Unmasking Sjögrens Syndrome: A Rare Presentation with Hypokalemic Quadriparesis and Distal Renal Tubular Acidosis

Sjögren's syndrome is an autoimmune disorder typically presenting as dry mouth and eyes (sicca syndrome). However, the disease can involve any organ, complicating diagnosis. Renal involvement may manifest as distal renal tubular acidosis, leading to hypokalemia. We report a case of a 28-year-old woman presenting with progressive quadriparesis. INTRODUCTION: Sjögren's syndrome is an autoimmune condition with clinical features of persistent dry mouth, parotid gland enlargement, or dental caries (known as “sicca” symptoms). Extra glandular symptoms like pancreatitis, renal tubular acidosis, and Raynaud's phenomenon may appear. Sjögren's syndrome is diagnosed using the European League Against Rheumatism (EULAR)/American College of Rheumatology criteria(1) without a specific therapeutic target beyond the relief of symptoms as the most important goal. In view of this scenario, the European League Against Rheumatism (EULAR. Taking into account ocular staining, autoimmune antibody testing, salivary gland inflammation on biopsy, and tear film salivary flow testing. The Antibodies linked to Sjögren's disease are those against Ro/SSA and La/SSB. CASE REPORT: A 28-year-old female presented with a 4-day history of fever, vomiting, and diarrhoea, followed by progressive weakness in all four limbs. She had been treated with IV methylprednisolone and acyclovir at a local hospital. Her medical and family histories were unremarkable. On admission to our ICU, she was conscious and oriented but tachypneic, requiring oxygen via a face mask. She was hemodynamically stable. Neurological examination revealed hypotonia and flaccid paralysis (MRC grade 0/5) in all four limbs, with preserved sensory function. Bilateral plantar reflexes were flexor. Other systemic examination findings were unremarkable. A non-contrast CT (NCCT) of the head performed was normal. CSF analysis showed a white cell count of 3 cells/µL, protein of 95 mg/dL, and glucose of 95 mg/dL. She required invasive mechanical ventilation due to progressive type 2 respiratory failure. Serial ABG analyses revealed non-anion gap metabolic acidosis with profound hypokalemia. The patient was treated with IV potassium, sodium bicarbonate and potassium citrate syrup. Her motor power and metabolic status gradually improved, and she was extubated after three days. Ophthalmology evaluation during her ICU stay was prompted by persistent dry eyes and an abnormal ocular appearance. Schirmer's test was positive (Figure 1) suggesting Sjögren's syndrome. Subsequently, Serological testing confirmed anti-La antibodies, establishing the diagnosis of primary Sjögren's syndrome. Her metabolic derangements were attributed to type 2 renal tubular acidosis (RTA) secondary to Sjögren's syndrome. DISCUSSION: Primary Sjögren's syndrome (PSS) has a high disease burden but unfortunately remains underdiagnosed. Sjogren's syndrome can present with extra glandular manifestations in 20%–60% of patients with the disease(2,3). We evaluated the patient's severe hypokalemia step-by-step which allowed us to diagnose distal RTA(4). PSS was diagnosed after RTA and additional investigation revealed a positive anti-SSA antibody. The pathogenesis of SS is not yet fully understood. Autoimmune activation of T and B lymphocytes is the most widely accepted explanation. Antibodies that have been found in patients with SS include SS-A (Ro), SS-B (La), rheumatoid factor, and ANAs. These, however, are not specific to the disease. CONCLUSION: Sjögren's syndrome with type 2 RTA should be considered in patients presenting with unexplained weakness and metabolic acidosis. Prompt diagnosis and correction of electrolyte abnormalities can result in significant clinical improvement.