Altitude Sickness

Scenario:

You are the expedition medic on a trek up Kilimanjaro. Last night, one of your group did not join the rest of the group for dinner as they said they were tired after the day. The next morning as you are walking you notice they are struggling to keep up with the rest of the group despite previously having appeared really strong. After a 10 minute rest to have something to eat and drink, they appear out of breath. They insist they are fine and keep going. 2 hours later you have arrived at your next camp and they appear worse. You go to check up on them, and do an A-E assessment.

D - nil

R – responds but is confused, unsure of where they are, slightly slurred speech and trouble word-finding.

(C) – no concerns for haemorrhage or C-spine.

A – airway is patent

B – basal crackles on auscultation. Cough with frothy sputum. RR is 26, O2 sats are 65% (if compared to rest of group other people have sats of 80%)

C – BP is 118/83, HR is 78, peripheral capillary refill > 2 seconds but weather is cold, centrally < 2sec. No concerns about bleeding into chest, abdo, pelvis or long bones.

D – glucose is 4.5, pupils equal and reactive to light.

E – need to take a SAMPLE history

SAMPLE history:

S – headache, nausea, loss of appetite, breathless, not feeling themselves.

A – nil.

M – taking prophylactic Diamox (acetazolamide).

P – nil significant.

L – sometime yesterday last ate, drinking normally.

E – feeling worse throughout the day, didn’t want to say anything to jeopardise their ability to summit the next day.

Midway through assessment patient should try and stand up wander away, ‘I need to keep going’, struggle with balance, appears almost drunk. 

Diagnosis – HAPE and HACE

Management – Diamox (acetazolamide) can be given but need to know dose already taken as often taken prophylactically, dexamethasone, oxygen, paracetamol, nifedipine, DESCENT!!!!

Altitude sickness notes:

• Can occur at altitudes from approx. 4000ft (Ben Nevis), but most common above 8000ft. Everest is 29,029ft.

• A spectrum of illness ranging from mild to potentially life-threatening.

• AMS is acute mountain sickness – symptoms include headache, feeling sick, sleep disturbance, anorexia, dizziness.

• If AMS you can take medication for symptom management – e.g. paracetamol, antiemetic. If severe acetazolamide (Diamox), oxygen and dex but must descend. Rest and allow time to recover. Do not ascend.

• HAPE, HACE – descend immediately. These can be rapidly life-threatening.

• HAPE will present with cough, breathless at rest, pink/white frothy sputum, orthopnoea. Clinical signs – tachypnoea, crackles on auscultation, central cyanosis. 

• Challenges of diagnosis – dry cough is common at altitude, distinguishing from pneumonia also a challenge. 

• Note that O2 sats will be significantly lower at altitude – sats of 70% at rest may be normal (due to lower partial pressure). 

• Nifedipine can be used to treat HAPE (calcium channel blocker, sildenafil can be used as well).

• HACE - The onset of neurological findings such as progressive decline in cognitive/mental function, declining level of consciousness, impaired coordination, slurred speech, and/or lassitude signify the transition from AMS to HACE. Typical evaluation consists of an abnormal neurological exam, with ataxia often being the earliest finding. Early symptoms may be misinterpreted as exhaustion and it is important to exclude these, as well as other disorders such as dehydration, hypoglycemia, hypothermia, or hyponatremia which all may have signs and symptoms that overlap with that of HACE. Dexamethasone can be used for treatment as well.

• Risk factors for high altitude sickness: rate of ascent, absolute altitude gain, previous history of AMS, physical exertion, pre-existing lung disease, muscles/obesity.