Infectious Disease and Immunology

Question 1

I/T Ratio

Answer 1

%Bands + %Immature Forms
%Neutrophils + %Bands + %Immature Forms

Normal <0.2

most predictive if measured between 1-4 hours after birth

Question 2

ANC

Answer 2

ANC <1000 - predictive of infection

%WBCs X ( %Immature Neutrophils + %Mature Neutrophils) x 0.01

Question 3

Early Onset Sepsis Organisms

Answer 3

Most common: Group B Strep, E. Coli, Listeria

Question 4

Late onset sepsis organisms

Answer 4

50% of cases caused by coagulase negative staph , GBS, E. Coli, Klebsiella common

E.Coli frequent cause of urosepsis

Question 5

CRP levels’ sensitivity increases with serial values ______ to ______ after onset of symptoms

Answer 5

24 to 48 hours

Question 6

CRP normal

Answer 6

<7-9

Question 7

Procalcitonin levels peak ______ hours after infection; Compared to CRP, procalitonin is more ________ but less _________.

Answer 7

more sensitive, but less specific

Question 8

Immature forms for Neutrophils

Answer 8

Bands, metamyelocytes, myelocytes

Question 9

Other names for neutrophils

Answer 9

segs, polys, PMNS (polymorphonuclear luekocytes)

Question 10

E. Coli Bacteria

Answer 10

gram negative rods

organism most commonly indicated in neonatal UTI

Question 11

GBS

Answer 11

gram positive diplococci

Question 12

Klebsiella

Answer 12

gram negative rod

Gram negative organisms such as klebsiella and E.coli are leading cause of LOS

3.5x higher risk of death than gram positive organisms; also common cause of EOS neonatal pneumonia

Question 13

Coagulate Negative Staphylococci

Answer 13

gram positive organisms frequently found in resp. tract and on skin,

s. epidermis is the most common CONS recovered from skin and mucous membranes,

most common source of LOS

commonly associated with catheter lines

Question 14

S. Aureus

Answer 14

an encapsulated gram + bacteria; symptoms begin after DOL 7

Treatment requires Vanc (preferred), clinda, linezolid

often associated with skin and soft tissue infections / omphalitis

Question 15

MRSA Treatment

Answer 15

vancomycin

Question 16

Chlamydia symptoms

Answer 16

can cause opthalmia neonatorum (conjunctivitis) or pneumonia

usually presents between 5-14 days of life ranging from mild eyelid edema to mucopurulent drainage with significant swelling

c. trachomatis pneumonia presents between 2-4 weeks of life

persistant staccato cough, tachypnea, nasal congestion without fever

symptoms occur from

Question 17

Gonorrhea

Answer 17

most common presentation is conjunctivitis with rare dissemination to bacteremia

usually presents between DOL 1-5 w/ profuse purulent drainage, bilateral eyelid edema

Question 18

Syphillis

Answer 18

50% of infants will be asymptomatic at birth

most common symptoms include:

• hepatitis
• hepatosplenomegaly
• radiographic bone changes (periostitis, osteochondritis)
• rash involving palms and soles of feet
• mucocutaneous lesions
• jaundice (both direct and indirect hyperbilirubinemia)
• bone marrow failure (thrombocytopenia, anemia)
• petechiae
• purpura
• snuffles (Rare)

Question 19

Interpretation of NTA syphilis titers

Answer 19

probable - NTA 4 fold maternal result (abnormal exam + positive darkfield test or PCR of lesions/fluids)

possible - NTA less than or equal to four fold maternal result (normal exam and either inadequate maternal treatment or no record OR mother treated less than 4 weeks prior to delivery)

less likely - NTA less than or equal fourfold maternal result (normal exam and both true 1. maternal tx >4 weeks bfeore delivery, 2. no evidence of maternal relapse

unlikely - NTA less than or equal to 4-fold higher than maternal result and normal exam and both true (mother treated adequately, maternal NTA low )

Question 20

Syphillis Treatment

Answer 20

for proven or probable disease

• Aqueous crystalline pcn G 50,000 units/kg/dose IV q12 for 7 days, then q8h for 3 more days
• OR Penicillin p procaine 50,000 units/kg/dose IM once daily for 10 days

for possible

• above options
• if evaluation completely normal - pencillin G benzathine 50,000 units/kg/dose IM x 1 dose

Question 21

Toxoplasmosis

Answer 21

caused by protozoan T. gondii

risk factors include low socioeconomic status, lower levels of education, and having 3+ kittens

3 presentations: subclinical/asymptomatic (79-90% of cases)

neonatal symptomatic disease

Delated onset → occurs w/i first 3 months - behaves like symptomatic disease

Question 22

Toxoplasmosis prenatal presentation on ultrasound

Answer 22

prenatal presentation - intracranial hyperechogenic foci, venticular dilation, anemia, hydrops, ascites, brain, splenic, and hepatic calcification

Question 23

Toxoplasmosis postnatal presentation

Answer 23

MANY HAVE NO SYMPTOMS AT ALL

⅓ present with generalized symptoms

⅔ present mostly with CNS symptoms: classic triad of congenital toxoplasmosis ( 1. chorioretinitis 2.diffuse intracranial calcifications 3. obstructive hydrocephalus)

other symptoms include: pleocytosis (WBCs in CSF), elevated protein count in CSF, microcephaly, seizures, direct hyperbilirubinemia, meningoencephalitis

Question 24

CSF White blood count indicative of meningitis

Answer 24

>1000 / mcl with predominately neutrophils

Question 25

CSF Blood glucose indicative of meningitis

Answer 25

CSF glucose <30 mg/dL in term infants and <20 mg/dL in preterm infants

Question 26

CSF Protein indicative of meningitis

Answer 26

Elevated CSF protein >100mg/dL in term or >150mg/dL in preterm

Question 27

Meningitis treatment for organism suspected to be gram-negative bacilli

Answer 27

Amp + Gent + cefotaxime for csf penetration

Question 28

Cefoxatime

Answer 28

added for treatment of meningitis for extended gram-negative coverage

Question 29

Rubella Symptoms

Answer 29

Cataracts, Glaucoma, SNHL, PDA, Peripheral Pulmonary Stenosis, Radioleucent Bone disease, Blueberry muffin rash, Mental Retardation

Question 30

CMV

Answer 30

Periventricular Calcifications, Retinitis, SNHL, Purpura

Question 31

Syphillis

Answer 31

Meningitis, osteochondritis, snuffles