considered if there is any indication of infection HIGH-ALTITUDE ILLNESS Goals of Treatment Early recognition and treatment can lead to complete recovery Severe illness needs to be treated with cardiopulmonary resuscitation and descent to prevent pulmonary edema and cerebral edema CLINICAL PEARLS AND PITFALLS The four major illnesses seen with altitude include high-altitude headache (HAH), acute mountain sickness (AMS), high-altitude cerebral edema (HACE), and high-altitude pulmonary edema (HAPE) Treatment for HAH or mild AMS includes acetazolamide, analgesics, hydration, and antiemetics For more severe AMS or HACE, oxygen, hyperbaric therapy, and dexamethasone are indicated, along with immediate descent if feasible Current Evidence Physiologic changes accompanying altitude may be attributed to hypobaric hypoxia As altitude increases, barometric pressure decreases, resulting in a reduction in the partial pressure of oxygen Temperature also decreases with altitude, so hypothermia can compound these hypoxic effects The individual’s response to hypoxia is to increase ventilation, which raises alveolar oxygen while reducing alveolar carbon dioxide simultaneously Hypocapnia produces an alkalosis that, in turn, will serve as a “check and balance” for the body by limiting further increases in the respiratory rate With time the pH returns to neutral as the kidneys excrete bicarbonate in response to this alkalosis Acetazolamide (Diamox) is used to inhibit carbonic anhydrase-dependent bicarbonate resorption in the tubules to facilitate bicarbonate excretion, inducing a metabolic acidosis that allows the ventilatory rate to remain high and to maintain better oxygenation Clinical Recognition The four major illnesses seen with altitude include high-altitude headache (HAH), acute mountain sickness (AMS), high-altitude cerebral edema (HACE), and highaltitude pulmonary edema (HAPE) Headache is typically the initial symptom upon climbing to higher altitudes; it may occur alone as in HAH or progress to