Visinska bolest: AMS, HAPE i HACE¶

High-altitude illness strikes hikers, skiers, mountaineers, and travelers who ascend above 2,500 meters (8,200 feet) faster than their bodies can acclimatize to lower barometric pressure. While mild Acute Mountain Sickness (AMS) causes an uncomfortable headache and nausea that resolves with rest at the same elevation, its two life-threatening progressions, High Altitude Pulmonary Edema (HAPE) and High Altitude Cerebral Edema (HACE), fill the lungs with fluid or cause fatal brain swelling within hours.

Following the Three Golden Rules of Altitude (recognize symptoms early, never ascend with symptoms, and descend immediately if symptoms worsen or involve the lungs or brain) is the single most effective way to prevent death in high mountains. Every trekking group, ski party, and high-altitude traveler should know how to perform the heel-to-toe balance test, recognize breathlessness at rest, and execute an immediate assisted descent.

Uradi ovo sada¶

1. Perform the 10-second "Heel-to-Toe Walking Test" (Tandem Gait Test) immediately: Draw a straight line in the dirt or snow and ask the person to walk heel-to-toe along the line like a police sobriety test. If they stagger off the line, wave their arms wildly for balance, or cannot stand straight with their eyes closed (ataxia), assume High Altitude Cerebral Edema (HACE) is developing and start an immediate assisted descent.
2. Check breathing after 10 minutes of complete sitting rest: It is normal to breathe hard while hiking uphill at altitude. However, if a person is still panting, gasping, or has a fast resting heart rate (over 110 beats per minute) and crackling chest sounds after sitting completely still for 10 minutes, assume High Altitude Pulmonary Edema (HAPE) and descend immediately.
3. Stop ascending immediately for any mild symptoms: If the person passes the balance test and breathes comfortably at rest, but has a headache alongside nausea, dizziness, or unusual fatigue, diagnose Acute Mountain Sickness (AMS). Halt all upward travel immediately; do not climb even 100 meters (330 feet) higher to reach a camp or pass.
4. Execute an immediate assisted descent of 500 to 1,000 meters (1,600 to 3,300 feet) for HAPE/HACE: Take the sick person's backpack, support their weight between two companions (or carry them on a litter or horse), and head down to the lowest possible elevation. Physical exertion increases blood pressure in the lungs and brain, so the patient must work as little as possible during descent.
5. Administer high-flow oxygen or a Gamow bag if descent is delayed: If bottled medical oxygen is available, deliver 4 to 6 liters per minute via mask or nasal cannula. If trapped by a blizzard or cliff terrain, seal the patient inside a portable hyperbaric chamber (Gamow bag) and pump continuously until weather allows descent.
6. Activate satellite rescue and keep the patient warm: Trigger an SOS on a satellite communicator (Garmin inReach, ZOLEO, or smartphone satellite SOS) or call your local emergency number (911 in the United States and Canada, 112 across the European Union, 999 in the United Kingdom) or check brojevi za hitne slučajeve if cellular coverage exists. Keep the patient warmly insulated; shivering and cold exposure constrict lung arteries and rapidly worsen HAPE.

Tactical decision flow for altitude illness triage¶

flowchart TD
    Symptom["Altitude Symptoms Above 2,500 m (8,200 ft): Headache, Fatigue, or Breathlessness"] --> Balance{"1. Heel-to-Toe Walk Test: Does Patient Stagger or Show Confusion?"}
    Balance -->|"Yes: Ataxia or Altered Mental State"| HACE["HACE (Brain Swelling): Immediate Assisted Descent 500 to 1,000 m"]
    Balance -->|"No: Normal Balance and Alert"| RestBreath{"2. Short of Breath After 10 Minutes of Complete Sitting Rest?"}
    RestBreath -->|"Yes: Breathless at Rest, Cough, or Blue Lips"| HAPE["HAPE (Fluid in Lungs): Sit Upright, Keep Warm, Descend 500 to 1,000 m Now"]
    RestBreath -->|"No: Comfortable at Rest, Headache + Nausea/Fatigue"| AMS["Mild to Moderate AMS: Stop Ascending, Rest 24 to 48 Hours, Hydrate"]
    AMS --> Worsen{"3. Do AMS Symptoms Worsen or Fail to Improve in 24 Hours?"}
    Worsen -->|"Da"| Descend["Descend at Least 500 m (1,600 ft) Until Symptoms Resolve"]
    Worsen -->|"No: Fully Resolved"| Resume["Resume Gradual Ascent: Max 300 to 500 m Sleeping Gain per Day"]
    HACE --> Rescue["Administer Oxygen (4 to 6 L/min) or Gamow Bag + Activate Mountain Rescue SOS"]
    HAPE --> Rescue

Barometric physics and physiological zones of high altitude¶

A common misconception is that the air at high mountain elevations contains a lower percentage of oxygen. In fact, atmospheric air contains the exact same 20.9 percent oxygen from sea level all the way to the summit of Mount Everest (8,849 meters / 29,032 feet). What changes is barometric pressure: as you climb higher, there is less overlying atmosphere pressing down from above, so air molecules spread farther apart. Because every lungful of thin mountain air contains fewer total oxygen molecules, the partial pressure of inspired oxygen (\(\text{PiO}_2\)) driving oxygen across your lung membranes into your bloodstream drops dramatically.

Clinical comparison: AMS vs HAPE vs HACE¶

Understanding why thin air causes fluid to leak out of capillaries into the brain and lungs helps you distinguish normal high-altitude breathing from a life-threatening emergency.

The Lake Louise AMS Self-Assessment Score and neurological checks¶

According to the International Consensus Lake Louise Scoring System (updated 2018) and the Wilderness Medical Society (WMS), Acute Mountain Sickness (AMS) is diagnosed when a person who has ascended to a new altitude above 2,500 meters (8,200 feet) within the past 6 to 96 hours experiences a Headache (scoring at least 1 point) plus at least one other symptom for a total score of 3 or more:

1. Headache:
2. 0 = Uopšte nijedno
3. 1 = Blaga glavobolja
4. 2 = Umjerena glavobolja
5. 3 = Teška, onesposobljavajuća glavobolja
6. Gastrointestinalni simptomi:
7. 0 = Good appetite
8. 1 = Poor appetite or mild nausea
9. 2 = Moderate nausea or vomiting
10. 3 = Teška, onesposobljavajuća mučnina i povraćanje
11. Umor i slabost:
12. 0 = Not tired or weak
13. 1 = Mild fatigue or weakness
14. 2 = Moderate fatigue or weakness
15. 3 = Severe, incapacitating fatigue or weakness (reluctant to leave tent for meals or water)
16. Dizziness or Lightheadedness:
17. 0 = Not dizzy
18. 1 = Mild dizziness
19. 2 = Moderate dizziness

20. 3 = Severe, incapacitating dizziness

21. Score 3 to 5 (Mild AMS): Stop all further ascent immediately. Rest at the current elevation for 24 to 48 hours, stay hydrated, avoid alcohol and sleeping pills, and re-evaluate every 4 hours.

22. Score 6 to 12 (Moderate to Severe AMS): Treat as high risk for imminent progression to HACE. If symptoms do not rapidly improve within a few hours of rest and oxygen, descend 300 to 500 meters (1,000 to 1,650 feet) before nightfall.

How to perform the Heel-to-Toe Tandem Gait Test and Chest Auscultation¶

Because early HACE and HAPE often begin silently at dusk or during the night, expedition leaders and trekking partners should perform two 30-second physical checks every evening and morning in camp:

• The Heel-to-Toe (Tandem Gait) Balance Test for HACE: Swelling in the cerebellum (the balance center at the back of the brain) is the earliest sensitive physical sign of HACE, often appearing before obvious confusion or coma. Scratch a straight 3-meter (10-foot) line in the dirt, gravel, or snow outside the tent. Ask the climber to walk along the line placing the heel of their front boot directly touching the toe of their back boot on every step, turn around, and walk back. A healthy, acclimatized climber can walk heel-to-toe smoothly. If the climber steps off the line repeatedly, staggers sideways like a drunk person, or cannot stand still with their feet together and eyes closed without swaying (Romberg sign), they have clinical ataxia (HACE) until proven otherwise and must be taken down the mountain immediately.
• Ear-to-Chest Listening and Resting Respiratory Count for HAPE: Ask the climber to sit quietly for 10 full minutes after taking off their pack. Count how many breaths they take in 60 seconds and check their pulse. At rest in camp, a breathing rate exceeding 25 to 30 breaths per minute alongside a resting pulse over 110 to 120 beats per minute is a major red flag for HAPE. Place your bare ear directly against the skin of their back just below the shoulder blades (especially under the right shoulder blade, where early HAPE fluid often collects first in the right middle lobe) while they take a deep breath in and out: if you hear fine crackling (like rubbing hair between your fingers or opening Velcro) or wet bubbling sounds, fluid is leaking into their alveoli.

Step-by-step field management for HAPE and HACE¶

When a team member fails the heel-to-toe balance test (HACE) or becomes breathless at rest (HAPE), every hour at altitude increases mortality. Remember that HAPE accounts for the majority of deaths from altitude illness, and roughly 50 percent of climbers with advanced HAPE develop secondary HACE simultaneously because their fluid-filled lungs cannot oxygenate their brain.

1. Execute immediate, low-exertion assisted descent¶

• Why descent works like a miracle: Descending even 300 to 500 meters (1,000 to 1,650 feet) increases atmospheric barometric pressure enough to raise alveolar oxygen tension immediately. A descent of 1,000 meters (3,300 feet) frequently reverses life-threatening HAPE and early HACE within 2 to 6 hours.
• Never let a HAPE or HACE patient carry weight or hike vigorously: Physical exertion increases cardiac output and spikes pulmonary artery pressure, forcing even more serum and red blood cells through ruptured lung capillaries into the air sacs. Strip the patient of their backpack immediately, distribute their gear among healthy teammates, support the patient under both arms using trekking poles, or evacuate them on a pack animal (horse, mule, or yak), wheeled litter, or improvised rope stretcher.
• Descend at night if necessary: Do not wait until morning for a HAPE or HACE patient to "rest up." Nighttime hypoxia between midnight and 4:00 AM is the deadliest window at high camp. Put on high-output LED headlamps, harness the patient between two strong teammates, and descend the trail immediately unless a blizzard, whiteout, or technical cliff makes night movement impossible.
• Keep HAPE patients seated upright: Whenever a HAPE patient rests on the trail, sits in a tent, or rides in a stretcher, prop their torso upright or semi-upright at a 45-to-90-degree angle. Laying a HAPE patient flat on their back causes pulmonary edema fluid to spread across the upper lung fields, triggering acute suffocation within minutes.

2. Protect strictly against cold and hypothermia¶

Cold exposure triggers sympathetic peripheral vasoconstriction throughout the skin and limbs, shunting blood volume inward into the central chest cavity and sharply elevating blood pressure inside the fragile pulmonary capillaries. Clinical mountain rescue studies prove that a climber who becomes chilled or develops hypothermia at altitude is far more likely to develop acute HAPE, and shivering increases oxygen consumption by up to 400 percent.

• Dress the patient immediately in their heaviest down parka, windproof shell, insulated pants, mittens, and warm hat.
• Insulate them from snow or frozen ground with two closed-cell foam sleeping pads, place hot water bottles wrapped in socks against their armpits and chest, and have them breathe through a fleece neck gaiter or balaclava to warm and humidify inspired mountain air.

3. Operating a portable hyperbaric chamber (Gamow Bag / PAC)¶

High-altitude expeditions, Himalayan trekking lodges, and alpine mountain huts frequently stock an inflatable cylindrical nylon hyperbaric chamber (such as a Gamow bag, Certec bag, or Portable Altitude Chamber). A hyperbaric bag is a life-saving bridge when a midnight blizzard, avalanche slope, or vertical terrain prevents immediate physical descent:

1. Pre-check the patient before sealing: Have the patient urinate before entering the bag. Check that their airway is clear, explain how the chamber works to prevent claustrophobia, and instruct them to swallow, chew gum, yawn, or pinch their nose and blow gently (Valsalva maneuver) as pressure rises so their eardrums equalize comfortably. If the patient has HAPE and cannot lie flat without gasping, place the entire inflated bag on an angled 30-to-45-degree snow ramp or boulder slope with their head at the high end.
2. Zip and pressurize to simulated lower altitude: Place the patient inside wrapped in a dry sleeping bag with a headlamp and water bottle, zip the heavy airtight pressure zipper closed completely, and pump the foot or hand pump rapidly for 2 to 3 minutes until the built-in pressure relief valve begins hissing continuously (typically calibrated to 105 to 140 millibars / 1.5 to 2.0 pounds per square inch above ambient mountain air pressure). This internal pressure increase simulates an instantaneous descent of 1,500 to 2,500 meters (5,000 to 8,000 feet).
3. Pump continuously at 10 to 15 strokes per minute without stopping: Once the chamber is fully inflated, a rescuer must keep pumping 10 to 15 full strokes every minute for the entire time the patient is inside. Continuous pumping does not just keep the bag firm; it flushes the patient's exhaled carbon dioxide (\(\text{CO}_2\)) out through the bleed valve and brings fresh oxygen in. Stopping pumping while a patient is zipped inside an airtight Gamow bag causes lethal carbon dioxide suffocation within 15 to 20 minutes.
4. Use the post-chamber window to walk the patient down the mountain: After 2 to 6 hours of continuous hyperbaric treatment, HACE and HAPE patients frequently regain enough balance, mental clarity, and breathing comfort to walk down the trail with assistance. Start the physical descent immediately upon unzipping the bag, because hyperbaric relief is temporary and cerebral/pulmonary edema will rebound within hours if the patient remains at high camp.

Differentiating altitude sickness from dehydration, hypothermia, hyponatremia, and CO poisoning¶

In high mountain environments, four other acute medical emergencies produce symptoms that closely mimic AMS, HAPE, and HACE. Misdiagnosing them can lead to fatal treatment errors:

• Severe Dehydration: Cold, bone-dry mountain air and hyperventilation cause climbers to lose 3 to 5 liters (3 to 5 quarts) of water per day through insensible respiratory vapor loss and sweat. Dehydration causes throbbing headache, nausea, dark yellow urine, weakness, and orthostatic dizziness. Field differentiation: If a climber has dark concentrated urine and a mild headache with normal balance and clear lungs at rest, have them sit in the shade and drink 1 liter (1 quart) of water with electrolytes over 60 minutes. If the headache disappears completely after rehydration, the cause was dehydration; if the headache persists or worsens despite pale urine, diagnose AMS and halt ascent.
• Exercise-Associated Hyponatremia (Over-Hydration / Water Intoxication): Well-meaning trekking guides sometimes tell hikers to "drink 6 to 8 liters of plain water a day to prevent altitude sickness." Chugging excessive quantities of plain, salt-free water dilutes blood sodium levels below 130 mmol/L (hyponatremia), causing water to rush osmotically into brain cells and triggering fatal cerebral edema, confusion, staggering ataxia, vomiting, and seizures identical to HACE. Field differentiation: Ask how much the climber has been drinking and urinating. If they have been forcing down liters of plain water and passing frequent, crystal-clear urine every 30 minutes before becoming confused or clumsy, stop all plain water intake immediately, give salty broth or salted snacks if conscious, and descend.
• Tent Carbon Monoxide (\(\text{CO}\)) Poisoning: Melting snow or cooking dinner with a liquid-fuel or canister camp stove inside a zipped tent or snow cave during a storm generates odorless carbon monoxide gas, which binds to hemoglobin 200 times more tightly than oxygen. At high altitude where blood oxygen is already low, carbon monoxide poisoning causes throbbing frontal headache, nausea, vomiting, staggering ataxia, and coma within 15 minutes, mimicking severe AMS and HACE. Field differentiation: If two or three tentmates develop the exact same sudden headache and nausea right after running a stove inside a tent or vestibule, throw the tent doors wide open immediately, drag everyone into fresh outside air, administer high-flow oxygen if available, and review our carbon monoxide and smoke inhalation first aid guide.
• Wilderness Hypothermia and Exhaustion: Moderate hypothermia (core temperature below 32 degrees Celsius / 90 degrees Fahrenheit) causes the "umbles" (stumbling, mumbling, fumbling, and grumbling), apathy, confusion, and loss of balance identical to HACE. Golden rule: If you cannot be 100 percent certain whether a stumbling, confused climber at 4,000 meters (13,100 feet) has HACE or hypothermia, treat aggressively for both at the exact same time by wrapping them in dry insulation with warm water bottles while carrying or assisting them down to lower elevation.

Prevention and safe acclimatization rules¶

According to the Wilderness Medical Society (WMS), the Centers for Disease Control and Prevention (CDC, United States), and the UIAA (International Climbing and Mountaineering Federation) Medical Commission, the vast majority of severe altitude illnesses are preventable by respecting human physiological acclimatization limits:

1. Stage your initial ascent to 2,500 to 3,000 meters (8,200 to 10,000 feet): Avoid flying or driving directly from sea level to sleep above 2,800 meters (9,200 feet) in a single day. If flying into high-altitude cities such as Cusco, Peru (3,400 m / 11,150 ft), La Paz, Bolivia (3,640 m / 11,940 ft), Lhasa, Tibet (3,650 m / 11,975 ft), Leh, India (3,500 m / 11,500 ft), or high Rocky Mountain ski towns (2,800 to 3,200 m / 9,200 to 10,500 ft), descend to sleep in a lower valley (such as the Sacred Valley at 2,800 m below Cusco) for your first 2 to 3 nights whenever possible, and avoid strenuous hiking or skiing for the first 48 hours.
2. Follow the 300-to-500-meter (1,000-to-1,650-foot) sleeping rule above 3,000 meters: Once you climb above 3,000 meters (10,000 feet), never increase your sleeping elevation by more than 300 to 500 meters (1,000 to 1,650 feet) per 24-hour night.
3. Schedule a mandatory rest day every 1,000 meters (3,300 feet): Spend two consecutive nights sleeping at the same camp elevation for every 900 to 1,000 meters (3,000 to 3,300 feet) of net altitude gain (or every 3 to 4 days of upward trekking).
4. Use "Climb High, Sleep Low" judiciously (only when symptom-free): Walking up 300 to 400 meters (1,000 to 1,300 feet) onto a ridge during the afternoon and descending back to your lower camp to sleep stimulates ventilatory acclimatization. However, never "climb high" if you have even a mild headache or fatigue, as exertion at higher altitude triggers HAPE.
5. Avoid respiratory depressants (alcohol, sedatives, and opioids): Never drink alcohol or take sedative sleeping pills (such as benzodiazepines, zolpidem, or opioid painkillers) during your first several nights at a new altitude. These drugs depress your brainstem's respiratory center during sleep, causing severe nocturnal oxygen desaturation.
6. Remember that physical fitness offers zero immunity: Elite marathon runners, cyclists, and military personnel develop AMS, HAPE, and HACE at the exact same rate (and frequently higher, because they ascend steep trails too fast) as sedentary travelers. Genetics, prior history of altitude illness, and speed of ascent determine your risk.

Često postavljana pitanja¶

Izvori provjereni¶

• Wilderness Medical Society (WMS): Clinical Practice Guidelines for the Prevention, Diagnosis, and Treatment of Acute Altitude Illness (2019 and 2024 Updates).
• Lake Louise Consensus Group: The 2018 Lake Louise Acute Mountain Sickness Score Consensus Statement.
• International Climbing and Mountaineering Federation (UIAA Medical Commission): Standardized Field Recommendations for AMS, HAPE, and HACE Management (UIAA MedCom Standard No. 2).
• Centers for Disease Control and Prevention (CDC, United States): CDC Yellow Book: Health Information for International Travel: High-Elevation Travel and Altitude Illness.
• NHS (United Kingdom) and Institute for Altitude Medicine (Telluride, United States): Altitude Sickness Recognition, Acclimatisation Profiles, and Emergency Descent Guidance.

Povezani vodiči¶

• Wilderness hypothermia and cold exposure
• Prva pomoć kod hipotermije i promrzlina
• Lost while hiking or camping survival
• Rock climbing and mountaineering accidents
• Prva pomoć udisanja dima i trovanja ugljičnim monoksidom
• Brojevi za hitne slučajeve po zemljama