Adventure Travel

Question 1

HAPE

Answer 1

gain in altitude plus:
- dyspnea at rest, cough, limited exercise tolerance, chest tightness’
incidence varies 0.1% - 8% depending on peak alt.
rare at altitudes <3,650m (12,000 ft)
CFR 11-40% if untreated (case fatality rate)

Question 2

AMS acute mountain sickness

Answer 2

gain in altitude
headache within 48 hours
plus one or more:
anorexia/n/v, fatigue/weakness, dizziness, difficulty sleeping
typically 1-2 days after “summit”, rarely life but often trip threatening - beginning step of HACE, HAPE

Question 3

HACE

Answer 3

gain in altitude plus:
- change in mental status + AMS
- ataxia + AMS
- ataxia + change in mental status
may have LOC, truncal ataxia (tandem gait), HA lethargy, weakness, disorientation
rare at < 3,650 m (12,000 ft)
CFR 13-60% (if comatose)

Question 4

Alt Illness pathophysiology theories

Answer 4

hypobaria? - decreased barometric pressure > gas expansion in body cavities
hypoxemia?
periodic breathing?
cerebral blood flow?
tight fit hypothesis? - susceptibility to AMS/HACE dependent on intracranial space available to compensate for increasing edema
neurooxidative stress?
nitric oxide?

Question 5

altitude illness

Answer 5

can occur at elevations of 2000-3500 m (6500-11,500ft)
AMS
Banff, Denver

Question 6

extreme altitude

Answer 6

3500 - 5500 m (11,500 - >18,000 ft)
increased risk of AMS
Himalayas, Andes

Question 7

common altitude destinations

Answer 7

Mount Kili - 5895 m
- Marangu route only 5 days, low success rate due to insufficient acclimatization
- Lemosho route - 7-8 days, higher cost but high success rate
Everest base camp 5380 m
Lhasa Tibet 3700 m
La Paz Bolivia 3690 m
Cuzco Peru 3399 m
Machu Picchu Peru 2430 m

Question 8

alt illness incidence

Answer 8

western US AMS 10-30% HAPE 1/10,000 1-2 day ascent
Lhasa/La Paz AMS 50-75% HAPE 1/100 (fly in)
Everest trek AMS 47% HAPE 1/65 (fly in)
or 12-14,000 feet AMS 23% HAPE 5/1000 (10-13 d)

Question 9

risk for alt illness

Answer 9

flat land residence
rapid ascent
target altitude
past hx AMS
alcohol consumption
age < 50 (for AMS)?
age, gender, fitness- not much effect
susceptibility

Question 10

prevent AMS

Answer 10

gradual ascent
- climb high, sleep low
- increas by no more than 500 m in 24 hours (after
reaching 2500 m)
spend 1-2 nights at 2500-3000 m to acclimatize
avoid alcohol and sedatives
avoid over exertion and dehydration

Question 11

AMS prevention

Answer 11

acetazolamide
dexamethasone
tadalafil/sildenafil
salmeterol
ginko biloba - mixed
ibuprofen - better than placebo

Question 12

acetazolamide

Answer 12

• blocks carbonic anhydrase, esp renal leading to bicarbonate diuresis and metabolic acidosis
• stimulates ventilation raising PO2
• promotes ion exchange across BBB
  optimal dosing 125-250 mg bid until 24h after peak
  
  • consider a test dose (125 good evidence)
• adverse effects: paraesthesias, metallic taste, dysgeusia, nausea, malaise

Question 13

dexamethasone

Answer 13

dex 8 mg bid - maybe best for hx of HAPE

Question 14

dive medicine - Pressurized gases

Answer 14

risk for nitrogen narcosis
decompression sickness

Question 15

dive medicine - Barotrauma

Answer 15

Descent:
air spaces - external ear, middle ear, sinuses, teeth with fillings, GI tract
air embolism
Ascent:
potential injuries:
sub q emphysema
pneumothorax
pneumomediastinum
air embolism

Question 16

diving contraindications - absolute

Answer 16

CHF, card shunting, valve dz, active RAD, hx pneumothorax, seizure hx, TIA/CVA hx

Question 17

diving relative contraindications

Answer 17

hx CAD, hx MI, HTN, hx RAD, hx migraine, hx otitis, hx sinusitis