AIDS Health Article

Late-stage AIDS

Late-stage AIDS usually is marked by a sharp decline in the number of CD4+ lymphocytes (a type of white blood cell), followed by a rise in the frequency of opportunistic infections and cancers. Doctors monitor the number and proportion of CD4+ lymphocytes in the patient's blood in order to assess the progression of the disease and the effectiveness of different medications. About 10% of infected individuals never progress to this overt stage of the disease.

OPPORTUNISTIC INFECTIONS. Once the patient's CD4+ lymphocyte count falls below 200 cells/mm³, he or she is at risk for opportunistic infections. The infectious organisms may include:

• Fungi. Fungal infections include a yeast infection of the mouth (candidiasis or thrush) and cryptococcal meningitis.
• Protozoa. The most common parasitic disease associated with AIDS is Pneumocystis carinii pneumonia (PCP). About 70-80% of AIDS patients will have at least one episode of PCP prior to death. PCP is the immediate cause of death in 15-20% of AIDS patients. It is an important measure of a patient's prognosis. Toxoplasmosis is another common infection in AIDS patients that is caused by a protozoan. Other diseases in this category include amebiasis and cryptosporidiosis.
• Mycobacteria. AIDS patients may develop tuberculosis or MAC infections. MAC infections are caused by Mycobacterium avium-intracellulare, and occur in about 40% of AIDS patients.
• Bacteria. AIDS patients are likely to develop bacterial infections of the skin and digestive tract.
• Viruses. AIDS patients are highly vulnerable to cytomegalovirus (CMV), herpes simplex virus (HSV), varicella zoster virus (VZV), and Epstein-Barr virus (EBV) infections. Another virus, JC virus, causes progressive destruction of brain tissue in the brain stem, cerebrum, and cerebellum (multifocal leukoencephalopathy or PML), which is regarded as an AIDS-defining illness by the Centers for Disease Control and Prevention.

AIDS DEMENTIA COMPLEX AND NEUROLOGIC COMPLICATIONS. AIDS dementia complex is a late complication of the disease. It is unclear whether it is caused by the direct effects of the virus on the brain or by intermediate causes. AIDS dementia complex is marked by loss of reasoning ability, loss of memory, inability to concentrate, apathy and loss of initiative, and unsteadiness or weakness in walking. Some patients also develop seizures.

MUSCULOSKELETAL COMPLICATIONS. Patients in late-stage AIDS may develop inflammations of the muscles, particularly in the hip area, and may have arthritis-like pains in the joints.

ORAL SYMPTOMS. Patients may develop a condition called hairy leukoplakia of the tongue. This condition also is regarded by the CDC as an indicator of AIDS. Hairy leukoplakia is a white area of diseased tissue on the tongue that may be flat or slightly raised. It is caused by the Epstein-Barr virus.

AIDS-RELATED CANCERS. Patients with late-stage AIDS may develop Kaposi's sarcoma (KS), a skin tumor that primarily affects homosexual men. KS is the most common AIDS-related malignancy. It is characterized by reddish-purple blotches or patches (brownish in African-Americans) on the skin or in the mouth. About 40% of patients with KS develop symptoms in the digestive tract or lungs. KS appears to be caused by a herpes virus.

The second most common form of cancer in AIDS patients is a tumor of the lymphatic system (lymphoma). AIDS-related lymphomas often affect the central nervous system and develop very aggressively.

Invasive cancer of the cervix is an important diagnostic marker of AIDS in women.

Diagnosis

Because HIV infection produces such a wide range of symptoms, the CDC has drawn up a list of 34 conditions regarded as defining AIDS. The physician will use the CDC list to decide whether the patient falls into one of these three groups:

• definitive diagnoses with or without laboratory evidence of HIV infection
• definitive diagnoses with laboratory evidence of HIV infection
• presumptive diagnoses with laboratory evidence of HIV infection

Physical findings

Almost all symptoms of AIDS can occur with other diseases. The general physical examination may range from normal findings to symptoms that are closely associated with AIDS. These symptoms are hairy leukoplakia of the tongue and Kaposi's sarcoma. When the doctor examines the patient, he or she will look for the overall pattern of symptoms rather than any one finding.