HIGH ALTITUDE ILLNESS

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Following are the slides from my talk on high
altitude illness (HAI). They summarize the main
points in HAI development, diagnosis, treatment
and prevention. For full tutorials on HAI and
other mountaineering-related health issues, check
MedCom UIAA and ISMM websites. For practical
medical advices, check-up and drug prescription,
contact your GP or a specialist in sport
medicine.
Ludmila Boublikova
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HIGH ALTITUDE ILLNESS
           
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HIGH ALTITUDE ILLNESS

• (MedCom UIAA and ISMM guidelines)
• 1. High altitude
• 2. Acclimatization
• 3. High altitude illness AMS
• HACE
• HAPE
• 4. Treatment of HAI
• 5. Prevention of HAI
• 6. Specific groups of people in high altitude
• 7. Other high altitude-related health problems

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HIGH ALTITUDE

• altitude gt 2 500 m (8 000 ft)
• main problem decreased availability of oxygen
  causing
• 
  a disorder of normal breathing
• other factors low temperature
• low air
  humidity
• high UV
  radiation

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REACTION TO HIGH ALTITUDE
adequate ? acclimatization insufficient ?
high altitude illness
adaptation
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ACCLIMATIZATION

• a gradual process of the body adaptation to high
  altitude

Symptoms/changes 1. breathing ?
hyperventilation (breathing deeper and faster)
? shortness of breath during
exertion ? changed
breathing pattern (periodic breathing)
and frequent awakening at
night 2. blood circulation ? tachycardia
(increased heart rate)
? decreased maximum heart rate
? higher number of red
blood cells 3. body fluid balance ? increased
urination (altitude diuresis)
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HIGH ALTITUDE ILLNESS (HAI)

• a disease caused by hypoxia in high altitude that
  is beyond the ranges the body can tolerate

• Forms of HAI (Lake Louise definition)

I. acute mountain sickness (AMS) II. high
altitude cerebral edema (HACE) III. high
altitude pulmonary edema (HAPE)
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ACUTE MOUNTAIN SICKNESS (AMS)

• symptoms caused by mild brain swelling due to
  hypoxia
• mild to severe
• incidence 25 85
• usually appears 6 12 hours after an ascent

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ACUTE MOUNTAIN SICKNESS (AMS)

• DIAGNOSIS
• ? headache
• 1 or more of the following symptoms
• ? loss of appetite, nausea, vomiting
• ? fatigue, weakness
• ? dizziness, light-headedness
• ? difficulty sleeping
• in the setting of a recent gain in altitude above
  2 500 m

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ACUTE MOUNTAIN SICKNESS (AMS)

• Predisposing factors
• 1. rate of ascent
• 2. altitude reached (sleeping altitude)
• 3. individual susceptibility (genetic)
• other exertion
• permanent residence in ? 1000 m above
  sea
• certain diseases (cardiopulmonary,
  blood)
• no significant association with age
• 
  gender
• 
  physical fitness

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HIGH ALTITUDE CEREBRAL EDEMA (HACE)

• severe swelling of the brain with deterioration
  of brain functions
• the most severe form of AMS, end-stage of AMS
• incidence 0.1 - 5
• often manifests at night
• can progress rapidly, lethal in few hours to 2
  days

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HIGH ALTITUDE CEREBRAL EDEMA (HACE)

• DIAGNOSIS
• at least 2 of the following symptoms
• ? AMS
• ? ataxia (loss of coordination of
  movements)
• ? mental status changes
  (quantitative or qualitative)
• in the setting of a recent gain in altitude
  above 2 500 m

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HIGH ALTITUDE CEREBRAL EDEMA (HACE)
Predisposing factors like in AMS HACE usually
develops from AMS
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HIGH ALTITUDE CEREBRAL EDEMA (HACE)

• PEOPLE WITH HACE ARE OFTEN
• CONFUSED AND MAY NOT RECOGNISE THEIR DISORDER !

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HIGH ALTITUDE PULMONARY EDEMA (HAPE)

• leak and accumulation of fluid in the lungs
  leading to respiratory failure
• not related to AMS, may occur without signs of
  AMS
• incidence 0.1 - 5
• often manifests at night (typically the second
  night of ascent)
• progresses rapidly, lethal within hours
• may lead to development of HACE

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HIGH ALTITUDE PULMONARY EDEMA (HAPE)

• DIAGNOSIS
• at least 2 of the following symptoms
• ? breathlessness at rest
• ? cough
• ? weakness, fatigue, drowsiness
• ? chest tightness, fullness,
  congestion
• at least 2 of the following signs
• ? gurgling or rattling breaths,
  crackles or wheezing
• ? central cyanosis (blue or dark
  purple lips)
• ? fast breathing
• ? increased heart rate
• in the setting of a recent gain in altitude
  above 2 500 m

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HIGH ALTITUDE PULMONARY EDEMA (HAPE)
Predisposing factors 1. young fit males 2.
exertion 3. cold
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TREATMENT OF AMS

• Mild to moderate forms
• NEVER continue in ascent !!!
• consider - rest at the same altitude with
  hyperventilation
• - descent
• fluids
• mild analgesics (paracetamol, aspirin, ibuprofen)
• acetazolamide (Diamox)
• Severe forms treat like HACE

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TREATMENT OF HACE

• immediate descent to the altitude where the
  person last slept well (500 - 1000 m if in
  doubts)
• oxygen
• event. hyperbaric bag
• acetazolamide (Diamox)
• dexamethason

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TREATMENT OF HAPE

• no exertion
• immediate transport to the altitude where the
  person last slept well (500 - 1000 m if in
  doubts)
• oxygen
• event. hyperbaric bag
• event. PEEP, CPAP
• nifedipin

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PORTABLE HYPERBARIC CHAMBER (hyperbaric bag)

• air-impermeable bags that can be inflated to high
  pressure, simulating descent
• main types Gamow
• Certec
• PAC (Portable
  Altitude Chamber)

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PORTABLE HYPERBARIC CHAMBER
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PORTABLE HYPERBARIC CHAMBER

• indications HACE or HAPE when descent is
  impossible
• contraindications
• absolute - lack of
  spontaneous breathing
• relative - middle ear
  congestion, claustrophobia

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PREVENTION OF HAI
1. gradual ascent within the tolerance zone and
good acclimatization
individual general rules usually apply ? one
night at altitude slightly below 3 000 m (10 000
ft) ? at altitudes above 3 000 m, sleeping
altitude increase ? 300 - 500 m (1 000 - 1 500
ft) per night ? a second night at the same
altitude for every 1 000 m (3 000 ft) of gained
altitude
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PREVENTION OF HAI
2. avoiding medications that cause depression of
breathing
? alcohol ? sleeping pills, sedatives ? strong
(narcotic) painkillers
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PREVENTION OF HAI
3. drugs
? acetazolamide (Diamox) 2 x 125 - 250 mg
indications forced rapid ascents
medical
history of repeated AMS ? ginkgo biloba 2 x 80
- 120 mg ? (inhaled beta-agonists, oral
nifedipine) (may prevent HAPE)
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THE GOLDEN RULES If you feel unwell at
altitude, it is high altitude illness until
proven otherwise. Never ascend with symptoms of
AMS. If you are getting worse or have HACE or
HAPE, get down immediately.
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SPECIFIC GROUPS OF PEOPLE IN HIGH ALTITUDE
? older people ? children ? pregnant women ?
medication (malaria prophylaxis) ? cold
exposition (hypothermia, frost-bites) ? people
with pre-existing diseases
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CARDIOVASCULAR DISEASES

• responsible for 30 of lethal accidents in the
  Alps (DAV, OEAV)
• the risk increases with the altitude
• may be the first manifestation of previously
  silent disease
• recommendation medical examination ETT
• for men? 50 and
  people with other risks

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OTHER HIGH ALTITUDE-RELATED DISEASES
? high altitude deterioration ? high altitude
retinopathy ? high altitude peripheral edema
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Links
Medical Committee of UIAA
www.uiaa.ch International Society for Mountain
Medicine www.ismmed.org