(AIDS) (cont.)

What are symptoms and signs of AIDS?

AIDS is an advanced stage of HIV infection. Because the CD4 cells in the immune system have been largely destroyed, people with AIDS develop symptoms and signs of unusual infections or cancers. When a person with HIV infection gets one of these infections or cancers, it is referred to as an "AIDS-defining condition." Examples of AIDS-defining conditions are listed in Table 1. Significant, unexplained weight loss is also an AIDS-defining condition. It is possible for people without AIDS to get some of these conditions, especially the more common infections like tuberculosis.
People with AIDS may develop symptoms of pneumonia due to Pneumocystis jiroveci, which is rarely seen in people with normal immune systems. They also are more likely to get pneumonia due to common bacteria. Globally, tuberculosis is one of the most common infections associated with AIDS. In addition, people with AIDS may develop seizures, weakness, or mental changes due to toxoplasmosis, a parasite that infects the brain. Neurological signs also may be due to meningitis caused by the fungus Cryptococcus. Complaints of painful swallowing may be caused by a yeast infection of the esophagus called candidiasis. Because these infections take advantage of the weakened immune system, they are called opportunistic infections.
The weakening of the immune system in AIDS can lead to unusual cancers like Kaposi's sarcoma. Kaposi's sarcoma develops as raised lesions on the skin which are red, brown, or purple. Kaposi's sarcoma can spread to the mouth, intestine, or respiratory tract. AIDS also may cause lymphoma (a type of cancer) of the brain or other types of lymphomas.
In people with AIDS, HIV itself may cause symptoms. Some people experience relentless fatigue and weight loss, known as "wasting syndrome." Others may develop confusion or sleepiness due to infection of the brain with HIV, known as HIV encephalopathy. Both wasting syndrome and HIV encephalopathy are AIDS-defining illnesses.

What are risk factors for AIDS?

Because AIDS is caused by HIV, the risk factors for developing AIDS are the same as for HIV. Specifically, behaviors that result in contact with infected blood or secretions pose the main risk of HIV transmission. These behaviors include sexual intercourse and injection drug use. The presence of sores in the genital area, like those caused by herpes, makes it easier for the virus to pass from person to person during intercourse. HIV also has been spread to health-care workers through accidental sticks with needles contaminated with blood from HIV-infected people, or when broken skin has come into contact with infected blood or secretions. Blood products used for transfusions or injections also may spread infection, although this has become extremely rare (less than one in 2 million transfusions in the U.S.) due to testing of blood donors and blood supplies. Finally, infants may acquire HIV from an infected mother either while they are in the womb, during birth, or by breastfeeding after birth.
The risk that HIV infection will progress to AIDS increases with the number of years since the infection was acquired. If the HIV infection is untreated, 50% of people will develop AIDS within 10 years. This time is shortened if the person already has a weak immune system or if HIV was acquired through transfusion. Of people with HIV, the risk of progressing to AIDS is increased if there is evidence that the immune system is weakening as shown by falling levels of CD4 cells or if the virus is reproducing rapidly as shown by a high number of viral particles in the blood (high viral load).
Treatment substantially reduces the risk that HIV will progress to AIDS. In developed countries, use of highly active antiretroviral therapy (HAART) has turned HIV into a chronic disease that may never progress to AIDS. Conversely, if infected people are not able to take their medications or have a virus that has developed resistance to several medications, they are at increased risk for progression to AIDS. If AIDS is not treated, 50% of people will die within nine months of the diagnosis.

What is the treatment for HIV/AIDS?

Medications that fight HIV are called anti-retroviral medications. Different anti-retroviral medications attack the virus in different ways. When used in combination with each other, they are very effective at suppressing the virus. These effective combinations are called highly active anti-retroviral therapy or HAART. It is important to note that there is no cure for AIDS or for HIV. HAART only suppresses reproduction of the virus.
All people with a diagnosis of AIDS should receive HAART therapy. Of course, it is even better to give the medications earlier in HIV infection to prevent progression to AIDS. Current Department of Health and Human Services guidelines recommend starting HAART when CD4 falls below 350 cells per milliliter. Most experts would also consider therapy if the viral load is more than 100,000 copies per milliliter or if the CD4 count is falling rapidly. Recent studies suggest that starting treatment earlier, at CD4 counts from 350 to 500 and possibly even when greater than 500 per milliliter, may be beneficial.
There are five major classes of anti-retroviral medications: (1) nucleoside reverse transcriptase inhibitors (NRTIs), (2) non-nucleoside reverse transcriptase inhibitors (NNRTIs), (3) protease inhibitors (PIs), (4) entry inhibitors, and (5) integrase inhibitors. These drugs are used in different combinations according to the needs of the patient and depending on whether the virus has become resistant to a specific drug or class of medications. Treatment regimens usually consist of three to four medications at the same time. The most commonly recommended regimen includes two medications from the NRTI class in combination with either a protease inhibitor or an NNRTI or, less commonly, an integrase inhibitor. Entry inhibitors and integrase inhibitors are relatively newer classes of anti-retroviral medications and are useful for those patients who have failed to respond to other agents or who have a resistant virus. Combination treatment with HAART is essential because using only one class of medication by itself allows the virus to become resistant to the medication.
Before starting HAART, blood tests are usually done to make sure the virus is not already resistant to the chosen medications. These resistance tests may be repeated if it appears the drug regimen is not working or stops working. Patients are taught the importance of taking all of their medications as directed and are told what side effects to watch for. Noncompliance with medications is the most common cause of treatment failure and can cause the virus to develop resistance to the medication. Because successful therapy often depends on taking several pills, it is important for the patient to understand that this is an "all or nothing" regimen. If the person cannot tolerate one of the pills, then he or she should call their physician, ideally prior to stopping any medication. Taking just one or two of the recommended medications is strongly discouraged because it allows the virus to mutate and become resistant. It is best to inform the doctor quickly about any problems so that a better-tolerated combination can be prescribed. To reduce the number of pills needed each day, there are pills that contain multiple medications.