HIV Flashcards
What type of virus is HIV?
HIV is an RNA retrovirus
What is the most common type of HIV?
HIV-1
What type of HIV is mainly found in Western Africa?
HIV-2
What is the pathophysiology of HIV?
The virus enters and destroys the CD4 T helper cells of the immune system
How can HIV be transmitted?
Unprotected anal, vaginal or oral sex
Vertical transmission
Exposure to infected bodily fluids
How does HIV replicate inside the body?
Once in the T helper cells, it uses the enzyme reverse transcriptase to convert viral RNA into a DNA copy
What is HIV seroconversion?
When the body starts to produce antibodies to HIV
- After seroconversion, HIV can be tested for
What are the symptoms of HIV seroconversion?
Flu-like illness symptoms
- Sore throat
- Lymphadenopathy
- Diarrhoea
- Malaise, myalgia
- Maculopapular rash
- Mouth ulcers
How long after infection does seroconversion occur?
3-12 weeks
What are the risk factors for HIV infection?
IV drug use
Homo and heterosexual unprotected intercourse
Percutaneous needlestick injury
Having another STI
Blood transfusion
What methods are used to diagnose HIV?
HIV antibodies
p24 antigen
How are HIV antibodies used to diagnose HIV?
ELISA test and a confirmatory Western Blot assay are used to detect antibodies to HIV
After how long can HIV antibodies be detected in the blood?
Most people have antibodies by 4-6 weeks, but 99% of people have antibodies by 3 months
How are p24 antigens used to diagnose HIV?
A viral core protein can be detected as RNA viral levels increase in the blood
When can p24 antigens be detected in the blood?
Between 1 weeks and 3-4 weeks after infection
How are most people diagnosed with HIV?
A test combining p24 antigen testing and HIV antibodies
When should an asymptomatic patient be offered testing after a possible exposure?
4 weeks after the exposure
- Repeated at 12 weeks if first test is negative
What are the differentials of HIV infection?
Infectious mononucleosis
CMV
Influenza
Viral hepatitis
Secondary syphilis
What is the normal CD4 count range?
500-1200 cells/mm3
Under what CD4 count puts a patient at risk of opportunistic infections?
200
What is the main treatment of HIV?
Anti-retroviral treatment
Who is antiretroviral treatment offered to?
All patients regardless of CD4 count - ART should be started as soon as a HIV diagnosis is made
What are the classes of ART?
Protease inhibitors
Integrase inhibitors
Nucleoside reverse transcriptase inhibitors
Non-nucleoside reverse transcriptase inhibitors
Entry inhibitors
What is the usual starting regime for HIV treatment?
Two NRTIs plus an additional drug (preferred combination is tenofovir/emtricitabine with a third agent)
What additional management is required in HIV?
Prophylactic co-trimoxazole for patients with CD4 count under 200
Yearly cervical smears
Up to date vaccinations
When can a woman with HIV have a normal vaginal birth?
If viral load is under 50
What drug can be given to a woman in labour to prevent vertical transmission?
IV zidovudine
What prophylaxis may be given to a baby with a HIV positive mother?
Zidovudine, lamivudine and nevirapine for 4 weeks
What is the safest advice to breastfeeding mothers that are HIV positive?
To avoid breastfeeding - HIV can be transmitted through breast milk
What is PEP?
Post exposure prophylaxis
- Given within 72 hours to patients who have been exposed to HIV
What is the current combination of drugs used in PEP?
emtricitabine/tenofovir (Truvada) and raltegravir for 28 days
What is PrEP?
Pre-exposure prophylaxis for HIV
What is the current combination of drugs used in PrEP?
emtricitabine/tenofovir (Truvada)
What are the most common AIDS defining illnesses?
Kaposi’s sarcoma
Pneumocystis jirovecii pneumonia
Cytomegalovirus infection
Candidiasis
Lymphomas
TB
When should children be tested for HIV?
Babies to HIV positive parents
When immunodeficiency is suspected
Young people who are sexually active and there are concerns
Needle stick injuries
Sexual abuse
IV drug use
What eye conditions may be seen in someone with HIV?
CMV retinitis
Kaposi’s sarcoma
HSV infection
VSV infection
Tuberculosis
What is the presentation of CMV retinitis?
Reduced visual acuity
Pizza pie appearance on fundoscopy
- areas of thick white infiltrate accompanied by retinal haemorrhages
What is the treatment of CMV retinitis?
Intra-ocular ganciclovir
Oral valganciclovir
What is Kaposi’s sarcoma?
A cancer caused by HSV-8 commonly seen in patients with HIV
Where does Kaposi’s sarcoma develop from?
Endothelial cells
- It is seen in the skin
What is the appearance of Kaposi’s sarcoma?
Purple papules or plaques on the skin
What is the treatment of Kaposi’s sarcoma?
Radiotherapy
Resection
What types of cancers is HIV associated with?
Anal
Liver
Lung
Hodgkin’s lymphoma
Burkitt’s lymphoma
Kaposi’s sarcoma
What is the treatment of pneumocystis jiroveci pneumonia?
Co-trimoxazole
What are the features of pneumocystis jiroveci pneumonia?
Bilateral bihilar interstitial infiltrates
Desaturating on exertion
Non-productive cough
Poorly controlled HIV
How should anti-retrovirals be taken?
They should be taken at the same time every day
What opportunistic infections occur in HIV but are not AIDS defining?
Oral candidiasis
Hairy leukoplakia
Shingles
Aspergillosis
