"Superscan" appearance in distal renal tubular acidosis.

Distal renal tubular acidosis (RTA) is known to cause metabolic bone abnormalities. For the first time to our knowledge, a case of distal RTA is reported in association with a superscan on bone scintigraphy. Reported cases of metabolic bone diseases producing a superscan appearance were reviewed, and underlying mechanisms are discussed. We speculate that impaired hydrogen ion secretion in this patient with distal RTA subclinically increased bone turnover, contributing to the superscan appearance on bone scintigraphy.