AIDS and HIV patho exam 1

AIDS is a chronic infectious disease caused

HIV, which destroys helper T lymphocytes, causing loss of the immune response and increased susceptibility to secondary infections and cancer.

An individual is considered HIV positive when

the virus is known to be present in the body but few, if any, clinical signs have developed.AIDS is the stage of active infection, with marked clinical manifestations and multiple complications.

An individual may be HIV positive for many years before

he or she develops AIDS.

HIV is a retrovirus, which means that?

it has an RNA genome

What body fluid contains the highest concentration of the HIV virus?

Blood

People who are high-risk sources of HIV include

intravenous drug users (shared needles) and those with multiple sexual partners.

The presence of HIV infection can be determined by using

a blood test for HIV antibodies, using HIV antigen from recombinant HIV or enzyme-linked immunosorbent assay for the primary test.

The procedure in primary use today is a three-stage process; each stage involves specific immunoassay tests to determine the following

Presence of HIV-1/HIV-2 antigen/antibody

2. Differentiation/identification between HIV-1 and HIV-2 antibodies

3. A nucleic acid test is used to confirm HIV-1 positivity and eliminate a false negative

PCR typing is used to

check the status of a newborn child who may carry the mother’s antibodies but not be infected.

A diagnosis of AIDS depends on

a major decrease in CD4-positive T-helper lymphocytes in the blood (see Fig. 7.13) and a change in the CD4-positive to CD8-positive ratio in the presence of opportunistic infection or certain cancers.B lymphocytes remain normal, and IgG is increased.

During the first phase, a few weeks after exposure,

viral replication is rapid, and there may be mild, generalized flulike symptoms such as low fever, fatigue, arthralgia, and sore throat. These symptoms disappear without treatment. Many persons are asymptomatic.

In the prolonged second, or latent, phase,

many patients demonstrate no clinical signs, whereas some have a generalized lymphadenopathy or enlarged lymph nodes. It appears that viral replication is reduced during this time.

The final acute stage, when immune deficiency is evident, is marked by numerous serious complications. The categories include

general manifestations of HIV infection, gastrointestinal effects, neurologic effects, secondary infections, and malignancies. Secondary infections and cancer are caused by the immunodeficiency. Each patient may demonstrate more effects in one or two categories, as well as minor changes in other systems

Generalized effects include

lymphadenopathy, fatigue and weakness, headache, and arthralgia. Gastrointestinal effects seem to be related primarily to opportunistic infections, including parasitic infections. The signs include chronic severe diarrhea, vomiting, and ulcers on the mucous membranes. Necrotizing periodontal disease is common, with inflammation, necrosis, and infection around the teeth in the oral cavity. Severe weight loss, malnutrition, and muscle wasting frequently develop.

HIV encephalopathy (general brain dysfunction), sometimes called AIDS dementia, refers to

the direct infection of brain cells by HIV. This is often aggravated by malignant tumors, particularly lymphomas, and by opportunistic infection of the brain with organisms such as herpesvirus, various fungi, and Toxoplasma gondii. Nutritional deficits, particularly vitamin deficits, are a contributing factor. Encephalopathy is reflected by confusion, progressive cognitive impairment, including memory loss, loss of coordination and balance, and depression. Eventually the person cannot talk or move, and seizures or coma may develop.

Secondary infections are common with AIDS and are the primary cause of

Death. Drug treatment of the secondary infection is often ineffective. In the lungs, P. carinii, now considered a fungus, is a common cause of severe pneumonia and is frequently the cause of death

Kaposi sarcoma is much rarer in

women than in men

It appears that women with AIDS have a higher incidence of

severe and resistant vaginal infections and pelvic inflammatory disease than women without AIDS, as well as more oral Candida and herpes infections.

Two positive PCR tests are required to confirm HIV infection in

young children

What is often the common cause of death in children with HIV?

P. carinii pneumonia

Prophylactic antimicrobial drugs are often prescribed to who with HIV?

Children

What type of drugs can reduce the replication of viruses, but they do not kill the virus, and thus are not a cure?

Antiviral drugs

Is probably the best-known single drug being used in the fight HIV;

AZT

The use of multiple drugs is referred to as

antiretroviral therapy

Treatment for HIV should start when the following conditions are present

Severe symptoms

• CD4-positive T cell count under 500

• Pregnancy

• HIV-related kidney disease

• Ongoing treatment for hepatitis B