HIV and AIDs

Question 1

Through what mechanisms can HIV be spread?

Answer 1

• Sexual transmission
• Injection drugs misuse
• Blood products
• Vertical transmission
• Organ transplant

Question 2

What cells do HIV attack?

Answer 2

The CD4 receptors on CD4+ lymphocytes

Question 3

How does CD4 count change with progressing HIV infection?

Answer 3

As the disease progresses, CD4 count decreases and the HIV viral load increases. This results in an increased risk of developing infections and tumours. The severity of these illnesses is greater the lower the CD4 count

Question 4

What is the normal CD4 count?

Answer 4

> 500

Most HIV diagnoses made at <200

Question 5

How is HIV classified?

Answer 5

Broadly classified as either symptomatic or asymptomatic disease
Can also be staged 1-4, with stage 1 being asymptomatic disease and stage 4 being severe disease

Question 6

What is an AIDs illness?

Answer 6

An illness that occurs due to HIV infection

Question 7

What is the prognosis of a HIV diagnosis?

Answer 7

The timeline of HIV/AIDS is extremely variable from patient to patient but around 2/3 of patients will have an AIDS illness in 10 years and 50% of sufferers will be dead at 12/13 years

Question 8

What is the natural history of HIV?

Answer 8

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

Question 9

What are the characteristics of a seroconversion illness?

Answer 9

Occurs when HIV antibodies first develop
Affects 30-60% of patients
Onset abruptly around 2-4 weeks post-exposure#
Self limiting, resolve within 1-2 weeks
Symptoms include a flu-like illness, fever, malaise/lethargy, pharyngitis, lymphadenopathy and toxic exanthema
Typical presentation- looks like glandular fever but EBV serology negative

Question 10

What is pneumocystis jiroveci pneumonia?

Answer 10

Commonest late stage (AIDS) infection.
Opportunistic infection that usually only occurs with a CD4 count of <200.
Usual history is of a dry cough and increasing breathlessness over several weeks

Question 11

What investigations can be done for pneumocystis jiroveci pneumonia?

Answer 11

Chest x-ray

Induced sputum production or bronchoscopy for PCR

Question 12

How is pneumocystis jiroveci pneumonia treated?

Answer 12

Primarily with cotrimoxazole

If contraindicated- pentamidine

Question 13

What treatment can be given for HIV?

Answer 13

Antiviral therapy, started at diagnosis without waiting for symptoms to present
Can control but not eliminate disease
Given as triple combined pill including three drugs from two of the following drug classes:
-Reverse transcriptase inhibitors
-Integrase inhibitors
-Protease inhibitors

Question 14

What is the required adherence to HIV treatment?

Answer 14

At least 90%

Question 15

What are the common side effects of HIV treatment?

Answer 15

Lipodystrophy

Metabolic disorders

Question 16

When can HIV treatment be adjusted and why?

Answer 16

After 4-6 weeks if viral load is not adequately suppressed

Question 17

When should resistance testing for HIV treatment be done?

Answer 17

Resistance testing should be conducted in cases of newly diagnosed HIV. Treatment most commonly fails due to poor adherence causing viral mutation and resistance

Question 18

What are the side effects of non-nucleoside reverse transcriptase inhibitors?

Answer 18

Skin rashes
Hypersensitivity
Drug interactions
Neuropsychiatric effects

Question 19

What are the side effects of protease inhibitors?

Answer 19

Drug interactions
Diarrhoea
Lipodystrophy
Hyperlipidaemia

Question 20

How is lipodystrophy managed?

Answer 20

Changing drugs

Cosmetic procedures

Question 21

What measures can aid in HIV prevention?

Answer 21

Behaviour change/condoms
Circumcision
Treatment as prevention (undetectable = untransmissible)
Pre-exposure prophylaxis (PrEP)
Post exposure prophylaxis for sexual exposure (PEPSE)

Question 22

What are the most common routes of spread of HIV in the UK?

Answer 22

Men who have sex with men
Injecting drugs (less common but varies regionally)

Question 23

What are the two types of HIV?

Answer 23

HIV-1

HIV-2

Question 24

Which is the most common type of HIV globally?

Answer 24

HIV-1

Question 25

How does HIV cause disease?

Answer 25

The virus attaches to cells with CD4 receptors on their surface and acts as a retrovirus. Retroviruses causes RNA to convert to DNA using reverse transcriptase

Question 26

How is HIV diagnosed?

Answer 26

Diagnosed in laboratory by blood tests for HIV antigens and antibodies

Question 27

What further lab tests can aid with management of HIV?

Answer 27

Viral load
HIV resistance testing
Avidity testing
Subtype determination
Tropism testing
Drug levels

Question 28

How is viral load used in practice?

Answer 28

HIV genome detection, or viral load allows detection of HIV RNA to monitor the effectiveness of HIV treatment. It can also be used diagnostically in cases of maternal antibodies

Question 29

How is HIV resistance testing done?

Answer 29

Involves sequencing of polymerase and protease genes to allow for identification of specific mutations. It can be used to give a baseline at diagnosis, in cases of suboptimal treatment response, treatment failing and any other reason that a treatment change is desired

Question 30

How can HIV be monitored?

Answer 30

CD4 count

Viral load