Altitude+illnesses

clinical home > environmental toc =Altitude illnesses = There are 3 main illnesses related to high altitude: acute mountain sicknes (AMS) high altitude cerebral oedema (HACE) high altitude pulmonary oedema (HAPE).

**HAPE and HACE are potentially fatal if not adequately treated** **descent** is //the// most important part of the treatment

Three rules to stop you dying of altitude illness
1. Learn the early symptoms of altitude illnesses and be willing to recognise these. 2. Never ascend to sleep at a higher altitude with any symptoms of altitude ilness. 3. Descend if symtoms are getting worse despite resting at a constant altitude.

High altitude illnesses:

Video showing effects of acute hypoxia: media type="youtube" key="qLQMupV3DLk" height="344" width="425"

AMS
The commonest altitude illness - approximately 50% people going to the altitude of Everest base Camp (5300m) would get AMS. It tends to occur around 3000m.

<span style="font-family: Verdana,Geneva,sans-serif;">Definition
<span style="font-family: Georgia,serif;">In the setting of a recent gain in altitude, the presence of headache and at least one of the following symptoms: <span style="font-family: Georgia,serif;"> - gastrointestinal (anorexia, nausea or vomiting) <span style="font-family: Georgia,serif;">- fatigue or weakness <span style="font-family: Georgia,serif;">- dizziness or lightheadedness <span style="font-family: Georgia,serif;">- difficulty sleeping

<span style="font-family: Verdana,Geneva,sans-serif;">Clinical features
<span style="font-family: Georgia,serif;">Headache is a common symptom of AMS; other symtpoms, often compared to those of a hangover, include nausea, vomiting and fatigue. <span style="font-family: Georgia,serif;">** If the casualty develops ataxia (problems with balance when walking) they must be descended; it indicates development of HACE. ** <span style="font-family: Georgia,serif;">The tandem Romberg test can be used - the feet are placed heel to toe (touching) and each hand is placed on the opposite shoulder. When healthy it should be possible to stay in this position with the eyes closed for 30 seconds.

<span style="font-family: Georgia,serif;">The[| Lake Louise Score] can be used to monitor symptoms from being at altitude & diagnose AMS

<span style="font-family: Georgia,serif;">This is what ataxia looks like - this trekker has HACE not AMS media type="youtube" key="0u7sSDI778Q?version=3" height="390" width="480"

<span style="font-family: Verdana,Geneva,sans-serif;">Prevention
<span style="font-family: Georgia,serif;">**The best treatment is prevention** through gradual ascent: <span style="color: #ff0000; font-family: Georgia,serif;"> **above 3000m do not increase the sleeping altitude by more than 300m/day and after every 3 days have a day where the sleeping altitude is not increased** <span style="font-family: Georgia,serif;">. In the day time ascent above the sleeping altitude can help acclimatisation. <span style="font-family: Georgia,serif;">Acetazolamide can be taken to reduce the risk of AMS. It aids acclimatisation but is not without problems; someone considering taking it as prophylaxis should take it at low altitude first to ensure they can tolerate the side effects.

<span style="font-family: Verdana,Geneva,sans-serif;">Treatment
<span style="font-family: Georgia,serif;">Simple pain relief for the headache is often sufficient treatment for AMS, which tends to settle over 2-3 days. Occasionally other symptomatic treatment, such as antiemetics are are used. <span style="font-family: Georgia,serif;">Acetazolamide can be used for treatment after symptoms develop. <span style="font-family: Georgia,serif;">Ideally one would not sleep higher until the symptoms of AMS have settled. This may not be possible; the patient must be closely observed and if their condition deteriorates while/after ascending the patient **must** be descended.

<span style="font-family: Verdana,Geneva,sans-serif;">HACE = high altitude cerebral edema (US spelling of oedema)
<span style="font-family: Georgia,serif;">This is swelling of the brain - as bad as it sounds <span style="font-family: Georgia,serif;">0.05 % trekkers to EBC develop HACE. <span style="font-family: Georgia,serif;">HACE tends to develop at around 4500m. <span style="font-family: Georgia,serif;">HACE and (mild) AMS can be viewed as being opposite ends of a spectrum of illness. <span style="color: #ff0000; font-family: Georgia,serif;">**HACE is life-threatening.**

<span style="font-family: Verdana,Geneva,sans-serif;">Prevention
<span style="font-family: Georgia,serif;">1) Gradual ascent as above for prevention of AMS <span style="font-family: Georgia,serif;">2) Following treatment guidelines for AMS - failure to descend a casualty with worsening AMS risks causing HACE

<span style="font-family: Verdana,Geneva,sans-serif;">Clinical Features
<span style="font-family: Georgia,serif;">Any neurological deficit at altitude should be viewed as a manifestation of HACE until proven otherwise.

<span style="font-family: Verdana,Geneva,sans-serif;">Treatment
<span style="color: #cd3f3f; font-family: Georgia,serif;">**<span style="color: #ff0000; font-family: Georgia,serif;">DESCENT ** <span style="color: #000000; font-family: Georgia,serif;">(even in the dark/adverse weather unless really impossible) <span style="font-family: Georgia,serif;">Keep slightly head up (may reduce ICP) <span style="font-family: Georgia,serif;">Oxygen if available <span style="font-family: Georgia,serif;">Dexamethasone is the main drug that is used (8mg initially orally or injected) <span style="font-family: Georgia,serif;">Acetazolamide is also given <span style="font-family: Georgia,serif;">Portable altitude chamber/Gamow bag or similar when descent is not possible.

<span style="font-family: Verdana,Geneva,sans-serif;">HAPE = high altitude pulmonary edema
<span style="font-family: Georgia,serif;">This is fluid collecting in the alveoli - the parts of the lungs that should be full of air to allow oxygenation of the blood <span style="font-family: Georgia,serif;">1 - 2 % trekkers to EBC. <span style="font-family: Georgia,serif;">Common around 4200m. <span style="font-family: Georgia,serif;">Can be fatal, though less so than HACE. <span style="font-family: Georgia,serif;">HAPE may develop on background of AMS but can be the first manifestation of altitude illness.

<span style="font-family: Verdana,Geneva,sans-serif;">Prevention
<span style="font-family: Georgia,serif;">Gradual ascent <span style="font-family: Georgia,serif;">Salmeterol inhaler (probably) but not salbutamol <span style="font-family: Georgia,serif;">For those who have to move rapidly to high altitude (e.g. to effect a rescue) dexamethason can be used for prevention, though this can have side effects and is not recommended for "normal" circumstances.

<span style="font-family: Verdana,Geneva,sans-serif;">Clinical Features
<span style="font-family: Georgia,serif;">**Dyspnoea** - exertional at first. <span style="font-family: Georgia,serif;">Since many people will be breathing fast when trekking at altitude one way to determine who is having problems is the assess the respiratory rate of mambers of the group after a short period of rest - in this time most will return towards normal, but someone with HAPE will remain markedly tachypnoeic. <span style="font-family: Georgia,serif;">**Cough** - may be dry or productive. This may also be due to "Khumbu cough" (a high altitude cough due to cold dry air) which is irritating and uncomfortable (and may lead to rib fractures) but a cough at altitude should initially be assumed to be HAPE until proven otherwise.

<span style="font-family: Verdana,Geneva,sans-serif;">Prevention
<span style="font-family: Georgia,serif;">In those who have hd HAPE before oral nifedipine and/or inhaled salmeterol (not salbutamol) may be useful drugs to reduce the risk of further HAPE but the best way to minimuse the risk is to acclimatise according to standard advice and to avoid over-exertion. <span style="font-family: Georgia,serif;">For those who have to move rapidly to high altitude (e.g. to effect a rescue) dexamethason can be used for prevention, though this can have side effects and is not recommended for "normal" circumstances.

<span style="font-family: Verdana,Geneva,sans-serif;">Treatment
<span style="color: #ff0000; font-family: Georgia,serif;">**DESCENT** <span style="color: #000000; font-family: Georgia,serif;">(even in the dark/adverse weather unless really impossible) <span style="font-family: Georgia,serif;">Sit casualty up <span style="font-family: Georgia,serif;">Oxygen if available <span style="font-family: Georgia,serif;">Nifedpidine is the traditional drug used to treat HAPE - 10mg capsule pricked several times chewed and swallowed with this repeated after 15 minutes providing the BP does not frop too far, and 30 minutes after the frst dose (again assuming the BP is OK) give 20mg of the MR preparation. Repeat the 20mg dose every 6 hours. <span style="font-family: Georgia,serif;">Sildenafil (viagra) has been used with excellent results <span style="font-family: Georgia,serif;">Acetazolamide is given if available <span style="font-family: Georgia,serif;">Loop diuretics do not really help in HAPE

PAC (portable altitude chamber) being used to treat HAPE on Mount Kilimanjaro:

<span style="font-family: Georgia,serif;">Use of the PAC: media type="youtube" key="5D3bgP8ZHyI?version=3" height="390" width="640" <span style="font-family: Georgia,serif;">(good video though I'd prefer the term "casualty" rather than "victim")

<span style="font-family: Verdana,Geneva,sans-serif;">Acclimatisation
<span style="font-family: Georgia,serif;">As altitude increases the oxygen available in the atmosphere decreases. Sudden exposure to the hypobaric hypoxaemia that is found at altitudes of several thousand metres <span style="font-family: Georgia,serif;">results in death. Acclimatisation is the response of the body to //gradual// exposure to increasing altitude. <span style="font-family: Georgia,serif;">Responses to high altitude include:
 * <span style="font-family: Georgia,serif;">Increased ventilation (both rate and depth) (though respiration may decrease during sleep)
 * <span style="font-family: Georgia,serif;">Increased heart rate
 * <span style="font-family: Georgia,serif;">Increased volume of urine

media type="youtube" key="hzg6fXf86eg?version=3" height="390" width="640"

<span style="font-family: Verdana,Geneva,sans-serif;">Links
<span style="font-family: Georgia,serif;">[|AMS] <span style="font-family: Georgia,serif;">[|High altitude illnesses]

<span style="font-family: Verdana,Geneva,sans-serif;">Recommended books
<span style="font-family: Georgia,serif;">[|Altitude Illness: prevention & treatment] <span style="font-family: Georgia,serif;">[|Travel at high altitude (Medex)]