Acute mountain sickness (AMS) is a common form of altitude sickness which affects between 10 to 80% of individuals climbing to high altitudes [1] [2] [3] [4] [5]. Symptoms are variable and usually commence within 24 hours of an unacclimatized individual ascending rapidly to altitudes > 8000 feet. Common symptoms include headaches, dizziness, vomiting, anorexia, fatigue, and insomnia [6] and they are due to the hypoxic and hypobaric environment at high altitudes [7]. Other symptoms like loss of appetite, light-headedness, lassitude, dyspnea and delirium may also be present. Some patients experience worsening of symptoms with the development of either cerebral edema (HACE - high altitude cerebral edema) and/or high altitude pulmonary edema (HAPE). But in a majority of the cases, the symptoms of AMS usually improve after a day unless the patient ascends again to a higher altitude, in which case the symptoms can worsen.

• Fatigue

  On ascent to 5085 m, ratings of perceived exertion (RPE ascent ), fatigue by Brunel Mood Scale, and AMS were recorded daily. [ncbi.nlm.nih.gov]

  […] and weakness : Not tired or weak = 0 Mild fatigue/weakness = 1 Moderate fatigue/weakness = 2 Severe fatigue/weakness = 3 Dizziness and lightheadedness: Not dizzy = 0 Mild dizziness = 1 Moderate dizziness = 2 Severe dizziness, incapacitating = 3 Difficulty [ultimatekilimanjaro.com]

  It is characterized by sudden onset of a bitemporal headache, nausea, fatigue, dizziness and can be life-threatening with the development of cerebral or pulmonary edema. [symptoma.com]

  However, increases in erythrocyte count, hematocrit and hemoglobin associated with EPO therapy have been shown to decrease fatigue and increase work capacity and exercise tolerance. [clinicaltrials.gov]

  […] sickness : altitude sickness that is experienced usually within several hours to one day of ascending above 8000 to 10,000 feet (about 2500 to 3000 meters) and that is marked by headache, nausea, loss of appetite, vomiting, insomnia, dizziness, and fatigue [merriam-webster.com]

• Malaise

  A 32-year-old Japanese woman with headache, anorexia and malaise, just after travelling cities of the altitude of over 4,000 m by a long-distance coach is described. [ncbi.nlm.nih.gov]

  Symptoms of mild AMS include mild headaches, increased breathing, rapid pulse, nausea, loss of appetite, lack of energy, and general malaise. These are warning signs not to go any higher than you already are. [nps.gov]

  Symptoms usually start 12-24 hours after arrival at altitude and include headache, dizziness, fatigue, shortness of breath, loss of appetite, nausea, disturbed sleep, and a general feeling of malaise. [medicinenet.com]

• Inflammation

  In total, 75 differentially expressed cytokines were identified between AMS-susceptible individuals and AMS-resistant individuals, most involved in inflammation. [ncbi.nlm.nih.gov]

  "This finding suggests that the pathophysiology of AMS may not only be dependent on arachidonic-acid pathway and inflammation triggered by ibuprofen, but also other mechanisms that mediate nociception influenced by acetaminophen," concluded Dr. [sciencedaily.com]

  Ibuprofen works by inhibiting the cyclooxygenase enzyme which is involved in mediating inflammation (swelling), and pain. [bestbets.org]

  Dexamethasone: This is a potent steroid hormone with qualities that suppress immune activity and inflammation. It is 20 to 30 times more potent than hydrocortisone and 4 to 5 times the strength of prednisone, and it reduces swelling of the brain. [medicalnewstoday.com]

• Dyspnea

  What are the initial manifestations of acute mountain sickness (1) Headache (Severe and persistent) (2) Lassitude (3) Drowsiness/Dizziness (4) Chilliness/Nausea and vomiting (5) Facial pallor/Dyspnea and cyanosis What are the late symptoms of acute mountain [quizlet.com]

  Other symptoms like loss of appetite, light-headedness, lassitude, dyspnea and delirium may also be present. [symptoma.com]

  Subjective benefits include improvement in sleep habits, tolerance to cold; decreased dyspnea, anginal symptoms and tachycardia and improved appetite, all of which are symptoms associated with high altitude illness. [clinicaltrials.gov]

  Initially, patients have dyspnea on exertion, decreased exertion tolerance, and dry cough. Later, dyspnea is present at rest. Pink or bloody sputum and respiratory distress are late findings. [merckmanuals.com]

  High-altitude pulmonary edema (HAPE) occurs most commonly two to three days after arrival at altitude and consists of dyspnea (difficulty breathing) with exercise, progressing to dyspnea at rest, a dry cough, weakness, chest tightness or congestion, and [hprc-online.org]

• Periodic Breathing

  The fraction of TIB spent with periodic breathing was determined as the sum of all cycle times of periodic breathing divided by TIB. Counts of oxygen saturation dips ≥4% and histograms of oxygen saturation averaged over 1 s periods were obtained 26. [erj.ersjournals.com]

  Periodic breathing is a common breathing pattern during sleep at high altitude. More than 100 years ago, Mosso [33] described this periodic breathing pattern, which consists of a series of 3-5 breaths followed by a short respiratory pause, or apnea. [emedicine.medscape.com]

  Periods of sleeplessness The need for more sleep than normal, often 10 hours or more Occasional loss of appetite Vivid, wild dreams at around 2500-3800m in altitude Unexpected momentary shortness of breath, day and night Periodic breathing that wakes [explorehimalaya.com]

  Periodic Breathing Periodic breathing (Cheyne Stokes breathing, or PB) is common at high altitude and becomes more frequent with increasing altitude. Periodic breathing involves alternating periods of deep breathing and shallow breathing. [altitude.org]

• Pneumonia

  […] orthopnea, and hemoptysis may occur as pulmonary edema worsens These are signs and symptoms of which type of acute mountain sickness HAPE HIGH ALTITUDE PULMONARY EDEMA What are the physical findings of HAPE 1) The clinical picture may resemble severe pneumonia [quizlet.com]

  Antibiotics may be given if a fever is present and pneumonia is possible. For more severe cases of high-altitude pulmonary edema, continuous positive airway pressure (CPAP) mask ventilation can be used. [emedicinehealth.com]

  HAPE is much more common at altitude than pneumonia, and more dangerous; many climbers have died of HAPE when they were mistakenly treated for pneumonia. Asthma might also be confused with HAPE. [ratnavoyages.com]

• Dyspnea at Rest

  […] at rest, and chest tightness. [quizlet.com]

  (fluid in the alveoli, with a dry cough that gets worse, fever and dyspnea at rest) and / or high altitude cerebral edema (HACE) (swelling of the brains, with headaches that no longer respond to analgesics, unsteady walk, increased vomiting and gradual [climbeverest.jimdo.com]

  High-altitude pulmonary edema (HAPE) occurs most commonly two to three days after arrival at altitude and consists of dyspnea (difficulty breathing) with exercise, progressing to dyspnea at rest, a dry cough, weakness, chest tightness or congestion, and [hprc-online.org]

  High-altitude pulmonary oedema dyspnea at rest, moist cough, severe weakness, drowsiness, cyanosis, tachycardia, tachypnea rales. [ncbi.nlm.nih.gov]

• Nausea

  Symptoms of mild AMS include: mild to severe headache; nausea; vomiting; lack of appetite; lack of energy; altered balance and coordination; dizziness. [bigislandhikes.com]

  = 1 Moderate nausea or vomiting = 2 Severe nausea or vomiting = 3 Fatigue and weakness : Not tired or weak = 0 Mild fatigue/weakness = 1 Moderate fatigue/weakness = 2 Severe fatigue/weakness = 3 Dizziness and lightheadedness: Not dizzy = 0 Mild dizziness [ultimatekilimanjaro.com]

  Whereas headache scores up to 6 hours in hypoxia were not correlated with other AMS symptoms, nausea was correlated with dizziness and fatigue (r=0.45 and 0.56, p [ncbi.nlm.nih.gov]

  Stay alert for acute mountain sickness symptoms such as headaches and nausea. [grindtv.com]

• Vomiting

  Stop it once below 2500m/8200ft AND after at least 3 days of treatment by tailing off the dose slowly (give the last 3 doses 12-hourly) ii) Diamox 250 mg 8 to12-hourly iii) Treat persistent vomiting with anti-vomiting medication Prop the victim up in [mountainmonarch.com]

  A 55-year-old female Nepali pilgrim presented to the Himalayan Rescue Association Temporary Health Camp near the sacred Gosainkund Lake (4380 m) north of Kathmandu, Nepal, with a complaint of severe headache, vomiting and light-headedness. [ncbi.nlm.nih.gov]

  Definition of acute mountain sickness : altitude sickness that is experienced usually within several hours to one day of ascending above 8000 to 10,000 feet (about 2500 to 3000 meters) and that is marked by headache, nausea, loss of appetite, vomiting [merriam-webster.com]

  = 2 Severe nausea or vomiting = 3 Fatigue and weakness : Not tired or weak = 0 Mild fatigue/weakness = 1 Moderate fatigue/weakness = 2 Severe fatigue/weakness = 3 Dizziness and lightheadedness: Not dizzy = 0 Mild dizziness = 1 Moderate dizziness = 2 [ultimatekilimanjaro.com]

• Loss of Appetite

  Definition of acute mountain sickness : altitude sickness that is experienced usually within several hours to one day of ascending above 8000 to 10,000 feet (about 2500 to 3000 meters) and that is marked by headache, nausea, loss of appetite, vomiting [merriam-webster.com]

  Other symptoms like loss of appetite, light-headedness, lassitude, dyspnea and delirium may also be present. [symptoma.com]

  Symptoms of mild AMS include mild headaches, increased breathing, rapid pulse, nausea, loss of appetite, lack of energy, and general malaise. These are warning signs not to go any higher than you already are. [nps.gov]

• Tachycardia

  What are the late symptoms of acute mountain sickness (1) Facial flushing/Irritability (2) Difficulty concentrating/Vertigo (3) Tinnitus/Visual and Auditory disturbances (4) Anorexia/Insomnia (5) Increased dyspnea/Weakness on exertion (6) Palpitations/Tachycardia [quizlet.com]

  History will reveal recent ascent to high altitude by the unacclimatized patient while physical examination may reveal tachycardia, tachypnea, and pulmonary rales if the patient is developing pulmonary edema. [symptoma.com]

  Subjective benefits include improvement in sleep habits, tolerance to cold; decreased dyspnea, anginal symptoms and tachycardia and improved appetite, all of which are symptoms associated with high altitude illness. [clinicaltrials.gov]

  Electrocardiography demonstrates sinus tachycardia and often, right ventricular strain. [ncbi.nlm.nih.gov]

  On examination, cyanosis, tachycardia, tachypnea, and low-grade fever (< 38.5° C) are common. Focal or diffuse crackles (sometimes audible without a stethoscope) are usually present. [merckmanuals.com]

• Pruritus

  Table 4 Adverse events in groups receiving prophylactic agents for AMS Difficulty in falling asleep 1 (0.98) 1 (0.98) Light sleep 3 (2.94) 1 (0.98) Dizziness 2 (1.96) 0 (0.00) Drowsiness 2 (1.96) 0 (0.00) Pruritus 1 (0.98) 1 (0.98) Dry hand 1 (0.98) 0 [bmccomplementalternmed.biomedcentral.com]

• Headache

  In AMS-, nitrate did not alter headache or sense of effort. [ncbi.nlm.nih.gov]

  Headache was so common among travelers along an ancient silk route in Central Asia that a Chinese official named the area “Great Headache Mountain” and “Little Headache Mountain.” [americanmigrainefoundation.org]

  Prevention and treatment of high altitude headache. Ibuprofen was significantly superior to placebo both in reducing headache severity and in speed of relief (a mean difference of 94 min in time to no/minimal headache). [bestbets.org]

• Dizziness

  […] and lightheadedness: Not dizzy = 0 Mild dizziness = 1 Moderate dizziness = 2 Severe dizziness, incapacitating = 3 Difficulty sleeping: Slept as well as usual = 0 Did not sleep as well as usual = 1 Woke many times, poor sleep = 2 Could not sleep at all [ultimatekilimanjaro.com]

  It is characterized by sudden onset of a bitemporal headache, nausea, fatigue, dizziness and can be life-threatening with the development of cerebral or pulmonary edema. [symptoma.com]

  […] acute mountain sickness : altitude sickness that is experienced usually within several hours to one day of ascending above 8000 to 10,000 feet (about 2500 to 3000 meters) and that is marked by headache, nausea, loss of appetite, vomiting, insomnia, dizziness [merriam-webster.com]

  It is mainly characterized by a headache which may be accompanied with nausea, vomiting, anorexia, dizziness, lethargy, fatigue, and sleep disturbance. [ncbi.nlm.nih.gov]

• Insomnia

  RESULTS: Results showed that, at 500 m, AISS and insomnia prevalence were higher in older individuals. After acute exposure to altitude, the HR, AISS, and insomnia prevalence increased sharply, and the increase in older individuals was more marked. [ncbi.nlm.nih.gov]

  Definition of acute mountain sickness : altitude sickness that is experienced usually within several hours to one day of ascending above 8000 to 10,000 feet (about 2500 to 3000 meters) and that is marked by headache, nausea, loss of appetite, vomiting, insomnia [merriam-webster.com]

  Common symptoms include headaches, dizziness, vomiting, anorexia, fatigue, and insomnia and they are due to the hypoxic and hypobaric environment at high altitudes. [symptoma.com]

• Irritability

  […] of acute mountain sickness (1) Headache (Severe and persistent) (2) Lassitude (3) Drowsiness/Dizziness (4) Chilliness/Nausea and vomiting (5) Facial pallor/Dyspnea and cyanosis What are the late symptoms of acute mountain sickness (1) Facial flushing/Irritability [quizlet.com]

  To recap, serious symptoms of altitude sickness include: A severe, enduring headache, which is not cured by ordinary painkillers Nausea and repeated vomiting Irritating dizziness or actual difficulty with balance and direction Visual disturbances with [mallatreknepal.com]

  It needs to be used cautiously, however, because it can cause stomach irritation, euphoria or depression. [peakfreaks.com]

  She added: "The symptoms of AMS (headache, nausea, dizziness, fatigue, loss of appetite, insomnia, irritability) occur in about 30% of people exposed to hypobaric hypoxia. [sciencedaily.com]

• Sleep Disturbance

  Sleep disturbance is the most common symptom, and the lower prevalence of headache on Day 3 may be due to the effects of medication and/or acclimatization. [ncbi.nlm.nih.gov]

  In subjects reporting severe headache, 40% did not report sleep disturbance. Sleep disturbance correlates poorly with other symptoms of AMS (Mean Spearman correlation 0.25). [journals.plos.org]

The clinician can diagnose AMS on the basis of the patient's clinical presentation, history, and physical examination findings. History will reveal recent ascent to high altitude by the unacclimatized patient while physical examination may reveal tachycardia, tachypnea, and pulmonary rales if the patient is developing pulmonary edema. Laboratory tests like complete blood count may be abnormal with elevated hematocrit, and erythrocytosis while arterial blood gas analysis will reveal respiratory alkalosis. Pulse oximetry values do not usually indicate the severity of AMS and are therefore not useful in either detecting or in the management of the condition although they may help to detect HAPE. An electrocardiogram may show variable features like right axis deviation, non-specific ST-T changes, sinus arrhythmias, and P wave abnormalities. Chest radiography is indicated only in patients suspected clinically to have HAPE.

The diagnosis and severity of AMS can be assessed using the Lake Louise score (LLS) [8] as well as the Environmental Symptoms Questionnaire (ESQ) [9] [10]. The LLS was developed by a consensus conference on Hypoxia and Mountain Medicine in 1991 and consists of a self-reported score which is the sum of responses to five questions [8] and can be verified by a clinician during an interview. The ESQ consists of an inventory of expected physiological and psychological symptoms and was developed by the United States army. A part of this inventory containing symptoms indicative of cerebral hypoxia (AMS-C) is used to assess AMS [11]. However, the two questionnaires do not corroborate to provide an identical diagnosis [12] and as yet there is no gold standard tool for the assessment of AMS [13] [14].

Despite the presence of AMS symptoms, magnetic resonance imaging does not detect brain edema or an increase in brain volume for up to 12 hours after hypoxia and is therefore not helpful in the diagnosis and management of AMS [14].

• Right Axis Deviation

  An electrocardiogram may show variable features like right axis deviation, non-specific ST-T changes, sinus arrhythmias, and P wave abnormalities. Chest radiography is indicated only in patients suspected clinically to have HAPE. [symptoma.com]

• Hypocapnia

  The current data revealed that on going to high altitude, the subjects experienced not only hypoxia but also developed hypocapnia, therefore, both hypoxia and hypocapnia may be the factors in genesis of AMS. [jpma.org.pk]

  Severe altitude illness occurs most commonly in this range. [10] Extreme altitude [ edit ] Above 5,500 metres (18,000 ft), marked hypoxemia, hypocapnia, and alkalosis are characteristic of extreme altitudes. [en.wikipedia.org]

  The hypoxic ventilatory drive causes hypocapnia and a reduction in respiratory drive [11]. [journals.plos.org]

• Non Specific ST-T Changes

  An electrocardiogram may show variable features like right axis deviation, non-specific ST-T changes, sinus arrhythmias, and P wave abnormalities. Chest radiography is indicated only in patients suspected clinically to have HAPE. [symptoma.com]

• Sinus Arrhythmia

  An electrocardiogram may show variable features like right axis deviation, non-specific ST-T changes, sinus arrhythmias, and P wave abnormalities. Chest radiography is indicated only in patients suspected clinically to have HAPE. [symptoma.com]

Symptomatic treatment, such as basic analgesics for headache and antiemetics, is often helpful. With conservative treatment, most patients successfully acclimatize over 24 to 48 hours and symptoms resolve. [openanesthesia.org]

Treatment of AMS 250 mg PO BD until symptoms resolve. [ncbi.nlm.nih.gov]

Nonpharmacologic treatment includes descent, rest, and oxygen therapy. Pharmacologic therapy with acetazolamide and/or dexamethasone is used for treatment and prophylaxis. [uspharmacist.com]

Small sample sizes limited the power to identify small differences (if any) between the two treatments. [bestbets.org]

What is the prognosis for HAPE? HAPE tends to get better quickly on descent and outlook (prognosis) is that there is usually complete recovery. [patient.info]

(Outcomes/Resolutions) Early diagnosis and immediate management of Acute Mountain Sickness does not pose any adverse long term effects on the patients Overall, the prognosis of AMS is good with early intervention Additional and Relevant Useful Information [dovemed.com]

The prognosis for a person that gets altitude sickness depends on the severity of the sickness. [emedicinehealth.com]

(Etiology) Acute Mountain Sickness primarily develops due to low level of oxygen and lowered air pressure at high altitudes The faster one’s ascent to high altitudes, the higher is the risk of developing AMS. [dovemed.com]

A hemangiogenic and lymphangiogenic origin of this angiosarcoma has been documented. [16] Etiology The most important single causative agent in Stewart-Treves syndrome is prolonged chronic lymphedema. [emedicine.medscape.com]

Cerebral etiology of acute mountain sickness MRI findings. Wilderness Environ Med 6: 229–230, 1995. Google Scholar Copyright information © Springer Science+Business Media New York 1999 Authors and Affiliations Peter H. Hackett 1 1. St. [link.springer.com]

Evid Based Complement Alternat Med. 2013, 2013: 718739- PubMed PubMed Central Google Scholar Swenson ER, Maggiorini M, Mongovin S, Gibbs JSR, Greve I, Mairbäurl H, Bärtsch P: Pathogenesis of high-altitude pulmonary edema: inflammation is not an etiologic [bmccomplementalternmed.biomedcentral.com]

Aims: Previous epidemiological investigations of the relationship between smoking and acute mountain sickness (AMS) risk yielded inconsistent findings. [ncbi.nlm.nih.gov]

Epidemiology: Prevalence Colorado ski resort: 25% of travelers Himalayas: 50% of travelers III. [fpnotebook.com]

Dengue in Vietnamese infants – results of infection-enhancement assays correlate with age-related disease epidemiology, and cellular immune responses correlate with disease severity. J Infect Dis 2008; 198: 516-24. [saripediatri.org]

Like the previous study these trekkers completed the LLS together with an epidemiological questionnaire. Then at 4,730m another set of trekkers, this time 189 were recruited (demographics: male = 108, female = 68, mean age 33, range 18-71). [climbkilimanjaroguide.com]

AIMS: Despite extensive research on acute mountain sickness (AMS), the underlying pathophysiology remains unclear. [ncbi.nlm.nih.gov]

The blood-brain barrier and intracranial hemodynamics are the two key elements in the pathophysiology of HACE and AMS. [link.springer.com]

BUD also could reduce LLS but not prevent AMS at 72 hours. Ipratropium bromide maybe the effective drug in COM work on the prevention of AMS alone. [ncbi.nlm.nih.gov]

They report that in 1 study, 2 spironolactone was more efficacious than placebo for preventing nausea in 19 subjects but was not found to prevent headache or insomnia. [mdedge.com]

RCT Prevention of acute mountain sickness incidence and severity. [bestbets.org]

Clinical Question What is the most effective method for preventing acute mountain sickness? Evidence-Based Answer Gradual ascent is the most effective method for preventing acute mountain sickness. [aafp.org]

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