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