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

  • PDF / 534,912 Bytes
  • 7 Pages / 595.276 x 790.866 pts Page_size
  • 47 Downloads / 188 Views

DOWNLOAD

REPORT


Rheumatology International https://doi.org/10.1007/s00296-020-04546-z

INTERNATIONAL

CASE BASED REVIEW

Hyperkalemia in type 4 renal tubular acidosis associated with systemic lupus erythematosus Döndü Üsküdar Cansu1   · Güven Barış Cansu2   · Sultan Güvenir3   · Cengiz Korkmaz4  Received: 3 November 2019 / Accepted: 29 February 2020 © Springer-Verlag GmbH Germany, part of Springer Nature 2020

Abstract 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 H ­ CO3 and fludrocortisone were initiated. Potassium (K) and H ­ CO3 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. Keywords  Systemic lupus erythematosus · Renal tubular acidosis · Hyperkalemia

Introduction Renal tubular acidosis (RTA) is a normal anion gap metabolic acidosis that appears as a result of decreased bicarbonate reabsorption in or impaired hydrogen excretion from * Döndü Üsküdar Cansu [email protected] Güven Barış Cansu [email protected] Sultan Güvenir [email protected] Cengiz Korkmaz [email protected] 1



Department of Rheumatology, School of Medicine, Eskişehir Osmangazi University Eskisehir, 26480 Eskişehir, Turkey

2



Department of Endocrinology, Kütahya Health Science University, Kütahya, Turkey

3

Division of Nephrology, Department of Internal Medicine, Eskişehir Osmangazi University, Eskişehir, Turkey

4

Division of Rheumatology, Department of Internal Medicine, Eskişehir Osmangazi University, Eskişehir, Turkey



kidneys. RTA is classified into three main groups including proximal RTA (type 2 RTA), hypokalemic distal RTA (type 1 RTA), and hyperkalemic distal RTA (type 4 RTA). Type 1 and type 2 present with hypokalemia in contrast to type 4, which is characterized by hyperkalemia due to deficiency of or resistance to aldosterone [1]. Some of the causes of hypokalemic RTA include tubu