Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0020538 (hypertension)
 170,190 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The decisive limiting parameter in such patients is the lower oxygen partial pressure in inhaled air. It is, however, still possible for patients with coronary heart disease, high blood pressure or bronchial asthma to tolerate high altitudes without having to experience health problems. Prerequisites, however, are adequate acclimatization, optimal medication and pre-travel stable status. In addition, patients must be informed about emergency measures and how to recognize high-altitude sickness. To prevent pneumothorax leading to rapid decompression during flights, particular attention must be addressed to the problem of trapped air in patients with emphysema or cystic fibrosis.
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PMID:[Toleration of high altitudes by patients with heart and pulmonary diseases]. 1266 39

Physical functioning is improved after liver transplantation but studies comparing liver transplant recipients with normal healthy people are lacking. How liver (and other organ) transplant recipients tolerate strenuous physical activities is unknown. There are no data on the tolerance of transplant patients at high altitude. Six liver transplant subjects were selected to participate in a trek up Mount Kilimanjaro 5895 m, Tanzania. Physical performance and susceptibility to acute mountain sickness were prospectively compared with fifteen control subjects with similar profiles and matched for age and body mass index. The Borg-scale (a rating of perceived exertion) and cardiopulmonary parameters at rest were prospectively compared with six control subjects also matched for gender and VO2max. Immunosuppression in transplant subjects was based on tacrolimus. No difference was seen in physical performance, Borg-scales and acute mountain sickness scores between transplant and control subjects. Eight-three percent of transplant subjects and 84.6% of control subjects reached the summit (p=0.7). Oxygen saturation decreased whereas arterial blood pressure and heart rate increased with altitude in both groups. The only difference was the development of arterial hypertension in transplant subjects at 3950 m (p=0.036). Selected and well-prepared liver transplant recipients can perform strenuous physical activities and tolerate exposure to high altitude similar to normal healthy people.
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PMID:Tolerance of liver transplant patients to strenuous physical activity in high-altitude. 1502 47

At altitudes higher than the threshold altitude of 2,500 m, high-altitude diseases may occur, usually after a delay of 6 to 12 hours. Apart from the headache associated with acute mountain sickness, life-threatening cerebral edema may develop. High-altitude pulmonary edema is a non-cardiac edema that often precedes acute mountain sickness. The most important preventive measure is a slow ascent. In the case of mountain sickness a prophylactic effect can be achieved with acetazolamide or dexamethasone possible, while for high-altitude pulmonary edema, nifedipine is the first-choice drug. Immediate descent and the administration of oxygen are always indicated. Patients with a high-altitude risk are those with cardiac or pulmonary disease. Nevertheless, it is still possible for patients with coronary heart disease, hypertension or bronchial asthma to attain to high altitudes. In contrast, patients with COPD, interstitial pulmonary disease or pulmonary hypertension are at appreciably greater risk.
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PMID:[Visiting high altitudes--healthy persons and patients with risk diseases]. 1534 35

For a healthy, active person, the chance that new ischemic events will occur up in the mountains is not any higher than in the valley. However, for inactive persons with health risks, there is a chance that the stress at the unaccustomed elevation could provoke a clinically silent coronary insufficiency. People with hypertension or diabetes should be able to monitor and adjust the dosage of their medication themselves. Asthmatic patients are often surprisingly fit even in the mountains. When the medication dosage is well established, they may also go mountain climbing at high elevations. On the other hand, when COPD or pulmonary hypertension is present, a pulmonologist should be consulted to determine whether high elevations could cause problems for the patient. Patients who have a medical history of thromboembolisms also require special preparation and prophylaxis. Migraine sufferers should acclimate themselves particularly conscientiously because migraine symptoms are very difficult to differentiate from that of acute mountain sickness.
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PMID:[Planned sojourn at high elevations--what the primary care physician should know]. 1621 26

The levels of distortion product otoacoustic emissions (DPOAEs) change at frequencies between 0.75 and 1.5 kHz along with intracranial pressure (ICP) and DPOAEs are suggested for monitoring ICP changes. Elevated ICP plays a major role in high-altitude disease, but direct measurement is unlikely to be feasible at high altitudes. The aim of the presented study was to measure DPOAEs at extreme altitudes in order to determine whether information about elevated ICP can be obtained. Data are presented from DPOAE measurements at the frequencies 1, 1.5, 2, 3 and 4 kHz in 13 climbers during an ascent to Gasherbrum II (8,035 m) up to an altitude of 7,400 m. Valid DPOAE measurements could be obtained in all climbers. DPOAE levels exhibited great variability concerning both the affected frequency range and the change. As expected due to elevated ICP, DPOAE levels decreased in some of the climbers at 1 kHz. However, an even more pronounced decline of DPOAE levels was observed at 3 and 4 kHz, which cannot be explained by intracranial hypertension. Possible other reasons for DPOAE level changes at extreme altitude are hypoxia, increased serum osmolarity and unbalanced middle ear pressure. Only one climber developed severe acute mountain sickness with clinical signs of intracranial hypertension. The most pronounced decline of DPOAEs at 1 kHz was seen on that occasion, which suggests a possible use of DPOAEs for detection of intracranial hypertension and early detection of high-altitude cerebral edema.
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PMID:Distortion product otoacoustic emissions for assessment of intracranial hypertension at extreme altitude? 1818 84

Cellular hypoxia is the common final pathway of brain injury that occurs not just after asphyxia, but also when cerebral perfusion is impaired directly (eg, embolic stroke) or indirectly (eg, raised intracranial pressure after head injury). We Review recent advances in the understanding of neurological clinical syndromes that occur on exposure to high altitudes, including high altitude headache (HAH), acute mountain sickness (AMS), and high altitude cerebral oedema (HACE), and the genetics, molecular mechanisms, and physiology that underpin them. We also present the vasogenic and cytotoxic bases for HACE and explore venous hypertension as a possible contributory factor. Although the factors that control susceptibility to HACE are poorly understood, the effects of exposure to altitude (and thus hypobaric hypoxia) might provide a reproducible model for the study of cerebral cellular hypoxia in healthy individuals. The effects of hypobaric hypoxia might also provide new insights into the understanding of hypoxia in the clinical setting.
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PMID:The cerebral effects of ascent to high altitudes. 1953 32

The patient is an 88-year-old male who presented to a weekly pharmacy-run blood pressure (BP) screening at the retirement community where he resides. His past medical history consists of hypertension, hyperlipidemia, and altitude sickness. The patient's BP was 122/48 mmHg, which was lower than his average (148/64 mmHg). The patient was asked a series of questions to determine the cause of the BP decline. He commented that he does not drink much water, stating, "It tastes bad." The patient started acetazolamide six years ago for treatment of altitude sickness and it was suspected that this was contributing to the patient's taste disturbance. The pharmacist apprised the physician that the patient was experiencing a probable adverse effect from a medication and then developed a program to taper the medication based on the pharmacokinetics of the drug. After the drug was completely tapered off, the patient reported that not only had his sense of taste returned to normal, but his cognition had improved as well. He previously could not perform some of his instrumental activities of daily living without help, but now believes he can continue to live independently. He reported no dizzy spells since discontinuing the medication and his BP has remained stable.
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PMID:Taste disturbances related to medication use. 1968 82

Syndromes thought to have cerebral venous hypertension as their core, such as idiopathic intracranial hypertension and jugular foramen outlet obstruction, classically result in headaches. Do they provide an insight into the cause of the headache that commonly occurs at altitude? The classic theory of the pathogenesis of high altitude headache has been that it results from increased intracranial pressure (ICP) secondary to hypoxemia in people who have less compliant intracranial volumes (Roach and Hackett, 2001). However, there does not appear to be a correlation between the headache of acute mountain sickness (AMS) and the presence of cerebral edema (Bailey et al, 2006; Wilson et al, 2009). Research has concentrated on arterial perfusion to the brain in hypoxia, but there has been little study of venous drainage. Hypoxia results in markedly increased cerebral blood flow; however, if it has been considered at all, venous outflow has to date been assumed to be of little consequence. Retinal venous distension and the increased venous blood demonstrated by near infra-red spectroscopy and more recently by MRI imply that, in hypoxia, a relative venous insufficiency may exist. Similarly, there is increasing evidence that manifestations of the fluid shift during microgravity is of similar nature to idiopathic intracranial hypertension, which is thought to be primarily a venous insufficiency condition. The unique anthropomorphic adaptations of large brained biped humans with cerebral venous systems that have to cope with large changes in hydrostatic pressure may predispose us to conditions of inflow/outflow mismatch. In addition, slight increases in central venous pressures (e.g., from hypoxia-induced pulmonary vasoconstriction) may further compromise venous outflow at altitude. A better understanding of cerebral venous physiology may enlighten us with regards the pathogenesis of headaches currently considered idiopathic. It may also enable us to trigger headaches for study and hence enable us to develop new treatment strategies.
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PMID:The headache of high altitude and microgravity--similarities with clinical syndromes of cerebral venous hypertension. 2208 27

The effects of altitude on pregnancy have been extensively studied in high altitude residents, but there is a lack of knowledge concerning the pregnant altitude visitor. Exposure to hypoxia results in physiologic responses which act to preserve maternal and fetal oxygenation. However, these reactions are limited and maternal/fetal complications may be observed, especially in association with exercise. Certain pre-existing conditions or risk factors of hypertension/preeclampsia and/or fetal growth restriction are contra-indications for traveling to high altitude, especially after 20 weeks. The acclimatization process has to be respected to avoid acute mountain sickness without taking drugs, and at least a few days of acclimatization are required before exercising.
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PMID:Travel to high altitude during pregnancy: frequently asked questions and recommendations for clinicians. 2272 9

High altitude exposure is often accompanied by weight loss. Postulated mechanisms are a reduction of nutritional energy intake, a reduction of intestinal energy uptake from impaired intestinal function and increased energy expenditure. Beyond the field of altitude, there are good reasons for renewed interest in the relationship between hypoxia and energy balance. The increasing prevalence of obesity and associated comorbidities represent a major health concern. Obesity is frequently associated with sleep disorders leading to intermittent systemic hypoxia with deleterious cardiovascular and metabolic consequences. Hypoxic regions may be present within hypertrophic white adipose tissue leading to chronic systemic inflammation. Among the increasing number of people commuting to altitude for work or leisure, obesity is a risk factor for acute mountain sickness. Paradoxically, exposure to intermittent hypoxia might be considered as a means to lose body mass and to improve metabolic risk factors. Daytime exposure to intermittent hypoxia has been used to treat hypertension in former Soviet Union countries and is now being experimented elsewhere. Such intermittent hypoxic exposure at rest or during exercise may lead to improvement in body composition and health status with improved exercise tolerance, metabolism and systemic arterial pressure. Future research should confirm whether hypoxic training could be a new treatment strategy for weight loss and comorbidities in obese subjects and elucidate the underlying mechanisms and signalling pathways.
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PMID:Hypoxia, energy balance and obesity: from pathophysiological mechanisms to new treatment strategies. 2355 35


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