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272 ROACH, BARTSCH, et
al
CHAPTER
26
THE LAKE LOUISE ACUTE
MOUNTAIN SICKNESS
SCORING SYSTEM
R.C. Roach, P. Bartsch, P.H. Hackett, O. Oelz
and the Lake Louise AMS Scoring Consensus Committee*
Introduction
In 1991, the Lake Louise Consensus Committee met and agreed on diagnostic
criteria and a scoring system for the symptoms and signs
of
acute mountain sickness!.
The goal was to provide enough sensitivity, specificity and flexibility to allow use
in many different settings and to facilitate comparisons
of
results among all studies
by using this instrument. Since then investigators have used the Lake Louise AMS
scoring system in different settings at different altitudes in several countries. The
previous standard, the Environmental Symptoms Questionnaire (ESQ), has 67 items,
takes time and patience for subjects to complete, and has been resisted by many
researchers2• In contrast, the Lake Louise AMS scoring system takes only a few
minutes to complete and score. Several groups have reported comparable results
regarding sensitivity and specificity between the Lake Louise AMS scoring system
and the
ESQ3-6.
Therefore, we recommend that this scoring system be adapted as
the standard for acute mountain sickness research.
INSTRUCTIONS: The Lake Louise AMS Scoring System
The Lake Louise scoring system consists
of
a short self-report questionnaire,
which
is
sufficient in itself,
or
to which may be added an additional clinical assess-
ment. The AMS Self-report score
is
the sum
of
responses to 5 questions; the find-
ings can be verified by interview
in
the clinical research setting. The Clinical Assess-
ment score is the interviewer's rating
of
three signs: mental status, ataxia and
peripheral edema. This score is added to the AMS Self-report questionnaire score.
An optional question
is
recommended to assess functional consequences
of
recorded
symptoms and signs. The scoring system
is
designed to allow use in both large surveys
and in smaller clinical trials.
Diagnostic Criteria for Acute Mountain Sickness
A diagnosis
of
AMS
is
based on a recent gain in altitude, at least several hours
at the new altitude, and the presence
of
headache and at least one
of
the following
*The Lake Louise AMS Scoring System Consensus Committee: Almas Aldashev, CIS; Buddha Basnyat,
Nepal; A.R. Bradwell, UK; Charles Clark, UK; Geoff Coates, Canada; Allen Cymerman, USA; Allen
Ellsworth, USA; R.F. Fletcher, UK; Eugene Gippenreiter, Russia; Colin Grissom, USA; Ben Honigman,
USA; Charles Houston, USA; Herb Hultgren, USA; Bengt Kayser, Switzerland; Toshio Kobayashi, Japan;
Gig Leadbetter, USA; Marco Maggiorini, Switzerland; N.D. Menon, India; Jim Milledge, UK; C. Carlos
Monge, Peru; Michiro Nakashima, Japan; Dick Nicholas, USA; Drummond Rennie, USA; Jean Paul
Richalet, France; Paul Rock, USA; Roberto Rodriguez Guaita, Chile; David Shlim, Nepal; John Sutton,
Australia;
S.
Takei, Japan; Gou Ueda, Japan;
Ray
Yip, USA.
1993 Roach RC, Bärtsch P, Oelz O, Hackett PH. The Lake Louise Acute
Mountain Sickness Scoring System. In: Sutton JR, Houston CS, Coates G,
Editors. Hypoxia and Molecular Medicine. Burlington, VT: Queen City Press;
1993. p. 272-274.
LAKE LOUISE AMS SCORING SYSTEM
273
symptoms: gastrointestinal upset (anorexia, nausea,
or
vomiting), fatigue or weakness,
dizziness
or
lightheadedness and difficulty sleeping. A score
of
three points
or
greater
on
the AMS Self-report questionnaire alone,
or
in combination with the Clinical
Assessment score constitutes AMS.
A) Self-report questionnaire. This portion
of
the scoring system
is
mandatory
and should be reported as a separate score. Each
of
the following five questions
is asked with the corresponding 0 to 3 rating
of
the response.
In
some studies, the
question "Difficulty sleeping" will not
be
relevant (e.g. rapid one day ascent) and
can be omitted. The sum
of
the responses on these questions is then calculated as
the AMS Self-report score.
It
is recommended that this score be reported separately,
even when used with the Clinical Assessment score. This procedure will allow the
comparisons
of
severity among the majority
of
studies. All will have the AMS Self-
report score, some will have both the AMS Self-report score and the Clinical Assess-
ment score.
1.
Headache. 0 No headache
I Mild headache
2 Moderate headache
3 Severe headache, incapacitating
2.
Gastrointestinal symptoms. 0 No gastrointestinal symptoms
I Poor appetite or nausea
2 Moderate nausea or vomiting
3 Severe nausea & vomiting, incapacitating
3. Fatigue and/or weakness. 0 Not tired or weak
I Mild fatigue/weakness
2 Moderate fatigue/weakness
3 Severe fatigue/weakness, incapacitating
4.
Dizziness/l ightheadedness. 0 Not dizzy
I Mild dizziness
2 Moderate dizziness
3 Severe dizziness, incapacitating
5.
Difficulty sleeping. 0 Slept
as
well
as
usual
I Did not sleep as well as usual
2 Woke many times, poor night's sleep
3 Could not sleep at
all
B)
Clinical Assessment. This portion
of
the scoring system contains information
gained
by
examination. The Clinical Assessment score
is
the sum
of
scores on the follow-
ing three questions.
274 ROACH, BARTSCH, et
al
6.
Change
in
mental status. 0 No change
in
mental status
1 Lethargy/lassitude
2 Disoriented/confused
3 Stupor/semiconsciousness
4 Coma
7. Ataxia (heel to toe walking) 0 No ataxia
1 Maneuvers to maintain balance
2 Steps off line
3 Falls down
4 Can't stand
8.
Peripheral edema. 1 No peripheral edema
1 Peripheral edema
at
one location
2 Peripheral edema at two or more locations
c)
Functional
Score. The functional consequences of the
AMS
Self-reported score
should be further evaluated
by
one optional question asked after the AMS Self-report
questionnaire. Alternatively, this question may be asked by the examiner
if
Clinical
Assessment is performed.
Overall,
if
you had any symptoms, how did they affect your activity?
o No reduction
in
activity
1 Mild reduction
in
activity
2 Moderate reduction
in
activity
3 Severe reduction
in
activity (e.g. bedrest)
References
I. The Lake Louise Consensus on the definition and quantification of altitude illness. In: Hypoxia
and Mountain Medicine, J.R. Sutton, G. Coates, C.S. Houston, editors. Burlington, YT: Queen
City Printers Inc., 1992, p. 327-330.
2. SAMPSON, J.B.,
A.
CYMERMAN, R.L. BURSE, J.T. MAHER, P.
B.
ROCK. Procedures for
the measurement
of
acute mountain sickness. Aviat. Space Environ.
Med.
54(12): 1063-1073, 1983.
3. HONIGMAN, B., J.L. ATKINS, R.C. ROACH, C.S. HOUSTON (Abstract). Acute mountain
sickness
in
the elderly at moderate altitude. In: Proceedings
of
the Eighth International Hypoxia
Symposium, Lake Louise, Canada, 1993.
4. BARTSCH, P.,
A.
MULLER,
D.
HOFSTETTER,
M.
MAGGIORINI,
P.
YOCK, O. OELZ. AMS
and HAPE scoring
in
the Alps (Abstract).
In:
Proceedings
of
the Eighth International Hypoxia Sym-
posium, Lake Louise, Canada, 1993.
5. ELLSWORTH, A., T. DUNCAN,
S.
GOLDBERG, L. JOHNSON, P. HACKETT. Measuring
acute mountain sickness using the Lake Louise Consensus Questionnaire (Abstract).
In:
Proceedings
of
the Eighth International Hypoxia Symposium, J.R. Sutton,
G.
Coates, C.S. Houston, editors.
1993.
6. LEADBETTER,
G.,
R.
ROBERGS,
B.
RUBY, D. LIUM. The effect
of
intermittent altitude ex-
posure on acute mountain sickness (Abstract).
SW
Chapter, Am. Coli. Sports. Med. 1992.
