Abstract
Renal function was studied in a 7-year-old girl with Rett syndrome (RS) complicated by persistent hyperchloremic hyperkalemic metabolic acidosis. The acidosis was associated with a urine pH above 5.5, positive urinary anion gap and decreased potassium excretion. Plasma renin activity, aldosterone and cortisol levels were normal. Therapy with sodium bicarbonate failed to lower urine pH below 5.5 or increase potassium excretion. Hydrochlorothiazide administration resulted in a fall in urine pH below 5.5 and an increase in potassium excretion as a result of increased distal sodium delivery and increased sodium reabsorption in the distal nephron. We conclude that a voltage-dependent type of derangement in the distal nephron, rather than aldosterone deficiency, is responsible for the impairment in urinary acidification observed in this patient. Early detection of impaired renal acidification in RS may prevent or slow the progression of growth failure.
This is a preview of subscription content, log in via an institution to check access.
References
Hagberg B, Hanefeld F, Percy A, Skjeldal O (2002) An update on clinically applicable diagnostic criteria in Rett syndrome. Eur J Paediatr Neurol 6:293–297
Armstrong DD (1997) Review of Rett syndrome. J Neuropathol Exp Neurol 56:843–849
Amir RE, Van den Veyver IB, Wan M, Tran CO, Franke U, Zoghbi HY (1999) Rett syndrome is caused by mutations in X-linked MECP2, encoding methyl-CpG-binding protein 2. Nat Genet 23:185–188
Schutz R, Glaze DG, Motil KJ, Armstrong DD (1993) The pattern of growth failure in Rett syndrome. Am J Dis Child 147:633–637
Batlle DC, Hizon M, Cohen E, Gutterman C, Gupta R (1988) The use of the urinary anion gap in the diagnosis of hyperchloremic metabolic acidosis. N Engl J Med 318:594–599
Levine DZ, Jacobson HR (1986) The regulation of renal acid excretion: New observations from studies of distal nephron segments. Kidney Int 29:1099–1109
Battle DC, Aruda JAL, Kurtzman NA (1981) Hyperkalemic distal tubular acidosis associated with obstructive uropathy. N Engl J Med 304:373–380
Assadi FK, Ziai M (1985) Impaired renal acidification in infants with fetal alcohol syndrome. Pediatr Res 19:850–853
Stokes JB (1982) Ion transport by the cortical and outer medullary collecting tubule. Kidney Int 22:473–484
Batlle DC, Istarayovngyuen K, Arruda JAL, Kurtzman NA (1982) Hyperkalemic hyperchloremic metabolic acidosis in sickle cell hemoglobinopathies. Am J Med 72:188–192
DeFraonzo RA (1980) Hyperkalemia in hyporeninemic hypoaldosteronism. Kidney Int 17:118
DuBose TD Jr, Good DW (1988) Effect of diuretics on renal acid–base transport. Semin Nephrol 8:282–294
Kurtzman NA (1990) Disorders of distal acidification. Kidney Int 38:720–727
Steinbaugh BJ, Schloeder FX, Tam SC, Goldstein MB, Halperin ML (1981) Pathogenesis of distal renal tubular acidosis. Kidney Int 19:1–7
Author information
Authors and Affiliations
Corresponding author
Rights and permissions
About this article
Cite this article
Assadi, F., Crowe, C. & Rouhi, O. Hyperkalemic distal renal tubular acidosis associated with Rett syndrome. Pediatr Nephrol 21, 588–590 (2006). https://doi.org/10.1007/s00467-006-0029-2
Received:
Revised:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s00467-006-0029-2