Respiratory infections related to HIV

　　The incidence of respiratory infections related to HIV is high, and the reasons for this are not yet fully clear. Recent studies have found that alveolar macrophages are also one of the target cells attacked by human immunodeficiency virus (HIV), with no decrease in cell number, but a decrease in function (such as antigen presentation). The ratio of helper T cells to suppressive T cells (T4H/TS) in bronchoalveolar lavage fluid decreases, while TS increases. The viral load of HIV is linearly related to the exhaustion of CD4 cells, and CD4 cells in the blood are an important indicator for predicting the possibility of immune deficiency and opportunistic infections in the lungs, as well as the type of infection and its pathogen spectrum.

　　HIV-related respiratory infections can complicate various serious bacterial, fungal, and/or viral infections. Pulmonary fungal infections are severe, and most have a history of long-term antibiotic treatment before diagnosis, which is a serious threat to the life of HIV patients. Common fungi include Candida, Aspergillus, Cryptococcus, zygomycetes (mainly Mucor), and Pneumocystis, etc.

　　The incidence of respiratory symptoms in HIV-related respiratory infection patients increases with the decrease of CD4+ count. The clinical manifestations lack diagnostic specificity because other complications in HIV patients can also occur with cough, dyspnea, and other respiratory symptoms. However, certain clinical symptoms are still helpful for indicating diagnostic clues, such as distinguishing the nature of cough, whether it is productive sputum or dry cough without sputum, the former usually requires consideration of bacterial pneumonia, while the latter is more common in Pneumocystis carinii pneumonia (PCP).

　　Fever and weight loss suggest systemic or disseminated diseases, such as mycobacterial or fungal infections. Extrapulmonary symptoms are helpful for diagnosis, such as CD4

　　HIV concurrent pulmonary infection can present with fever, tachycardia, cyanosis, and hypotension, often indicating an acute course (such as bacterial sepsis).

　　HIV-related respiratory infections are mainly to prevent the infection of HIV, and the specific preventive measures are described as follows.

　　1. Adhere to self-respect, avoid prostitution and pimping, and avoid premarital and extramarital sexual behavior.

　　2. Prohibit drug use and do not share needles with others.

　　3. Do not donate blood or use blood products independently, and use them under the guidance of a doctor.

　　4. Do not borrow or share personal items such as toothbrushes, razors, and face shavers.

　　5. Using a condom is one of the most effective measures to prevent sexually transmitted diseases and HIV during sexual life.

　　6. Avoid direct contact with the blood, semen, breast milk, and urine of HIV patients to cut off the transmission route.

　　The examination of HIV-related respiratory infections includes blood tests, arterial blood gas analysis, and other auxiliary examinations, and the specific examination methods are described as follows.

　　Blood routine

　　The blood leukocyte count in HIV-infected patients with concurrent pulmonary bacterial infection is higher than the baseline value (because the baseline leukocyte value in HIV-infected patients is often lower than the normal value), accompanied by left shift. The risk of pulmonary bacterial and fungal (such as aspergillosis) infections is significantly increased in HIV patients with granulocytopenia.

　　Serum lactate dehydrogenase (LDH)

　　If it is Pneumocystis carinii pneumonia (PCP), the serum LDH level is usually elevated, but it can also be elevated in other pulmonary diseases (such as bacterial pneumonia and tuberculosis) or non-pulmonary diseases, so it lacks specificity. LDH has a high sensitivity in severe PCP patients, while the sensitivity of LDH in mild PCP is poor. The LDH level is related to the treatment response and prognosis of PCP.

　　3. Arterial blood gas

　　When HIV-positive patients have concurrent pulmonary infection, they usually have abnormal arterial blood gas, such as hypoxemia and increased alveolar-arterial oxygen pressure difference [PO2 (A-a)]. Carbon dioxide alkalosis, but lacks diagnostic specificity. For PCP, it is helpful for judging the prognosis and deciding whether to admit the patient, or whether to use corticosteroids.

　　4. Other auxiliary examinations

　　1. Chest X-ray examination Chest X-rays can provide clues for the diagnosis of HIV pulmonary infection and provide reference for the selection of diagnostic steps.

　　2. Chest CT examination It can be helpful for the differential diagnosis of multiple pulmonary lesions. If most nodules have a diameter less than 1 cm and are centrally distributed along the bronchus, they are generally pulmonary opportunistic infections; if accompanied by mediastinal lymphadenopathy and nodules larger than 1 cm, consider neoplasms. Kaposi's sarcoma often has peripheral vascular dilatation around the bronchus in addition to pulmonary nodules.

　　Patients with respiratory infections associated with HIV should eat foods that enhance immunity; they should eat high-protein foods; they should eat anti-inflammatory foods; they should eat antiviral foods. They should avoid high-alcohol foods; they should avoid spicy and dry foods; they should avoid foods that easily induce infections; they should avoid cold and cool foods.

　　For respiratory infections associated with HIV, the antimicrobial treatment is basically the same as that for general patients, but attention should be paid to the fact that the incidence and severity of adverse reactions to antiviral chemotherapy are higher in HIV/AIDS patients, and close observation and prevention should be carried out.

　　Antiretroviral therapy for HIV should refer to CD4+ and viral load. If CD4+ < 500 μl and viral load per milliliter > 500 copies, there is a treatment indication; for those with CD4+ > 500/μl and viral load > 500 copies, there is no unified opinion on whether to treat, and treatment can be considered if the patient cooperates; for those with CD4+ < 200/μl and viral load below detectable levels, no treatment is required, and regular follow-up is needed.

　　The most commonly used treatment regimens are two nucleoside reverse transcriptase inhibitors (NRTIs) and one protease inhibitor (PI).