Delayed Neurotoxic Envenomation Following Yellow Cobra Bite Leading to Acute Respiratory Failure: A Case Report

Abstract

Introduction: Neurotoxic envenomation by Naja sumatrana (yellow cobra) represents a life-threatening medical emergency in Southeast Asia. Delayed hospital presentation significantly aggravates the clinical course and may culminate in acute respiratory failure requiring intensive care. We report a case of severe cobra envenomation with an 8-hour pre-hospital delay leading to progressive neurotoxicity and acute respiratory failure mandating mechanical ventilation.

Case Illustration: A 21-year-old male agricultural worker presented to Rumah Sakit AR. Bunda Lubuklinggau, South Sumatera, 8 hours after sustaining a yellow cobra bite to the right cruris while tapping rubber in a plantation. On arrival, the patient was somnolent with a deteriorating Glasgow Coma Scale (GCS) of E3M6V4, tachycardia (HR 104 bpm), tachypnoea (RR 23 breaths/min), and SpO2 98% on supplemental oxygen. Local examination revealed puncture marks, pain, and oedema at the bite site. Laboratory investigation disclosed leukocytosis (16,200/μL), elevated erythrocyte sedimentation rate (ESR; 21 mm/hour), and eosinophilia (7%). The patient was classified as snakebite Grade III with impending respiratory failure. Despite initial anti-snake venom (ASV) administration of 2 vials, neurological deterioration progressed requiring emergency orotracheal intubation and admission to the Intensive Care Unit (ICU). A total cumulative ASV dose of 20 vials was administered over 24 hours per anesthesiologist protocol, in addition to broad-spectrum antibiotic therapy (meropenem 3×1 g), ketorolac, and central venous catheterisation. The patient achieved satisfactory clinical improvement and was successfully weaned from mechanical ventilation.

Discussion: This case highlights the critical impact of delayed medical presentation on the severity of neurotoxic cobra envenomation. Alpha-neurotoxins of Naja sumatrana competitively and reversibly block post-synaptic nicotinic acetylcholine receptors, producing descending flaccid paralysis that may progress to acute respiratory failure if not promptly treated. Delayed antivenom administration, compounded by initial subtherapeutic dosing due to limited vial availability, resulted in progressive envenomation requiring mechanical ventilation and high-dose repeated ASV therapy. This case underscores the importance of early recognition, rapid referral, adequate antivenom supply, and multidisciplinary ICU management in rural healthcare settings.

Conclusion: Delayed hospital presentation following neurotoxic cobra bite is associated with life-threatening respiratory failure. Early identification of neurotoxic signs, prompt emergency referral, aggressive antivenom administration, and airway protection are paramount to favourable outcomes. Rural healthcare facilities must maintain adequate ASV stockpiles and capacity for emergency intubation.