HIV Flashcards
Origin of HIV infection?
- Zoonotic infection with simian immunodeficiency virus (SIV)
- First infecting local hunters
- HIV-1 is the cause of global pandemic
- HIV-2 causes similar illness but with slower progression
What are the modes of transmission of HIV?
- Sexual contact
- Exposure to blood
- IV drug use
- Health case workers
- Blood products
- HIV infected mothers
- In utero
- Breastfeeding
What is the major route of transmssion?
Heterosexual
What determines the risk of contracting HIV after exposure?
- Integrity of exposed site
- Type and volume of fluid
- Level of viraemia in source person
Name some factors which increase the risk of transmission of HIV?
- High viral load
- Rectal/vaginal lacerations
- Uncircumcised male partner
- Receptive anal intercourse
Describe the properties of HIV?
- Enveloped RNA retrovirus
- From lentivirus family
Describe the pathophysiology of HIV?
- After exposure, HIV travels to lymph nodes via dendritic cells
- Viraemia occurs
- Dissemintation to lymphoid organs
- Main sites of viral replication
What cells does HIV infect?
- Cells bearing the CD4 receptor
- T-helper lymphocytes
- Monocyte-macrophages
- Dendritic cells
- Microglial cells in CNS
Describe the diagnosis of HIV testing?
- Detecting host antibodies with:
- Rapid point of care tests
- Labarotory ELISA tests
- Positive antibody test from two different immunoassays confirms infection
What patients should be offered HIV testing in the UK?
- Patients accessing sexual health services
- Patients accessing primary and secondary care
- With relevant risks
- Prison inmates
Name some important aspects counselling following a positive HIV result?
- Explain meaning of the result
- Assess coping strategy
- Stress important of partner disclosure
- Facilitate notification of sexual partners
Name some important baseline investigations investigating someone with HIV?
- CD4 count
- Viral load
- Screening for other investigations
- HBV, HCV, syphilis, TB
- FBC, LFTs
What is the most important indicator of immune suppression in HIV?
How often should it be monitored?
- CD4 count
- Measured every 3-6 months
What is a normal CD4 count?
What CD4 count results in severe immune suppression?
> 500 cells/mm3
< 200 cells/mm3
How is the CD4 lymphocyte count determined?
Flow cytometry
Describe measurements of viral load in HIV?
- Quantitative PCR of HIV RNA
- High viral loads experience more rapid declines of CD4 count
What a re the clinical features of a primary HIV infection?
- Fever
- Maculopapular rash
- Pharyngitis
- Lymphadenopathy
- Oral and genital ulceration
- Bell’s palsy
What does the appearance of anti-HIV antibodies occur?
2-12 weeks after the development of symptoms
Describe AIDS?
- Defined by development of:
- Specific oppurtunistic infections
- Cancers
- Severe manifestations of HIV
Name some conditions which an HIV patient is at risk of when there CD4 count is . less than 500?
- Tuberculosis
- Herpes zoster
- Kaposi’s sarcoma
- Oropharyngeal candidiasis
Name some conditions which an HIV patient is at risk of when there CD4 count is . less than 200?
- Pneumocystis jiroveci pneumonia
- Chronic herpes simplex ulcers
- HIV-associated dementia
Name some conditions which an HIV patient is at risk of when there CD4 count is less than 100?
- Cerebral toxoplasmosis
- Cryptococcal meningitis
- Progressive multifocal leucoencephalopthy
Globally, what is the most common cause of morbidity and mortality in HIV patients?
Tuberculosis
What is HIV wasting syndrome?
- Sign of advanced HIV infection
- Weight loss of > 10% body weight plus 1 of:
- Diarrhoea for over 1 month
- Chronic weakness
- Prolonged fever
What is used to treat pneumocystis jiroveci pneumonia in AIDS?
- Co-trimoxazole
- Adjunctive prednisolone
What is used to treat cerebral toxoplasmosis in AIDS?
- Pyrimethamine
- Sulphadiazine
What is used to treat cryptococcosis in AIDS?
- Amphotericin B
- Flucytosine
What is used to treat oesophageal candidiasis in AIDS?
Fluconazole
Describe Kaposi’s sarcoma?
- Spindle cell tumour
- Due to sexually transmitted HSV-8
- Mucocutaneous lesions and lymphoedema +/- B symptoms
Describe primary HIV infection?
- Incubation period 2-4 weeks after exposure
- Often presents similar to glandular fever
- Maculopapular rash can differentiate HIV
- Lymphopenia, thrombocytopenia and elevated liver enzymes
Differentials for primary HIV infection?
- Glandular fever
- Primary toxoplasmosis
- Secondary syphilis
What is the median time from infection to AIDS development in adults with asymptomatic HIV infection?
9 years
Describe progressive multifocal leucoencephalopathy (PML)?
- Stroke-like episodes and cognitive impairment
- Vision impairment due to involvement of occipital cortex
- Diagnosis:
- Characteristic MRI appearance
- JC virus in CSF by PCR
- No specific treatment exists
Co-trimoxazole prophylaxis in HIV patients?
- Reduces risk of oppurtunistic infections:
- Pneumocystis jiroveci pneumonia
- Cerebral toxoplasmosis
- Malaria
- SE: hypersensitivity causing maculopapular rash
What can be used as prophylaxis for TB in HIV patients?
- Isoniazid
- All of the following must be absent:
- Cough
- Fever
- Weight loss
- Night sweats
What are the goals of anti-retroviral therapy in HIV?
- Keep viral load low for as long as possible
- Increase CD4 count over 200 cells/mm3
- Improve quality of life
- Reduce HIV transmission
What are the different categories of anti-retroviral drugs for HIV?
- Nucleoside reverse transcriptase inhibitors (NRTIs)
- Non-nucleoside reverse transcriptase inhibitors (NNRTIs)
- Protease inhibitors (PIs)
- Integrase inhibitors
- Chemokine receptor inhibitor
Examples of NRTIs?
- Abacavir
- Tenofovir
Examples of NNRTIs?
- Efavirenz
- Rilpivirine
Example of PIs?
Atazanavir
Example of integrase inhibitors?
Raltegravir
Example of chemokine receptor inhibitor?
Maraviroc
What is the standard anti-retroviral regimens?
- 2 NRTIs + 1 of:
- NNRTI
- Protease inhibitor
- Integrase inhibitor
Complications of anti-retroviral therapy?
- Immune reconstitution inflammatory syndrome (IRIS)
- Lipodystrophy
- Hypersensitivity rashes
Anti-retroviral in pregnancy?
- CD4 count falls by 25% in pregnancy due to haemodilution
- HIV disease progession is not altered
- Begin anti-retroviral treatment at beginning of second trimester
- Caesarean section is associated with lower risk of transmission
Describe PrEP?
- Pre-exposure prophylaxis
- Daily tenofovir plus emtricitabine
- Reduces risk of HIV acquisition
Describe PEP?
- Post-exposure prophylaxis
- First dose within 6 hours
- HIV antibody testing at 3 months post exposure
Describe hairy leukoplakia?
- EBV-associated lesion on the side of the tongue
- Indicative of HIV
- Cannot be scraped off
- Candida lesions can be scraped off the tongue
What is the test for EBV diagnosis?
Monospot test
What would you do if you come across hairy leukoplakia?
- Test for HIV
- Do not perform the monospot test
In terms of CD4+ count, which diseases fall within the 200-500 region?
- Oral thrush
- Shingles
- Hairy leukoplakia
- Kaposi sarcoma
In terms of CD4+ count, which diseases fall within the 100-200 region?
- PMLE
- HIV dementia
- Cryptosporidiosis
- Cerebral histoplasmosis
- Pneumocystic jiroveci pneumoniae
In terms of CD4+ count, which diseases fall within the 50-100 region?
- Aspergillosis
- Oesophageal candidiasis
- Cryptococcal meningitis
- Primary CNS lymphoma
In terms of CD4+ count, which diseases fall within the <50 region?
Cytomegalovirus retinitis
