Renal Tubular Acidosis Presenting with Muscle Weakness.

Muscle weakness is a common neurological symptom but is rarely due to hypokalaemia consequent on renal disease, as in the patients reported here. Two types of acidosis occur in renal disease. The more common and unfortunately incurable is that complicating chronic renal failure. Less common, but since it is treatable, more important, is renal tubular acidosis. That described by Lightwood (1935) presents during infancy, while the second is diagnosed only during adult life because of its complications (Albright, Burnett, Parson, Reifenstein, and Roos, 1946). Smith (1960), reviewing the clinical signs of the disorder in 28 adults, of whom 70% were females, found that 50% had osteomalacia, 7000 renal calculi, 75% nephrocalcinosis, while 45% showed evidence of hypokalaemia. The same year, Owen and Verner (1960) were able to describe nine patients with renal tubular acidosis who presented with muscle weakness due to hypokalaemia. They could find only 13 other examples described previously in the literature, but emphasized nevertheless the importance of making the diagnosis and instituting appropriate therapy as soon as possible. We have had the opportunity to observe two women in whom severe muscle weakness consequent upon hypokalaemia was the presenting feature of renal tubular acidosis. Both patients responded completely to a simple alkali mixture.