Medical Guide
HACE and HAPE on Kilimanjaro
Emergency Medications and Descent Protocol
Altitude Kills. Not Falls.
High Altitude Cerebral Edema and High Altitude Pulmonary Edema are rare on Kilimanjaro — affecting roughly 1–2% of climbers. But they are the two conditions that kill. Unlike AMS (Acute Mountain Sickness), which is common and self-limiting, HACE and HAPE do not resolve with rest. They progress. Without immediate action, they are fatal.
This is not a scare article. It is a decision framework: what each condition feels like, what medications to carry, what doses to give, and exactly when descent is the only option. Read it before your climb. Share it with your group. The climbers who survive altitude emergencies are the ones who understood the protocol before they needed it.
The Progression — AMS to HACE to HAPE
AMS — Acute Mountain Sickness: Common, Manageable
Symptoms: Headache, nausea, fatigue, dizziness, sleep disturbance. Affects 14–51% of Kilimanjaro climbers depending on route and ascent rate.
Treatment: Rest, hydrate, and — if symptoms are moderate — descend 300–500m. Acetazolamide (Diamox) 125mg twice daily can relieve symptoms and accelerate acclimatisation. AMS is not life-threatening. It is the warning signal.
Critical point: AMS at altitude is like a fever — it tells you something is wrong. Climbers who ignore it and push higher almost always progress to something more serious.
HACE — High Altitude Cerebral Edema: Rare, Life-Threatening
Incidence: 0.1–2% of climbers above 3,000m — roughly 1 in 200 on Kilimanjaro. HACE is a cascade from untreated severe AMS. Mechanism: cerebral capillary leakage causes brain tissue to swell.
Symptoms: Ataxia (cannot walk heel-to-toe in a straight line), confusion, slurred speech, hallucinations, and loss of coordination. Can kill within 12–24 hours. No traveller with HACE should walk unaccompanied — ataxia means they cannot navigate; confusion means they cannot make sound decisions.
Critical point: HACE and HAPE can occur simultaneously. Any confusion at altitude above 4,000m is HACE until proven otherwise.
HAPE — High Altitude Pulmonary Edema: Rare, Life-Threatening
Incidence: Approximately 1% of Kilimanjaro climbers. Mechanism: hypoxic pulmonary vasoconstriction causes uneven capillary pressure, rupturing walls and flooding the lungs with fluid.
Symptoms: Extreme shortness of breath at rest (not just on exertion), persistent cough, reduced exercise tolerance, cyanosis (blue lips and fingertips). Pink frothy sputum is a late and critical sign. Can kill within 24–48 hours.
Critical point: HAPE can develop rapidly. A climber who is stable at dinner can be critical by morning. Continuous guide monitoring above 4,000m is not optional.
Internal link: This article is part of our altitude medicine series. Read kilimanjaro-altitude-sickness for prevention protocols and kilimanjaro-altitude-illness-guide for full Lake Louise scoring and AMS decision trees.
HACE Emergency Protocol — Medications and Evacuation
Descend. This is non-negotiable.
HACE at altitude does not stabilise. It progresses. Every minute without descent worsens cerebral oedema. Minimum descent: 500–1,000m. The affected climber must be accompanied at all times — they cannot walk alone and cannot be left.
Dexamethasone — 8mg initial dose
Drug class: Corticosteroid (glucocorticoid). Reduces cerebral oedema by stabilising the blood-brain barrier and suppressing inflammatory response.
Dose: 8mg initially (oral tablet or intramuscular injection). Then 4mg every 6 hours until descent is complete or symptoms fully resolve.
Route: Oral (preferred if climber is conscious and able to swallow). IM injection if consciousness is impaired.
Effect onset: 1–2 hours. Not instant. Descent must begin immediately alongside medication.
Contraindication: Do NOT give dexamethasone to a climber you also plan to evacuate by air. Steroids cause blood pressure instability that makes air evacuation contraindicated. If helicopter evacuation is possible, avoid steroids — use the Gamow bag and oxygen as bridge instead.
Portable Hyperbaric Chamber (Gamow Bag)
If descent is physically impossible — injury, weather, terrain — the Gamow bag is the last resort. It is a portable altitude chamber pressurised by a foot pump, simulating descent of 1,500–2,000m within 10–15 minutes.
Effect: Buys 6–8 hours of time. The climber must remain in the chamber during this period. Continuous pumping is required (one person pumping every 2–3 minutes).
Not a substitute: The Gamow bag stabilises. It does not resolve HACE. Descent must happen as soon as conditions permit.
Supplemental Oxygen
Dose: 2–4L/min via nasal cannula. Raises arterial SpO2 rapidly — measurable improvement within 3–5 minutes.
Limitation: Oxygen is a temporising measure. It does not treat the underlying cause (altitude). Without descent, symptoms will return when oxygen is removed.
Note: Commercial Kili operators rarely carry oxygen above base camp. Bobby Tours guides carry oxygen as standard emergency kit above 4,000m.
Internal link: Helicopter evacuation from high altitude requires pre-arranged agreements with kilimanjaro-emergency-evacuation. Our evacuation protocol is covered in kilimanjaro-rescue-emergency.
HAPE Emergency Protocol — Medications and Evacuation
Descend. HAPE kills by hypoxia, not by the fluid itself.
Getting lower raises the oxygen fraction in every breath within minutes. HAPE progresses because hypoxic pulmonary vasoconstriction is an altitude-driven feedback loop. Medications interrupt the loop — they do not break it.
Nifedipine — 20mg slow-release every 12 hours
Drug class: Calcium channel blocker. Reduces pulmonary artery pressure by causing smooth muscle relaxation in pulmonary vasculature.
Dose: 20mg slow-release orally every 12 hours. Standard field dose. Do not crush or bite slow-release tablets — this destroys the extended-release mechanism.
Effect onset: 30–60 minutes. Peak effect: 2–3 hours.
Side effect warning: Nifedipine causes hypotension (low blood pressure). Monitor the climber's BP. If systolic drops below 90mmHg, hold the dose. Do not combine with dexamethasone without careful BP monitoring.
Phosphodiesterase-5 Inhibitors — Tadalafil or Sildenafil
Evidence: Maggiorini et al. (2006) demonstrated pulmonary vasodilator efficacy in acute altitude illness. These drugs enhance nitric oxide activity, reducing pulmonary vascular resistance.
Dose: Tadalafil 10mg once daily, or sildenafil 50mg three times daily.
Role: Alternative to nifedipine when BP is already low or nifedipine is unavailable. Can be used alongside nifedipine in severe cases under guide supervision.
What NOT to Use for HAPE
Dexamethasone: Not first-line for HAPE alone. It addresses cerebral oedema, not pulmonary fluid. Only use if HACE is also suspected (co-occurrence in ~50% of severe cases).
Acetazolamide (Diamox): No role in active HAPE treatment. Diamox prevents AMS and accelerates acclimatisation. It does not reduce pulmonary oedema once fluid has accumulated.
Lying flat: Sit the climber upright. Lying flat redistributes blood volume to the lungs and worsens pulmonary oedema. 45-degree semi-recumbent position is optimal for HAPE management.
Supplemental Oxygen — 4–6L/min
Dose: 4–6L/min for HAPE (higher rate than HACE due to greater V/Q mismatch).
SpO2 improvement: Measurable within 5–10 minutes. SpO2 should rise from critical levels (~65–70%) toward safer territory (~80–85%).
Positioning: Keep the climber sitting upright throughout. Monitor SpO2 every 5 minutes during descent.
Internal link: Understand the underlying physiology in our kilimanjaro-altitude-physiology guide. The kilimanjaro-diamox-acetazolamide-guide covers Diamox's role in prevention (not treatment).
Why Kilimanjaro Is Specifically Higher Risk Than Most Trekking Peaks
Kilimanjaro summit is at 5,895m — the altitude at which HACE and HAPE risk is genuinely elevated. Many Kili climbers ascend from sea level to 5,895m within 5–7 days. That is a rapid ascent profile by any standard. On Denali or Everest, mountaineers spend weeks crossing altitude bands before reaching equivalent elevations.
The Lemosho and Machame routes both cross 4,600m before the summit attempt — the critical elevation window where HAPE risk begins. On the 7-day Machame, you reach 4,600m on Day 5. If you summited on Day 7, you spent only 2 days above 4,600m with minimal acclimatisation.
Unlike Annapurna or Everest Base Camp, there is no evacuation road near Kilimanjaro's summit. The descent from Uhuru Peak (5,895m) to Barafu Camp (3,100m) takes 4–6 hours for an unacclimatised climber. If HACE or HAPE develops on the summit descent, evacuation is slow.
Unlike Everest, there is no medical oxygen routinely available above base camp on commercial Kilimanjaro climbs. On Everest, supplemental O2 is standard equipment above 7,000m. On Kili, your guide's emergency kit is the only oxygen source until rescue arrives. This makes self-rescue knowledge — recognising symptoms early and descending immediately — more critical on Kilimanjaro than on many higher peaks.
Internal link: Compare route acclimatisation profiles in our route comparison. Our safety record and guide training are covered in kilimanjaro-safety-guide.
Field Decision Framework — How to Decide in the Moment
HACE Screen — The Ataxia Test
- 1.Ask the climber to walk heel-to-toe in a straight line for 10 steps.
- 2.Watch for stumbling, stepping off the line, or inability to maintain balance.
- 3.Positive test = suspected HACE. Begin descent immediately. Do not wait for a second opinion or a better moment. Administer dexamethasone 8mg while organising evacuation.
HAPE Screen — SpO2 and Symptoms
- 1.SpO2 below 70% at rest above 4,000m = suspected HAPE.
- 2.SpO2 below 80% persisting despite 5 minutes on supplemental oxygen = critical HAPE.
- 3.Dyspnoea at rest (not just on exertion) = suspected HAPE regardless of pulse oximeter reading.
- 4.Pink frothy sputum = late-stage HAPE. Begin descent and call evacuation immediately.
The Decision Is Always Yours
Medications support descent — they do not replace it. Dexamethasone does not cure HACE. Nifedipine does not cure HAPE. They buy hours. The decision framework is binary: if HACE or HAPE is suspected, descent begins. Every minute of delay is a risk multiplied.
As the climber or trip leader, the decision to descend is yours. No guide, no operator, no summit goal is worth a life. Descend early.
Internal link: Pulse oximetry monitoring protocol is covered in kilimanjaro-blood-oxygen-pulse-oximeter. Our pre-climb preparation guide at kilimanjaro-summit-night-guide covers altitude preparation and acclimatisation planning.
What Bobby Tours Guides Do Differently
Arusha-based guides with altitude-specific emergency training. Our guides carry nifedipine, dexamethasone, and supplemental oxygen as standard emergency kit above 4,000m. They are trained in altitude monitoring protocols — not just first aid, but altitude medicine decision-making.
Twice-daily clinical monitoring above 4,000m. Every morning and evening, your guide documents Lake Louise scores and SpO2 readings. A score of 6 or above, or an SpO2 below 80% at rest, triggers the descent protocol automatically — not as a discussion, but as a clinical decision.
Satellite phone and helicopter evacuation agreement. HACE or HAPE evacuation from 5,000m requires helicopter extraction. We have pre-arranged agreements with Kilimanjaro National Park rescue services and Arusha-based medical evacuation operators.
48 years of altitude emergency experience. Our guides have managed altitude emergencies before. They know the mountain's patterns. They have the authority — and the obligation — to turn climbers around when the data says turn around. Summit is never worth a life.
The Bottom Line
HACE and HAPE are medical emergencies. They are also survivable — with fast recognition and immediate descent. The medications in this guide are field interventions that buy critical time. They are not hospital care. They do not replace evacuation.
Carry the medications. Know the doses. Know the routes of administration. Understand the contraindication warnings before your climb. Do the ataxia test yourself before you need to do it on someone else.
Descend early. The climbers who survive altitude emergencies are the ones who descended when it was uncomfortable — not when it was catastrophic.
If you have a personal history of altitude illness, are over 45, or have any cardiorespiratory condition — speak with our Arusha team before booking. We review every climber's health profile and recommend the itinerary and preparation protocol that matches your risk profile.
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