skip to main content

Severe hypoglycaemia — MCCQE Part 1 MCQ

Instant feedback + full explanation. One question, done properly.

HardAltered Level of ConsciousnessSevere hypoglycaemiaMCCQE Part 1

Three family members are found confused with headache and nausea after using a fuel-burning heater indoors. One patient's pulse oximeter reads 99% on room air and the chest examination is normal. What is the most appropriate immediate management?

Educational content. Not a substitute for clinical judgement or local policy.

Reveal the answer and explanation

Correct answer: E — Give 100% oxygen and obtain carboxyhaemoglobin by co-oximetry

A shared indoor exposure with headache, nausea, and confusion strongly suggests carbon monoxide poisoning. Standard two-wavelength pulse oximetry cannot distinguish oxyhaemoglobin from carboxyhaemoglobin and may appear normal. High-concentration oxygen should begin immediately while carboxyhaemoglobin is measured with co-oximetry; treatment must not wait for the result. The exposure source must be controlled and the patients assessed for neurologic and cardiac injury. Poison-centre or hyperbaric consultation depends on severity, pregnancy, neurologic features, cardiac involvement, and measured concentration. Naloxone does not treat carbon monoxide, and pneumonia does not explain simultaneous illness in several exposed household members.

Reference: CDC, Clinical Guidance for Carbon Monoxide Poisoning: https://www.cdc.gov/carbon-monoxide/hcp/clinical-guidance/index.html