AIDS AND HIV
INTRODUCTION
First cases in 1981 after PCP cases in homosexuals
Defect in cell mediated immunity (CD4 T helper cells)
AIDS = CD4 99%
False -ve testing: “window-period” where infection occurs but antibodies
aren’t formed yet (may be months): 95% +ve by 3 months
False -ves: seroreversion, atypical strains
False +ves: blood transfusion from someone with antibodies to HIV, children
35 (prednisone 40 mg po
bid with a taper over 3 weeks)
Treatment generally for 3 weeks
Many do not clear the infection
Adverse effects of septra 20Xs more common in AIDS patients: N/V, rash,
neutropenia, thrombocytopenia, hyponatremia, hepatitis
PCP prophylaxis: recommended when CD4 200 and patient
is alert with no focal findings but most will do CT first anyways
See Figure 126-1
CT typical for toxo: treat and no LP
CT with lesions but not typical for toxo: LP, may need stereotactic bx
CT with no lesion: LP
Note: CT head without contrast may miss subtle lesions (go on to CT with
contrast or MRI)
Lumbar puncture: DO NOT forget to send cytology (CNS lymphoma),
cryptococcal antigen latex agglutination, coccidioidomyocosis titer,
viral/fungal/TB cultures (phone lab and ask how much volume needed for
these tests), opening pressure can help
HIV Encephalopathy
AIDS dementia complex
Occurs in 1/3
Progressive process cuased by direct HIV infection
Initial presentation with loss of recent memeory, subtle cognitive defects
Early presentation may be confused with depression, anxiety, etc
Later: frank mental status changes, seizure, frontal release, incr. DTRs
Must r/o other CNS pathology
Neuroimaging shows atrophy and diffuse deep mater hyperintensities
LP is typically norma;
Cryptococcus neoformans
10% of AIDS patients
Focal cerebral lesions or diffuse meningoencephalitis
Fever, headache, nausea, vomiting is the MC initial symptoms
Can present with visual changes, seizures, focal deficits
Dx = CSF identification
Cryptococcal antigen latex agglutination is nearly 100% sensitive and specific
(India ink staining is 70% sensitive, fungal culture 90%, serum cryptococcal
antigen 90%)
Treatment: amphotericin B +/- flucytosine X 10 weeks (high relapse rate)
Chronic suppression therapy with fluconazole after initial treatment
Bone marrow suppression is a problem with treatment regimen
Toxoplasma gondii
MC focal encephalitis in AIDS patient
Headache, fever, altered LOC, seizures, focal deficits in up to 80%
PEARL: HIV/AIDS and looks like a stroke; infection is acutally more
common
Serology useless as most people have been exposed to it
CSF antibody is helpful but there are many false +ves
Dx: MULTIPLE SUBCORTICAL LESIONS on CT head
May not be seen on non-contrast CT head; repeat if highly suspicious (or
MR)
Brain lesion ddx: toxo, lymphoma, TB, fungi, progressive multifocal
leukoencephalopathy, CMV, KS, hemorrhage
Suggestive of toxo: multiple lesion, predominace for BG and corticomedullary
area
Lymphoma: usually single slesion in periverntricular matter or corpus
callosum
Treatment: Pyrimethamine po + sulfadiazine po + folinic acid to reduce the
incidence of pancytopenia
Dexamethasone for significant brain edema
Dilantin for seizure prophylaxix for significan edema
Chronic suppression therapy with pyrimethamine, sulfadiazine, and folinic
acid
Prophylaxis: indicated for +ve seriology and CD4 5000
but significant variation exists (some treat all with measurable viral loads)
Drug Regimens
No universal concensus
First line regimen: two NRTIs + one PI or two NRTIs + one NNRTI
Prophylaxis mostly based on the CD4 count which is the best predictor of
opportunistic infections
Prophylaxis: PCP, TB, toxo, MAC, others
Immunizations
NO LIVE VIRUS or BACTERIA vaccines
Pneumococcal vaccination for all > 2yo
Influenza generally recommended
HBV immunization if at risk
HAV immunization b/c of suceptibility to liver insult
Td booster: some recent evidence of increased viral expression following
administration of Td but clinical significance unknown
Disposition
Admission
- FUO
- Hypoxemia
- PCP pneumonia
- TB
- New CNS symptoms
- Intractable diarrhea
- Suicidal
- CMV retinitis
- Zoster involving the eye
- Unable to care for self
- No follow up
Discharge
- Normal vitals
- Stable condition
- Able to take meds and self care
- Good follow-up
- Caregivers to help