S8) Blood Borne Viruses – HIV Flashcards

1
Q

What are some key signs of HIV?

A
  • Oral candidiasis
  • Kaposi’s sarcoma
  • PCP (Pneumocystis pneumonia)
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2
Q

In terms of infection model, outline the possible outcomes for a patient with HIV

A
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3
Q

Describe HIV acquisition by risk group

A
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4
Q

Which parts of England have had the biggest increases in HIV transmission in the last 10 years?

A
  • East of England
  • North East
  • Midlands
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5
Q

Identify and describe the 4 key features in viral structure and behaviour

A
  • Genome – RNA or DNA (ss/ds)

- Capsid – protein shell, protects the genome (helical/icosahedral)

- Lipid envelope – derived from host cell membranes (present/absent)

- Replication strategy

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6
Q

What is the Human Immunodeficiency Virus?

A
  • HIV is a retrovirus which infects cells with CD4+ surface receptor (T-helper cells, monocytes / macrophages)
  • It replicates inside cells, destroys the cell, causes inflammation and spreads to / infects more cells
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7
Q

How is HIV transmitted?

A

Transmission through contact of infected bodily fluids with mucosal tissue / blood / broken skin

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8
Q

What are the 5 different ways in which HIV can be transmitted?

A
  • Sexual contact
  • Transfusion
  • Contaminated needles
  • Medical procedures (organ donation, skin grafts, blood products)
  • Perinatal transmission (transplacental, during delivery, through ingestion of breast milk)
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9
Q

Outline the 7 steps involved in retroviral replication

A

⇒ 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

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10
Q

Outline the 4 different phases of an HIV infection in terms of CD4+ count and viral load

A
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11
Q

Identify the different stages of HIV, in terms of the symptoms and CD4 count

A
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12
Q

What are the main symptoms of Acute HIV infection, with regards to the following areas:

  • Systemic
  • Lymph nodes
  • Skin
  • Gastric
  • Muscle
  • Mouth
A
  • Lymph nodes – lymphadenopathy
  • Skin – rash
  • Muscles – myalgia
  • Systemic – fever, weight loss
  • Gastric – nausea, vomiting
  • Mouth – sores, thrush
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13
Q

What are the factors affecting HIV transmission?

A
  • 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
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14
Q

What are 4 factors which enable people with HIV to live healthy lives?

A
  • Early detection
  • Treatment
  • Adherence
  • Healthy living
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15
Q

Outline Serology as a diagnostic test for HIV

A
  • Detects HIV antigen (Ag) and HIV antibody (Ab)
  • Result on same day
  • May get false negative result (if performed too early –wait 4 weeks)
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16
Q

Outline PCR as a diagnostic test for HIV

A
  • Detects HIV nucleic acid
  • Highly sensitive (detects very early infection)
  • Expensive
  • Slow results (up to 1 week)
  • Used for follow-up / treatment response
17
Q

Outline Rapid tests as a diagnostic test for HIV

A
  • Detects HIV antibody
  • Blood test (finger-prick) / oral (saliva)
  • May get false positive result (confirm with serology)
18
Q

Who should be tested for HIV?

A

Everyone

19
Q

What are the aims of HIV treatment?

A
  • Undetectable HIV viral load
  • Reconstitute CD4 count
  • Reduce general inflammation
  • Reduce risk of transmission
  • Normalise lifespan & QoL
20
Q

Which 2 medicinal strategies would you use to treat and reduce the prevalence of HIV?

A
  • Anti-retrovirals (ARVs)
  • Vaccination
21
Q

When should one start HIV treatment?

Compare and contrast previous and current guidance

A
  • Previous guidance – CD4 < 350, primary HIV infection, any AIDS-defining illness, cancer/lymphoma, prevent transmission to others, patient choice
  • Current guidance – treat everyone ASAP, regardless of CD4 (significant benefits in AIDS & non-AIDS morbidity and mortality)
22
Q

Which ARVs can be used?

A

Nucleoside reverse transcriptase inhibitor (2x)

+ Non-nucleoside reverse transcriptase inhibitor

OR + Protease inhibitor

OR + Integrase inhibitor & CCR5 (entry) inhibitor

23
Q

Why give 3 ARVs?

A
  • Virus mutates & replicates largely
  • Resistance to drugs develops in days
  • Harder to develop resistance to 3 drugs
24
Q

Which 5 non-medicinal strategies would you use to treat and reduce the prevalence of HIV?

A
  • Increase condom usage
  • Prevent vertical transmission
  • Medical circumcision
  • Post-exposure prophylaxis (PEP)
  • Pre-exposure prophylaxis (PrEP)
25
Q

Identify and describe some aids-defining illnesses

A
  • 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