infections
Human Immunodeficiency Virus (HIV) Infection
More severe symptoms
For some people, the first symptoms are those of AIDS. AIDS is defined as the development of very serious opportunistic infections or cancer—the ones that usually develop only in people with a CD4 count of less than 200 cells per microliter of blood. The specific opportunistic infections and cancers that develop cause many of the symptoms. These infections occur more frequently or are more severe in people with HIV infection than in those without the infection. Serious opportunistic infections may cause various symptoms depending on the organ affected: Lungs:Fever, cough, or shortness of breath Brain:Headache, weakness, loss of coordination, or deterioration of mental function Digestive tract:Pain, diarrhea, or bleeding HIV can also cause symptoms when it directly infects and damages organs such as the following: Brain:Brain damage with memory loss, difficulty thinking and concentrating, or both, eventually resulting in dementia if HIV infection is not treated, as well as weakness, tremor, or difficulty walking Kidneys:Kidney failure with swelling in the legs and face, fatigue, and changes in urination, but often not until the infection is severe Heart:Heart failure with shortness of breath, cough, wheezing, and fatigue (uncommon) Genital organs:Decreased levels of sex hormones, which may cause fatigue and sexual dysfunction in men HIV is probably directly responsible for a substantial loss of weight (AIDS wasting) in some people. Wasting in people with AIDS may also be caused by a series of infections or by an untreated, persistent digestive tract infection. 