Altitude Related Disorder Flashcards
What are the 3 main types of altitude related disorder? What are they due to?
Acute mountain sickness (AMS), which may progress to:
High altitude pulmonary oedema (HAPE)
OR
High altitude cerebral oedema (HACE)
Hypobaric hypoxia that develops at high altitude
Describe acute mountain sickness
Generally self-limiting
Starts to develop at 2,500-3,000m gradually over 6-12h
Lasts a few days
List 3 symptoms of AMS
headache
nausea
fatigue
What is the risk of AMS positively correlated to?
Physical fitness
Describe preventative measures for AMS
Gain altitude at no more than 500m per day
Acetazolamide (carbonic anhydrase inhibitor)
Describe the MOA of Azetazolamide in preventing AMS
Causes a primary metabolic acidosis + compensatory respiratory alkalosis which increases RR + improves oxygenation
What is the treatment of AMS?
Descent
Describe the mechanism of HAPE
Hypobaric hypoxia
→ uneven hypoxic pulmonary vasoconstriction
→ uneven blood flow in lungs
→ areas of lung receiving more blood experience an increase in capillary pressure
→ more fluid leakage.
Hypoxia may also directly increase capillary permeability, exacerbating fluid leakage into the alveolar space.
How does HAPE present?
Classical pulmonary oedema features
Describe management of HAPE
Descent
Nifedipine, Dexamethasone, aAetazolamide, phosphodiesterase type V inhibitors*
Oxygen if available
Describe mechanism of HACE
Hypoxia → cerebral vasodilation → elevated cerebral blood volume
+
Hypoxia → increase in permeability of blood-brain barrier → capillaries in brain more leaky → leads to fluid accumulation in extracellular spaces
→ cerebral oedema
List 3 S/S of HACE
Headache
Ataxia
Papilloedema
Describe management of HACE
Descent
Dexamethasone
