Lecture 6: HIV, AIDS and Opportunistic Infections Flashcards
How are HIV1 and HIV2 different in terms of virulence and geographical distribution?
- HIV1 isolated in America, Europe and Central Africa
- HIV2 in West Africa; less virulent and not spread as rapidly and widely
HIV consists of 2 positive ssRNA held together by which protein?
p7 protein
What is the HIV capsid protein?
p24
Which 3 genes of HIV are the most important for making structural proteins for new virus particles?
gag, pol, env
The capsid of HIV contains which 3 enzymes required for HIV replication?
- Reverse transcriptase
- Integrase
- Protease
In regards to the pathogenesis of HIV the hallmark of symptomatic HIV infection is what?
Immunodeficiency caused by continuing viral replication
What are 7 opportunistic infections of HIV when CD4 counts are around 500?
- Bacterial infections
- Tuberculosis
- Herpes simplex
- Herpes zoster
- Vaginal cadidiasis
- Hairy leukoplakia
- Kaposi sarcoma
What are the 5 opportunistic infections for HIV patients with CD4 <200?
- Pneumocystosis
- Toxoplasmosis
- Cryptococcosis
- Coccidioidomycosis
- Cryptosporidiosis
What are 4 opportunistic infections of HIV when CD4 is <50?
- Disseminated MAC infection
- Histoplasmosis
- CMV retinitis
- CMV lymphoma
HIV diagnosis is made using a combo immunoassay for what?
HIV Ab with a test for HIV p24 Ag
A positive result on HIV-1/2 Ag/Ab combination assay is followed by which test?
HIV-1/2 Ab differentiation immunoassay
If HIV samples on HIV-1/2 Ab differentiation test are negative, what test is done next?
HIV-1 nucleic acid amplification test (NAAT)
If HIV specimens are positive on initial combination assay, and then are negative on Ab differentiation immunoassay and NAAT, this tells us what?
False-positive test
What is the most widely used marker to provide prognostic information and to guide therapy decisions in HIV patient?
CD4 lymphocyte count
What is the most common opportunistic infection associatd with AIDS?
Pneumocystis Jirovicii
What is the cornerstone of diagnosis for pneumocystis jirovecii pneumonia and what will be seen?
- Chest radiograph
- Diffuse or perihilar infiltrates are most characteristic
If pleural effusions are seen on CXR of pt with suspected pneumocysti jirovecii pneumonia, how does this change the DDx?
Think bacterial pneumonia, TB, or pleural Kaposi’s
How is the definitive diagnosis of Pneumocystis made; what if this test is negative and pneumocystis is still suspected?
- Definitive dx via Wright-Giemsa stain or dirext fluorescence antibody (DFA) test of the SPUTUM
- If negative, can do a Bronchoalveolar lavage to establish diagnosis
Which lab values may be elevated in Pneumocystis Pneumonia; which is more sensitive and specific?
- ↑↑↑ LDH
- Serum beta-glucan test = more sensitive and specific
A CD4 count >______ within 2 months prior to evaluation of respiratory sx’s makes a diagnosis of Pneumocystis pneumonia unlikely.
A CD4 count >250 within 2 months prior to evaluation of respiratory sx’s makes a diagnosis of Pneumocystis pneumonia unlikely.
Which DLco and findings on high-resolution CT scan of the chest would make dx of Pneumocystis pneumonia very unlikely?
- A normal diffusing capacity of CO (DLco)
- NO interstitial lung disease on CT of chest
What are the most common causes of pulmonary disease in HIV-infected patients?
- Community-acquired pneumonia
- Bacterial, mycobacterial, and viral pneumonias
What is seen on unenhanced CT scan of Toxoplasmosis infection?
Multiple subcortical lesions w/ a predilection for the basal ganglia
Imaging showing multiple ring-enhancing lesions with surrounding areas of edema is characteristic of what?
Toxoplasmosis
A patient with known HIV infection presents with changes in his vision and upon fundoscopic exam you see this; what should you be thinking about?
CMV retinitis
