As increasing numbers of people live, work and holiday at high altitude, so awareness of the neurological consequences has become more important. Despite studies examining altitude sickness, the underlying mechanisms of the spectrum of altitude related illnesses are still elusive.
Research continues to learn more about the condition, but misconceptions persist about what it is and how debilitating it can be.
High altitude sickness is a common name for illnesses that can occur at high altitude, usually over 3000 meters above sea level. Another term used is acute mountain sickness. The cause is hypoxia (meaning a deficiency in the amount of oxygen reaching body tissues) but the underlying physiological process is a complex mixture of factors.
There are many different types of headaches. Although not all headaches are the same, they all share at least one thing in common — they cause pain. But many headaches also cause other unwanted symptoms, including nausea and vomiting. This article addresses the most common headache symptoms associated with the different types of headaches.
The International Headache Society (IHS), an international group of headache specialists, has included a definition of High Altitude Headache in the second edition of their International Classification of Headache Disorders.
Their definition is:
A. Headache with at least two of the following characteristics and fulfilling criteria C and D
Frontal or frontotemporal (at the front of the head in the region of the temples)
Dull or pressing quality
Mild or moderate intensity
Aggravated by exertion, movement, straining, coughing, or bending
B. Ascent to altitude above 2500 metres
C. Headache develops within 24 hours after ascent
D. Headache resolves within eight hours of descent.
The symptoms of migraine headaches can occur in various combinations and include:
- Moderate to severe pain (often described as pounding, throbbing pain) that can affect the whole head, or can shift from one side of the head to the other
- Sensitivity to light, noise or odors
- Blurred vision
- Nausea or vomiting, stomach upset, abdominal pain
- Loss of appetite
- Sensations of being very warm or cold
- Fever (rare)
- Bright flashing dots or lights, blind spots, wavy or jagged lines (aura)
According to the NHF, a migraine is generally diagnosed after a patient has had at least five previous headaches that lasted between four and 72 hours. Migraine-related pain is usually felt on one side of the head, and it can be accompanied by nausea and sensitivity to light (photophobia) or sound (phonophobia).
A number of things can trigger migraines including lack of sleep, sunlight, certain foods, hormone levels, noises, staring at a screen, and stress. Brain cells set off the release of chemicals that cause blood vessels around the brain to swell and transmit pain signals.