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A 28-year-old man is found unconscious in a public toilet by paramedics. On arrival in the emergency department his GCS is 6 (E1 V1 M4), respiratory rate is 6/min and shallow, oxygen saturation 84 percent on room air, heart rate 50/min, blood pressure 96/60 mmHg, and his pupils are 1 to 2 mm and poorly reactive. There are fresh needle-track marks in both antecubital fossae. His capillary glucose is 5.6 mmol/L.
Questions
a) What is the most likely diagnosis and which triad defines it? (2 marks)
Opioid overdose (likely heroin, given IV use). The defining opioid (narcotic) triad is: depressed level of consciousness/coma, respiratory depression (bradypnoea), and pinpoint pupils (miosis). The needle marks and clinical context support the diagnosis, which is clinical and confirmed by a response to naloxone.
b) Outline the immediate stepwise resuscitation. (3 marks)
- Airway — open and protect; oropharyngeal/nasopharyngeal airway, position laterally.
- Bag-valve-mask (BMV) ventilation with 100 percent oxygen FIRST, before naloxone — restores oxygenation immediately and prevents hypoxic cardiac arrest while naloxone is drawn up.
- Naloxone titrated to respiratory rate (aim over 10 to 12/min), not full alertness. In this opioid-naive-presenting-but-unknown-tolerance patient start 0.04 to 0.4 mg IV, repeat every 2 to 3 minutes.
- IV access, cardiac monitoring, and send bloods including paracetamol and salicylate levels (co-ingestion).
- Endotracheal intubation only if he cannot be ventilated by BMV or fails to respond to an adequate naloxone dose.
c) Give the naloxone doses by route, the titration endpoint, and the reason for the observation period. (3 marks)
- Routes/doses: IV 0.04 to 0.4 mg (opioid-naive 0.4 mg; opioid-tolerant 0.04 to 0.1 mg titrated); IM/SC 0.4 mg; intranasal 8 mg (community). Repeat every 2 to 3 minutes up to a cumulative ~10 mg.
- Titration endpoint: a respiratory rate over 10 to 12/min with adequate oxygenation — NOT full alertness, to avoid precipitating acute withdrawal.
- Observation period: naloxone's half-life is 1 to 2 hours, shorter than most opioids, so the patient must be observed for at least 2 to 4 hours (for short-acting opioids) for re-narcotisation; 24 to 48 hours for methadone, sustained-release, or fentanyl.
d) Name two serious complications of opioid overdose and one key element of the discharge harm-reduction bundle. (2 marks)
- Complications (any two): non-cardiogenic pulmonary oedema (treated with oxygen and PEEP/NIV; not reversed by naloxone); aspiration pneumonitis; rhabdomyolysis and compartment syndrome from prolonged immobilisation; anoxic brain injury; precipitated withdrawal from over-aggressive naloxone.
- Harm-reduction bundle element: provision of take-home intranasal naloxone with overdose-recognition training for the patient and family; and/or referral to opioid agonist therapy (methadone or buprenorphine), the single most effective intervention to reduce mortality.