HIV Flashcards
What is HIV?
HIV is classified as a retro virus. What does that mean?
Virus enters and destroys CD4 TH cells leading to immunodeficiency
Retro virus:
-means that virus inserts DNA into genome of host cell in order to use host cell mechinary to build viral proteins
What are the 3 main routes of transmission for HIV?
Sexual transmission
Parenteral transmission
-inoculation by contaminated needle or infected by products
Vertical transmission
-mother to child i.e. pregnancy/delivery/breast feeding
Where in the world has the highest prevalence of HIV?
Subsaharan africa
Thailand
Caribbean
Eastern Europe
What are the features associated with primary HIV/HIV seroconversion?
Flu like symptoms
- fever
- rash
- lymphadenopathy
- pharyngitis
- headache
- fatigue
High viral load
I.e. high risk of transmission during this period
Initial depletion of CD4 cells
I.e. can present with candida
How does a chronic HIV picture differ from primary HIV infection?
Asymptomatic
- ab has been generated and body is controlling the disease
- Steadying declining CD4 count
Might get HIV indicator diseases after number of years (occur at higher frequency in those with HIV compared to general population
Can develop to AIDs i.e. present with AIDs defining conditions
How would you summarise the natural history of HIV?
What changes to the serology occur at each stage?
Primary HIV infection
- sudden rise in HIV viral load
- sudden drop in CD4 count
- rising levels of HIV Ab
Asymptomatic
- slight gradual decline in viral load
- slight gradual decline in CD4 count
- constant HIV Ab
Symptomatic non AIDs
- sudden rise in viral load
- sudden fall in CD4
- constant HIV Ab
AIDS
- highest viral load of disease history
- lowest CD4 count
- constant HIV Ab
What are HIV indicator disease?
TB Seborrhoeic dermatitis Gingivitis Warts Molluscum contagiosum Herpes Zoster Sinusitis Herpes Simplex Oral candidiasis
What are examples of AIDS-defining illnesses?
Why do they occur?
Kaposis sarcoma Pneumocysits jirovecii pneumonia (PCP) Cytomegalovirus infection Candidiasis (oesophageal or bronchial) Lymphomas Tuberculosis
CD4 levels drop to level that allows unusual opportunistic infections and malignancies to appear
How is HIV diagnosed?
Is a finger prick test enough to diagnose someone with HIV?
Antibody blood test
P24 antigen
- HIV specific antigen
- faster result than antibody test which can be negative for 3 months after exposure
PCR
-HIV RNA i.e. indicates the quantity of HIV virus ==VIRAL LOAD
No:
-finger prick test will only be able to classify someone as HIV reactive so would need venous sample to confirm
What are the advantages of early diagnosis?
Access to anti-retroviral treatment
-reduces morbidity
- reduces mortality I.e. people with HIV can have normal LE if given the appropriate treatment
- reduces transmission due to viral load being lower on treatment and diagnosis can change behaviour
- reduced cost of HIV treatment due to decreased number of opportunistic infections
When is targeted testing for HIV appropriate?
settings where prevalence of HIV >2/1000
blood donors
dialysis patients
organs donors/recepients
Patients identified as being at risk:
- diagnosed with STI
- partner known to be HIV positive
- Men who have sex with men
- female contacts of MSM
- injecting drug use
- country of high prevalence
- sexual contact with person from country of high prevalence
All patient presenting to healthcare where HIV enters differential diagnosis
In which diseases should HIV tests be offered?
TB Bacterial pneumonia Meningitis Severe psoriasis Chronic diarrhoea Lung cancer H+N cancer Cervical cancer Cervical intraepithelial neoplasia Thrombocytopenia Pyrexia of unknown cause Any lymphadenopathy of unknown cause Hep B/C Pregnancy
How is HIV monitored?
CD4 count
- 500-1200= normal
- <200= end-stage HIV/AIDs
- indicates the risk of opportunistic infections
Viral load
-number of copies of HIV RNA per ml of blood
How is HIV treated?
What is the aim of treatment?
Combination of antiretroviral therapy (ART)
(Given regardless of viral load and CD4 count)
AIM:
- achieve normal CD4
- undetectable viral load
Starting regime:
-Tenofovir + Emtricitabine (2 x NRTIs)
What additional management should be considered in HIV?
Prophylactic co-trimoxazole when CD4< 200
-protects against PCP
Monitor for CVD risk factors
Yearly cervical smears
-predisposes to HPV + cervical cancer
Vaccinatiosn -flu -hep A/B -tetanus -diptheria -polio AVOID LIVE VACCINES
