UNUSUAL CAUSE OF ENCEPHALOPATHY IN AN INFANT - ORGANOPHOSPHATE POISONING

Abstract

A 45-day-old infant was brought to an emergency room in Chennai (Tamil Nadu, India) with history of irritablity, poor feeding and loose stools for two days duration. There was no history of fever. On examination baby had tachycardia with a heart rate of 190/min, respiratory rate of 67/min, with increased work of breathing, afebrile and glasgow coma scale (GCS) was 6. Infant had bilateral constricted pupils, and was hypotonic. Baby was noted to have non convulsive status epilepticus and was controlled with 2 doses of inj lorazepam and loading dose of inj phenobarbitone and was intubated in view of poor GCS. Initial blood sugars were 250 mg/dl, urine was negative for ketone, and blood gases were suggestive of respiratory alkalosis. Electrolytes, urea, creatinine, complete blood counts, SGOT, SGPT, lactate and ammonia were within normal limits. CT brain was normal. Lumbar puncture revealed a normal CSF. At 6 h of admission infant was found to have dehydration, with excessive tracheal and oral secretions. Pupils were pin point at this examination, infant had persistent tachycardia. Urine output was 2 ml kg-1 h-1. In view of persistent encephalopathy without fever, profuse secretions and sweaty moist skin with dehydration possiblity of OPC poisoning was thought of and samples were sent for serum pseudocholinesterase levels. A trial of atropine (0.05 mg/kg) was given and the heart rate further increased to 260/minute after two doses. ECG revealed sinus tachycardia. Infant received Pralidoxime infusion (25 g kg-1 dose-1 for two doses). On day 2 of admission infant had no excessive secretions, heart rate was within normal limits and GCS improved to 12. Infant was weaned off the ventilatory support and on day 4 pupils increased in size and was normal at discharge on day 6 of hospitalization. Initial plasma pseudocholinesterase levels were very low 825 micro /l (normal 6000-8000 micro /l). Repeat pseudocholinesterase levels on day 6 of illness had increased to 3400 U/l. Retrospective history did not reveal the exact source of poisoning, however the mother gave a history that the infant enroute to the clinician visit on the first day of illness was through a paddy field where recent insecticide spraying activity was undertaken.