ID Flashcards
Most useful test for diagnosing congenital HIV?
HIV DNA PCR
- perform at birth, 2months, 4 months and 12months
- reassuring if negative at 4months
HIV antibodies not useful until >18mo due to transplacental passage of ab’s
What medication is used to treat infants at low risk of HIV Mother-Child transmission?
4 week course of PO or IV zidovudine prophylaxis
Features of congenital syphilis?
IUGR
Anaemia and thrombocytopenia
Hepatosplenomegaly
Fever and rash
“snuffles”
Chorioretinitis and cataracts
Periostitis and osteochondritis
Common causes of osteomyelitis
S aureus most common
S pneumoniae
Kingella
Neonates: S aureus, GBS and gram negs
IVDU: pseudomonas
CGD: catalase positive microbes such as serratia, s aureus and candida
Which bacteria cause gastroenteritis by ingestion of preformed toxins?
Staph aureus
Bacillus cereus
Side effects of ciprofloxacin
photosensitivity
tendon rupture
seizures
prolonged QTc
Mechanism of methicillin resistance in MRSA
Many staph aureus carry the mecA gene that encodes for penicillin binding protein 2a, which has a low affinity for beta lactams so beta lactams are unable to bind and inhibit cell wall synthesis
Antibiotics with MRSA cover
Vancomycin
Clindamycin
Bactrim
Linezolid
Features of congenital CMV?
Microcephaly
Sensorineural hearing loss
Developmental delay
Thrombocytopenia
Hepatosplenomgealy, hepatitis
IUGR
Calcifications which CircuMVent the ventricles
Chorioretinitis in 10-20% (ie less than toxo)
Organism most likely responsible for infection post dog or cat BITE?
Pasteurella multocida
Organism most likely responsible for infection post cat SCRATCH?
Bartonella henselae
Neonatal conjunctivitis: gonococcal vs chlamydia
- Gonococcal more likely to present early (2-7 days after delivery), chlamydia more likely to present later (onset 7-14days after delivery)
- Chlamydia associated with neonatal pneumonia in first 4months
Management of neonatal chlamydia infection (conjunctivitis or pneumonia)
Azithromycin 20mg/kg PO for 3 days (per ASID guidelines)
Which organisms have inducible resistance to cephalosporins on treatment? ie inducible beta-lactamase activity that is chromosomally mediated
ESCAPPM organisms
* Enterobacter species
* Serratia marcescens
* Citrobacter fruendii (not koseri)
* Aeromonas species
* Proteus species
* Providencia species
* Morganella morganii
What % of children with invasive pneumococcal disease have an underlying immune deficiency syndrome?
1.3% overall.
Meningitis:
3.5% of children >5yrs
10.6% of children <15yrs
Pneumonia: 8%
Management of gonococcal ophthalmia
Ceftriaxone
and further investigate with BC and/or LP
Treatment of latent TB
3mo of Rifamp + isoniazid OR
3mo of rifapentin + isoniazid OR
4mo rifampicin only OR
6mo of isoniazid only
(RCH)
Treatment of TB disease
2mo of Rifampicin, Isoniazid, Pyrazinimide, Ethambutol +
4 months of rifampicin and isoniazid (if non-severe can do 2mo)
Who gets window prophylaxis in TB?
Children <5yrs should get latent TB treatment if TST/IGRA negative whilst awaiting repeat TST/IGRA in 3months
Side effects of ethambutol
E= eyes
Optic neuritis
Red-green colour blindness
Side effects of rifampicin
R= red urine
Thrombocytopenia
LFT derangement
Side effects of isoNiazid
Peripheral Neuropathy
transaminitis
acne
Give pyradoxine (vit B6)
Definitions for positive TST in TB?
- 5+mm if high risk (immunocompromised, symptomatic + known close contact)
- 10+mm if mod risk (age <4, high prevalence area)
- 15+mm if low risk (age >4 w/o risk factors)
CSF findings in TB meningitis
High protein (>5)
Low glucose (<0.3 CSF: serum ratio)
Neutrophils <100
Lymphocytes 50-1000 but maybe normal
Transmission of leptospirosis
Rat urine
Which infection commonly causes a relative bradycardia/ pulse-temperature dissociation?
Typhoid fever
Most common organism causing cellulitis?
Group A strep (followed by staph aureus)
Why is mycobacteria pneumoniae resistant to beta lactams?
It is an atypical bacteria that lacks a cell wall and therefore has intrinsic resistance to beta lactam antibiotics
When to start treatment for HIV?
ASAP when diagnosis made, regardless of age
Usually 2x NRTIs + 3rd drug of different class
Risk factors for MTCT of HIV?
- Highest risk at delivery (60-75%)
- High maternal viral load, low CD4 count, placental infection or STI
- Prematurity, low birthweight
- PROM, NVD or instrumental
- Breastfeeding
What maternal viral load is considered ‘low risk’ in HIV?
Maternal viral load <50copies/ml
Rifampicin resistance gene in TB?
rpoB gene
Which TB medication has poor CNS penetration (and is often not used in TB meningitis)?
Ethambutol
How does zika virus present?
“Influenza like syndrome” with rash
Can cause guillain barre syndrome
Congenital zika virus presents with severe microcephaly, hypertonia, contractures, macular scarring
What is cutaneous larva migrans?
Skin disease from animal hookworm (cat or dog faeces)
- pruritic serpiginous tracts in skin
Management of hookworm (ancylostoma) infection?
Albendazole
What is cystic echinococcosis?
AKA Hydatid disease
tapeworm found in dogs (definitive host) and sheep, cattle, goats, and pigs (intermediate hosts).
Causes slowly enlarging cysts in lung and liver
Management of echinococcocis (hydatid disease)
Cysts <5cm may be managed with anti-parasitic treatment (albendazole) alone
Larger, or complicated cysts need albendazole + surgical removal eg percutaneous aspiration, injection of chemicals, respiration (PAIR)
Anopheles mosquito transmits which infection?
Malaria
Classic triad of congenital toxoplasmosis?
- Chorioretinitis
- Calcifications - scattered throughout the brain
- Hydrocephalus (CSF)
also can get anaemia, thrombocytopenia, jaundice, hepatosplengomegaly, pneumonitis, rash
