Big Nasty Infections (HIV/Malaria/TB) Flashcards
Percentage of children infected with HIV who develop AIDS each year?
~5%
What time-frame post exposure to TB will Mantoux be positive?
4-6wks post exposure
What type of immune reaction is a Mantoux test?
Delayed hypersensitivity to Tuberculin
Fetal risks associated with HAART therapy during pregnancy?
Associated with prematurity
Currently no documented evidence for teratogenicity
Treatment for Baby post delivery in Mother with known HIV infection?
4/52 AZT
OR 4/52 HAART if Mum untreated and viraemic
Exclusive formula feeding
What is a more accurate measure of viral load in infants, CD4 count or CD4%
CD4% more accurate as CD4 counts are higher in infants
Classification of CD4% as immunosuppression marker in infants (none, moderate, severe)?
None: >25%
Moderate: 15 - 24
Severe: <15%
List 8 AIDS defining illnesses.
Extensive Candidiasis Cryptosporosis Diarrhoea Disseminated Histoplasmosis CMV Atypical Mycobacterium PCP HSV (persistent or disseminated) Toxoplasmosis (cerebral)
Lymphoid interstitial pneumonia occurs in what percentage of children with vertically acquired HIV?
40%
What are the 7 steps in the HIV life cycle?
- Attachment (bind to host cell CD4)
- Fusion (inject into cell)
- Reverse transcriptase (transcribe info into DsDNA
- Intergration (transport of DNA into host cell DNA)
- Protein production
- Packaging and Budding (exocytosis before moving on to other cells)
- Protease (maturation of budded virus)
Side effects of NRTIs (Nucleotide reverse transcriptase inhibitors)?
Lactic acidosis
GI upset
Lipdystrophy
Side effects of NNRTIs (Non-nucleoside reverse transcriptase inhibitors)?
P450 inducers
Rash (SJS)
Hepatitis
Site of action of NRTIs and NNRTIs?
Act at point where double stranded RNA is converted to double stranded DNA
Where do protease inhibitors work?
Ibhibit final step just after virus has budded (virus unable to mature)
Side effects of protease inhibitors?
P450 Inhibitors lipdoystrophy Insulin resistance dyslipidemia GI upset
What kind of bug is Mycobacterium Tuberculosis?
Non-motile bacillus
Straight rod
Obligate anaerobe
Acid fast bacillus
Describe difference between TB infection and disease?
TB infection means bacillus has been taken up by macrophages and is within body, but not causing active disease
Interferon gamma tests measure what for TB?
Measure the immune response to TB
Antigens are: ESAT-6 and CFP-10
Standard treatment for TB? (NICE guideline)
Rifampicin + Isoniazid for 6mths (10mths CNS disease) AND
Ethambutol + Pyrazinamide for 2mths
Treatment for a positive skin test or positive interferon release assay?
Isoniazid 6mths
Isoniazid + rifampcin 2mths
When after commencing treatment are TB patients considered non-infectious?
After 2 weeks of treatment
Who is at risk for severe malarial disease?
Asplenia
Sickle cell disease
Immunocompromised
What is first line treatment for malaria?
Quinine
Note: induces hyperinsulinism
Quinine resistance is Rare (as hens teeth)
Define Multi-drug resistant TB?
Resistant to Isoniazid & Rifampicin
Define Extensively drug resistant TB?
Resistance to; Isoniazid + Rifampicin + Fluoroquinolones + One of three of; Amikacin, capreomycin, kanamycin
Number of new cases of TB worldwide per year?
8.7 million new cases
Number of deaths secondary to TB worldwide?
1.4 million deaths (3800 deaths per day)
Risk fo Vertical transmission HIV if Mum on ART?
<2%
**without treatment is as high as 35%
Why are ARTs ineffective at treating latent HIV infection?
Only target replicating virus (latent infection means virus is not replicating)
