Lung Problems

Most infections of the lung, or pneumonias, regardless of their cause, have the same symptoms: cough, shortness of breath, and fever. In some lung infections, the cough is productive—that is, the cough produces sputum; in other lung infections, the cough is dry.

Cough and shortness of breath are relatively common symptoms of other medical conditions as well. Causes of these symptoms include asthma, influenza, bronchitis, and chronic lung diseases like those brought on by long-term smoking. When these symptoms occur in some­one who has not previously had lung problems, when they are more se­vere than usual, or when they are accompanied by fever, the cause could be pneumonia. People with HIV infection get different kinds of pneu­monias, but the most important are pneumocystis pneumonia, tubercu­losis, and certain common bacterial pneumonias. The standard diag­nostic tests for these symptoms include a blood count, a chest X-ray, and culture of the sputum. Additional diagnostic tests will largely depend on the specific symptoms and on the results of the first set of tests.

Dry Cough, Shortness of Breath, and Fever

Symptoms that include a dry cough, shortness of breath, and fever when the CD4 count is below 200 are most likely to be Pneumocystis jiroveci pneumonia (PCP). The most characteristic symptom of PCP, compared to other pneumonias, is a dry cough that does not produce sputum and that begins subtly and progresses slowly. People with PCP first notice shortness of breath only with exercise, then begin to notice it with min­imal activity; eventually, they notice it even when they are at rest.

PCP is caused by a fungus called Pneumocystis jiroveci. PCP is rel­atively common late in the course of HIV infection: of the first 100,000 people who had AIDS in the United States, 80 percent had PCP some­time during the course of the infection, and 60 percent had PCP as their first major complication. These numbers are now way, way down. The reason the numbers are down by so much is that both HIV treatments and PCP prophylaxis are so effective. Nevertheless, PCP is still the most common important complication of late HIV infection.

PCP in people with AIDS evolves slowly, and most people have had the symptoms for weeks before they seek medical attention. PCP is seri­ous, however, and if left untreated, it is fatal: at first approximately 25 percent of people with HIV died because of PCP. PCP continues to be a major cause of death in people with HIV infection, but primarily in those who do not respond to antiretroviral treatment and don’t take the drugs to prevent PCP. This percentage is now decreasing because drugs are given to prevent PCP in people with CD4 counts below 200.

The tests to diagnose PCP can be tedious and unpleasant. People of­ten ask if the testing process can be simplified, and indeed, the person’s symptoms and chest X-ray results are occasionally compelling enough to diagnose PCP without looking for the fungus. This approach, though simple and efficient, can occasionally lead to an inaccurate diagnosis; that is, the person is assumed to have PCP, and an alternate and treat­able infection may be overlooked. Similarly, a delay in treating PCP may allow it to progress to the point where it is difficult to reverse. For these reasons, most physicians experienced in caring for people with AIDS will treat PCP aggressively when symptoms suggest it.

A variety of drugs can be used to treat PCP. The most common are antibiotics: trimethoprim-sulfamethoxazole (the trade names are Bactrim and Septra), dapsone plus trimethoprim, clindamycin plus primaquine, atovaquone (Mepron), and pentamidine. Most people respond well to treatment, but recovery is slow. Those who recover are likely to develop PCP again; in fact, the recurrence rate is about 70 percent within one year. Recurrences can be prevented. The drugs that prevent the recur­rence of PCP include pentamidine taken by aerosol, trimethoprim­sulfamethoxazole taken by mouth, dapsone taken by mouth, or atova- quone (which is very expensive) taken by mouth. People who are candidates for preventive treatment include not only anyone with HIV infection who has previously had PCP, but also people with HIV infec­tion who have not had PCP but whose CD4 counts are less than 200. The best way to prevent PCP is to increase the CD4 count by treating HIV infection. When the CD4 count has increased to 200 to 250 or more for three months, many studies show you can safely stop treatment, but treatment should resume if the CD4 count decreases to 200 later on. Otherwise, when the CD4 count is below 200, the best treatments are the antibiotics listed above to prevent PCP.

Productive Cough, Shortness of Breath, Fever

Productive cough, shortness of breath, and fever are symptoms of tu­berculosis and pneumonia caused by certain types of bacteria; these symptoms may also be caused by PCP, certain viruses, Kaposi’s sarcoma in the lung, and several other unusual conditions.

Tuberculosis (TB). The most common symptoms of TB are cough, bloody sputum, shortness of breath, fever, weight loss, chest pain with breathing, and night sweats. As with PCP, the tempo of tuberculosis is generally slow, usually progressing over a period of weeks or months. During this time the person is usually fatigued, has night sweats, and loses weight.

Mycobacterium tuberculosis, the only contagious mycobacterial in­fection, can be transmitted from one person to another by close contact, usually over a period of several months. For this reason, the people most likely to be infected are those who live with the infected person. But an infected person who has been treated with drugs against TB for several days is less likely to transmit the infection to others. This means that once treatment has started, the likelihood that it will be spread to oth­ers is reduced or nil. The only way to find out whether a person has dor­mant or inactive TB is to take the skin test most people are familiar with, done on the forearm. The skin test is a shallow injection of a protein called a purified protein derivative, or PPD, made from Mycobacterium tuberculosis. If the area around the injection becomes red and thickened two or three days later, the person’s immune system has responded to the bacterium. That means that Mycobacterium tuberculosis is in the body and the person has TB, either active or inactive. A positive skin test is followed by sputum tests for TB and X-rays. If the sputum test is also positive, or if the X-ray shows new changes, the person has active TB. Otherwise, the TB is inactive.

It is especially important for people with HIV infection to have a skin test. The risk of developing active TB is 100 times greater with HIV infection than without HIV infection. About 5 percent of all people with HIV infection get active tuberculosis, and about 5 percent of people with tuberculosis have HIV infection.

Physicians are under appropriate pressure to pursue tuberculosis ag­gressively and to take precautions to prevent its spread. A patient in a hospital who might have tuberculosis must be in a single room, and any­one entering the room must wear a mask. Visitors are often excluded, and patients are not allowed to leave the room except for medical pro­cedures. The patient feels lonely and bored, but isolation is necessary: hospitals have had big epidemics of TB, and health care workers often get infected by exposure in the workplace. TB is the major microbial cause of death in the world. Virtually everyone is vulnerable, and strict public health measures are an important method of control.

Inactive TB can be treated with a drug, isoniazid (INH), which will prevent active TB. Active TB is treated more aggressively, usually with four drugs. People with tuberculosis must take the full course of the these drugs for at least six months and should do so under direct observation. If they don’t take the full course, they cause two problems: the infection recurs, and this time they are likely to have a resistant strain that will be difficult or impossible to treat. Direct observation means going to a clinic to have someone give the medicine.

Bacterial pneumonias. Bacteria have always been a major cause of serious pneumonias. The symptoms of bacterial pneumonias are chills, fever, shortness of breath, and a cough that often produces thick yellow or green sputum. For some people, the major symptom is chest pain, es­pecially when they breathe. Unlike PCP and TB, bacterial pneumonias usually begin rather abruptly, and people see physicians within days rather than weeks or months.

The diagnosis of bacterial pneumonias is usually established with a chest X-ray and sometimes with sputum tests. Treatment with antibi­otics is highly effective when begun early in the infection. Trimethoprim­sulfamethoxazole, which prevents PCP, will help prevent pneumococcal pneumonia as well. Pneumococcal vaccine (Pneumovax) may also pre­vent pneumococcal pneumonia and is advocated for people with HIV infection; it helps best when it is given early in the course of HIV infec­tion. Bacteria other than pneumococcus cause pneumonias as well. Haemophilus influenzae is common and easy to treat. Pseudomonas aeruginosa occasionally causes pneumonia in the late stage and is hard to treat.

Viral pneumonias. Influenza viruses are like many viruses that attack the respiratory system. They are common in people without HIV infec­tion, and there is no evidence that they are more common or severe in those with HIV infection, even those in advanced stages of HIV infec­tion. Most people with a viral pneumonia have bronchitis—cold symp­toms with a cough—but a negative X-ray because the lungs are not in­fected. Influenza vaccine is advised for people with HIV infection in part because symptoms may cause undue concern about PCP and other lung problems. In addition, we’re not sure that influenza is totally safe in peo­ple with HIV infection, and the vaccine usually works well. Many other viruses can cause similar symptoms.

Miscellaneous lung conditions. Other causes of lung problems in peo­ple with HIV infection are less common than those above. Mycobac­terium avium complex (MAC), though it usually infects other parts of the body, sometimes infects the lungs. Cytomegalovirus, or CMV, may cause pneumonia in the late stages of HIV infection when the CD4 count is less than 50—though this is unusual. Kaposi’s sarcoma may be found in the lungs, where it causes cough and shortness of breath. People with Kaposi’s sarcoma in the lungs will probably have changes on a chest X- ray and will also have Kaposi’s sarcoma on the skin (see below, “Skin Problems”). Lymphomas are tumors of the lymph system that are com­mon with HIV infection and often cause lung complications. Occasion­ally, people with HIV infection will have a pneumonia called lympho­cytic interstitial pneumonia, which appears to be due to HIV itself and often responds to treatment with corticosteroids.