HIV and AIDS Flashcards
What is HIV?
Human immunodeficiency virus, a virus that targets cells within the immune system causing it to fail
What is AIDS?
Acquired immunodeficiency syndrome, describes the complications that occur when an immune system fails
Where is the highest prevalence of HIV/AIDS?
Sub-Saharan Africa contains 2/3 of all people in the world living with HIV/AIDS
What is the main route of HIV infection in the UK?
homosexual sexual transmission is main route and injecting drug use is low route
What sex is HIV more common in in the UK?
M>F
What sex is HIV more common in in Africa?
F>M
Name the routes of infection for HIV
Main route of spread varies geographically
Sexual transmission
Intravenous drug misuse
Organ transplant
Vertical transmission/Mother-to-child
Unscreened blood/blood products
Which of the two types of HIV virus is most predominant?
HIV-1
What type of virus is HIV?
Single stranded RNA retrovirus
Describe the basic virology of HIV?
Virus targets cells with CD4 molecule, such as lymphocytes/T helper cells, dendritic cells and macrophages
HIV attaches to CD4 molecule and then a co-receptor via GP120 protein to gain access into cell
Once HIV is in the cell, RNA is converted to DNA using reverse transcriptase
The lack of accuracy during replication leads to virus diversity which leads to persistent infection of the cell and the ongoing opportunity to transmit
What are the 5 steps of HIV/AIDS (natural history of HIV)?
Acute infection/seroconversion
Asymptomatic
HIV related illness
AIDS defining illness
Death
What is the diagnostic window?
The window period is the time during which markers of infection are not detectable.
Testing during this period for antibody/antigen can result in false negative results
What viral labartory tests are used in HIV diagnosis?
Antigen and antibody tests
- ELISA allows simultaneous detection of antibody and antigen
RNA/DNA test
- Confirmatory test
What investigations, except diagnostic lab tests, are used in HIV diagnosis and monitoring?
Viral load/HIV genome Detection
CD4 Count
HIV Resistance Testing
Avidity testing
Subtype determination
Tropism testing, determinswhich co-receptor the virus used to enter CD4 cells
Drug levels, to determine compliance
When should HIV testing for asymptomatic patients be done?
4 weeks post possible exposure
When should HIV testing for asymptomatic patients be repeated?
12 weeks
What happens to viral loads and CD4 count when treatment is initiated?
When a patient initiates antiretroviral treatment, their viral load will fall and their CD4 count will rise
What is a normal CD4 count?
>500
What CD4 count is diagnostic of AIDS?
<200
How does acute HIV/seroconversion illness present?
Flu-like illness
Fever
Malaise and lethargy
Pharyngitis
Lymphadenopathy
Toxic exanthema (widespread rash)
When does seroconversion illness occur?
Occurs when antibodies first develop at 2-4 weeks post-exposure
How long does seroconversion illness last?
lasting for 1-2 weeks
What percentage of patients experience seroconversion illness?
30-60% of patients
Give examples of HIV related illness
Oral Thrush/candida Albicans
Unexplained weight loss
Unexplained lymphadenopathy
Guillain-Barre
Dementia
Aspergillosis
Anal or lung Cancer
Give examples of AIDS defining illness
TB
Kaposi’s Sarcoma, caused by HHV8
Pneumocystis jirovecii pneumonia
Progressive multifocal leukoencephalopathy (PML)
Cryptococcal Meningitis
Persistent Cryptosporidiosis
Non-Hodgkin’s lymphoma
Cervical cancer
CMV (Cytomegalovirus) retinitis
What is the most common late stage/AIDS infection?
Pneumocystis Jiroveci Pneumonia, occuring at CD4 count of less than 200
Give features of pneumocystis jiroveci pneumonia
Desaturation on exercise
Patchy opacities in the right apex and bilateral hilar enlargement on xray
Few chest signs
How is pneumocystis jirovecii pneumonia managed?
Co-trimoxazole
IV pentamidine in severe cases
What is the most common neurological infection seen in HIV?
Cerebral toxoplasmosis
Give features of cerebral toxoplasmosis
Multiple brain lesions with ring enhancement
Give features of progressive multifocal leukoencephalopathy
Multifocal non enhancing lesions
Ataxia/coordination difficulties
Give features of cryptococcus neoformans
CSF contains organisms stained with india ink
Meningitis/headache
What is the most common cause of diarrhoea in HIV?
Cryptosporidium
How is HIV managed?
Combination antiretroviral therapy (cART)
- 3 drugs from at least 2 groups in 1 pill
- Initiated on diagnosis, regardless of CD4 and viral count
When should antiretroviral therapy be adjusted?
Adjust if VL is not low enough after 4-6 weeks of starting treatment
What are the 4 classes of antiviral drugs?
Nucleoside reverse transcriptase inhibitors
Non-nucleoside reverse transcriptase inhibitors
Protease inhibitors
Integrase inhibitors
Name the side effects of nucleoside reverse transcriptase inhibitors
Marrow toxicity
Neuropathy
Lipodystrophy
Name the side effects of non-nucleoside reverse transcriptase inhibitors
Skin rashes
Hypersensitivity
Drug interactions
Neuropsychiatric effects
Name the side effects of protease inhibitors
Drug interactions
Diarrhoea
Lipodystrophy
Hyperlipidaemia
Name the side effects of Integrase inhibitors
Rashes
Disturbed sleep
What is the preventative management of HIV?
Behaviour change and condoms
Circumcision
Treatment: Undetectable means it is untransmissible
Pre exposure prophylaxis (PrEP)
Post exposure prophylaxis (PEP)
When is PEP given?
When someone has sex with an HIV patient or gets a needlestick injury potentially contaminated with HIV
When does PEP have to be given by?
Within 72 hours
What medication is given for PEP?
Truvada
Kaltetra
What should patients with a CD4 count lower than 200 be prescribed?
Co-trimoxazole for prophylaxis against pneumocystis jiroveci pneumonia
