Medicine JC102: HIV Positive: HIV Related Diseases, Accidental Needle Prick Injury Flashcards
HIV virus
Human immunodeficiency virus
- **RNA **Retrovirus
- Family: Retroviridae
- Genus: Lentivirus
2 species:
- HIV 1 (more virulent, cause global HIV pandemic)
- HIV 2
Structure:
- 120 nm in diameter
- 2 +ve single-stranded RNA
- RNA bound to enzymes: reverse transcriptase, proteases, ribonuclease, intergrase
- Envelope protein: gp120, gp41
- Primarily infects: T helper cells, macrophages and dendritic cells (CD4 receptor, CCR5 receptor)
Effect:
- Failing immune system —> AIDS —> Life-threatening opportunistic infection
Transmission:
- Bodily fluid: Blood, Semen, Vaginal fluid, Breast milk
- Exist as **Free virus particles / **Virus in infected immune cells
1. Sexual (majority) (Heterosexual / Homosexual)
2. Blood-borne (IVDU, contaminated blood / organs / needles, needle stick injury)
(SpC Medicine:
Rule of 3 for needle stick injury: 0.03% HIV, 3% Hep C, 30% Hep B)
3. Mother-to-child
Virulence protein:
- Transmembrane glycoproteins (**gp120 + **gp41) —> attach virus to host cells
- Viral membrane (lipid layer)
- Reverse transcriptase
- Integrase
- Polymerase
- RNA
Epidemiology of HIV
Endemic:
- South Africa
- Congo
- Tanzania
- India
- China
- Russia
- North + South America
Risk factors for HIV
- High HIV viral load
- Lack of circumcision
- ***Unprotected sex (M to F: 0.08% per act, F to M: 0.04% per act)
- ***Receptive anal (1.7% per act)
- Presence of ***ulcerative STD e.g. genital herpes, syphilis (300 times)
—> carrying high number of infected lymphocytes - ***HIV superinfection (infected with 2nd strain after 1st strain) / coinfection (2 strains simultaneously)
***Diagnosis of HIV
HIV Ab testing (2 step testing)
**ELISA to detect **Anti-HIV-1 (for initial screening)
—> reactive ELISA
—> re-test
—> ***Western blot (test for protein) for confirmation (indeterminate Western: repeat 1 month)
Public health laboratory centre of CHP
Window period:
- time period between contracting HIV + testing positive for HIV Ab
- within 3 months (up to ***6 months)
—> need to repeat testing after window period if has suspicion
HIV reporting system in HK
- Voluntary reporting
- Anonymous
Major fields of information:
1. Gender
2. Ethnicity
3. Age
4. Source of reports
5. Progression to AIDS
6. Route of transmission
7. Suspected place of infection
Source of reports:
- Physicians
- Confirmatory laboratories
HIV in HK
- Reported case only tip of iceberg
- ***Homosexual transmission route majority in HK, Bisexual 2nd
- ***M>F
- Chinese majority
- 20-40 majority
- Public hospital / clinics majority
***Natural course of HIV infection
Primary infection
—> Acute HIV syndrome (Wide dissemination of virus, seeding of lymphoid organs) (CD4 ↓↓, HIV RNA ↑↑)
—> Small rebound ↑ of CD4 to ~600, HIV RNA ↓
—> Clinical latency (***8-10 years, CD4 gradual ↓, HIV RNA gradual ↑)
—> Constitutional symptoms (CD4 <200, HIV RNA ↑)
—> Opportunistic infection
—> Death
- HIV alone =/= AIDS
- HIV + ***AIDS-defining illness = AIDS
- ***CD4 <200 (SpC Medicine: reversed CD4:CD8 ratio: normally 1-4)
- Without treatment —> 50% will progress to AIDS in 10 years
- Underlying immunosuppression —> Development of major clinical complications e.g. opportunistic infections, cancers
Acute HIV infection
- ***Mild fever >1 month
- ***Chronic diarrhoea >1 month
- ***Thrush
- Vaginal candidiasis
- Oral hairy leukoplakia
- ***Herpes zoster x 2 / >1 dermatome
- Peripheral neuropathy
- ***Bacillary angiomatosis (Bartonella)
- Cervical dysplasia
- Cervical CIS
- ITP (Idiopathic thrombocytopenic purpura)
- PID
- Listeriosis
***AIDS-defining illnesses
ALL patients with **CD4 <200
1. **PCP (Pneumocystis pneumonia)
2. **TB (technically not since endemic in HK)
3. Other fungal infections (e.g. **Esophageal candidiasis)
4. Penicilliosis (Penicillium marneffei: Dimorphic fungi)
5. **Kaposi’s sarcoma (HHV8)
6. Non-TB mycobacterial infections (e.g. Disseminated M. avium infection, Mycobacterium Avium Complex)
7. **Wasting
8. **CMV disease
9. **Toxoplasmosis (Toxoplasma gondii: opportunistic CNS infection)
10. ***Molluscum contagiosum (Poxvirus)
11. Mycobacterium haemophilum (Immune reconstitution syndrome)
12. HIV-associated dementia
13. Recurrent bacterial pneumonia
14. Immunoblastic lymphoma
15. Chronic cryptosporidiosis
16. Burkitt lymphoma
17. Disseminated histoplasmosis
18. Invasive cervical cancer
19. Chronic Herpes simplex
***Treatment of HIV
Currently no vaccine / cure
Classes of drugs:
1. Fusion inhibitor: Maraviroc (CCR5), Enfuvirtide (gp41) (for resistance case)
2. NRTI: Zidovudine, Lamivudine, Tenofovir, Stavudine
3. NNRTI: Efavirenz
4. Integrase inhibitor: Raltegrase, Dolutegravir (for resistance case)
5. PI: Ritonavir, Lopinavir
Post exposure prophylaxis:
- ***Truvada (Emtricitabine + Tenofovir) (4 weeks)
Treatment:
**HAART:
- Start CD4 **<350 (500 now, early commencement increase survival)
- ***2x NRTI + PI / NNRTI
- Average life expectancy: >30 years from time of infection
SE:
- Lipodystrophy
- Dyslipidaemia
- Insulin resistance
- CVS risks
DDx for HIV lung infections
- ***PCP
- ***MTB
- ***Legionella pneumophila
- ***Mycoplasma
- Strept pneumoniae
PCP infection
Diagnosis:
- Positive ***IF staining of sputum
Treatment:
- **Septrin (Co-trimoxazole) + **Prednisolone 40mg BD (suppress cytokine reaction)
Kaposi’s sarcoma
Treatment: Intralesional ***Vinblastine
Regular testing for Key populations
<=every 12 months
1. MSM, Transgender
2. Female sex workers + male clients
3. IVDU
4. Spouse / regular partner of HIV infected
Key messages for HIV prevention
- Condom for safe sex
- Break needle habit —> Use methadone
- Pregnant women should attend early for antenatal HIV testing
- Infected people should receive HIV treatment + care asap
