Abstract
Editorial note
The following article is an English translation of guidelines that were originally published in China in 1996. The translation is reproduced by permission of Wu Tianyi, who is president of the Chinese Medical Association for High Altitude Medicine and co-editor of the Chinese Journal of High Altitude Medicine. The translation was made by Wu Tianyi, Jason X.-J. Yuan, Wang Jun, and Zhenxing Fu. Drs. Yuan and Fu are in the Department of Medicine at the University of California, San Diego.
Although the article was published 15 years ago, it is still of interest, although some changes have occurred in the meantime. In particular, Chinese physicians no longer use the diagnostic criteria described here for chronic high altitude diseases at high altitude. Instead they follow the guidelines described in the Consensus Statement published in High Altitude Medicine & Biology (6:147–157, 2005). In addition, many Chinese physicians use the Lake Louise criteria for the diagnosis of acute mountain sickness. However, some physicians continue to use the criteria set out in this article. In fact, our attention was drawn to these guidelines by the article titled “Incidence of High Altitude Illnesses among Unacclimatized Persons Who Acutely Ascended to Tibet” (Ren et al., High Alt. Med. Biol. 11:39–42, 2010). This study was remarkable for the fact that the incidence of AMS was described in 3628 recruits who were airlifted to an altitude of 3600 m. At that time, the reviewers of the article were surprised to see that the criteria for the diagnosis of AMS were different from those of the Lake Louise score. The result of using the diagnostic criteria described here is that the incidence of acute mountain sickness is considerably higher than when using the Lake Louise score. Nevertheless, we think that this article will be of interest to readers.
Guidelines of the Third Chinese National Symposium on High Altitude Medicine, Chinese Medical Association, September 1995
High altitude disease (HAD) is a unique disease occurring in the hypoxic environment of high altitude. Hypobaric hypoxia in high altitude is the major cause of the disease. The pathogenic mechanisms of the disease involve hypoxia-mediated pathophysiological changes, and the clinical signs and symptoms are also related to the severity of the pathophysiological changes. The relief of signs and symptoms occurs following the patient's transfer to a low-altitude area. HAD can be divided into two categories based on the disease course: acute and chronic HAD. Further, HAD can be clinically classified into different types based on the tissues, organs, and/or systems that are affected by hypoxia. Owing to the geographic environment of high altitude related to the disease in China, the nomenclature is basically started with “high altitude” followed by the name of the disease (i.e., high altitude … disease). According to the International Classification of Disease act (Geneva, WHO, 1997), “disease” is used at the end in all nomenclature.
Nomenclature and Classification of High Altitude Disease (HAD)*
Acute high altitude disease (AHAD) 1.1 Mild type 1.1.1 Acute mild high altitude disease (AMHAD) 1.2 Severe type 1.2.1 High altitude pulmonary edema (HAPE) 1.2.2 High altitude cerebral edema (HACE) Chronic high altitude disease (CHAD) 2.1 High altitude deterioration (HADT) 2.2 High altitude polycythemia (HAPC) 2.3 High altitude heart disease (HAHD) 2.4 Chronic mountain sickness (CMS) or Monge's disease, also referred to as mixed type of CHAD
Clinical Diagnostic Criteria of High Altitude Disease (HAD)
Diagnostic criteria and scoring system of acute mild high altitude disease (AMHAD): Table 1 shows the questionnaire scoring system used to classify the disease based on the severity of symptoms. Table 2 shows the degree and grade based on the severity of the disease.
Diagnostic criteria of high altitude pulmonary edema (HAPE)
2.1 Field (or on site) diagnosis
2.1.1 Cause of the disease: Recent arrival at high altitude area (generally, ≥3000 m above sea level).
2.1.2 Symptoms: dyspnea at rest, chest distress, cough with white or pinkish froth sputum, fatigue, asthenia or decreased capacity of activities.
2.1.3 Signs: moist rales or wheezing in one or both lung fields, central cyanosis, tachycardia, and tachypnea.
The final diagnosis of HAPE should include at least two of the symptoms and signs given above.
2.2 Clinical diagnostic criteria
2.2.1 Recent arrival at high altitude area (generally, ≥3000 m above sea level), dyspnea at rest, cough with white or pinkish froth sputum.
2.2.2 Central cyanosis, pulmonary moist rales.
2.2.3 Chest X ray is the major criteria for diagnosis. Patients often have a patchy or “cloudy” infiltrate shadow centered on the hila and radiated to one or two sides of the lung fields. The opacification in the lung is often diffused and irregular, but can also be diffused into an enlarged shadow. Cardiac imagine is often normal, but can show changes indicative of pulmonary hypertension and right -heart enlargement.
2.2.4 The diagnosis requires exclusion of acute myocardial infarction, acute cardiac failure due to heart disease, pneumonia, and other cardiopulmonary diseases on the basis of clinical examination and ECG.
2.2.5 Prompt improvement of the signs and symptoms after bed rest and oxygen therapy or after descending to low altitude. Disappearance of x-ray abnormalities within a short period of time.
Diagnostic criteria of high altitude cerebral edema (HACE)
3.1 Field (or on site) diagnosis
3.1.1 Recent arrival at high altitude area (generally, ≥3000 m above sea level); patients often had severe AMAD prior to HACE.
3.1.2 The presence of mental status changes and/or ataxia in a person with AMAD, or the concurrent presence of mental status changes and ataxia in a person without AMAD. The changes in mental status are graded, according to severity, into apathy, lethargy or lassitude, disorientation or confusion, stupor or semiconsciousness, and coma. The severity of ataxia can be determined on the basis of the following signs and symptoms: loss of control of balance, inability to walk straight or step off line, falling, and inability to stand.
3.2 Clinical diagnostic criteria
3.2.1 Recent arrival at high altitude (generally ≥3000 m above sea level).
3.2.2 Neurological and mental (psychological) symptoms: severe headache, vomiting, apathy, mental depression or euphoria and polylogia, dysphoria, staggering (or reeling) gait, ataxia (Romberg's test positive). It is then followed by mental confusion, haziness, drowsiness or somnolence, and coma, or coma directly. Physical incapacity: the signs and symptoms due to meningeal irritation and/or positive pyramidal sign may occur as well.
3.2.3 Ocular fundus: may have papilledema and/or retinal hemorrhage.
3.2.4 Cerebrospinal fluid (CSF): increased pressure, no change in cells and protein. On rare occasions, blood or red blood cells are present in CSF.
3.2.5 Exclude the possibility of acute cerebral vascular disease, acute toxic effect of medication, acute poisoning by carbon monoxide, epilepsy, meningitis, and central nervous system infection.
3.2.6 Prompt improvement of the signs and symptoms after treatment with oxygen, diuretics, and steroid, or descending to low altitude.
Diagnostic criteria of high altitude deterioration (HADT)
4.1 HADT occurs in (Han Chinese) immigrants who live at an altitude of ≥3000 m above sea level for a long time and in climbers who live at high altitude (>5000 m above sea level) for a long time.
4.2 Mental deterioration is characterized by headache, dizziness, difficulty sleeping (insomnia), hypomnesia, hypoprosexia, decreased capability of thinking and judgment, emotional lability, and apathy.
4.3 Physical deterioration is characterized by anorexia, weight loss, fatigue, decreased working capacity, sexual disorders (dysfunction), and irregular menstruation.
4.4 Concomitant signs and symptoms include hypotension, hair loss, odontoptosis, koilonychia (spoon nails), intermittent edema, and slightly enlarged liver.
4.5 No erythrocytosis and significant pulmonary hypertension.
4.6 Course of the disease varies along time, which is characterized by undulatory changes in signs and symptoms, but gradually becomes severe, followed by sustained and progressive deterioration. The signs and symptoms are gradually improved or disappear when patients are transferred to a low-altitude or sea-level area.
Diagnostic criteria of high altitude polycythemia (HAPC)
5.1 HAPC occurs mostly in (Han Chinese) immigrants who live at an altitude ≥3000 m; some
5.2 Clinical manifestation: The common signs and symptoms include headache, dizziness, fatigue, difficulty sleeping (insomnia), cyanosis, conjunctival congestion, and violet- red skin color (i.e., common signs and symptoms for patients with polycythemic disease).
5.3 Laboratory hematological findings: The diagnosis should include the following three parameters: RBC ≥6.5 × 1012/L, Hb ≥200 g/L, and Hct ≥65%.
5.4 Exclude polycythemia vera and other causes of secondary polycythemia.
5.5 The signs and symptoms gradually improve and the values of RBC, Hb, and Hct gradually decrease when patients are transferred to low altitude.
Diagnostic criteria of high altitude heart disease (HAHD)
6.1 Diagnostic criteria of pediatric HAHD
6.1.1 HAHD occurs mostly in (Han Chinese) infants or children at an altitude ≥3000 m; a few susceptible individuals who live at an altitude of approximately 2500 m can also develop the disease.
6.1.2 HAHD commonly occurs in infants born at high altitude whose parents are sea-level residents who immigrated to high altitude and in infants born at sea level who then immigrated to high altitude. Occasionally, a few lifetime-inhabitant infants at high altitude can also develop the disease.
6.1.3 The most susceptible pediatric patients are under the age of 2 years, although children at any age can develop the disease. The course of the disease is considered subacute, which usually takes weeks to months to resolve.
6.1.4 The prominent clinical manifestations are dyspnea, cyanosis, and congestive heart failure, accompanied by pulmonary arterial hypertension and severe right-heart enlargement (or right ventricular hypertrophy) based on the evidence obtained from the following examination results: ECG, echocardiography, chest X ray, and right-heart catheterization; the final diagnosis of pediatric HAHD should have at least two positive results from these examinations).
6.1.5 Rule out other heart diseases, such as pericarditis, myocarditis, congenital heart disease, and rheumatic heart disease.
6.1.6 The signs and symptoms significantly improve after descending to low altitude.
6.2 Diagnostic criteria of adult HAHD
6.2.1 HAHD occurs at high altitude, generally at ≥3000 m above sea level. The condition is more prevalent in (Han Chinese) immigrants than in lifetime inhabitants at high altitude.
6.2.2 The prominent clinical manifestations include palpitations, breathlessness, dyspnea, weakness, cough, cyanosis, and P2 accentuation and splitting (accentuated and split pulmonic second sound). The patients with severe HAHD may also have the signs and symptoms of right-heart failure, such as oliguria, hepatomegaly, peripheral edema, and ascites.
6.2.3 Pulmonary arterial hypertension is characterized by the following features: (a) ECG (right-axis deviation of QRS and marked right ventricular hypertrophy); (b) echocardiography (outflow tract of the right ventricle is ≥33 mm, and internal diameter of the right ventricle is ≥23 mm); (c) chest X ray (diameter of the right descending pulmonary artery is ≥17 mm and/or the ratio of the diameter of the right descending pulmonary artery to the diameter of the trachea is ≤1.10); and (d) cardiac catheterization (mean pulmonary arterial pressure is ≥3.33 kPa or 25 mmHg). If pulmonary arterial pressure is not measured, the diagnosis has to be based on the positive results obtained from at least two of the above-mentioned examinations.
6.2.4 Rule out other heart disease, especially chronic obstructive pulmonary disease and cor pulmonale.
6.2.5 The signs and symptoms are gradually improved and pulmonary hypertension and cardiac abnormalities are gradually normalized after descending to low altitude or sea level.
Clinical diagnostic criteria of mixed type of chronic high altitude disease: chronic mountain sickness (CMS) or Monge's disease
7.1 CMS mainly occurs in sea-level immigrants who live at an altitude of ≥3000 m for a long time; some lifetime inhabitants in high altitude can also develop the disease. The patients usually acclimatize to high altitude for a number of years and then gradually develop the disease. The course of the disease is considered chronic.
7.2 No other cardiopulmonary diseases or pneumoconiosis.
7.3 The prominent clinical manifestations are the sum of the signs and symptoms of those with HAPC and HAHD.
7.4 Same as the diagnostic criteria for pulmonary hypertension in patients with HAHD.
7.5 Same as the hematological criteria as indicated for diagnosis of HAPC.
7.6 The signs and symptoms gradually improve after descending to low altitude or sea level.
Footnotes
*
Translated from Gao Yuan Yi Xue Za Zhi (Chinese Journal of High Altitude Medicine 6(1):1–4, 1996) by Tianyi Wu, Zhenxing Fu, Jun Wang, and Jason X.-J. Yuan. The original article in Chinese was also reprinted in Xi Zang Yi Yao Za Zhi (Tibetan Medical and Medicinal Journal 17(3):1–3, 1996).