Critical Hyponatraemia with Acute Heart Failure: Diagnostic Puzzles of Guillain-Barré Syndrome—A Case Report

Guillain-Barré syndrome (GBS) is an eminent cause of acute flaccid neuromuscular paralysis triggered by post-infection aberrant immune response. Establishment of GBS diagnosis is challenging by virtue of its diverse neurological manifestations and imitation of major cardiac or electrolyte disorders. A 49-year-old lady presented with the chief complaint of vertigo for 3 days associated with bilateral distal extremities numbness and vomiting. Initial clinical assessment attributed the neurological symptoms to the critical hyponatraemia. Despite intravenous normal saline and hypertonic saline infusion, the critical hyponatraemia perpetuated and it was complicated with new onset dyspnoea. At day 2 of presentation, she was intubated due to respiratory distress and her arterial blood gas showed type 2 respiratory failure. Further, the serum pro-brain natriuretic peptide level was in keeping with acute heart failure which corroborated with the point of care ultrasound findings. The aetiology remained obscured until admission to intensive care unit which demonstrated the presence of areflexic quadriparesis and type 2 respiratory failure recurrence. Finally, the diagnosis of GBS was established via multidisciplinary collaboration and IV immunoglobulin (IVIG) 400 mg/kg/day for 5 days was administered. Post-GBS stabilisation, a follow-up echocardiogram showed normalization of cardiac function without the need of further diuretic therapy. Overall, this vignette exemplifies a rare manifestation of GBS with concurrent critical hyponatraemia and acute heart failure which were reversible with IVIG and intensive care. Further insights from this case highlight the clinical imperative of familiarisation with GBS atypical manifestations which are important from both diagnostic and therapeutic perspectives.