Primary Sjӧgren’s Syndrome Unveiling Type 1 Renal Tubular Acidosis: A Rare Case Report of Hypokalemic Periodic Paralysis from a Developing Country

Abstract

Primary Sjogren syndrome is a systemic autoimmune disorder commonly presenting with dryness involving the eyes and mouth due to inflammation and resultant pathology of the lacrimal and salivary glands. Sjogren syndrome is managed by replacing moisture at affected glandular sites and diminishing the autoimmune response locally as well as systemically. This case illustrates the life threatening consequences, such as hypokalemic periodic paralysis in a 56 year old woman in whom the discovery of type 1 distal Renal Tubular Acidosis (RTA) led to the diagnosis of primary Sjӧgren’s syndrome (SS) and its further management. HPP is a rare disorder caused by skeletal muscle ion channel mutations, mainly affecting calcium or sodium channels. HPP causes include genetic mutations, familial vs acquired cause due to hyperthyroidism, and certain triggers include strenuous exercise, high carbohydrate meal, stress, cold temperature, etc. She experienced bilateral lower limb weakness, along with progressive upper limb and neck muscle weakness over a week. Laboratory tests (alkaline urine pH and bicarbonate drop) and arterial blood gas (ABG) indicating RTA with hypokalemia raised clinical suspicion of Sjӧgren’s syndrome. Further investigations revealed a positive Schirmer’s test and Immunologic workup showed a strongly positive ANA, with positive antibodies to SSA and SSB thereby confirming primary Sjӧgren’ssyndrome. The case underscores the idea that acute hypokalemia from unrecognised renal tubular acidosis (RTA) may unmask Sjӧgren’s syndrome in patients with sicca complaints and other renal involvements.