Altitude Illness - Cerebral Syndromes Follow-up

  • Author: N Stuart Harris, MD, MFA, FACEP; Chief Editor: Rick Kulkarni, MD   more...
 
Updated: Apr 30, 2010
 

Further Inpatient Care

  • Hospitalization is not indicated for AMS.
  • Hospitalization is usually indicated for patients with HACE, depending on severity. Patients with focal neurologic deficits or persistent mental status changes should be admitted. After descent, care is supportive.
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Further Outpatient Care

  • After descent, further outpatient care is not usually indicated for patients with AMS.
  • Patients with mild HACE should have follow-up appointments in 24 hours to check for clearance of symptoms.
  • Patients with concurrent HAPE should be immediately reported to the International HAPE Registry.
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Inpatient & Outpatient Medications

  • Residual headache or nausea in patients with AMS should be treated symptomatically.
  • Continue dexamethasone for 1-2 days after descent in patients with uncomplicated HACE or until the mental status clears in patients with severe HACE who require hospitalization.
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Deterrence/Prevention

  • Recommendations on staged ascents are by and large adequate for the average person, but some persons will still become ill despite a slow, staged ascent. Persons traveling to high altitude should allow adequate time for acclimatization and pay careful attention to symptoms. Helpful guidelines to avoid altitude illness include the following:
    • Avoid abrupt ascent to sleeping elevations over 3000 m (10,000 ft).
    • Spend 1-2 nights at an intermediate elevation (2500-3000 m) before further ascent.
    • Above 3000 m, sleeping elevations should not increase by more than 300-400 m per night.
    • When topography or village locations dictate more rapid ascent, or after every 1000 m gained, spend a second night at the same elevation.
    • Day hikes to higher elevations, with return to lower sleeping elevations help to improve acclimatization.
    • Avoid overexertion.
    • Avoid alcohol consumption in the first 2 days at a new, higher elevation; in addition to concerns about respiratory depression and exaggerated sleep hypoxemia, an AMS headache the next morning is all too easily dismissed as a hangover.
  • Many travelers wonder how long acclimatization lasts after a sojourn to high altitude. Some value in preventing AMS may persist for a week or more.
  • Acetazolamide effectively prevents AMS; it accelerates acclimatization by inducing a bicarbonate diuresis, stimulating ventilation and improving sleep-breathing patterns. It does not mask symptoms of AMS. Acetazolamide prophylaxis is indicated for persons with an unavoidable rapid ascent, such as flying in to a high city (eg, Lhasa, Tibet; La Paz, Bolivia), or with a past history of recurrent AMS. Since it is also useful for treatment, acetazolamide should be in the high altitude traveler's medical kit, along with written instructions. A recent survey concluded that most trekkers carrying acetazolamide did not know how to use it properly.
  • Dexamethasone also effectively prevents AMS but does not improve acclimatization. Because of the concern of rebound symptoms and the side effect profile, this medication cannot be routinely recommended for prophylaxis.
  • In the past, ginkgo biloba had been suggested for AMS prophylaxis. Importantly, a number of recent well-designed studies have found it to be ineffective at preventing AMS. The studies that also included acetazolamide found that acetazolamide alone was effective and that combining ginkgo and acetazolamide did not provide any increased effectiveness.[3, 4] Ginkgo cannot be recommended for AMS.
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Complications

  • Symptoms of HACE, particularly ataxia, commonly persist for days to weeks after descent.
  • In rare cases, patients may have long-term neurologic deficits after severe or prolonged HACE.
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Prognosis

  • The prognosis is excellent for AMS and for survivors of HACE; reascent with caution is acceptable after patients have completely recovered (ie, are fully asymptomatic). It is common for climbers to develop AMS, descend slightly, and 1 or 2 days later (after resolution of their symptoms) continue their ascent.
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Patient Education

  • Educate patients on staged ascents (see Deterrence/Prevention) and on the golden rules of altitude illness.
  • The golden rules of altitude illness
    • If you feel unwell at altitude, it is altitude illness unless proven otherwise.
    • If you have symptoms of altitude illness, go no higher.
    • If your symptoms are worsening, fail to improve with treatment, or if HACE or HAPE are present, descend immediately.
  • For excellent patient education resources, visit eMedicine's Environmental Exposures and Injuries. Also, see eMedicine's patient education article Mountain Sickness.
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Contributor Information and Disclosures
Author

N Stuart Harris, MD, MFA, FACEP  Chief, Division of Wilderness Medicine, Massachusetts General Hospital (MGH) Fellowship Director, MGH Wilderness Medicine Fellowship. Attending Physician, MGH Assistant Professor in Surgery, Harvard Medical School

N Stuart Harris, MD, MFA, FACEP is a member of the following medical societies: American Academy of Emergency Medicine, American College of Emergency Physicians, International Society for Mountain Medicine, and Massachusetts Medical Society

Disclosure: Nothing to disclose.

Coauthor(s)

Sara W Nelson, MD  Staff Physician, Harvard Affiliated Emergency Medicine Residency, Brigham and Women's Hospital and Massachusetts General Hospital

Sara W Nelson, MD is a member of the following medical societies: American College of Emergency Physicians, Emergency Medicine Residents Association, and Phi Beta Kappa

Disclosure: Nothing to disclose.

Specialty Editor Board

Dan Danzl, MD  Chair, Professor, Department of Emergency Medicine, University of Louisville Hospital

Dan Danzl, MD is a member of the following medical societies: American Academy of Emergency Medicine, American College of Emergency Physicians, American Medical Association, Kentucky Medical Association, Society for Academic Emergency Medicine, and Wilderness Medical Society

Disclosure: Nothing to disclose.

Francisco Talavera, PharmD, PhD  Adjunct Assistant Professor, University of Nebraska Medical Center College of Pharmacy; Editor-in-Chief, Medscape Drug Reference

Disclosure: Medscape Salary Employment

Eddy S Lang, MDCM, CCFP(EM), CSPQ  Associate Professor, Senior Researcher, Division of Emergency Medicine, Department of Family Medicine, University of Calgary Faculty of Medicine; Assistant Professor, Department of Family Medicine, McGill University Faculty of Medicine, Canada

Eddy S Lang, MDCM, CCFP(EM), CSPQ is a member of the following medical societies: American College of Emergency Physicians, Canadian Association of Emergency Physicians, and Society for Academic Emergency Medicine

Disclosure: Nothing to disclose.

John D Halamka, MD, MS  Associate Professor of Medicine, Harvard Medical School, Beth Israel Deaconess Medical Center; Chief Information Officer, CareGroup Healthcare System and Harvard Medical School; Attending Physician, Division of Emergency Medicine, Beth Israel Deaconess Medical Center

John D Halamka, MD, MS is a member of the following medical societies: American College of Emergency Physicians, American Medical Informatics Association, Phi Beta Kappa, and Society for Academic Emergency Medicine

Disclosure: Nothing to disclose.

Chief Editor

Rick Kulkarni, MD  Attending Physician, Department of Emergency Medicine, Cambridge Health Alliance, Division of Emergency Medicine, Harvard Medical School

Rick Kulkarni, MD is a member of the following medical societies: Alpha Omega Alpha, American Academy of Emergency Medicine, American College of Emergency Physicians, American Medical Association, American Medical Informatics Association, Phi Beta Kappa, and Society for Academic Emergency Medicine

Disclosure: WebMD Salary Employment

Additional Contributors

The authors and editors of eMedicine gratefully acknowledge the contributions of previous author, Thomas E Dietz, MD, to the development and writing of this article.

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High-altitude cerebral edema (HACE). Image courtesy of Dr Peter Hackett.
A very ataxic man with high-altitude cerebral edema (HACE) at 4250 m being assisted toward the Gamow bag.
Ultrasonography - Optic nerve sheath diameter measurement. Top of field is cornea, bottom of field reveals retina, then optic nerve in lowest field. Images courtesy of Dr Peter Fagenholz et al.
Horse evacuation of nonambulatory altitude illness. Patient in the Khumbu, Nepal. Image courtesy of Dr Peter Fagenholz.
 
 
 
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