[Acute Mountain Sickness and High-Altitude Cerebral Edema].

If not properly acclimatized ascent to high altitude may result in hypoxia-related illnesses as acute mountain sickness (AMS), high altitude cerebral edema (HACE) or high altitude pulmonary edema (HAPE). AMS is most frequent and usually harmless but may progress to HACE. HACE and HAPE are rare but potentially lethal. This paper focuses on AMS and HACE. Whether AMS and HACE represent different severity of clinical manifestation of the same underlying pathophysiology is still a matter of debate. AMS presents 4-8 hours after ascent above 2300 m with unspecific symptoms as headache, anorexia, nausea, dizziness and sleep disturbance. The Lake-Louise-Score is useful for diagnosing AMS and assessing its severity. Headache not responding to usual treatment or repetitive emesis may indicate progression to HACE, which is characterized by impaired consciousness and truncal ataxia. Altitude-related illnesses can be prevented most effectively by slow ascent and pre-acclimatization. An average ascent of not more than 300-500 m per day (referring to the altitude at which one sleeps) is recommended. If this is not possible prophylaxis with acetazolamide (125-250 mg bid) or corticosteroids (dexamethasone 4 mg 2-3 x / day or equivalent dosage of other corticosteroids) can be recommended for not pre-acclimatized individuals. Mild AMS can be treated without descent by a day of rest and by common nonsteroidal anti-inflammatory drugs and / or anti-emetics. If symptoms do not resolve or worsen descent is necessary. In case of severe AMS or HACE immediate descent facilitated by dexamethasone 4-8 mg initially, followed by 4 mg every 6-8 hours is mandatory.