HIV/AIDS
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- What causes HIV infection?
- The retrovirus named HIV-1 is the most common cause of infection in most of the world. HIV-2 is the predominant retrovirus in most of West Africa although HIV-1 also exists there.
- What is a retrovirus?
- A virus that stores genetic information into RNA rather than DNA and is capable of incorporating itself into the DNA of cells causing the virus to repeat itself throughout the body.
- What is the specific mechanism of infection from the HIV-1 retrovirus?
- HIV-1 attacks the white blood cells called lymphocytes, reducing and destroying the body's immunity to infections and cancers.
- What is the relationship of HIV-1 infection to the disease of AIDS?
- AIDS (acquired immunodeficiency syndrome) is the primary disease from HIV-1 infection. Other oportunistic infections and cancers result from the severely compromised immunity.
- What immune system cells are attacked and destroyed in AIDS?
- CD+4 cells, also called T lymphocytes.
- In the 1980's epidemologists indentified which two conditions among US homosexual men that led to the identification of HIV/AIDS?
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1. pneumocystis pneumonia, caused by a fungus that non-compromised immune systems can fight
2. Kaposi's scaroma, a rare cancer characterized by skin lesions - What is the normal CD4+ lympocyte blood count?
- roughly 800-1300 cells per miroliter
- The critical level of CD4+ for vulnerability to infection is 200 cells/microliter. (T or F)
- True. Vulnernability to infection (ie, degree of immunosupression) decreases as CD4+ drops. A CD4+ blood level below 200 is one marker for the presence of AIDS.
- What are the three CDC (Center for Disease Control) categories of degree of immunosuppression?
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All are based on CD4+ blood levels:
1. >500
2. 200-499
3. <200 - What are the three CDC classification systems for history of clinical symptoms?
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A. medically asymptomatic or only transient illness since blood seroconversion to HIV infection
B. HIV minor opportunistic infections
C. more serious AIDS defining illnesses like KS or pnuemonocstis cariniii pneumonia. - The DCD criteria for AIDS are based on which two criteria?
- Either a CD4+ < 200 OR a category C clinical complication.
- What antibodies are directed at the HIV virus itself?
- B lymphocytes. These are produced in excess but do not have any effect on the opportunistic infections that are problematic in HIV infection/AIDS.
- What are the initial and minor symptoms of HIV infection?
- Fever, rash, swollen lymph notes, general discomfort, weight loss (called wasting), fatigue, diarrhea, anemia, thrush.
- Waht are the main opportunistic infections resulting from AIDS?
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Thrush
Vaginal yeast infections
Cryptococcal Meningitis
Pneumocystis carini
Toxoplasmosis
Tuberculosis
Mycobacterium avium complex
Crytosporidium
Progressive multifocal leukoencephalogy (PML)
Cytomegalovirus (CMV) encephalitis - What are common tumors from AIDS?
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Kaposi's scarcoma
Lymphomas
Cancers of the cervix (women)/rectum(men) - Describe CNS involvement from AIDS
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1 HIV enters the CSN early in the course of the disease.
2 Mild cognitive sequelae are common; dementia is primarily a late stage phenomenon
3 Some individuals, a very small group, present with severe dementia as the initial manifestation of AIDS - True or False: HIV directly damages neurons.
- False. HIV does not appear to directly infect neurons. HIV seems to activate microphages/microglia which can increase ctyokines which in turn damage neuronal structures either directly or by disturbing other cells like astrocytes that are important in maintaining the viability of neurons.
- Is AIDS dementia cortical or subcortical?
- Subcortical. HIV is predominately in subcortical regions and when it produces dementia, it subcortical in type. It does affect neocortical structures but to a lesser degree.
- What are the neuroimaging findings for HIV infection?
- Atrophy, white matter lesions, abnormal metabolism
- Classify the neurocognitive sequealae for HIV/AIDS.
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Primary: directly resulting from the effects of the virus
Secondary: from the immunodeficiency secondary infections or other adverse events from infection or treatment. - What is a common secondary neurocognitive sequela from AIDS?
- Delirium
- What are the characteristics of HIV related Mild Neurocognitive Disorder (MND) also called Minor Cognitive Motor Disorder (MCMD)?
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Impaired concentration
Unusual fatigabiltiy
Subjective sense of slowness
Mild memory problems
Impaired processing speed
Divided attention
Impaired effortful performance
Deficient learning and recall of new material
(Problems solving, abstract reasoning, and motor speed occasionally impaired but not main feature) - Verbal skills are less affected than other cognitive funcitons in AIDS (True or false)
- Generally true, although verbal fluency may be slow.
- What are the neurocognitive impairments typical of HIV-Associated Dementia (HAD)?
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Neurocognitive deficts are severe and interfere with social/occupational functioning. They are typical of subcortical dementia and include:
learning and recall impairment
reduced psychomotor speed
reduced fluency
impaired executive funcions
affective lability
irritability
withdrawal and apathy
inappropriate behavior
ataxia
weakness
impaired coordination - Does HIV Associated Dementia impact survival rates?
- Yes. The presence of dementia is correlated with decreased survival time.
- What neuropsychiatric disorders typically accompany AIDS?
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Adjustment Disorder
Anxiety Disorders (GAD, Panic, OCD)
Mood Disorders (Depression and Manic states)
Psychosis (may be a comorbid conditon-eg schizophrenics are at higher risk than other groups for contracting HIV)
Substance abuse (may also be comorbid) - Do antiviral agents used to treat HIV/AIDS impact the neurocogntive sequelae?
- Not well. This has and is a challenge in AIDS treatment research. The earlier antiviral drugs like AZT (zidovudine) inefficiently crossed the blood brain barrier with levels only 10-25% of plasma values. Newer drugs like protease inhibitors (indinavir) and combinations of the reverse transcriptase inhibitors like AZT and 3-TC or lamivudine that act synergistically hold hope for treatment of HIV mild cognitive impairment and development of dementia.