High altitude climbers at risk for brain bleeds

November 28, 2012

New magnetic resonance imaging (MRI) research shows that mountain climbers who experience a certain type of high altitude sickness have traces of bleeding in the brain years after the initial incident, according to a study presented today at the annual meeting of the Radiological Society of North America (RSNA).

High altitude cerebral edema (HACE) is a severe and often fatal condition that can affect mountain climbers, hikers, skiers and travelers at high altitudes—typically above 7,000 feet, or 2,300 meters.

HACE results from swelling of due to leakage of fluids from the capillaries. Symptoms include headache, loss of coordination and decreasing levels of consciousness.

"HACE is a life-threatening condition," said Michael Knauth, M.D., Ph.D., from the University Medical Center's Department of Neuroradiology in Goettingen, Germany. "It usually happens in a hostile environment where neither help nor proper diagnostic tools are available."

Dr. Knauth and colleagues at the University Hospitals in Goettingen and Heidelberg, Germany, compared MRI findings among four groups of mountaineers: climbers with well documented episodes of HACE; climbers with a history of high altitude illness; climbers with a history of severe acute mountain sickness (AMS); and climbers with a history of isolated pulmonary edema (HAPE), a life-threatening accumulation of that occurs at high altitudes. Two neuroradiologists assessed the brain MRI findings without knowing the status of the mountaineers and assigned a score based on the number and location of any microhemorrhages.

"In most cases, these microhemorrhages are so small that they are only visible with a special called susceptibility-weighted imaging," Dr. Knauth said. "With this technique, the microhemorrhages are depicted as little black spots."

The MRI results showed brain microhemorrhages almost exclusively in HACE survivors. Of the 10 climbers with a history of HACE, eight had evidence of microhemorrhages on MRI. The other two had uncertain results. Only two of the remaining 26 were positive for microhemorrhages.

"It was previously thought that HACE did not leave any traces in the brains of survivors," Dr. Knauth said. "Our studies show that this is not the case. For several years after, microhemorrhages or microbleeds are visible in the brains of HACE survivors."

Survivors of the most clinically severe cases of HACE had the most prominent evidence of microhemorrhages on MRI. The bleeds were found predominantly in the corpus callosum, the thick band of nerve fibers that connects the right and left halves of the brain, and showed a characteristic distribution different from other vascular diseases like vasculitis, or blood vessel inflammation.

"The distribution of microhemorrhages is a new and sensitive MRI sign of HACE and can be detected years after HACE," Dr. Knauth said. "We will further analyze our clinical and MRI data on patients with , which is thought to be a precursor of HACE."

In the meantime, Dr. Knauth does not think HACE survivors need to give up climbing.

"We cannot give such a strong recommendation," he said. "However, mountaineers who have already experienced HACE once should acclimatize to the altitude very slowly."

Explore further: Researchers identify potential risk factors for severe altitude sickness

Related Stories

US scientists head to Mount Everest for research

April 20, 2012

(AP) -- A team of American scientists and researchers flew to the Mount Everest region on Friday to set up a laboratory at the base of the world's highest mountain to study the effects of high altitude on humans.

Fetal alcohol exposure affects brain structure in children

November 25, 2012

Children exposed to alcohol during fetal development exhibit changes in brain structure and metabolism that are visible using various imaging techniques, according to a new study being presented today at the annual meeting ...

Recommended for you

Can physical exercise enhance long-term memory?

November 25, 2015

Exercise can enhance the development of new brain cells in the adult brain, a process called adult neurogenesis. These newborn brain cells play an important role in learning and memory. A new study has determined that mice ...

Brain connections predict how well you can pay attention

November 24, 2015

During a 1959 television appearance, Jack Kerouac was asked how long it took him to write his novel On The Road. His response – three weeks – amazed the interviewer and ignited an enduring myth that the book was composed ...

New insights on how cocaine changes the brain

November 25, 2015

The burst of energy and hyperactivity that comes with a cocaine high is a rather accurate reflection of what's going on in the brain of its users, finds a study published November 25 in Cell Reports. Through experiments conducted ...


Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.