Pediatric Sjogren syndrome with distal renal tubular acidosis and autoimmune hypothyroidism: an uncommon association

Abstract

A 14-year-old female came with the history of sudden onset weakness; during work up, she was found to have hyperchloremic metabolic acidosis with normal anion gap and normal renal function suggesting the possibility of renal tubular acidosis (RTA). On further evaluation of RTA, she had positive antinuclear antibody, anti-Ro, and anti-La antibodies. On nuclear scan of salivary glands, her left parotid gland was nonfunctional. Her parotid biopsy revealed dilated interlobular ducts engulfed by lymphoid cells. She also had autoimmune hypothyroidism as suggested by raised TSH and positive anti-TPO antibodies. At admission, her serum potassium levels were low and she was treated with intravenous potassium chloride. After she recovered from acute hypokalemic paralysis, she was started on oral potassium citrate along with phosphate supplements, hydroxychloroquine, oral prednisolone and thyroxine supplements. Over the next 6 months, she has significant reduction in the dosage of potassium, bicarbonate and phosphate and gained 3 kg of weight and 3.5 cm of height. As primary Sjogren syndrome itself is rare in pediatric population and its association with renal tubular acidosis is even rarer, we suggest considering Sjogren syndrome as a differential diagnosis during the RTA work-up is worth trying.

Hypokalemic Paralysis: A Hidden Card of Several Autoimmune Diseases

“… 25 Distal renal tubular acidosis is generated due to tubulitis and/or tubular atrophy, 26 leading to the complete loss of H+-ATPase pumps in the collecting ducts. Their presence is valued as a more severe compromise 27 and is valued within the ESSDAI (EULAR Sjögren’s syndrome disease activity index) score as low or moderate according to the presence of renal failure. 28 Early treatment with immunosuppressive drugs has been shown to maintain or improve renal function.…”

Distal Renal Tubular Acidosis in Sjögren's Syndrome: A Case Report

“…However, only 22% of patients have been reported to meet the AECG or American College of Rheumatology's (ACR) criteria for diagnosis as the required tests are not often performed in clinical practice [3]. Moreover, the current diagnostic criteria have been shown to have limited scope in juvenile cases, thereby posing a diagnostic challenge in adolescents who present heterogeneously and do not have classical sicca symptoms [6,7].…”

“…If the patient had undergone additional diagnostic studies, glucocorticoid therapy could have been initiated. However, while glucocorticoid therapy is the universal treatment modality for patients with Sjögren's-induced renal involvement, a review of the literature has demonstrated the recurrence of hypokalemia and acidosis with glucocorticoid tapering, especially in cases where early treatment was not started [6,1,16]. As curative treatments remain to be elucidated, monitoring for complications such as nephrocalcinosis, nephrolithiasis, and rickets/osteomalacia should also take place along with ongoing treatment of metabolic derangements and symptoms.…”

Distal renal tubular acidosis and severe hypokalemia: a case report and review of the literature

“…Progressively, it can lead to marked acid-base abnormalities, including hyperchloremic metabolic acidosis and severe hypokalemia, which can be fatal. In children, dRTA is usually associated with a genetic defect or anatomic abnormality of the urinary system [3]. In contrast, dRTA in adults is frequently related to acquired conditions such as infections, drugs, and autoimmune diseases.…”