acidosis type 1.

A girl, 12 years of age, was referred for short stature. Clinical examination and laboratory investigations currently performed in a case of growth failure gave normal results. Renal echography revealed a hyper-echogenic renal medulla. An excretory urogram showed medullary sponge kidney with bilateral renal calculi. An ammonium chloride loading test revealed a defect in acid excretion and led to the diagnosis of incomplete renal tubular acidosis. Treatment with oral bicarbonate was associated with an increase in growth velocity.