Human Immunodeficiency Virus

Question 1

What is the definition of human immunodeficiency virus (HIV)?

Answer 1

Single stranded RNA retrovirus that replicates within the human immune system using host CD4 cells.

Question 2

What are the methods of transmission of HIV?

Answer 2

Sexual
Parental (IVDU, infected blood products, iatrogenic)
Mother-to-child (in utero, delivery, breastfeeding)

Question 3

What are some risk factors that increase sexual transmission of HIV?

Answer 3

Anoreceptive
Trauma
Genital ulceration
Concurrent STI

Question 4

What is the pathophysiology of HIV infection?

Answer 4

Infection of CD4+ cell
Transport to regional lymph nodes
Infection established within 3 days of entry
Dissemination of virus

Question 5

What is the effect of HIV virus on immune response?

Answer 5

Reduced circulating/proliferation of CD4+ cells
Reduction in CD8+ T cell activation (dysregulated expression of cytokines)
Reduction in antibody class switching (reduced affinity of antibodies produced)
Chronic immune activation

Question 6

What are people with HIV more susceptible to?

Answer 6

Viral infections
Fungal infections
Mycobacterial infections
Infection-induced cancers

Question 7

What are some clinical features of primary HIV infection?

Answer 7

Fever
Maculopapular rash
Myalgia
Pharyngitis
Headache/aseptic meningitis

Question 8

What are some AIDS- defining conditions?

Answer 8

Opportunistic infections:
- Pneumocystis pneumonia
- Tuberculosis
- Cerebral toxoplasmosis
- Cytomegalovirus
- Neurocognitive impairment
- Progressive multifocal leukoencephalopathy
- Skin infections (herpes zoster, herpes simplex, HPV)

HIV associated wasting (Slim’s disease)

Cancers:
- Kaposi’s sarcoma
- Non-Hodgkin’s lymphoma
- Cervical cancer

Question 9

What is a typical presentation of pneumocystis pneumonia?

Answer 9

CD4+ <200
Insidious onset SOB and dry cough
Exercise oxygen desaturation

Question 10

How is pneumocystis pneumonia diagnosed and managed?

Answer 10

Diagnosis: BAL and immunofluorescence +/- PCR
Management: high dose co-trimoxazole

Question 11

What is a typical presentation of cerebral toxoplasmosis?

Answer 11

CD4+ <150
Multiple cerebral abscesses and chorioretinitis
Headache, fever, focal neurology, seizures, reduced consciousness, raised ICP

Question 12

What is a typical presentation of cytomegalovirus?

Answer 12

CD4+ <50
Retinitis, colitis, oesophagitis
Reduced visual acuity, floaters, abdominal pain, diarrhoea, PR bleeding

Question 13

What is a typical presentation of progressive multifocal leukoencephalopathy?

Answer 13

CD4 <100
Rapidly progressing focal neurology, confusion, personality change

Question 14

What is a typical presentation of Kaposi’s sarcoma?

Answer 14

Cutaneous, mucosal, visceral (pulmonary, GI) vascular tumours

Question 15

What are some non-AIDS symptomatic features of HIV?

Answer 15

Mucosal candidiasis
Seborrhoeic dermatitis
Diarrhoea
Fatigue
Worsening psoriasis
Lymphadenopathy
Parotitis
Eosinophilic folliculitis

Question 16

What are some neurological presentations of HIV?

Answer 16

Distal sensory polyneuropathy
Mononeuritis multiplex
Vacuolar myelopathy
Aseptic meningitis
Guillan-Barre syndrome
Cryptococcal meningitis
Neurosyphilis

Question 17

What are some investigations for HIV?

Answer 17

HIV antibody test
(4th generation test may be falsely negative in first 45 days following infection)

Question 18

What drug treatment is used to reduce viral HIV load to undetectable levels in serum?

Answer 18

HAART

Question 19

What are some drug preventions of HIV?

Answer 19

Pre exposure prophylaxis (PrEP)
Post exposure prophylaxis (PEP) within 72 hours

Question 20

How can mother to child transmission of HIV be prevented?

Answer 20

HAART during pregnancy
Vaginal delivery if undetected viral load
C-section of detected viral load
2-4/52 PEP for neonate
Exclusive formula feeding