Snakebite in Australia: a practical approach to diagnosis and treatment.

Snakebite is a potential medical emergency and must receive high-priority assessment and treatment, even in patients who initially appear well. Patients should be treated in hospitals with onsite laboratory facilities, appropriate antivenom stocks and a clinician capable of treating complications such as anaphylaxis. All patients with suspected snakebite should be admitted to a suitable clinical unit, such as an emergency short-stay unit, for at least 12 hours after the bite. Serial blood testing (activated partial thromboplastin time, international normalised ratio and creatine kinase level) and neurological examinations should be done for all patients. Most snakebites will not result in significant envenoming and do not require antivenom. Antivenom should be administered as soon as there is evidence of envenoming. Evidence of systemic envenoming includes venom-induced consumption coagulopathy, sudden collapse, myotoxicity, neurotoxicity, thrombotic microangiopathy and renal impairment. Venomous snake groups each cause a characteristic clinical syndrome, which can be used in combination with local geographical distribution information to determine the probable snake involved and appropriate antivenom to use. The Snake Venom Detection Kit may assist in regions where the range of possible snakes is too broad to allow the use of monovalent antivenoms. When the snake identification remains unclear, two monovalent antivenoms (eg, brown snake and tiger snake antivenom) that cover possible snakes, or a polyvalent antivenom, can be used. One vial of the relevant antivenom is sufficient to bind all circulating venom. However, recovery may be delayed as many clinical and laboratory effects of venom are not immediately reversible. For expert advice on envenoming, contact the National Poisons Information Centre on 13 11 26.

Correlation of paired toxic plasma and saliva paracetamol concentrations following deliberate self-poisoning with paracetamol.

WHAT IS ALREADY KNOWN ABOUT THIS SUBJECT: • Paracetamol is commonly used in deliberate self poisoning (DSP) and this requires blood sampling to refine risk assessment. If saliva concentrations agreed with plasma concentrations, then this could support the development of non-invasive testing. Our pilot work supports this hypothesis, but was largely confined to nontoxic concentrations. WHAT THIS STUDY ADDS: • We found agreement between the indications for treatment of paracetamol DSP based on plasma and saliva paracetamol concentrations. Saliva may hold promise as a non-invasive method to risk stratify paracetamol poisoning. AIMS: Paracetamol is commonly used in deliberate self poisoning (DSP) and requires blood sampling to refine risk assessment. We aimed to test the agreement between plasma and saliva paracetamol concentrations in the toxic range in DSP. METHODS: Contemporaneous paired plasma and saliva paracetamol concentrations were measured. Saliva was collected using a Sarstedt Salivette® device and the concentration was measured using a colorimetric method. RESULTS: Fifty-six patients (44, 78% female) median age 26 years (IQR 20-41) were enrolled. The median reported paracetamol ingestion was 10 g (IQR 6-14). Specimens were collected at a median of 4 h (IQR 4-5.3) post ingestion. The median plasma and saliva paracetamol concentrations were 29 mg l(-1) (IQR 8-110) and 38 mg l(-1) (IQR 10-105) respectively [mean difference 8 mg l(-1) , 95% confidence interval (CI) 2, 14]. Lin's concordance correlation was 0.97 (95% CI 0.96, 0.98). There were 15 patients who were treated with N-acetylcysteine. Their median reported paracetamol ingestion was 14 g (IQR 10-23) and samples were collected at a median of 4 h post ingestion. The median plasma and saliva paracetamol concentrations were 167 mg l(-1) (IQR 110-200) and 170 mg l(-1) (IQR 103-210) respectively (mean difference 15 mg l(-1) , 95% CI -4, 35). Lin's concordance correlation was 0.94 (95% CI 0.88, 0.99). No patient needing treatment would have been missed using saliva concentrations only. CONCLUSIONS: The agreement between the indications for treatment of paracetamol DSP based on plasma and saliva paracetamol concentrations extends into the toxic range, but with slightly lower agreement. Saliva may hold promise as a non-invasive method to risk stratify paracetamol poisoning.

Brain abnormalities detected on magnetic resonance imaging of amphetamine users presenting to an emergency department: a pilot study.

OBJECTIVES: To determine the prevalence of occult brain abnormalities in magnetic resonance imaging of active amphetamine users. DESIGN, SETTING AND PARTICIPANTS: Prospective convenience study in a tertiary hospital emergency department (ED). Patients presenting to the ED for an amphetamine-related reason were eligible for inclusion. We collected demographic data, drug use data, and performed a mini-mental state examination (MMSE). MAIN OUTCOME MEASURES: The proportion of patients with an abnormality on their MRI scan. RESULTS: Of 38 patients enrolled, 30 had MRI scans. Nineteen were male and their mean age was 26.7 +/- 5.4 years (range 19-41 years). The mean age of first amphetamine use was 18 years (range 13-26 years). Sixteen patients used crystal methamphetamine (mean amount 2.5 g/week), nine used amphetamine ("speed") (mean amount 2.9 g/week), and 23 used ecstasy (mean amount 2.3 tablets/week). Marijuana was smoked by 26 (mean amount 5.9 g/week), and 28 drank alcohol (mean amount 207 g/week). The median MMSE score was 27/30 (interquartile range, 26-29). Abnormalities on brain MRI scans were identified in six patients, most commonly an unidentified bright object (n = 4). CONCLUSION: In this pilot study of brain MRI of young people attending the ED with an amphetamine-related presentation, one in five had an occult brain lesion. While the significance of this is uncertain, it is congruent with evidence that amphetamines cause brain injury.

Clotting factor replacement and recovery from snake venom-induced consumptive coagulopathy.

INTRODUCTION: Using clotting factors (fresh frozen plasma and/or cryoprecipitate) to treat snake venom-induced consumptive coagulopathy (VICC) is controversial. We aimed to determine if factor replacement after antivenom is associated with an earlier return of coagulation function. METHODS: We retrospectively analysed VICC cases due to brown snake (genus Pseudonaja), tiger snake (Notechis, Tropidechis, and Hoplocephalus), and taipan (Oxyuranus) envenoming. Recovery of international normalized ratio (INR)/prothrombin time (PT) was compared between patients who did not receive factor replacement and those who did, and between patients who received factor replacement

Amphetamine-related presentations to an inner-city tertiary emergency department: a prospective evaluation.

OBJECTIVE: To describe the prevalence, characteristics and outcomes of amphetamine-related presentations to a tertiary hospital emergency department (ED). DESIGN, SETTING AND PARTICIPANTS: Prospective observational study of amphetamine-related presentations to the ED of the Royal Perth Hospital (RPH), an adult, inner-city, tertiary referral hospital, between 3 August and 2 November 2005. For all patients presenting to the ED, the treating doctors were automatically prompted by the computerised data entry system to consider amphetamine use. MAIN OUTCOME MEASURES: Proportion of ED presentations related to amphetamine use; demographic features and usage practices of amphetamine users; characteristics of presentations and admissions; associated psychiatric illnesses and use of other drugs. RESULTS: Over the study period, there were 13 125 presentations, of which 156 (1.2%) were judged to be causally related to amphetamine use. Of those 156 patients, over half were habitual drug users (89 [57.1%] used amphetamines at least weekly), and the majority were men (111 [71.2%]). The mean age was 28 years (range, 16-55 years). Presentations were of high acuity: 104 patients [66.7%] were rated 1, 2 or 3 on the Australasian Triage Scale; 50 (32.1%) arrived by ambulance; and 25 (16.0%) arrived with police. The mean time spent in the ED was 6 h (range, 0.5-24 h). Fifty patients (32.1%) required sedation, and the likelihood of requiring sedation increased almost threefold if the heart rate was over 100 beats/min on presentation. Sixty-two patients (39.7%) were admitted and 58 (37.2%) required psychiatric evaluation. Repeat attendance was common, with 71 patients (45.5%) having previous amphetamine-related presentations to the RPH ED. CONCLUSIONS: Amphetamine-related presentations comprise 1.2% of all ED attendances and have a major impact on hospital EDs. Patients are often agitated and aggressive, require extensive resources, and frequently re-attend. The burden of amphetamine-related illnesses on EDs is likely to increase in the future.