Acute altitude illnesses
BMJ 2011; 343 doi: https://doi.org/10.1136/bmj.d4943 (Published 15 August 2011) Cite this as: BMJ 2011;343:d4943
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We thank Dr Pun for his kind letter regarding the review on acute
altitude illnesses (1).
We recognize that certain topics such as the pathophysiology of high
altitude headache were not discussed (due to word constraints) and would
suggest a more detailed account can be found in the review 'The cerebral
effects of ascent to high altitude' (2). We are delighted the sharpened
test is thought by others to be helpful (3).
Since many patients will seek herbal remedies, we felt it was
important to highlight the conflicting evidence surrounding the use Ginko
biloba at altitude, so that informed medical advice can be given.
Dr Pun's thoughts on the use of glucocorticoids in acute mountain
sickness reflect our own views and these are recorded in the text.
We thank Dr Pun for drawing the readers' attention to the use of
acetazolamide in the treatment of high altitude cerebral and pulmonary
oedema. In the Wilderness Medical Society consensus guidelines (4) the
level of evidence supporting the use of acetazolamide in the treatment of
Acute Mountain Sickness and High Altitude Cerebral Oedema is given as 1C
or strong recommendation, low or very low quality of evidence. The level
of evidence supporting the use of acetazolamide in the treatment of High
Altitude Pulmonary Oedema is given as 2C or weak recommendation, low or
very low quality of evidence.
Chris Imray, Adam Booth, Alex Wright and Arthur Bradwell
1. Imray C, Booth A, Wright A, Bradwell A. Acute altitude illnesses.
BMJ 2011; 343:d4943
2. The cerebral effects of ascent to high altitudes. Wilson MH,
Newman S, Imray CH. Lancet Neurology. 2009 Feb;8(2):175-91.
3. Johnson BG, Wright AD, Beazley MF, Harvey TC, Hillenbrand P, Imray
CHE and BMRES. The Sharpened Romberg Test for assessing mild acute
mountain sickness. Wilderness and Environmental Medicine 2005; 16: 62-66.
4. Luks AM, McIntosh SE, Grissom CK, Auerbach PS, Rodway GW, Schoene
RB et al.
Wilderness Medical Society consensus guidelines for the prevention and
treatment of acute altitude illness. Wilderness Environ Med 2010 Jun;
21(2): 146-55
Competing interests: No competing interests
The first sentence of the second last paragraph should read:
". . . (authors have suggested to consider for moderate as
well). . .."
Thank you,
mati
Competing interests: No competing interests
Dear Editor,
I would like to thank Dr Imray et al (1) for their excellent clinical
review intended for educational purpose to clinicians. Here, I want to
highlight some of the important aspects with reference to this review that
should have been either included or carefully discussed to help clinicians
who accompany in the field or tend to manage acute altitude illnesses.
I'm glad that authors note high altitude headache as a separate
clinical entity but it is rather incomplete as they don't discuss its
pathophysiology and management considering its commonest prevalence of all
acute altitude illnesses discussed here. Similarly, the simple and easy
clinical approach for the diagnosis of acute mountain sickness; Sharpened
Rhomberg Test should have been included (2).
The review gives special attention to Gigko biloba without any
compelling data in its favor with the note that it has unstandardised
preparation. It will rather cause confusion and may lead to further use
without benefit to the matter of fact that it is over-the-counter
available.
The Glucorticoids (e.g Dexamethasone) should not be considered in
acute mountain sickness unless it is severe (authors have suggested to
consider for mild as well). If they are used, the patient should not
continue climbing/hiking. Otherwise, it is likely that risks outweigh
benefit.
It is surprising that the review does not include Acetazolamide in
the management of High Altitude Cerebral Edema (3, 4) and High Altitude
Pulmonary Edema (4) despite the fact that it improves blood oxygen
saturation and easily accessible as compared to likes of Tadalafil and
expiratory positive airway pressure in the field.
Acknowledgement:
I would like to thank Dr Marc J Poulin, University of Calgary and Dr
Buddha Basnyat, Mountain Medicine Society of Nepal for their
encouragement.
References:
1. Imray C, Booth A, Wright A, Bradwell A. Acute altitude illnesses.
BMJ 2011; 343:d4943
2. Johnson BG, Wright AD, Beazley MF, Harvey TC, Hillenbrand P, Imray
CH ; Birmingham Medical Research Expeditionary Society. The sharpened
Romberg test for assessing ataxia in mild acute mountain sickness.
Wilderness Environ Med. 2005 Summer;16(2):62-6.
3. Hackett PH, Roach RC. High-altitude illness. N Engl J Med.
2001;345:107-114
4. Luks AM, McIntosh SE, Grissom CK, Auerbach PS, Rodway GW, Schoene
RB et al. Wilderness Medical Society consensus guidelines for the
prevention and treatment of acute altitude illness. Wilderness Environ
Med. 2010 Jun;21(2):146-55.
Competing interests: No competing interests
I once had the priviledge of meeting Sir Edmund Hillary in the Nepal
himalaya. It was well known that he suffered from altitude sickness in
later life, despite having climbed to the highest point on the planet. I
heard a rumour that those accompanying the great man sometimes had
difficulty knowing if his symptoms were due to the excess of local
hospitality or the height above sea level.
I have no idea if this story is true, but it serves to illustrate two
points. Firstly, alcohol should be avoided where altitude sickness is a
risk. Secondly, no-one is immune to the effects of high altitude. There is
no room for complacency.
Competing interests: No competing interests
Re: Acute altitude illnesses
Hi. I'm interested in mountaineering and in outdoor medicine, particularly related to mountains.
Our mountaineering society met this article with mixed feelings. Medical part of acute mountain sickness is described perfect. Controversies appeared with non-medical measures to prevent mountain sickness.
This review offers gradual type of slow ascent. In particular - "individuals travelling above 3000 m should ascend at less than 300 m per day, with a rest day for every 1000 m climbed."
The case is that above altitude of 5800 m (at "extreme altitude") this type of ascent will lead to deterioration, acclimatization will be far from ideal.
The most experienced mountaineers of USSR and now - Russia - use "serrated" (or "notched") type of slow ascent. This type of ascent DOES work with extreme altitudes.
The scheme will show two lines of these two types of acclimatizations (for illustration). It's attached.
These graph is demonstrating ascent to hypothetical mountain with maximal altitude 7200 m. It shows days of ascent and altitude in meters.
Here green line is the diagram of slow gradual ascent which is recommended by current review.
The red line is typical notched gradual ascent which is typical and considered to be safest in our community.
The differences are obvious: slow gradual ascent, which is recommended in the article - suggests having a sleep above 5800. But acclimatization does not accelerating on these altitudes... But acute mountain sickness - does.
We believe, there's a need in correction of recommendations concerning rate of ascent. Slow gradual ascent is suitable for low altitudes, but not for high and extreme altitudes.
I know that currently Cochrane team reviews acute mountain sickness prevention. I guess there's a definite need in comparison of these two types of ascent profiles. Comparative study is strongly needed.
Thank you.
Competing interests: No competing interests