Altitude Illness
Altitude Illness: Excerpt from The 5-Minute Pediatric Consult
Patrick Solari, MDPaige L. Wright, MDGeorge A. Woodward, MD, MBA
Altitude Illness - BASICS
Altitude Illness - description
- Acute mountain sickness (AMS): Failure to adapt to the hypoxic demands of altitude. Includes a group of clinical signs and symptoms seen in travelers to altitudes >2,500 m
- Mild mountain sickness: Headache in morning and on exertion, anorexia, nausea, dizziness, vomiting, shortness of breath on exertion, insomnia, irritability, periodic breathing (Cheyne-Stokes respiration), poor performance
- Moderate mountain sickness: Severe headache, lassitude (weariness, indifference, antisocial), weakness, anorexia, nausea, ataxia, decreased urine output, diminished judgment and coordination. Capable of activities with difficulty.
- Severe mountain sickness: Insidious or acute onset, usually 2–4 days after ascent. Can progress to life-threatening situation within hours. Can include pulmonary and cerebral edema.
- High-altitude cerebral edema (HACE): Develops over 1–3 days after ascent, usually preceded by AMS. Headache, vomiting, lassitude, irritability, drowsiness, ataxia, slurred speech, cranial nerve paralysis, hypo- or hyperreflexia, hemiparesis, hemiplegia, mental status changes (confusion, irrationality, depression, disorientation, amnesia, hallucinations, severe nightmares), decreased urine output, seizures, papilledema, coma, death
- High-altitude pulmonary edema (HAPE): OFTEN develops over several days and may be associated with or exacerbated by concurrent viral illness. Initially with dyspnea on exertion, then at rest, decreased exercise capability, dry cough, fatigue, tachypnea, low-grade fever <38.5°C [99.5°F]. Develop pink frothy sputum, cyanosis, wheezing, rales, tachycardia, low-grade fever, and orthopnea
- Other altitude-related issues: High-altitude syncope, amnesia, edema (facial and extremity), retinopathy (hemorrhages), pharyngitis and bronchitis, flatus, immune suppression, thrombosis, coagulation abnormalities (thrombolic events), platelet changes, chronic mountain illness (Monge disease, polycythemia), weight loss
Altitude Illness - general prevention
- Avoid rapid ascent:
- Limit ascents to 300 m (1,000 ft) per day above 3,000 m (>10,000 ft).
- Gradual acclimatization
- Do not fly or drive to heights above 3,000 m.
- Allow at least 24 hours for each 1,000 m (3,300 ft) gained.
- Exercise is not a substitute for acclimatization (or protection against AMS).
- Early recognition of symptoms (even if minor).
- Assume symptoms secondary to AMS unless proven otherwise.
- Go no higher until symptoms resolve.
- Descend if worsening.
- Climb high, sleep low.
- Avoid alcohol, codeine, sedative-hypnotics, and respiratory depressants.
- Exercise within individual capacity:
- Avoid heavy exercise after passive ascent for at least 24 hours.
Altitude Illness - risk factors
- Travel in high-altitude areas
- Rapid ascent
- Underlying medical conditions, such as sickle cell disease, hypertension, sleep apnea, obstructive lung disease, cerebrovascular disease, or concurrent infections, may predispose one to development of altitude illness.
Altitude Illness - pathophysiology
- HAPE linked to elevated pulmonary artery pressure (PAP). Medications that lower PAP may prevent HAPE.
- Early fluid retention also linked to development of AMS
Altitude Illness - etiology
Ophthalmologic:
- Retinal vessel engorgement
- Retinal hemorrhages: Usually resolves in 7 to 10 days without symptoms. 100% of people at 6,500 m (21,450 ft)
- Macular hemorrhages: More severe, associated with visual changes
- Ultraviolet keratitis
Altitude Illness - DIAGNOSIS
Altitude Illness - signs & symptoms
- See “Description.”
- Symptoms either insidious or acute onset, usually 2–4 days after ascent:
- Can become life threatening within hours
- Morning headache, progressive with ascent:
- Insomnia, difficulty falling asleep, frequent waking:
- Suggests hypoxia, early AMS
- Periodic breathing (hyperpnea to apnea):
- Suggests moderate to advanced AMS
- GI: Anorexia, nausea, vomiting, abdominal cramps, flatus:
- Potentially related to ascent
- Pulmonary: Dry cough, shortness of breath, sore throat, dyspnea on exertion and at rest, decreased exercise capability:
- Potential progression to HAPE
- Neurologic: Lassitude, weariness, indifference, fatigue, irritability, dizziness, ataxia, or weakness:
- Decreased urine output edema or fluid retention:
- Indicative of fluid shifts, fluid losses, inadequate replacement, or dehydration
Altitude Illness - history
- Previous altitude illness:
- Suggests symptoms in future with ascent to similar altitude
- Altitude where symptoms occurred, method of arrival at altitude, and rate of ascent:.
- Rapid ascent minimizes time for natural acclimatization and increases risk of developing altitude illness.
- Exertion level:
- Increased exertion on ascent may increase speed of symptom development.
- Medication, drug, or alcohol use, predisposing medical illness (asthma, restrictive lung disease):
- Underlying medical conditions, such as sickle cell disease, hypertension, sleep apnea, obstructive lung disease, cerebrovascular disease, or concurrent infections, may predispose one to development of altitude illness.
- Medication use or presumed medical illness may mask or mimic signs and symptoms of altitude illness.
Altitude Illness - physical exam
- Normal in early AMS:
- Physical examinations are nondescript early in development.
- Abnormalities usually occur after 12–24 hours at altitude (range, 2–96 hours).
- Lake Louise Score (LLS): (0–15)
- Elevation Gain + Headache + Score >3 is considered diagnostic of AMS.
| Score | 0 | 1 | 2 | 3 |
| Headache | None | Mild | Mod | Severe |
| GI | None | Mild upset | Mod upset | Vomiting |
| Fatigue | None | Mild tired | Mod tired | Incapacitating |
| Dizziness | None | Mild dizzy | Mod dizzy | Severe dizziness |
| Sleeping | None | Less sleep | Mod waking | No sleep |
- Children’s LLS: (0–15)
- Used in preverbal children.
- Fussiness + Symptom Score >7 is considered diagnostic of AMS.
- Fussiness Score = Mean of Amount and Intensity of Fussiness
| Score | 0 | 3 | 6 |
| Amount | None | Some | Constant |
| Intensity | Not fussy | Moderate | Extremely Fussy |
- Symptom Score (0–9):
- Sum of Eating, Playing, Sleeping scores
| Score | 0 | 1 | 2 | 3 |
| Eating | Norm | Mild | Mod Eating | Not eating; vomiting |
| Playing | Norm | Mild less | Play | No play at all |
| Sleeping | Norm | Mild less | Difficult sleep | Unable to sleep |
Altitude Illness - tests
ECG:
- Rule out myocardial etiology of symptoms or consequence of ascent.
Altitude Illness - lab
- Toxicologic screen:
- Rule out medication effect for presenting symptoms.
- Electrolytes:
- Assess hydration status, fluid shifts, and glucose.
- Arterial blood gas:
- Check oxygenation, ventilation, and acid–base status.
- Carbon monoxide level:
- Ensure that carbon monoxide poisoning is not a factor.
- CBC:
- Assess oxygen-carrying capacity of blood.
- Look for anemia, polycythemia, and platelet abnormalities.
Altitude Illness - imaging
- Chest x-ray:
- Vasocongestion, patchy or diffuse infiltrates, often worse than physical exam suggests.
- Ventilation and perfusion scan:
- Structural pulmonary assessment
- Brain CT scan:
- Assess for structural abnormalities and cerebral edema.
Altitude Illness - differencial diagnosis
- Environmental:
- Alcohol toxicity, hangover, drug effects, hypothermia, carbon monoxide poisoning
- Medical/metabolic:
- Dehydration, viral illness
- Psychosocial:
- Exhaustion, sleep deprivation, personality traits (irritability), insomnia
Altitude Illness - TREATMENT
Altitude Illness - initial stabilization
- Suspect AMS
- Stop ascent
- Partial or full descent
- Gamow portable hyperbaric chamber may be used as a stopgap until descent can be arranged.
- Oxygen if available
- Fluids
- Consider acetazolamide
- Avoid alcohol, codeine, sedative-hypnotics:
- Red wine reported to perhaps have beneficial effect with regard to HAPE
- Avoid respiratory depressants
Altitude Illness - general measures
- Mild AMS:
- Treatment may not be needed.
- Symptomatic headache relief with ibuprofen, acetaminophen, aspirin, prochlorperazine
- Temporal artery massage
- Halt descent until symptoms improve.
- Moderate to severe AMS:
- Descent
- Oxygen (relieves hypoxia, reduces pulmonary hypertension)
- Furosemide (be careful of volume depletion)
- Acetazolamide
- Consider dexamethasone (if allergic to sulfa or cannot take acetazolamide)
- Vasodilators (nifedipine, morphine)
- HACE:
- Descend immediately.
- Oxygen, furosemide, dexamethasone
- Consider intubation and hyperventilation.
- HAPE:
- Descend immediately.
- Oxygen
- Furosemide
- Acetazolamide
- Vasodilators (nifedipine, morphine) and bronchodilators may be useful.
- Consider antibiotics.
- Positive-pressure breathing
- Pursed-lip breathing, mask, intubation
- Knee-chest position with abdominal squeeze
- Portable hyperbaric chamber
- Symptoms may recur when positive pressure removed.
Altitude Illness - diet
- Increase fluid and calorie consumption with altitude and exertion.
- Increased carbohydrate diet.
- Avoid alcohol, tobacco, sedatives, and recreational drugs.
Altitude Illness - special therapy
Altitude Illness - comp alt-medicine
- Gingko biloba not shown to be effective at preventing altitude illness.
- Sildenafil and tadalafil shown to decrease pulmonary artery pressure (PAP) at high altitude and may reduce incidence of HAPE, not studied in children.
Altitude Illness - medication
- Acetazolamide (Diamox, a carbonic anhydrase inhibitor): A diuretic that induces mild metabolic acidosis with concomitant reflex hyperventilation:
- Hastens natural respiratory changes that occur during acclimatization
- Can help prevent AMS
- Effectiveness in treating established AMS not clear
- General guidelines for use:
- Use in conjunction with (not in place of) gradual ascent, with passive transport to 3,000 m (9,850 ft) and rapid active transport.
- Prophylaxis if previous history of AMS, history of periodic breathing, insomnia
- Treatment of early AMS
- Sulfa: Caution if allergy is present
- Dosage: 5–10 mg/kg/d divided b.i.d. (125–500 mg b.i.d. or t.i.d. in adults), 24 hours prior to ascent and 1–2 days at altitude
- Side effects: Mild diureses, paresthesias, nausea, drowsiness, taste changes, anorexia, blurred vision
- Dexamethasone (Decadron)
- Helpful for AMS treatment, early HACE
- Dosage: 4 mg b.i.d.–q.i.d.
- Nifedipine
- Dosage: 20-mg sustained release q8–12h may be useful for treatment and prevention of HAPE, 24 hours prior to ascent and for 2–3 days at altitude.
Altitude Illness - FOLLOW UP
Altitude Illness - prognosis
- Expect improvement with mild mountain sickness in 1–2 days.
- Moderate mountain sickness clears with descent and acclimation.
- Severe mountain sickness clears with descent and therapy.
- Excellent if recognized quickly, ascent stopped, and/or descent and therapy initiated
- Can be poor if symptoms go unrecognized or noted without appropriate descent and therapy
Altitude Illness - bibliography
- Bartsch P, Mairbaurl H, et al. Physiological aspects of high-altitude pulmonary edema. J App Physiol. 2005;98:1101–1110.
- Basnyat B, Murdoch DR. High-altitude illness. Lancet. 2003;36:1967–1974.
- Carpenter TC, Niermeyer S, Durmowicz AG. Altitude-related illness in children. Curr Probl Pediatr. 1998;28:177–198.
- Chow T, Browne Y, Helleson HL, et al. Gingko biloba and acetazolamide prophylaxis for acute mountain sickness. Arch Intern Med. 2005;165:296–301.
- Dumont L, Mardirosoff C, Tramer MR. Efficacy and harm of pharmacological prevention of acute mountain sickness: Quantitative systematic review. Brit Med J. 2000;321:267–272.
- Gallagher SA, Hackett. High-altitude illness. Emerg Med Clin N Am. 2004:329–355.
- Yaron Waldman N, Niermeyer S, et al. The diagnosis of acute mountain sickness in preverbal children. Arch Pediatr Adolesc Med. 1998;152:683–687.
Altitude Illness - CODES
Altitude Illness - icd9
- E902.0 Altitude illness due to residence or prolonged visit at high altitude
- 993.2 Other and unspecified effects of high altitude
Altitude Illness - FAQ
- Q: Can one develop AMS at moderate altitudes, such as during a ski vacation?
- A: Yes, although the altitudes encountered rarely lead to the development of severe symptoms in this population.
- Q: Will physical conditioning prior to ascent decrease the risk of developing altitude illness?
- A: No. In fact, better conditioning may inadvertently increase the risk of developing altitude illness, as one may achieve higher altitudes more quickly.
- Q: Are children more likely to develop HAPE than adults?
- A: Children from low altitudes have no greater risk of developing HAPE than adults; however, children who reside at high altitudes are more likely than adults to develop re-entry HAPE.
- Q: Should everyone in whom a headache develops when at a higher than usual altitude be treated (pretreated) with acetazolamide?
- A: No. One must weigh other options and severity of illness prior to decision to treat or provide prophylaxis for AMS.
- Q: Should athletes avoid altitude in their training regimens?
- A: No. In fact, living at altitude, but training at a lower altitude, has been shown to improve performance, reportedly by an increase in erythropoietin.
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Book Source Details
- Book Title: The 5-Minute Pediatric Consult
- Author(s): M. William Schwartz MD; et al.
- Year of Publication: 2008
- Copyright Details: The 5-Minute Pediatric Consult, Copyright © 2008 Lippincott Williams & Wilkins.
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Copyright notice for book excerpts: Copyright © 2008 Lippincott Williams & Wilkins. All rights reserved.
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More About This Book:
Title: The 5-Minute Pediatric Consult
Authors: M. William Schwartz MD; et al.
Publisher: Lippincott Williams & Wilkins
Copyright: 2008
ISBN: 0-7817-7577-9
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