Snakebite is a commonly encountered envenomation emergency in the rural areas of Hong Kong. The majority of cases do not warrant antivenom therapy. We looked into those receiving antivenom to enhance the understanding of the results of antivenom therapy. Methods: This was a retrospective review of the snakebite cases treated with antivenom in Tuen Mun Hospital from 1st January 2000 to 31st August 2005, focusing on both the therapeutic and side effects of the antivenom. Results: Twelve patients were identified. All had local symptoms of swelling or numbness. Two of them subsequently developed skin necrosis requiring operative treatment. Thrombocytopenia was less amenable to correction than prolonged INR. No early or late allergic reactions were observed. Conclusion: Because of the small number of cases, the apparent safety of the antivenoms in the current review warrants larger trials in future.

Methadone overdose is expected to result in intoxication simulating the other opioids. We report a case of hypoglycaemia following accidental methadone ingestion. A 21-year-old woman presented to a local accident and emergency department 10 hours after ingestion of 800 mg of methadone. She was found to have coma, respiratory suppression, hypotension, prolonged QTc and hypoglycaemia. The hypoglycaemia was reversed by dextrose replacement. The patient required intubation and inotropic support because of cardio-respiratory instability. She eventually recovered without consequence. To date, this is the first reported case of methadone overdose induced hypoglycaemia.

To identify and analyse the characteristics of carbon monoxide (CO) poisoning due to burning charcoal in our locality. Methods: This was a 3-year retrospective study. All patients presenting with CO poisoning by burning charcoal from August 1999 to December 2002 were recruited. The demographic data, initial vital signs, blood results, treatment regimens and outcomes were collected. Association between clinical outcomes and parameters were calculated. Results: The study identified 148 patients (mean age 34.7 years) suffering from CO poisoning by burning charcoal. One hundred and forty-six cases (98.6%) were suicidal. Twenty-five patients (16.9%) were unconscious (GCS ≤ 8) on arrival. The mean initial carboxyhaemoglobin (COHb) level was 21.0%. The mortality rate was 5.4%. Fifteen cases (10.1%) required intensive care. Twelve cases (8.1%) had neurological complications and five (3.4%) suffered from delayed neurological sequelae. Initial blood results showing hyperkalemia and acidosis were associated with likelihood of unconsciousness on arrival (p = 0.007, p = 0.019 respectively). Hyperkalemia and unconsciousness on arrival were associated with longer hospital stay (p < 0.001, p < 0.001 respectively) as well as likelihood of systemic complication (p < 0.001, p < 0.001 respectively). There was no relationship between co-ingestion, age, initial COHb level, initial systolic and diastolic blood pressure with consciousness level on arrival (p = 0.188, p = 0.846, p = 0.264, p = 0.224, p = 0.755 respectively). Age, initial COHb level, acidosis, initial systolic and diastolic blood pressure did not correlate with the duration of hospital stay (p = 0.679, p = 0.176, p = 0.501, p = 0.313, p = 0.868 respectively). Conclusion: Suicide almost accounted for all the CO poisonings by burning charcoal in our study group. It caused significant mortality and morbidity. Hyperkalemia, unconscious state and acidosis had prognostic values.

A man sustained conjunctivitis of the left eye after being spat by the venom of a Chinese cobra (Naja atra). He received fluid irrigation, topical antibiotic and topical steroid treatment. The conjunctivitis resolved without sequalae after 4 days. Various treatment options are discussed. (Hong Kong j.emerg.med. 2009;16:26-28) Keywords: Conjunctivitis, eye injuries, Naja atra, snakes, venom CaseIn August 2007, a 56-year-old man with chronic blurred vision of the left eye was spat by the venom of a Chinese cobra (Naja atra) into the left eye at a two feet distance while he was kneeling down to clean up objects outside his home. He experienced immediate pain but no subjective deterioration of the left eye vision. Irrigation with large quantity of water was performed at scene. He attended the emergency department 30 minutes post-injur y. Marked conjunctival injection was noted. Visual acuity was 20/20 on the right eye and 20/70 on the left eye. There was no photophobia, blepharospasm, iritis or pupil asymmetry. Fluorescent staining and slit-lamp examination did not reveal evidence of corneal or anterior chamber damage.Copious saline irrigation was commenced followed by instillation of topical antibiotic solution containing polymyxin, neomycin and gramicidin. At 10 hours post-injury, the pain steadily reduced to 20% of the initial level and the visual acuity was static. He was then discharged for ophthalmology assessment on the next day when 7 days of 0.1% fluorometholone eye drop was prescribed. He was completely pain free 2 days after the venom exposure. At 4 days postenvenomation, the conjunctival injection abated leaving no consequences. DiscussionThe venom of cobra is sprayed during defence as a stream from the forward facing apertures at the tips of the fangs as a result of the forceful contraction of the masseter muscles. Although many species of cobras are

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