Signs and Symptoms
HIV initially causes an acute illness with non-specific, flu-like symptoms such as fatigue, headache, fever, and enlarged lymph nodes. Some people will not experience any noticeable symptoms. During this time period, the virus is present in large numbers and is carried throughout the body. HIV infects immune cells called CD4 T-cells (also called helper T cells) and slowly begins to decrease their numbers. The virus sets up house in places such as the brain and lymph nodes, where it will linger even during future drug treatment.
The person's immune system responds to the acute HIV infection by producing antibodies against the virus. In most people, the initial symptoms go away after a short time period. The person may be apparently healthy for a decade or more, but behind the scenes HIV is still replicating and destroying CD4 T-cells. If the infection is not treated, the affected person's immune system is eventually compromised to the extent that they begin having symptoms such as:
- Persistently enlarged lymph nodes
- Weight loss
- Recurrent yeast infections
- Herpes infections
- Memory loss or difficulty concentrating
In children who are infected with HIV at or before birth, symptoms may emerge within a couple of years. They may have delayed development and be frequently ill.
Development of AIDS
The term AIDS applies to the most advanced stages of HIV infection. According to the CDC, AIDS is diagnosed when someone's CD4 T-cell count drops below 200 cells/mm3 or when the person has HIV and an AIDS-related illness, such as tuberculosis or pneumonia caused by the microorganism Pneumocystis jirovecii (carinii). In people with AIDS, opportunistic infections are often severe and sometimes fatal because the immune system is so damaged by HIV that the body cannot fight off certain bacteria, viruses, fungi, or parasites.
Opportunistic infections common in people with AIDS cause symptoms such as:
- Coughing and shortness of breath
- Seizures and lack of coordination
- Difficult or painful swallowing
- Mental symptoms such as confusion and forgetfulness
- Severe and persistent diarrhea
- Vision loss
- Nausea, abdominal cramps, and vomiting
- Weight loss and extreme fatigue
- Severe headaches