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1

What can HIV cause/lead to?

AIDS - Acquired Immunodeficiency Syndrome
Opportunistic infections
AIDS-related cancers

2

What is the life expectancy of people with HIV?

"near normal"

3

What is HIV?

A retrovirus

4

Describe HIV-1

Originated in Central/West African chimpanzees
Responsible for pandemic starting in 1981

5

Describe HIV-2

Originated in West African Sootey mangabey (Simian ID virus)
Less virulent

6

What is CD4?

CD4+ receptors are the target site for HIV
A glycoprotein found on the surface of a range of cells

7

What cells are CD4 receptors found on?

T helperlymohocytes (CD4+ cells)
Dendritic cells
Macrophages
Microglial cells

8

What do CD4+ Th lymphocytes do?

Essential for induction of adaptive immune response
Recognition of MHC2 antigen-presenting cell
Activation of B-cells
Activation of cytotoxic T-cells (CD8+)
Cytokine release

9

What does HIV do to the immune response?

Reduced circulating and proliferating of CD4 cells
Dysregulation expression of cytokines
Increased susceptibility to viral infections
Reduced affinity of antibodies produced

10

What are HIV sufferers susceptible to?

Viral infections
Fungal infections
Mycobacterial infections
Infection-inducing cancers

11

What is the normal range of CD4+Th cells?

500-1600 cells/mm*3

12

What number of CD4+Th cells give risk to opportunistic infections?

<200 cells/mm*3

13

Describe HIV viral replication?

Rapid replication in early and late infection
New generation every 6-12 hours

14

What is the prognosis of HIV without treatment (on average)?

9-11 years

15

How does the infection take place?

Infection of mucosal CD4 cell (Langerhans and Dendritic cells
Transport to regional lymph nodes
Infection established within 3 days of entry
Dissemination of virus

16

How long after infection does it take for symptoms to present?

Usually 2-4 weeks

17

What are the symptoms of a primary HIV infection?

Fever
Rash (maculopapular)
Myalgia
Pharyngitis
Headache/ aseptic meningitis

18

What occurs in asymptomatic HIV infection?

Ongoing viral replication
Ongoing CD4 count depletion
Ongoing immune activation
Risk of transmission

19

What is the definition of an Opportunistic infection?

An infection caused by a pathogen that does not normally produce disease in a healthy individual. But does when afforded the opportunity by a weakened immune system.

20

What organism causes Pneumocystis pneumonia and what CD4 count is needed for this?

Organism - Pneumocystis jiroveci
CD4 count: <200

21

What are symptoms and signs of Pneumocystis pneumonia

Symptoms: insidious onset, SOB, dry cough
Signs: Exercise desaturation

22

How do you diagnose Pneumocystis pneumonia?

BAL and immunoflourescence +/- PCR

23

What is the treatment and prophylaxis for Pneumocystis pneumonia?

Treatment: High dose co-trimoxazole (+/- steroid)
Prophylaxis: Low dose co-trimoxazole

24

What other opportunistic infection that effects the respiratory system can occur in HIV?

TB

25

What organism causes Cerebral Toxoplasmosis and what CD4 level is needed?

Organism: Toxoplasma gondii
CD4 level: <150

26

What is cerebral toxoplasmosis?

reactivation of latent infection
Multiple cerebral abscess (Chorioretinitis)

27

What are symptoms/signs of cerebral toxoplasmosis?

Headache
Fever
Focal neurology
Seizures
Reduced conscioussness
Raised ICP

28

What organism causes Cytomegalovirus and what CD4 count is needed?

Organism: CMV
CD4 level: <50

29

What is CMV?

Reactivation of latent infection.

30

What are causes of CMV?

Retinitis
Colitis
Oesophagitis