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HIV
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Path
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· Env gene
· Gp120: attach HIV to cells
· Gp40: Fusion + entry into cells
· gag gene
· p24: capsid
· p17: viral matrix protein
· pol gene:
· Reverse transcriptase
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Dx
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· Fourth-generation combination HIV-1/2 immunoassay
· best initial test
· detects both
o HIV-1 and HIV-2 antibodies
o HIV p24 antigen
· interpretation
o if negative → ø
o if positive: perform an HIV-1/HIV-2 antibody differentiation immunoassay → Confirm Dx
o if the differentiation immunoassay is negative or indeterminate → perform a viral load
· CD4+ T-cell count and percentage
· HIV genotyping
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Tx
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· 2 NRTI + 1 other (integrase inhibitor)
· The MCC of tx failure is nonadherence
· Pregnancy and HIV:
· Tx the same except ⤵️
· Avoid: dolutegravir – elvitegravir – tenofovir alafenamide
· If viral load >1000 → C-Section + IV Zidovudine
· AVOID BREASTFEEDING ❌
· For the baby:
· If viral load <1000 → Zidovudine for 4-6 weeks
· If viral load >1000 → zidovudine, lamivudine, and nevirapine in the infant for 6 weeks
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PPx
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· Post-exposure prophylaxis
· first-line treatment given immediately after HIV exposure (such as in health care personnel)
· initiate within 72 hours
· drug regimen: tenofovir, emtricitabine, and raltegravir
· Pre-exposure prophylaxis
· to prevent HIV infection in high-risk patients
· tenofovir and emtricitabine
· HIV is an indication for obtaining the following vaccines:
· pneumococcal
· hepatitis B (if not already immune)
· meningococcal
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Common causes of diarrhea in AIDS
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CD4 count
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Sx
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Cryptosporidium
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< 180
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· Severe watery diarrhea
· Low-grade fever
· Weight loss
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Mycobacterium avum complex
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< 50
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· Watery diarrhea
· High fever >39
· Weight loss
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CMV
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< 50
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· Frequent small diarrhea
· Hematochezia
· Abdominal pain
· Low-grade fever
· Weight loss
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Opportunistic organisms in HIV
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PCP
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CD4+ < 200
Oral candidiasis
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TMP-SMX
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Toxo
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CD4+ <100
+Toxoplasma IgG Ab
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TMP-SMX
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MAC
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CD4+ < 50
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Azithro
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Histoplasma
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CD4+ <150
Endemic area / Caves
Ohio+ Mississippi river
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Itraconazole
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Pneumocystis Jirovicii
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Clx
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· Indolent (HIV) or acute respiratory failure (immunocompromised)
· Fever, dry cough, ↓ oxygen levels (HYPOXIA)
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Dx
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· ↑ LDH level
· CXR: ⓑ Diffuse reticular infiltrates
· Induced sputum or BAL (stain)
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Tx
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· TMP-SMX
· Prednisone if ⤵️ O2 levels
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PPx
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· TMP-SMX (CD4 <200)
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CMV Pneumonitis
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CMV is a common opportunistic infection that may cause pneumonitis.
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Marked by:
– dyspnea,
– nonproductive cough,
– low-grade fever,
– diffuse ground-glass opacities on CT scan.
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Disseminated Mycobacterium avium complex (MAC)
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Sx
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Nonspecific sx (eg, fever, cough, abdominal pain, diarrhea, night sweats, weight loss)
+ splenomegaly
+ ALP
in pt w/ CD4 cell count <50/mm3.
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Dx
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Blood cultures (or lymph node or bone marrow biopsy)
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PPx
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CD4 cell count <50/mm3 should receive azithromycin prophylaxis against MAC.
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Tx
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1˚ clarithromycin or azithromycin.
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DDx
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CMV: check lgG/lgM
TB: check hx, cxr, skin test
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HIV drug
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SE
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NRTI
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· BM suppression (can be reversed with G-CSF and EPO),
· peripheral neuropathy,
· lactic acidosis (nucleosides),
· anemia (ZDV),
· pancreatitis (didanosine).
· Abacavir contraindicated if patient has HLA-B*5701 mutation due to risk of hypersensitivity.
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NNRTI
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· Rash and hepatotoxicity are common to all NNRTIs.
· Vivid dreams and CNS symptoms are common with efavirenz.
· Delavirdine and efavirenz are contraindicated in pregnancy.
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Protease inhibitor
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· Hyperglycemia,
· GI intolerance (nausea, diarrhea),
· lipodystrophy (Cushing-like syndrome).
· Nephropathy, hematuria, thrombocytopenia (indinavir).
· Rifampin (potent CYP/UGT inducer) reduces protease inhibitor concentrations; use rifabutin instead.
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Integrase inhibitor
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⤴️ CK
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Fast HY Review 