High-altitude illness — DTM&H MCQ

Correct answer: C — Immediate descent and oxygen

The correct answer is C, immediate descent and oxygen. Headache with ataxia and confusion at high altitude, in someone hypoxic and worsening despite rest, defines high-altitude cerebral oedema (HACE), a life-threatening progression of acute mountain sickness. Ataxia is the single most important clinical sign marking the transition from benign AMS to HACE, and once neurological signs appear the only definitive treatment is rapid descent to lower altitude, supplemented by oxygen (and dexamethasone if descent is delayed or not immediately possible). Waiting or continuing to rest at altitude risks coma and death, so descent must not be delayed once this diagnosis is suspected. Why the other options are wrong: E. Continue ascent slowly: further ascent worsens hypoxia and cerebral oedema and is the opposite of what is required; any further gain in altitude in established HACE can be fatal. B. Praziquantel treatment: this is an antihelminthic used for schistosomiasis and other fluke infections, entirely unrelated to hypoxic cerebral oedema and irrelevant to this presentation. A. Chloroquine prophylaxis: this is antimalarial prophylaxis, not a treatment for altitude illness, and has no role in a neurologically deteriorating trekker with hypoxia. D. Oral rehydration alone: dehydration does not explain ataxia and confusion at altitude, and fluids alone do not reverse cerebral oedema or correct the underlying hypoxic-ischaemic process. Key point: new ataxia or confusion at altitude signals HACE, and immediate descent with oxygen (plus dexamethasone if descent is delayed) is mandatory, since continuing ascent or delay can be fatal.

Reference: Patient.info (reviewed clinical content), 'Altitude Sickness: Risk, Prevention and Treatment' - High-altitude cerebral oedema section: descent is the essential treatment, with oxygen and dexamethasone as adjuncts if descent is delayed. https://patient.info/travel-and-vaccinations/health-advice-for-travel-abroad/altitude-sickness