HIV Flashcards
What is HIV?
Single stranded RNA retrovirus
Infect and replicate with CD4 (T helper) cells
Describe the life cycle of HIV
1 Penetrate into host CD4 and empty contents
2 Reverse transcriptase to convert viral RNA into double stranded DNA
3 Integrase - DNA combined with host DNA
4 Infected cell divide - viral DNA also read and viral proteins made
5 Immature virus push out of cell retaining some cell membrane
6 Virus mature when protease cut viral protein chains - assemble to create working virus
7 Host cell destroyed
What happens to CD4 levels for a patient with HIV?
Upon seroconversion (making anti HIV antibodies) patient may experience flu like symptoms and CD4 levels fall - extremely infectious
Over next months-years, infection enter latent phase - CD4 drop and viral load increase but asymptomatic
HIV can then become symptomatic and eventually develop into AIDS
How is HIV transmitted?
Unprotected sexual contact
Sharing injecting equipment
Medical procedures - blood products, skin grafts, organ donation, artificial insemination
Vertical transmissio
What groups of people should HIV testing be encouraged in?
MSM
IV drug users
High prevalence areas
Unprotected sex with partner who has lived or been to Africa
How does HIV present in the seroconversion illness phase?
1-6 weeks post infection
Sore throat Fever Lymphadenopathy Malaise Arthralgia Diarrhoea Maculopapular rash Mouth ulcers
How does symptomatic HIV after the latent phase present?
Weight loss
High fever
Frequent opportunistic infections
What is important to explain in the counselling before a HIV test?
Check understanding
Explain significance of window period
Explain results need to be in medical record
Positive test must be disclosed in insurance application
Informed consent
Benefits of HIV testing
Arrange results appointment
Hep B and C test - if due to needle sharing
STI testing - if due to unprotected sex
What is the window period for HIV?
Time between infection and antibodies appearing - usually 4-6 weeks but can take upto 12
What are the benefits of HIV testing?
If negative - reassured
If +vs - effective treatment can prevent illness and ensure infection not transmitted
What would you do with the results from a HIV test?
-ve = consider retest due to window period \+ve = repeat test to confirm
What investigations are done for HIV?
Clotted blood sample - combined HIV antibody and P24 antigen
FBC - anaemia, thrombocytopenia, lymphocytopaenia, CD4
ESR - raised
Screen for STI’s
Baseline CXR
Describe the use of a HIV antibody test
Most common and accurate test
Usually consist of ELISA and western blot
Most people develop antibodies at 4-6 weeks, 99% by 12
No indication of disease progression
Describe the use of the P24 antigen test
Positive between 1 and 4 weeks for HIV
Used as additional screening tool
How is HIV managed?
HAART -
2 NRTI (nucleoside reverse transcriptase inhibitor) + either
Protease Inhibitor or NNRTI (non-nucleoside reverse transcriptase inhibitor)
What is an example of an NRTI and its adverse effects?
Zidovudine
Peripheral neuropathy, myopathy, anaemia, black nails
What is an example of an NNRTI and its adverse effects?
Nevirapine
P450 interaction, rash
What is an example of a protease inhibitor and its adverse effects?
Indinavir
Diabetes, hyperlipidaemia, buffalo hump, central obesity, p450 inhibitor
What other drugs can be used for HIV?
Integrase inhibitor - raltegravir
Entry inhibitor - Maraviroc
What are the general side effects for HAART?
Hypersensitivity - fever or rash Psychiatric - nightmares, sleep disturbance, mood changes Hyperlipidaemia Lipodystrophy T2DM Fanconi syndrome - proximal tubule dysfunction Lactic acidosis and hepatic toxicity Peripheral neuropathy Bone marrow suppression Pancreatitis
What non pharmacological measures are used for patients with HIV?
Promote CVS health - at more risk
Annual cervical cancer screening
Immunisations upto date
How is HIV monitored?
CD4 - reflect degree of immunocompromise
- Variable so trend more important than single value
- Determinant for opportunistic infection prophylaxis
Viral load - reflect rate of viral replication
- Rising load may indicate non adherence
- linked to CD4 decline and disease progression
What are the risks associated with a CD4 count 400-500?
Hodgkins lymphoma
Cervical cancer
What are the risks associated with a CD4 count 350-400?
Bacterial skin infections Recurrent bacterial chest infections TB Oropharyngeal candida Fungal infections Seborrhoeic dermatitis
Lymphadenopathy and sweats
What are the risks associated with a CD4 count 200-350?
Oral hairy leukoplakia (EBV)
Shingles
PCP
Persistent herpes infection
Non-hodgkins lymphoma
Weight loss
What are the risks associated with a CD4 count 100-200?
Oesophageal candida Histoplasmosis Cryptococcal meningitis Cerebral toxoplasmosis Cryptosporidosis
Kaposis sarcoma
Diarrhoea, wasting
What are the risks associated with a CD4 count <100?
CMV infections
Atypical mycobacterium infections
Primary cerebral lymphoma
Dementia
How is HIV transmission risk reduced in pregnancy?
ART during pregnancy
Short course ART for newborn
C section - can do vaginal in women with ART and undetectable viral load
Avoid breastfeeding
What prophylaxis is given if someone is suspected to have been exposed to HIV?
Post exposure prophylaxis if within 72 hours
1 month:
Truvada (OD) + Raltegravir (BD)
How is HIV diagnosed?
HIV PCR and p24 antigen
4 wks after possible exposure in asymptomatic
If - and asymptomatic - repeat at 12 weeks
