Altitude sickness/Acute mountain sickness Flashcards
Risk factors for altitude sickness or acute mountain sickness?
- History of it
- Quick ascent to >2500m and exertion
- Pulmonary conditions, sickle cell disease, and uncontrolled chronic condition (e.g. CV conditions)
Briefly describe the possibly pathophysiology of acute mountain sickness?
- High altitude: atm pressure lower, less oxygen available
- Predispose travellers to risk of hypoxia
- Leads to hyperventilation to adapt to drop in arterial partial pressure
- Increases water loss, causes a decrease in arterial partial
pressure of carbon dioxide, resulting in respiratory alkalosis and nocturnal periodic
breathing - Hypoxia also causes increase in cerebral blood flow and hydrostatic capillary pressure resulting in capillary leak and edema
Risk classifications of acute mountain sickness and their treatment recommendations
- Low risk: no need prophylaxis
- Medium risk: Consider prophylaxis
- High risk: Prophylaxis strongly recommended
State the dosing regimen of acetazolamide to PREVENT acute mountain sickness in an adult?
Acetazolamide 125 - 250 mg BD, start 24h before ascent
- Discontinue upon start of descent
- Discontinue after 2-4d of staying in same altitude
State the dosing regimen of acetazolamide for the TREATMENT of acute mountain sickness in an adult?
Acetazolamide 250 mg BD
- Continue until descent OR 24h after symptom resolution
Class of medications use to treat the headache caused by acute mountain sickness
NSAIDs
A steroid used to treat or prevent acute mountain sickness. What is the dose and frequency?
Dexamethasone
- Prevention: 4mg BD, discontinue upon descent or 2-4d after staying at the same altitude. Max 10d tx
- Treatment: 4mg QDS, until symptoms resolve or descent completed for max 7d
Warning signs of acute mountain sickness that warrants a descent immediately
- Symptoms do not resolve after 24h (with or without treatment)
- Change in behaviour, impaired walking, confusion
- SoB, especially at rest
- Cough with pink frothy sputum
- Chest tightness
What are the common signs and symptoms of acute mountain sickness?
- HEADACHE
- Nausea and vomiting, loss of appetite
- Lethargy
- Dizziness
- Insomnia
Non-pharmacological management/ counselling points to prevent acute mountain sickness?
- Ascend gradually if possible
- Avoid alcohol and sedatives in the first 48h
- Avoid vigorous exercise in the first 48h
- Look out for signs and symptoms of acute mountain sickness and descend if symptoms do not improve within 24h
Factor that immediately puts a patient at a minimum moderate risk for mountain sickness?
- History of mountain sickness
- Increase sleep altitude >500m or 3000m with acclimatisation every 1000m
Factors that put patient at high risk of mountain sickness hence warranting prophylaxis
- Ascending >2800m in 1 day with history
- History of high-altitude cerebral edema (HACE) or high-altitude pulmonary edema (HAPE)
- Ascending rapidly without acclimatisation
A 48yo healthy male asks if he needs prophylaxis for mountain sickness. In the past, he climbed a mountain but had a severe headache and was treated for HACE. He has allergy to sulfa drugs and experienced anaphylaxis. He is going to ascend to a height of 3000m over a total of 5 days with proper acclimatisation.
State if the patient requires prophylaxis for acute mountain sickness and suggest a drug and its regimen if prophylaxis is required
- Need prophylaxis (high risk due to history of HACE)
- PO dexamethasone 4 mg BD. Start 24h before ascent, continue until descent or for 2-4d upon staying at the same altitude
If a patient experiences mild headache at high altitudes, what are the non-pharmacological advices for the patient?
- Rest
- Sleep upright
- Maintain hydrated
- Avoid alcohol
- If symptoms persists for 24h, descend
- If descend not possible, use supplemental oxygen or gammow bag
