11 - HIV Flashcards
What are some severe signs of HIV?
- Oral candidiasis
- Kaposi’s sarcoma (HPV8)
- PCP (Pneumocystis pneumonia fungal)
OPPORTUNISTIC INFECTIONS
In terms of the infection model what are the possible outcomes for patients with HIV?
Who are at most risk of acquiring HIV and what parts of England have acquired the highest?
- East of England
- North East
- Midlands
What are the key features of viral structure and behaviour?
What is HIV?
- Retrovirus which infects cells with CD4+ surface receptor (T-helper cells, monocytes / macrophages)
- Replicates inside cells, destroys the cell, causes inflammation and spreads to / infects more cells
What is a retrovirus?
Backwards
e.g goes in HIV goes from ssRNA to DNA back to ssRNA
How does HIV replicate?
⇒ Virus binds to a CD4+ on cell surface & fuses with cell
⇒ Virus penetrates & empties contents into cell (infection)
⇒ Viral ssRNA → dsDNA by reverse transcriptase
⇒ Viral DNA is integrated into host’s DNA by integrase
⇒ Viral DNA is transcripted during infected cell division
⇒ Viral protein chains assemble & bud out of cell (immature – breaks free)
⇒ Virus matures as protein chains are cut by protease
How is HIV transmitted?
Transmission through contact of infected bodily fluids with mucosal tissue / blood / broken skin
What are the different phases of HIV infection in terms of viral load and CD4+ count?
What are the different stages of HIV and what defines each stage?
Why is a HIV diagnosis often missed early on?
Symptoms are similar to glandular fever
What are the main symptoms of Acute HIV infection, with regards to the following areas:
- Systemic
- Lymph nodes
- Skin
- Gastric
- Muscle
- Mouth
Identify and describe some aids-defining illnesses
- TB – coughing, fatigue, weight loss
- PCP – high fever, cough, difficulty breathing
- Cryptococcal disease – pneumonia, brain swelling, skin infections and UTI
- CMV – difficulty with vision, pneumonia and gastroenteritis
- Cryptosporidiosis – severe diarrhoea, abdominal cramps
What factors affect HIV transmission?
- Type of exposure – type of sexual act, transfusion / needlestick / mucous membrane
- Viral level in blood
- Condom use
- Breaks in skin/mucosa – other STI / sexual assault
What are 4 factors which enable people with HIV to live healthy lives and what is the average life expectancy for someone with HIV?
- Early detection
- Treatment
- Adherence
- Healthy living
- 78 years (earlier diagnosis the better)
What are some diagnostic tests for HIV?
- Serology
- PCR
- Rapid tests
Outline serology as a test for HIV.
- Detects HIV antigen (Ag) and HIV antibody (Ab)
- Result on same day
- May get false negative result (if performed too early –wait 4 weeks)
Outline PCR as a test for HIV.
Not used for initialy testing, for follow up and treatment response
Outlin the rapid test for HIV.
- Detects HIV antibody
- Blood test (finger-prick) / oral (saliva)
- May get false positive result (confirm with serology)
- Low cost less than hour can be at home
- If negative it is accurate
Who should be tested for HIV?
- Everyone if rate is >2/1000
- Especially in patients with things such as cancers, HIV, recurrent infections, weight loss etc
What are the aims of HIV treatment?
Which 2 medicinal strategies would you use to treat and reduce the prevalence of HIV?
- Anti retroviral drugs
- Vaccinations not available
When should one start HIV treatment?
Compare and contrast previous and current guidance
Which ARV’s are available and what are used?
Why give 3 AVR’s to treat HIV?
- Virus mutates & replicates largely
- Resistance to drugs develops in days
- Harder to develop resistance to 3 drugs
Which 5 non-medicinal strategies would you use to treat and reduce the prevalence of HIV?
- Increase condom usage
- Prevent vertical transmission (c-section and no breastmilk)
- Medical circumcision
- Post-exposure prophylaxis (PEP)
- Pre-exposure prophylaxis (PrEP)
What cancers are EBV linked to?
- Hodgkin’s Lymphoma
- Nasopharynx cancer
- Burkett’s lymphoma
Lots of viruses can be linked to causing cancer
How does EBV establish in the body and cause an immune response?
- IgG antibodies and CTL keep EBV under control but cannot eliminate it, once infected always there
How should you approach a patient about HIV testing in the ED?
Opt-out policy - patient given sufficient information and given time to process it, can say they dont want to be tested
How does a new HIV case establish itself in the target cell?
Firstly attach to CD4 receptor then to a co-receptor, CCR5 or CXCR4
What is the protocol after a needle stick injury?
- First aid
- PEP if necessary
- Inform occupational health
- Hep B vaccine
- Treatment for Hep C if present
Identify and describe some aids-defining illnesses.
- TB
- Toxoplasmosis
- PCP
- Cryptococcal disease
- CMV
- Cryptosporidosis
A patient with HIV has toxoplasmosis and TB, what will their x-ray appear like and how is this treated?
- TB: isoniazid and rifampicin for 6 months
- Toxoplasmosis: pyrimethamine, sulfadiazine and folinic acid or pyrimethamine and clindamycin
How should you treat a patient with HIV and an STI causing milky discharge from penis?
- Doxycycline for clap
- Ceftriaxone for gonorrhea
What conditions should HIV testing be offered, give a few examples for infections affecting the following areas:
- Respiratory
- Neurology
- Dermatology
- GI
- Oncology
- Other
What are some of the issues with HIV around a patients identity when they find out they are infected?
- Family and intimate relationships
- Lack of social opportunities etc
How does HIV status and patient confidentiality work?
Have to breach confidentiality if someone is at risk of transmitting
What is an acid-fast stain?
Usually used for TB
