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Biomedical subjects

B Basnyat

Publications and source records attributed to B Basnyat.

At least 19 recordsLinked to original sources
PubMed2001

Infections at high altitude.

Every year, thousands of outdoor trekkers worldwide visit high-altitude (>2500 m) destinations. Although high-altitude areas per se do not harbor any specific agents, it is important to know the pathogens encountered in the mountains to be better able to help the ill sojourner at high altitude. These are the same pathogens prevalent in the surrounding lowlands, but various factors such as immunomodulation, hypoxia, physiological adaptation, and harsh environmental stressors at high altitude may enhance susceptibility to these pathogens. Against this background, various gastrointestinal, respiratory, dermatological, neurological, and other infections encountered at high altitude are discussed. Because there are few published data on infections at high altitude, this review is largely anecdotal and based on personal experience.

Altitude↗
PubMed2001

Letter from Dolpa.

Explore the source record for details and available documents.

Anecdotes as Topic↗
PubMed2001

Isolated facial and hypoglossal nerve palsies at high altitude.

A variety of neurological disorders other than high altitude cerebral edema have been described at high altitude. This report documents isolated facial and hypoglossal nerve palsies that occurred in two travellers at high altitude in the Nepal Himalaya. The possible pathophysiological mechanisms of these neurological deficits are discussed.

Diagnosis, Differential↗
PubMed2000

Acute medical problems in the Himalayas outside the setting of altitude sickness.

Well-recognized medical threats at high altitude (>2,500 m) include acute mountain sickness (AMS), high altitude pulmonary edema (HAPE), and high altitude cerebral edema (HACE). Thousands of travelers in the Himalayas are exposed annually to these often life-threatening syndromes. Their recognition and treatment has advanced considerably in recent years. In the Himalayas, we frequently see acute medical problems outside the setting of AMS and the two types of altitude edemas. Many of these other conditions are also hypoxia related and sometimes may mimic the classic high altitude illnesses of AMS, HAPE, and HACE. Although the vast majority of these medical problems are neurological, pulmonary and other organ system dysfunction also occur. These "non-high altitude sickness" disease entities in persons who sojourn to remote mountainous environments are reviewed in this paper to enhance their recognition, diagnosis, and treatment.

Acute Disease↗
PubMed2000

Cerebral autoregulation in subjects adapted and not adapted to high altitude.

BACKGROUND AND PURPOSE: Impaired cerebral autoregulation (CA) from high-altitude hypoxia may cause high-altitude cerebral edema in newcomers to a higher altitude. Furthermore, it is assumed that high-altitude natives have preserved CA. However, cerebral autoregulation has not been studied at altitude. METHODS: We studied CA in 10 subjects at sea level and in 9 Sherpas and 10 newcomers at an altitude of 4243 m by evaluating the effect of an increase of mean arterial blood pressure (MABP) with phenylephrine infusion on the blood flow velocity in the middle cerebral artery (Vmca), using transcranial Doppler. Theoretically, no change of Vmca in response to an increase in MABP would imply perfect autoregulation. Complete loss of autoregulation is present if Vmca changes proportionally with changes of MABP. RESULTS: In the sea-level group, at a relative MABP increase of 23+/-4% during phenylephrine infusion, relative Vmca did not change essentially from baseline Vmca (2+/-7%, P=0.36), which indicated intact autoregulation. In the Sherpa group, at a relative MABP increase of 29+/-7%, there was a uniform and significant increase of Vmca of 24+/-9% (P<0.0001) from baseline Vmca, which indicated loss of autoregulation. The newcomers showed large variations of Vmca in response to a relative MABP increase of 21+/-6%. Five subjects showed increases of Vmca of 22% to 35%, and 2 subjects showed decreases of Vmca of 21% and 23%. CONCLUSIONS: All Sherpas and the majority of the newcomers showed impaired CA. It indicates that an intact autoregulatory response to changes in blood pressure is probably not a hallmark of the normal human cerebral vasculature at altitude and that impaired CA does not play a major role in the occurrence of cerebral edema in newcomers to the altitude.

Adaptation, Physiological↗
PubMed2000

Disoriented and ataxic pilgrims: an epidemiological study of acute mountain sickness and high-altitude cerebral edema at a sacred lake at 4300 m in the Nepal Himalayas.

OBJECTIVE: To determine the incidence of high-altitude cerebral edema (HACE), acute mountain sickness (AMS), and high-altitude pulmonary edema (HAPE) in pilgrims. Although it is well known that western trekkers suffer from acute mountain sickness (AMS) in the Himalayas, not much is documented about the incidence of AMS in the local population of Nepal that go to high altitude. METHODS: The design was a randomized study set at a sacred high-altitude lake at 4300 m at Gosainkund in the Nepal Himalayas. There was a control study at 1300 m at Pashupatinath in Kathmandu, Nepal. The subjects were pilgrims of different ethnic Nepali backgrounds. The Lake Louise consensus for AMS, HACE, and HAPE was used, and oxygen saturation with a pulse oximeter was performed on HACE subjects. RESULTS: Out of 5000 pilgrims, 228 were randomly chosen. Sixty-eight percent had AMS, 31% had HACE, and 5% had HAPE. The mean oxygen saturation of HACE subjects at that altitude was 77%, 87% being normal for 4300 m altitude. Seventy-three percent of the study population were men, yet women had a significantly higher rate of AMS (odds ratio, 4.34; 95% confidence interval, 1.83-10.68), HACE (odds ratio 3.15, confidence interval 1.62-6.12), and HAPE (odds ratio, 5.2; 95% confidence interval, 1.24-24.73). CONCLUSIONS: Such a high incidence of HACE in an epidemiological study using the Lake Louise criteria has, to our knowledge, not been reported before. High-altitude pilgrims, especially women pilgrims in this study, seem to be a very susceptible group. Preventive measures in these pilgrims need to be adopted to avoid AMS, specifically life-threatening HACE and HAPE.

Acute Disease↗