HIV Flashcards

1
Q

How is HIV spread?

A
Sexual transmission
IV drug users
Blood products (transfusions)
Vertical transmission (maternal)
Organ transplant
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2
Q

Who are high risk categories for HIV?

A

IV drug use

MSM

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3
Q

What are the two distinct HIV viruses and which is more common?

A

HIV-1
HIV-2

HIV-1 Group M is most common

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4
Q

How does the HIV virus infect someone?

A

It attaches to glycoproteins on cell surface and targets T-Helper cells that have CD4 receptors

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5
Q

What co-factor is present for attachment of HIV to CD4 cells?

A

CCR-5

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6
Q

How do you diagnose HIV?

A

combined HIV antigen and antibody tests

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7
Q

How long does it take before you can get a positive HIV test? What is the significance of this?

A

After exposure to the infection, it can take up to 3 months to become positive

This window period can vary between individuals and is crucial because an individual is still highly infectious and can have false-negative results

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8
Q

What is the viral load?

A

The amount of HIV virus in the blood (copies/ ml blood)

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9
Q

What is the viral load used for?

A

To monitor the effectiveness of HIV treatment

and used for diagnosis in babies in the presence of maternal antibody

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10
Q

How does the viral load vary with disease progression?

A

Initial HIV viral load = high during acute infection
Falls to a low level
Only rises again in the later stages of disease (6-8 years of infection)

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11
Q

What influences the disease progression?

A

Age
HLA type
History of seroconversion illness

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12
Q

How do you monitor HIV infection?

A

CD4 lymphocyte count
HIV viral load
Clinical features

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13
Q

How does the HIV virus replicate?

A

Each virus has 2 chains of RNA, the virus needs a host cell to replicate and must be transcribed into DNA first

Integrase facilitates integration into host cell DNA
Contains protease enzyme needed for maturation of virus

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14
Q

At what CD4 count do most AIDS diagnoses occur?

What is the normal CD4 count?

A

CD4 count < 200
The severity is greater the lower the CD4 count

Normal CD4 > 500

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15
Q

What problems can occur during virus replication + what is the significance?

A

Lack of accuracy -> causes virus diversity

Persistent infection of cell -> ongoing opportunity to transmit

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16
Q

What is the difference between HIV and AIDS?

A

HIV= asymptomatic with HIV infection

AIDS= weakened immune system leading to infections + tumours that are classified as AIDS illnesses

17
Q

Describe the first stage of HIV?

note there are 4 clinical stages

A

Asymptomatic

Generalised lymphadenopathy

18
Q

Describe the second stage of HIV

A

Weight loss

Recurrent respiratory infections

Herpes zoster

Mucocutaneous manifestations (fingal nail, oral ulcerations, angular chelitis)

19
Q

Describe the third stage of HIV

A

Weight loss > 10% of body weight

Chronic diarrhoea > 1 month

Unexplained Prolonged fever > 1 month

Oral candidiasis (thrush)

Bacterial infections (e.g. pneumonia, bone/joint infection, empyema)

Tuberculosis

Oral hairy leukoplakia (white hairy patch on tongue)

Performance (activity level): bedridden

20
Q

Describe the fourth stage of HIV

A
HIV wasting syndrome
Pneumocystic pneumonia
Toxoplasmosis of the brain
Recurrent severe bacterial pneumonia
Chronic herpex simplex infection
Progressive multifocal leukoencephalopathy
Kaposi's Sarcoma
Cytomegalovirus infection of organs
HIV encephalopathy

Many more symptoms + diseases…

21
Q

Give some examples of AIDS defining conditions

A
Tuberculosis
Pneumocystis
Cerebral toxoplasmosis
Cryptococcal meningitis
Progressive multifocal leukoencephalopathy
Kaposi's sarcoma
Non-Hodgkin's lymphome
Primary cerebral lymphoma
Cytomegalovirus retinitis 
Cervical cancer

(try remember a few examples)

22
Q

What is the progression + prognosis?

A
  1. Acute infection- seroconversion
  2. Asymptomatic
  3. HIV related illness
  4. AIDS defining illness
  5. Death
23
Q

What is a seroconversion illness?

A

It is the period of time in which HIV antibodies develop and become detectable

Occurs in first few weeks of initial infection

It is often accompanied by flu-like symptoms

24
Q

What are the flu-like symptoms that accompany seroconversion of HIV?

A
fever
malaise
lethargy
pharyngitis
lymphadenopathy
25
Q

What are the classes of HIV antiviral drugs?

A

Reverse transcriptase inhibitors
Integrase inhibitors
Protease inhibitors

These different classes act on different stages in HIV lifecycle

26
Q

Give some examples of specific antivirals

A

AZT - Zidovudine

DDI - Didanosine

27
Q

What is combination antiretroviral therapy?

A

Means at least 3 drugs from at least 2 classes are used

This is to prevent drug resistance (that occurs with monotherapy)

28
Q

Why does antiviral patient adherence need to be good?

A

Needs to be over 90% or patient will develop drug resistance and viral mutation

29
Q

What side effects are there for the reverse transcriptase inhibitors?

A

Nucleoside reverse transcriptase inhibitors: neuropathy, marrow toxicity, lipodystrophy

Non-nucleoside reverse transcriptase inhibitors: nightmares, hypersensitivity, skin rashes

30
Q

What side effects are there for the protease inhibitors?

A

Drug interactions, diarrhoea, lipodystrophy, hyperlipidaemia

31
Q

What side effects are there for the integrase inhibitors?

A

Rashes

32
Q

When should treatment be started?

A

Start treatment in all patients regardless of CD4 count

If CD4 < 350 - start antivirals
If CD4 < 200 need to start PCP prophylaxis

Any pregnant women - start before third trimester

33
Q

What is the treatment length for HIV?

A

Life long

Treatment may be altered if there is drug resistance/ side effects

34
Q

What is the life expectancy with HIV?

A

According to CD4 Nadir (lowest CD4 before starting therapy)
Earlier treatment started = better outlook

Note:
CD4 + life expectancy 
<100= 52 years
100-200= 62 years
>200= 70+ years
35
Q

What challenges occur with HIV?

A
  • Osteoporosis
  • Cognitive impairment
  • Malignancy
  • Cerebrovascular disease
  • Renal disease
  • Ischaemic heart disease
  • Diabetes
36
Q

What HIV prevention is there?

A

Behaviour change and conditions
Circumcision
Treatment as prevention: best form of prevention
• Pre-exposure prophylaxis (PrEP)
• Post- exposure prophylaxis for sexual exposure (PEP)