Diversity of initial manifestations in renal tubular acidosis

Chang, Hye Ryun; Lee, Jay Wook; Heo, Nam Ju; Park, Jung Hwan; Park, Dong Jun; Seong, Eun Young; Joo, Kwon Wook; Kim, Yeon Su; Ahn, Cu Rie; Han, Jin Suk; Kim, Suhng Gwon; Lee, Jung Sang

Abstract

BACKGROUND: Diagnosis of RTA (renal tubular acidosis) is not easy due to its nonspecific and various manifestations. To find out the clues to diagnosis, we investigated initial manifestations, laboratory features and clinical course of RTA patients.
METHODS
Thirty-seven patients with RTA type I or II, whose follow-up period was over 6 months were included in the study. We reviewed their medical records retrospectively.
RESULTS
Male to female ratio was 5:32 and the average age at the time of diagnosis was 38.7 (15~60). Twenty-five patients had RTA type I, nine had type II, and three had both. The average follow-up period was 6.4 years. Initial manifestations were asthenia (54%), nausea (46%), urinary stone (24%), paresthesia (24%), lower extremity weakness (22%), and paralysis (11%). Underlying diseases at the time of diagnosis include Sjogren's syndrome (14%), SLE (8%), drug-induced nephropathy (11%), diabetic nephropathy (5.4%), Sjogren's syndrome combined with SLE (2.7%), and medullary sponge kidney (2.7%). Laboratory tests revealed acidosis with hypokalemia (59%), acidosis without hypokalemia (14%), and hypokalemia without acidosis (24%). The level of total CO2 was 22 mmol/L or lower in 27 patients. The Na:Cl ratio on the average was 1:1.26 and for 33 patients below 1:1.35. Renal function deteriorated in 8 patients and 7 of them had underlying diseases. Urinary stone developed in 2 patients with RTA type I.
CONCLUSION
When patients with nonspecific symptoms show decreased levels of serum total CO2, potassium, or Na:Cl ratio, RTA should always be considered.