Infectious, Immunology and Derm

Question 1

Recommended timing and type of testing for HIV-exposed infants

Answer 1

HIV 1/2 DNA PCR at 2 weeks

Due to only 40% being positive in initial 48h, up to 93% if done at 2 weeks

Question 2

Timing for repeat HIV testing in exposed infants

Answer 2

1-2 months and 4-6 months

Question 3

Treatment for HIV-exposed infants a) if mother was on PPX and b) if she received no treatment

Answer 3

a) Zidovudine for 6 weeks (start within 12h of birth)
b) Zidovudine for 6 weeks plus Nevaripine for 3 doses

Question 4

Lymphocytic choriomeningitis virus (LCMV) 1) vector 2) maternal signs 3) neonatal signs 4) longterm sequelae

Answer 4

1) rodents (feces)
2) aseptic meningitis, flu-like illness
3) ventriculomegaly, chorioretinitis, microcephaly, periventricular calcifications,
4) severe delays, seizures, blindness but NOT deafness

Question 5

Cytomegalovirus (CMV) 1) vector 2) neonatal signs 3) longterm sequelae

Answer 5

1) humans
2) largely asymptomatic…IUGR, microcephaly, thrombocytopenia, chorioretinitis, hepatosplenomegaly, periventricular calcifications, blueberry muffin rash
3) deafness, blindness

Question 6

Toxoplasmosis 1) vector 2) neonatal signs

Answer 6

1) feline (feces)
2) largely asymptomatic…TRIAD: hydrocephalus, chorioretinitis, scattered intracranial calcifications

Retina has large scars beside acute inflammation

Question 7

Congenital rubella findings

Answer 7

1) Blueberry muffin rash (extramedullary hematopoesis)
2) PDA or supravalvular pulmonary stenosis
3) Glaucoma, cataracts, and microophthalmia

Question 8

An increase in transplacental passage of IgG is seen around week ___, but the bulk of IgG is transferred after ___ weeks.

Answer 8

22 and 36 (Relates to both “good” and “bad” antibodies , i.e. immunity purposes and if there’s alloimmunization)

Question 9

Management of an asymptomatic infant born to a mother with active genital lesion but prenatal h/o HSV

Answer 9

Surface cultures and blood PCR for HSV at 24 hours of age; no treatment (if asymptomatic)

Question 10

Management of an asymptomatic infant born to a mother with a concerning genital lesion without a prior h/o HSV

Answer 10

Surface cultures, blood and CSF PCR for HSV, LFTs, and acyclovir ALL at 24 hours

If infant symptomatic, do investigation and start treatment earlier

Question 11

Under what instance might you do HSV surface cultures before 24 hours of age?

Answer 11

If rupture of membranes (ROM) was >6h

Question 12

Classic test for severe combined immunodeficiency (SCID)

Answer 12

Flow cytometry for lymphocyte subtypes (Demonstrates low T-cell count, can have low B- and NK-cell as well but those can also be normal)

NBS SCID test is “TREC” (T cell receptor excision circles)

Question 13

Gene mutation most commonly associated with SCID

Answer 13

Interleukin-2 (IL-2)

This form: T-cell/NK-cell deficient, normal number B-cells but dysfunctional 2-2 of T-cell stimulation

Question 14

Test for chronic granulomatous disease

Answer 14

Dihydrorhodamine oxidation assay, AKA neutrophil oxidative burst

Question 15

Histology finding for erythema toxicum

Answer 15

Eosinophils

Question 16

Histology findings on transient neonatal pustular melanosis

Answer 16

Neutrophils (on Wright stain)

Question 17

Cause of acrodermatitis enteropathica

Answer 17

Zinc deficiency (congenital or acquired) Looks erosive and or crusted mainly on mouth, extremities and diaper when FORMULA FED

Question 18

What can look like congenital varicella but not dermatomal in distribution

Answer 18

Epidermolysis bullosae (especially junctional)

Question 19

Classic two mucocutaneous findings in Rubella

Answer 19

Blueberry muffin rash (extramedullary hematopoeisis) and petechiae on hard palate

Question 20

What’s a fairly distinguishing finding between Rubella and Toxo (since both have blueberry muffin rash)

Answer 20

Chorioretinitis MUCH more prevalent in Toxo, (Rubella’s “buzzword” supravalvular pulmonic stenosis)

Retinitis classically is small focus of acute inflammation beside a huge scar

(AAO.org)

Question 21

Classic appearance of chorioretinitis from congenital syphillis

Answer 21

“Salt and pepper” (since vasculopathy of the smallest vessels)

(https://webvision.med.utah.edu/)

Question 22

Characteristics of the most common hemangioma in neonates

Answer 22

Infantile hemangioma:

Benign tumor

Enlarges in first year (flat or raised, red or purple), then involutes

Think of PHACES if on head

Question 23

What is Kasabach-Merritt

Answer 23

DIC-like process from consumption of factors and platelets in large vascular malformation

Question 24

Syndromes associated with cafe au lait macules

Answer 24

Tuberous Sclerosis

Neurofibromatosis

McCune-Albright

Think of these if >5

Question 25

Where do congenital nevi come from and what risk do they confer

Answer 25

Neural crest cells that produce melanin

If large, have risk of melanoma

Question 26

What is the PC name for hairy epidermal nevi and what risk do large ones confer

Answer 26

Smooth muscle hamartoma, no risk!

Question 27

Triad for McCune Albright

Answer 27

Cafe au lait spots (coast of Maine)

Polyostotic fibrous dysplasia (fibrous, weak bones)

Precocious puberty

Question 28

Findings in Peutz-Jegher syndrome

Answer 28

Pigmented macules/“freckles” all around lips GI polyps

Question 29

Chediak Higashi findings (think of three)

Answer 29

Albinism Granular cell dysfunction—platelet and granulocytes (PMNs etc) Peripheral neuropathy/seizures DIE FROM LYMPHOPROLIFERATIVE DZ See giant granules in cells on a smear

Question 30

Clinical tetrad for Chediak Higashi and histologic finding

Answer 30

1. Albinism (hypopigmentation)
2. Infections (dysfunction granulocytes)
3. Bleeding (dysfunctional platelets)
4. Neurologic degeneration/seizures

HUGE granules in those cells

Question 31

Dermatologic findings in incontinentia pigmenti

Answer 31

Vesicular, then verrucous, then hyper- or hypopigmented

All follow lines of Blaschko (Christmas tree on back!)

(Have seizures/delay, blindness)

Question 32

Most common cause of colloidon membrane

Answer 32

Congenital Icthyosiform Erythroderma (CIE)

Colloidon: Thick, parchment-like skin

Mutation: ALOXE3 or ALOX12B

CIE causes ALOXI skin problems

Question 33

Most severe form of ichthyosis

Answer 33

Harlequin, most die in first few days from sepsis/uncontrollable fluid loss

Mutation: ABCA12

Question 34

Most benign ichthyosis

Answer 34

Ichthyosis vulgaris

Association: Atopic dermatitis

Question 35

Most severe form of epidermolysis bullosae and its classic assocation

Answer 35

Junctional and pyloric atresia

This form can affect the mucosa as well (ie. GI)

Question 36

Two distinguishing features of dystrophic epidermolysis bullosa

Answer 36

1. Dystrophic nails
2. Blisters heal with scarring and hundreds of milia

Question 37

What inborn error of metabolism (IEM) should you think of in E. Coli sepsis

Answer 37

Galactosemia

Also have liver failure/hyperbilirubinemia and Fanconi syndrome (PCT HCO3 and nutrient/electrolyte wasting)

Question 38

Classic findings in Leukocyte Adhesion Deficiency (LAD)

Answer 38

1. Delayed (>1 month) separation of the umbilical cord
2. Recurrent infections with lack of pus (if infectious sites biopsied/examined, see complete lack of PMNs)
3. Usually caused by a beta-integrin mutation

Question 39

Diagnosis in an infant with: failure to thrive, chronic diarrhea (and/or cough), and eosinophilia

Answer 39

Severe Combined Immunodeficiency (SCID)

IL2RG mutation (most common), common part of all interleukins and those are needed for T-, B- and NK-cell development

Question 40

What is one of the only “absolute” indications for a cephalosporin in neonates

Answer 40

Gonococcal exposure

(You treat with ceftriaxone x1 IV even if infant asymptomatic)

Question 41

What are the requirements for an infant to be considered minimal-risk for syphillis transmission

Remember for an antibody titer, it’s a 1:y (if y is higher, the problem is worse)

Answer 41

Maternal penicillin treatment finishing >4 weeks before delivery

AND resulting in a titer decrease of four-fold or greater

Question 42

One of the only absolute contraindications to breastfeeding

Answer 42

Active tuberculosis (ie. with an abnormal XR)

(Infant must be isolated from mother until both are on treatment)

Question 43

Diagnosis in an infant with a history of generalized erythema that now has skin blistering and peeling, and sterile bullous fluid

Answer 43

Staphylococcal scalded skin syndrome (SSSS)

S. aureus exotoxin

See “Nikolsky sign” (skin separates with minimal friction)

(emedicine.medscape)

Question 44

Congenital infection with: large placenta, hepatosplenomegaly, osteochondritis i.e. Wimberger sign

Answer 44

Congenital syphillis

Almost always transplacental, maternal infection at later GA confers GREATER risk of fetal infection

Question 45

What titer-fold change indicates a POSITIVE non-treponemal test in infant?

Answer 45

Four-fold INCREASE [compared to maternal] is worse

Remember, it’s how many times did you have to dilute serum to get rid of reaction! Non-treponemals are VDRL and RPR

Question 46

The two bacterial pathogens most likely to transmit transplacentally

Answer 46

Listeria and syphillis

• Which are two bacterial that have birth findings!*
• Listeria: chocolate/”meconium”-stained fluid*
• Syphillis: huge placenta (and IUGR, hydrops)*

Question 47

Which conjunctivitis presents at 2-5 days (first week)

Answer 47

Neisseria gonorrhea

• Remember the GOO (erythro PPX) helps prevent the GOnorrhea*
• This is the one that’s the most emergent to treat [with 3rd generation cephalosporin]*

Question 48

The most common infectious conjunctivitis

Answer 48

Chlamydial

• Tends to present after first week which watery drainage that turns purulent*
• Treat with oral erythromycin!*

Question 49

The most common pathogen for both osteomyelitis and septic arthritis

Answer 49

S. aureus

Both also most commonly acquired via hematogenous spread