injuries poisoning
Altitude Illness
Symptoms and Signs of Altitude Illness
Acute mountain sickness is by far the most common form of altitude illness. AMS is unlikely unless altitude is above 2440 m (8000 ft), but it can develop at lower elevations in some highly susceptible people. It is characterized by headache plus at least one of the following: fatigue, gastrointestinal symptoms (anorexia, nausea, vomiting), or persistent dizziness. Poor sleep was previously considered a symptom of AMS but is no longer considered one of the diagnostic criteria. Symptoms typically develop 6 to 10 hours after ascent and, in most cases, subside in 24 to 48 hours. AMS is common at ski resorts, and some people affected by it mistakenly attribute it to excessive alcohol intake (hangover) or a viral illness. HACE occurs rarely, anywhere from 1 to 5 days following ascent. Marked cerebral edema manifests as headache and diffuse encephalopathy with confusion, drowsiness, stupor, and coma. Gait ataxia is a reliable early warning sign. Seizures, focal deficits (eg, cranial nerve palsy, hemiplegia), fever, and meningeal signs are uncommon and should prompt concern for other diagnoses. Papilledema may be present but is not necessary for diagnosis. Coma and death may occur within a few hours unless HACE is treated promptly. HAPE typically develops 24 to 96 hours after rapid ascent to>2500 m (>8000 ft) and is responsible for most deaths due to altitude illness. It may be preceded by AMS, but can also develop in isolation in people who were not manifesting other evidence of altitude illness. Initially, patients have dyspnea on exertion, decreased exertion tolerance, and dry cough. Later, dyspnea is present with simple activities or at rest. Pink or bloody sputum and respiratory distress are late findings. 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. HAPE may worsen rapidly; coma and death may occur within hours unless HAPE is treated promptly. Peripheral and facial edemais common at high altitude even in the absence of altitude illness. Headache,without other symptoms of AMS, is also common. Retinal hemorrhagescan develop at altitudes as low as 2700 m (9000 ft) and are common at>5000 m (>16,000 ft). They are usually asymptomatic unless they occur in the macular region, in which case they typically present as painless vision loss; they resolve over weeks without sequelae. With symptomatic hemorrhages, descent is indicated and further ascent is contraindicated until hemorrhages have resolved. Ophthalmology evaluation is warranted following descent for all patients with symptomatic high-altitude retinal hemorrhages. People who have had radial keratotomy or LASIK may have significant visual disturbances at altitudes>5000 m (>16,000 ft). These symptoms disappear rapidly after descent. Chronic mountain sickness(Monge's disease) is a disease that affects long-time high-altitude residents; it is characterized by excessive polycythemia, fatigue, dyspnea, aches and pains, and cyanosis. The disorder often involves alveolar hypoventilation. Patients should descend to low altitude and remain there permanently if possible, but economic factors often prevent them from doing so. Repeated phlebotomy can help by reducing polycythemia. In some patients, long-term treatment withacetazolamideresults in improvement. 