HIV: Pathophysiology and Presentation

Question 1

What is the target site for HIV?

Answer 1

CD4+ receptors

Question 2

What is CD4?

Answer 2

a glycoprotein found on the surface of a range of cells

Question 3

What cells have CD4 on them?

Answer 3

T help lymphocytes (CD4+ cells); dendritic cells; macrophages and microglial cells

Question 4

What is the function of CD4+ cells?

Answer 4

recognition of MHC2 APCs; activation of B cells; activation of CD8+ cells; cytokine release

Question 5

What effect does HIV infection have on immune response?

Answer 5

sequestration of cells in lymphoid tissues; reduced proliferation of CD4+ cells; reduction cyctotoxic T cell activation; reduction in antibody class switching; chronic immune activation

Question 6

What is the effect of sequestering of cells in lymphoid tissue in HIV?

Answer 6

reduced circulating CD4+ cells

Question 7

Waht si the effect of reduced cytotoxic T cell activation in HIV?

Answer 7

dysregulated expression of cytokines and increasing susceptibility to viral infections

Question 8

What is the the effect of a reduction in antibody class switching in HIV?

Answer 8

reduces affinity of antibodies produced

Question 9

What types of infections are patients with HIV more susceptible to?

Answer 9

viral; fungal; mycobacterial infections and infection-induced cancers

Question 10

What is the normal range of CD4+ cells?

Answer 10

500-1600cells/mm3

Question 11

Below what level of CD4+ cells is there a risk of opportunistic infections?

Answer 11

<200

Question 12

How long does it take to create a new generation of HIV virus?

Answer 12

every 6-12 hours

Question 13

How long does it take someone to die with HIV without treatment?

Answer 13

9-11 years

Question 14

What cells are initially infected iwth HIV?

Answer 14

infection of mucosal CD4 cells- Langerhans and Dendritic cells

Question 15

How long does it take for HIV to become established after entry?

Answer 15

3 days

Question 16

When does primary HIV infection usually occur after infection?

Answer 16

2-4 weeks

Question 17

What are the symptoms of priamry HIV infection?

Answer 17

fever; rash (maculopapular); myalgia; pharyngitis; HA/aseptic meningitis

Question 18

What organism causes pneumocystis pneumonia?

Answer 18

pneumocystis jiroveci

Question 19

What is the typical sign with pneumocystis pneumonia?

Answer 19

exercise desaturation

Question 20

How is PCP diagnosied?

Answer 20

BAL and immunofluorescence +/- PCR

Question 21

What is the treatment for PCP?

Answer 21

co-trimoxazole

Question 22

What are the symptoms of cerebral toxoplasmosis?

Answer 22

HA; fever; focal neurology; seizures; reduced consciousness; raised intracranial pressure

Question 23

What is the CD4 threshold for cerebral toxoplasmosis?

Answer 23

<150

Question 24

What is the CMV CD4 threshold?

Answer 24

<50

Question 25

What is the presentaiton of CMV?

Answer 25

reduced visual acuity; floaters; abdo pain; diarrhoea and PR bleeding

Question 26

What is done to monitor CMV in HIV patients?

Answer 26

ophthalmic screening for all individuals CD4<50

Question 27

Waht is the presentation of HIV-associated neurocognitive impairment?

Answer 27

reduced short term memory +/- motor dysfunction

Question 28

What is the presentation of progressive mulifocal leukoencephalopathy?

Answer 28

rapidly progressing; focal neurology; confusion; personality change

Question 29

What causes progresive multifocal leukoencephalopathy?

Answer 29

JC virus

Question 30

Waht is the CD4 threshold for PML?

Answer 30

<100

Question 31

What are the causes of HIV-assocaited wasting?

Answer 31

chronic immune activation; anorexia; malabsorption/diarrhoea; hypogonadism

Question 32

What causes Karposi's sarcoma?

Answer 32

human herpes virus 8

Question 33

What is Karposi's sarcoma?

Answer 33

vascular tumour

Question 34

What virus causes non-hodgkins lymphoma?

Answer 34

EBV

Question 35

What is the presentation of non-hodgkins lymphoma?

Answer 35

B symptoms; bone marrow involvement; extranodal disease; increased CNS involvement

Question 36

What organism is responsible for cervical cancer?

Answer 36

HPV

Question 37

What are the non-opportunistic problems associated iwth HIV?

Answer 37

mucosal candidiasis; seborrhoeic dermatitis; diarrhoea; fatigue; worsening psoriasis; lypmhadenopathy; parotitis

Question 38

What factors increase the transmission risk of HIV?

Answer 38

anoreceptive sex; trauma; genital ulceration; concurent STI

Question 39

WHat is the risk of mother to child transmission if viral laod is undetected at delivery?

Answer 39

<0.1%

Question 40

What group is most likely to be undiagnosed and present late?

Answer 40

heterosexual men

Question 41

How many people in Scotland with HiV are unaware of their infection?

Answer 41

1 in 6

Question 42

What is a high prevalence area in the UK?

Answer 42

>0.2%

Question 43

When should a patient be tested for HIV if incapacitated?

Answer 43

only if in patients best interests but if safe, wait until patient regains capacity

Question 44

Is consent from relatives required to do an HIV test on an incapacitated patient?

Answer 44

no

Question 45

What markers are used to detect HIV infection?

Answer 45

viral RNA; capsule protein p24-antigen; antibody

Question 46

What do thrid generation HIV tests look at?

Answer 46

HIV-1 and HIV-2 antibody- IgM and IgG

Question 47

What is the window period for third generation HIV antibody test?

Answer 47

20-25 days

Question 48

What do 4th generation HIV tests test?

Answer 48

combined antibody and antigen

Question 49

What is the window period for 4th generation HIV tests?

Answer 49

14-28days

Question 50

How long does it take to get results with rapid HIV tests?

Answer 50

20-30mins

Question 51

What is the function of recent infection testing algorithms?

Answer 51

used to identify if an infection occurred within the preceding 4-6 months by looking at measuring different types of antibodies or stregth of antibody binding