Patient’s characteristics
7 male patients with PTE who hospitalized the medical station from May to December 2020 were enrolled in this study. All of them fell ill at altitude above 5000 m and were send down to the medical station for further treatment. The basic diagnostic information and characteristics of patients were showed in Table 1 and 2, respectively. Patients ranged in age from 20 to 31, with an average age of 24±3.6. They are all residents from low altitude area, the altitude of their settlements is above 5000 meters after entering HA area.
Patient’ s basic diagnostic information
The timing of their migration varies, with symptoms appearing in as few as 8 days and up to 210 days. 6 of 7 patients were initially diagnosed with pulmonary inflammation and 4/7 with HAPE by CT or X-ray, and empirical treated with antibiotic drugs, dehydrant, oxygen supply and other symptomatic support therapy (SST). The further examinations were performed due to poor therapeutic effect. Finally, PTE was definitely diagnosed by CTPA. Only one patient sought medical attention due to lower extremity pain and was diagnosed as DVT of lower extremity by color Doppler Ultrasonography. The existence of PTE was confirmed by further examination. Notably, in addition to PTE in patient 2, cerebral venous sinus thrombosis (CVST) and right ventricular thrombosis were also clearly diagnosed. In patient No. 3, the time from symptom onset to definite diagnosis was so long that the effective treatment was relatively delayed, leading to aggravation of the disease and subsequent failure of respiratory and circulatory system. Furthermore, thrombosis in the right renal vein system was also present in patient No. 7, which resulted in severe acute kidney injury. Subsequent follow-up revealed marked atrophy of the right kidney and a significant decrease in the glomerular filtration rate.
Clear history of catching cold prior to the onset of symptoms and developed pneumonia displayed in six patients, and four of them developed HAPE (Table 2). Smoking and alcohol consumption were present in the minority of them, but weight lost occurs in majority patients, and the weight lost was positively correlated with residence time in HA.
Patient’s clinical features and clinical examination profiles
Abnormal manifestations in respiratory tract were the main symptoms, especially respiratory infection-related symptoms (Table 3). Majority of them with cough, expectoration, chest tightness, shortness of breath as the primary performance. In the course of exacerbation, chest pain, cough pink bubbling sputum appeared in a small proportion of the population. Two of the three patients with definite diagnosis of DVT presented with lower extremity pain, and only one had DVT related symptoms as the first manifestation. Similarly, abnormal signs of the respiratory system, including tachypnea and abnormal breath sounds, were observed in most patients. Others, such as tachycardia, cyanosis, engorgement of the neck vein, and percussion tenderness over kidney region were present in faction.
As mentioned before, majority had pre-infection history, so the first blood routine examination suggested that 5 of them had increased white blood cell and neutrophil counts (Table 4). This result mentioned that infection may plays an important role in the pathogenesis of PTE. With the increase of residence time at HA, hemoglobin and hematocrit also presents an upward trend, but whether there is a correlation with PTE remains to be determined. Abnormalities in coagulation function were observed in all patients, with a definite increase in D-dimer and changes in fibrinogen (FIB) and thrombin time (TT). Imaging results showed that all patients had pulmonary artery branch thrombosis, and 3 patients with pulmonary trunk thrombosis. Renal vein, right ventricle and superior sagittal sinus thrombosis were reported in 1 case, respectively (Table 5).
Treatment and prognosis of all patients
Because of the different classification conditions of medical institutions, each patient goes through the process from the local health center to the medical station and then to the hospital. Anticoagulant therapy is applied to every patient after diagnosis, including oral and anticoagulant subcutaneous injection anticoagulant (Table 6). Two patients were given inferior vena cava filter implantation after consultation with multidisciplinary doctors due to their medical conditions. Because of compliance with the surgical guidelines, patient No. 3 underwent thrombectomy and pulmonary artery catheter directed thrombolysis therapy under general anesthesia. However, the patient experienced progressive deterioration of the respiratory and circulatory system, he had to use extracorporeal membrane oxygenation (ECMO) for life support, but the final outcome is regrettable. Except for patient No. 3, other patients improved gradually after comprehensive treatment and followed up regularly.