Complete Hypokalemic Quadriparesis as a First Presentation of Sjögren Syndrome

Abstract

Rationale:We hope to increase awareness that hypokalemic paralysis may be the first presentation of Sjögren syndrome, for which potassium-sparing diuretics can be an effective adjunct to potassium replenishment.Presenting concerns:A 73-year-old female presented to a peripheral hospital with quadriparesis and a critically low serum potassium of 1.6 mmol/L with U waves on the electrocardiogram (ECG). The initial arterial blood gas showed a pH of 7.19, bicarbonate of 13 mEq/L, and a CO2 of 35 mm Hg. Over the next 6 days, she was administered a total of 450 mEq of potassium supplements. Despite this, her potassium never increased above 2.9 mmol/L and was thus transferred to the University Hospital for further management. On arrival, her vital signs were within normal limits. Her only other symptoms were fatigue and ocular dryness. Physical exam showed slightly weakened quadriceps muscles bilaterally, graded 4/5. Examination was otherwise unremarkable. Admission investigations included a potassium of 2.8 mmol/L, chloride 118 mmol/L, sodium 136 mmol/L, and eGFR 48 mL/min/1.73 m2. Renin aldosterone ratio was normal.Diagnoses:Distal renal tubular acidosis (RTA) was diagnosed based on a normal anion gap metabolic acidosis, positive urine anion gap, and elevated urine potassium to creatinine ratio. Investigation of underlying causes revealed a positive Antinuclear antibody (ANA), elevated rheumatoid factor, and high anti-Ro/SSA titre which directed us toward a unifying diagnosis of Sjögren syndrome. A renal biopsy was undertaken as an outpatient and demonstrated severe interstitial nephritis with acute and chronic components, parenchymal scarring, atrophy, and small vessel arteriosclerosis.Interventions:In the acute setting, the patient was treated with bicarbonate and amiloride in addition to potassium supplementation.Outcomes:The patient’s hypokalemic paralysis and metabolic acidosis were corrected.Lessons Learned:Severe hypokalemic paralysis in distal RTA associated with Sjögren syndrome can be successfully treated with amiloride in addition to potassium supplementation. We also review the literature on the aberrancies seen in H+ATPase, Band 3, Pendrin, and carbonic anhydrase that may underlie the pathogenesis of distal RTA in Sjögren syndrome.

Multisystem presentation of primary Sjögren syndrome

“…In extreme cases, Sjögren-related potassium wasting may lead to hypokalemic paralysis. 8 Our patient, although not paralyzed, was very weak on admission to hospital and had trouble walking, which most likely led to her fall.…”

“…Amiloride and potassium citrate (which we used in our patient) have also been noted to be effective. 8 The neurologic manifestations of Sjögren syndrome are wide ranging. The peripheral nervous system may be affected in up to 25% of patients, 9 including sensory neuropathies of the limbs, cranial neuropathies and autonomic dysfunction.…”

Renal Tubular Acidosis Type I with Prominent Hypokalemia and Nephrolithiasis as a Presentation of Sjögren’s/Systemic Lupus Erythematosus Disease

“…Hypokalemic paralysis may precede sicca syndrome from 3 months to 4 years in the patient with final diagnosis of primary SS. Such cases have been initially diagnosed as RTA; some of these patients with hyperglobulinemia complained of dryness of the mouth and were later diagnosed as SS, while SS without hyperglobulinemia is rarely complicated by RTA [ 4 , 5 ]. In our patient, RTA appeared 5 years before the presentation of Sjögren's disease.…”

28-Year-Old Woman With Chronic Kidney Disease, Fatigue, and Polyarthralgias

“…Case reports have been published in which hypokalemia secondary to this distal RTA, in some cases so profound as to lead to paralysis, as the initial presentation for SS. 8 Other renal manifestations can include mild isolated electrolyte disturbances, nephrolithiasis, immunoglobulin A nephropathy, membranous nephropathy, focal segmental glomerulosclerosis, immune complexmediated membranoproliferative glomerulonephritis, and a few case reports of crescentic glomerulonephritis. 2 Biopsy specimens from cohorts of patients with TIN secondary to primary SS have shown that interstitial infiltrates are composed predominantly of CD4þ T cells.…”