Infectious Diseases Flashcards
Most common site of origin of osteomyelitis
Metaphysis
Femur>Humerus>Tibia
Can spread to epiphysis because of blood supply
Most common site for GBS osteo
Humerus
Most common site for GBS septic arthritis
Hip
Most common GBS serotype?
Serotype 3
Indications for GBS IAP
- Previous infant with GBS disease
- GBS bacteriuria during current pregnancy
- Positive GBS screening culture during pregnancy (unless planned C/S)
- GBS unknown status, delivery<37 weeks, ROM>18 hours and maternal fever
Infective organism associated with placental microabscesses?
Listeria
*gram positive rod, present in unpasteurized dairy and deli meats
Chocolate colored or ‘meconium-like’ stained amniotic fluid is associated with which organism?
Listeria -> early onset disease with small papular rash (granulomas on histopath)
How long are ‘snuffles’ in congenital syphilis infective?
Until after 24 hours of treatment
Which infection can have an unexplained large placenta?
Treponema/syphilis
Type of rash in syphilis?
Desquamating maculopapular rash
3 most common types of infections with gonorrhea in neonates?
- Conjunctivitis with copious purulent discharge, can lead to corneal ulceration. Needs ceftriaxone x1
- Scalp abscess if scalp electrode is used
- Arthritis
Systemic disease needs 7 days Rx, 10-14 if meningitis
Most common cause of infectious conjunctivitis?
Chalmydia.. Also most common manifestion of neonatal chlamydia.
Typically B/L.
Prophylactic erythromycin does not prevent (only prevents gonorrheal)
Triad of congenital HSV infection
- Brain: microcephaly, intracranial calcifications, hydranencephaly, seizures, hypertonicity
- Eyes: Chorioretinitis, cataracts, blindness
- Skin: vesicular rash
Also presents with IUGR
Which virus replicates within RBCs
Parvovirus B19
Retic count and type of anemia with Parvo?
Aplastic anemia, so low retic
Can lead to hydrops, congestive heart failure
Which pathogen has a primary reservoir outside of human and primates?
Toxoplasma
What causes granulomatosis infantiseptica?
Listeria
Which clinical factor has the highest sensitivity for maternal chorio?
Maternal fever
Which GBS serotype is most commonly associated with meningitis?
GBS serotype 3
How long after infection are osteomyelitis bony changes detectable on X-ray?
7-10 days.
By MRI you can see them within 24-48 hours
What is Wimberger sign?
Destruction of metaphysis of tibia, and is seen with congenital syphilis
Which virus replicates within RBC precursors?
Parvovirus
During what time period is there greatest risk of VZV infection in infant?
Between 5 days before delivery until 2 days after.
There is insufficient time for protective antibodies to cross to the fetus
At what time period is there highest risk of congenital varicella infection?
Between 8 and 20 weeks gestation
Indications for VariZIG
- Infant with mother who develops infections between <5 days prior to delivery until 2 days after
- <28 weeks or <1000g if significant exposure
- > 28 weeks if significant exposure and mother is seronegative
- Term healthy infant if exposed within 2 weeks post delivery and mom is seronegative
- If infant is exposed between 2-7 days postnatally
At what gestational age is the highest risk of congenital anomalies with rubella?
Weeks 1-12
100% of fetuses will have deafness and congenital cardiac abnormalities
After which week of gestation are congenital anomalies from rubella rare?
Week 20
Hallmarks of congenital rubella?
Hydrops in utero
Sensorineural hearing loss, microcephaly
Cataracts, salt and pepper chorioretinitis
Blueberry muffin rash
Cardiac anomalies (PDA most common -> PPS)
Long bone radiolucencies
Mechanism of blueberry muffin rash
Dermal extramedullary hematopoiesis
Most common intrauterine infection?
CMV
Intranuclear and cytoplasmic inclusions are seen with which virus?
CMV
What does hearing loss in CMV correlate with?
Presence of periventricular calcifications
Type of hearing loss in CMV?
Progressive sensorineural, often bilateral, moderate to profound
Treatment for congenital CMV and what do you monitor?
Oral valganciclovir for 6 months
Monitor for neutropenia and GI disease
Which outcomes does oral valganciclovir have an effect on in congenital CMV?
Improves hearing and neurodevelopmental outcomes
What are cortical calcifications seen with?
Toxoplasmosis
Which cells does HIV infect?
Helper T lymphocytes and macrophages
Most common infection in children in the US leading to diagnosis of HIV?
Pneumocystis carinii pneumonia
Test of choice to diagnose HIV in infants?
HIV-1 DNA PCR
If positive in first 2 days of life, infection transmitted in utero
If between 2-6 weeks, then infected during intrapartum
Which fungal infection is associated with lipid emulsions?
Malassezia
Test medium to diagnose chlamydia
Giemsa stain
Test medium to diagnose Neisseria
Thayer Martin
Test medium to diagnose pertussis
Bordet Gengou
Test buzzword to diagnose pseudomonas
Oxidase positive, catalase positive
Test buzzword to diagnose rubella
Hemagglutination inhibition
Organisms causing chorioretinitis?
CHoRioreTinitiS CMV, Candida Herpes Rubella Toxoplasmosis Syphilis (early congenital)
Listeria findings
Think hot chocolate made with unpasteruized milk
Chocolate colored amniotic fluid
Microabscesses and granulomas ‘marshmallows’,
What are the non treponemal tests and what do they detect?
RPR, VDRL
Test cell membrane cardiolipin IgG Ab
Used for screening, assessing response to treatment and determining reinfection
Positive if titer is 4x that of mom
What’s the treponemal test and what does it detect?
FTA-ABS
Detects specific antibody. Used to establish presumptive diagnosis.
Reactive for life
What causes a positive treponemal test?
Antinuclear antibodies
Asymptomatic, positive PPD or IGRA, negative sputum, CXR, and contact with contagious person
INH and pyridoxine for 9 months
Active TB disease in pregnant mother
INH, rifampin, ethambutol for 6-9 months
Add pyridoxine to prevent B6 deficiency
Asymptomatic neonate, mother with positive PPD and active disease
Start INH for 3-4 months in neonate, if positive PPD continue for total 9 months
if negative PPD -> d/c INH and follow serial PPDs
Isolate from mom is symptomatic
Asymptomatic neonate, mother with positive PPD, negative CXR
No need to separate
No treatment
Most common congenital viral disease?
CMV
Also most common cause of sensorineural hearing loss
Hearing loss is usually bilateral, moderate to profound
Treatment with ganciclovir will reduce severity of hearing loss
Most common congenital parasitic disease?
Toxoplasmosis
Kittens more likely to transmit the disease
Infants may develop learning and visual impairments later in life, asymptomatic at birth
Rx with pyrimethamine and sulfadiazine and folinic acid for 1 year
Which GBS serotype is associated with EOS and LOS?
Type 3
Which vaccines should an HIV positive baby not receive?
MMR
Varicella
Oral polio
BCG
Congenital infections increasing risk of stillbirth?
Parvovirus
Listeria
Syphilis
At which time point during pregnancy would varicella infection lead to greatest risk to fetus?
5 days before and 2 days after delivery (insufficient time for immunoglobulins to pass)
Give the baby VZIG
Transmission of syphilis at which time during pregnancy leads to more severe disease?
Later in pregnancy
Which congenital infection has a U-shaped distribution of transmission?
Rubella. More severe if earlier
Limb hypoplasia is characteristic of which infection?
Congenital varicella
Characteristic features of congenital varicella?
Limb hypoplasia and cicatricial scarring
Cataracts
Chorioretinitis
Brain abnormalities
Most common organisms for omphalitis? And most common complication?
Polymicrobial with skin flora
Most common complication is sepsis
Recommended treatment for syphilis during pregnancy?
A single intramuscular (IM) dose of benzathine penicillin G
Eradicates maternal disease and prevents congenital syphilis
Treatment options for congenital syphilis
Aqueous crystalline PCN IV for 10 days
Procaine PCN IM for 10 days
Benzathine PCN IM x1 (only if all tests are negative)
When is screening for vertical HCV done?
Antibody testing is done at 18 months (because maternal antibodies can be present till then)
You test NAAT at 3 years to determine whether to treat. Treatment isnt approved before 3 years
