Hyperkalemia in type 4 renal tubular acidosis associated with systemic lupus erythematosus

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Üsküdar Cansu D., Cansu G. B., Guvenir S., Korkmaz C.

RHEUMATOLOGY INTERNATIONAL, vol.40, no.11, pp.1895-1901, 2020 (SCI-Expanded) identifier identifier identifier

  • Publication Type: Article / Review
  • Volume: 40 Issue: 11
  • Publication Date: 2020
  • Doi Number: 10.1007/s00296-020-04546-z
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus, Academic Search Premier, BIOSIS, CAB Abstracts, EMBASE, MEDLINE, Veterinary Science Database
  • Page Numbers: pp.1895-1901
  • Keywords: Systemic lupus erythematosus, Renal tubular acidosis, Hyperkalemia
  • Eskisehir Osmangazi University Affiliated: Yes


Renal tubular acidosis (RTA) is a normal anion gap metabolic acidosis that manifests with insufficiency of hydrogen ion excretion or bicarbonate (HCO3) reuptake as a result of renal tubular dysfunction independent of glomerular filtration rate. Hypokalemic RTA subtypes co-existing with autoimmune diseases particularly appear in Sjogren's syndrome, but rarely in systemic lupus erythematosus (SLE). Type 4 RTA associated with hyperkalemia is very rare during the course of SLE and hence has been scarcely reported in the literature. Here, we report a 42-year-old patient for whom regular follow-up was ongoing due to class IV lupus nephritis when she developed hyperkalemia. The patient had normal anion gap hyperkalemic metabolic acidosis and her urine pH was 5.5. Type 4 RTA was considered and, therefore, tests for renin and aldosterone levels were requested, which revealed that renin was suppressed and aldosterone was decreased. Upon diagnosis of SLE-associated type 4 RTA, short-term oral HCO(3)and fludrocortisone were initiated. Potassium (K) and HCO(3)levels improved at day 15 of therapy. In this review, we analyzed our case along with five other reports (a total of seven cases) of SLE-associated type 4 RTA we identified through a literature search. We wanted to highlight RTA for differential diagnosis of hyperkalemia emerging during SLE/lupus nephritis and we also discussed possible underlying mechanisms.