ID/Immunology Flashcards
1
Q
Which bacterial infections can go transplacental?
A
Listeria
Syphilis
TB
2
Q
What is timing for early onsent sepsis? Late onset?
A
EOS: first 72 hours (sometimes first 6 days)
Late: 7-90 days (may be later in preemie)
3
Q
What has greater mortality, early or late sepsis?
A
Early - mortality 15-45%
Late - mortality 10-20%
4
Q
What are top 2 causes of EOS? Late?
A
Early: 1. GBS 2. E coli
Late: 1. Staph epi 2. S aureus
5
Q
What is the most common etiology for osteomyelitis in neonates? Most common site?
A
Hematogenous spread
Site (metaphysis): 1. Femur 2. Humerus
*usually multiple bones
6
Q
What is most common bacteria im osteomyelitis?
A
Staph aureus (way less common… GBS, E coli) Of note: GBS osteo 3-4 wks, humerus
7
Q
How long until xray findings in osteo? How many with pos bcx?
A
7-10 days
60% with positive bcx
8
Q
What are most common organisms in omphalitis?
A
- S aureus
- Group A strep
Others: gram neg bacilli, anaerobes
Via direct invasion by skin
9
Q
When does most meningitis occur? Most common organisms?
A
During first month of life (premature 10x risk)
Organisms: 1. GBS 2. E coli (K1 antigen) 3. Listeria
10
Q
Do males or females get UTI more common in neonates? Which org?
A
Males
E coli (then Klebsiella, enterobacter)
Hematogenous or ascending, often anomalies
11
Q
What does GBS look like on gram stain?
A
Gram positive diplococci in chains
12
Q
Which GBS serotype causes most late onset sepsis?
A
Serotype III
13
Q
Is there more meningitis in Early or late GBS infection?
A
Late: 30-40% meningitis
Early: 5-10%
Early is more often pna (35-55%) and sepsis (25-40%)
14
Q
What is gram stain of Listeria? Sx?
A
Gram positive rod Granulomatous rash Placental microabscesses Inc risk of stillbirth/miscarriage Via transplacental route
15
Q
How is congenital syphilis transmitted?
A
Transplacental (greater GA, greater risk of infection) Risk: Untreated primary - 70-100% Early latent - 40% *30-40% infected fetuses are stillborn
16
Q
Sx of congenital syphilis?
A
2/3 asymptomatic Large placenta HSM Snuffles Wimberger sign (destruction of medial metaphysis tibia > humerus)
17
Q
Will treponemal or non-treponemal be pos for life? What do they test for?
A
- Treponemal pos for life (FTA-ABS)
- Non-treponemal (RPR or VDRL) tests for cell membrane cardiolipin nonspecific IgG Ab, sign of response to host tissue damage, gives titer
Treponemal: detects specific Ab (IgG or IgM) to Treponema pallidum
18
Q
What is appropriate response in maternal titers to syphilis tx?
A
Four fold decrease
19
Q
What is gram stain for Neisseria gonorrheae?
A
Gram negative intracellular diplococci in pairs
20
Q
What are sx of gonorrhea in neonate?
A
Most common: arthritis
Others: conjunctivitis, scalp abscess (fetal monitor), pna, sepsis
21
Q
What type of growth medium do you need to culture gonrrhea?
A
Thayer-Martin growth medium (need to plate rapidly)
22
Q
What is rx for gonorrhea in neonate?
A
If born to untreated mom: 1 IM CTX
Conjunctivitis: 1 IV CTX
Systemic: 7+ days cephalosporin
23
Q
What does chlamydia look like on gram stain? What kind of stain is needed?
A
Gram negative cocci but Very hard to gram stain, obligate intracellular bacteria
Stain: Giemsa stain
24
Q
What are sx of chlamydia pneumonia?
A
5-20% of pts with chlamydia, 4-12 weeks with staccato cough
70% have Eosinophilia (50% with hx of chlamydia conjunctivitis)
25
Can mother breatfeed on isoniazid?
Yes, it latent. Infant needs pyridoxine.
26
When should infant exposed to TB have PPD?
3-4 months (wont be positive before)
27
What do you use to treat neonate with TB?
```
Isoniazid
RIF (turns body fluid orange)
Pyrazinamide
Aminoglycoside
If meningitis: steroids (shown to reduce mortality and NDI)
```
28
What is gram stain and pathophysiology of botulism?
Anaerobe, gram positive bacillus
Toxin inhibits release of acetylcholine from nerves
Need human-derived botulinum antitoxin **dont give aminoglycosides (will make worse, inc neuromuscular blockade)
29
What is prognosis/recovery for botulism?
Several weeks, toxin binds irreversibly
30
What bacteria typically cause brain abscesses?
Citrobacter and Enterobacter
31
What disorder gives you an increased risk of E coli UTI?
Galactosemia
32
What antibiotic may be needed in gram neg that produce extended spectrum beta lactamases?
Meropenem
33
What is rate of neonatal hsv if genital lesions at delivery and primary hsv? Same but recurrent hsv? Which is more common?
Primary with lesions: 25-60% will be infected
Recurrent: <5%
*exposed to recurrent mothers more common, 50% of neonatal hsv born to secondary HSV mothers
>75% neonates w HSV asymptomatic mothers or without known hx (75% due to HSV2)
34
What is the common histology finding of hsv?
Multinucleated giant cells
| Also: eosinophilic intranuclear inclusions vis Tzanck smear
35
What is most common presentation of neonatal HSV disease? Highest mortality? Worst outcome?
Common: Skin, eye, mucous mem (SEM) 40-45% (disseminated 20%, CNS 30-35%)
Mortality: Disseminated (30%) (minimal if SEM, and 4-10% CNS)
Outcome: CNS worst (30% normal), disseminated 30-80% normal, SEM >90% normal
36
What is length of treatment for hsv SEM, disseminated and CNS?
Acyclovir 14 days SEM
| 21 days CNS or disseminated
37
What is mechanism of action of acyclovir?
Inhibits viral DNA replication
| Activated by thymidine kinase
38
What type lf virus is RSV? Which strain more common? Can transmit to fetus?
RSV is an RNA paramyxovirus
Strain A more common
Cannot transmit to fetus (no viremia)
39
What type of virus is hep B? When is greatest transmission time? What impacts transmission risk?
Double stranded DNA
Greatest transmission at birth
If Hep BeAg present, 10–>85% chance of transmission (bc high amt replication)
40
What type of virus is hep D? Whats unique?
Defective RNA virus, only can infect with hep B (needs hep B surface antigen for its surface coat)
41
What type of virus is hep C? Rate of transmission from mother?
Single stranded RNA
| Rate of transmission 5% (higher if mom has hiv also, liver disease, or high viral load)
42
What type of virus is hep A?
Single stranded RNA
| Fecal/oral transmission (perinatal rare)
43
What type of virus is hep E?
RNA, rare in US. Very high mat mortality (20%) and stillbirth/prematurity. Does NOT cause chronic hepatitis
44
What type of virus is Parvovirus B19?
Single stranded DNA
Diagnose by mat IgM levels or PCR amniotic fluid/fetal blood
Can cause hydrops, myocarditis, low plts, neutropenia, liver disease. *majority normal *
45
What type of virus is Varicella-zoster virus? When is worst time for maternal infection?
DNA herpes virus
Worst time: 5 days before delivery to 2 days after (not enough time for antibodies to cross placenta) 17% chance of acute infection with 30% mortality
46
When is highest risk of congenital varicella syndrome? What are sx?
First 20 weeks gestation
| Limb abnormalities, scarring, severe mental deficiency, intracranial calcifications
47
What are indications for varicella zoster immunoglobulin?
1. Mom develops VZV 5 days before to 2 days after delivery.
2. 28 weeks or more with sig exposure only if mom nonimmune
3. <28 weeks if sig exposure
48
How do you treat neonatal varicella infection? What is isolation need?
Acyclovir (higher dose than for HSV)
| Isolation: airborne and contact
49
What type of virus is Rubella? When is infection greatest risk to fetus? When is greatest risk of fetal infection?
RNA virus
Infection greatest risk: before 20 weeks (earlier=worse). 1-12 wks=85% chance of anomalies. <10 wks: 100% cardiac and deaf
Risk of infection inc w GA, 100% born after 36 weeks infected. (But dont have anomalies)
50
What are typical sx of congenital rubella syndrome?
```
Sensorineural hearing loss - 60%
Salt and pepper chorioretinitis
Cataracts
Blueberry muffin rash
Cardiac (most common torch with cardiac)
```
51
How do you diagnose rubella?
```
Fetal: fetal IgM from cord blood
Neonate: viral culture (NP, blood, csf, urine). Also IgM serum, will have abnormal long bone films.
Hemagglutinin inhibition (used to determine mat status, if inhibited=rubella Ab present)
```
52
How long is congenital rubella contagious? Postnatal?
1 year congenital
| 7 days after rash for postnatal
53
What is the most common intrauterine infection worldwide? What type of virus?
CMV, double stranded DNA herpes virus with intranuear and cytoplasmic inclusions
54
What is risk of primary maternal CMV if non immune? Risk of transmission? Risk of sx?
1-4% pregnant women will be infected
40% fetuses infected
85-90% infants asymptomatic but 5-15% with sequelae
Of 10-15 % symptomatic, 90% with sequelae
55
What isolation is needed for CMV?
None, standard precautions
56
What causes toxoplasmosis?
Protozoal organism, intracellular parasite (Toxoplasma gondii)
From undercooked meat and cat feces
57
What is common presentation of congenital toxo?
70-90% asymptomatic at birth
Those w sx: chorioretinitis (80%), iugr, microcephaly, cortical brain calcifications
** many will have poor neurologic outcome, improved if treated
58
How do you treat maternal toxo? Neonate tx?
Maternal:
1. If primary toxo, use spiramycin to dec trasmission rate (will not help if fetus infected already)
2. If fetal infection confirmed after 17 wks or if maternal 3rd tri infection, tx with pyrimethamine and sulfadiazene (reduce fetal effects)
Neonate: tx with pyrimethamine and sulfadiazene x 1 year (symptoms or not). Give folic acid to prevent neutropenia.
59
What are distinguishing feature or rubella? CMV? Toxo?
Rubella: cataracts (50%) and heart disease (75%)
CMV: periventricular calcifications (15%), microcephaly, more HSM/jaundice
Toxo: cortical calcifications (45%), chorioretinitis (90%!)
60
What type of virus is HIV? What cell does it infect
Retrovirus (RNA virus with its own reverse transcriptase)
| CD4 cells
61
How do you diagnose HIV in neonates?
HIV-1 DNA PCR (preferred test <18 months)
30-40% will have positive by 48 hrs, 93% by 2 weeks, 95% by 1 month
*dont use cord blood *
An infant is considered infected if 2 DNA pcrs are positive
62
When is HIV-1 rna pcr helpful?
If elevated, can be diagnostic of HIV
Most helpful to monitor disease progression by quantifying viral load
If negative, does NOT exclude HIV (need hiv dna pcr)
63
What do you use for neonatal hiv ppx after maternal infection?
Zidovudine (ZDV aka AZT)
| *all neonates hiv exposed should get bactrim starting at 1 month for PCP ppx
64
What type of virus is enterovirus? What are examples?
Single stranded rna virus
| Ex: echovirus, coxsackievirus, polio, enterivirus
65
What is impact of maternal polio? Maternal coxsackie?
Polio: inc spont abortions (mostly 1st tri), no cong anomalies, small inc prematurity
Coxsackie: no inc risk of abortion, possible inc risk anomalies. Small inc prematurity
66
What is outcome of neonatal polio? Neonatal echovirus?
Polio: severe, 50% mortality, 1/2 survivors w paralysis
Echovirus: type 11 terrible, often fatal, sepsis w hepatic necrosis, dic
The other enteroviruses are not so bad. If life-threatening, consider IVIG
67
What type of virus is rotavirus?
Double stranded RNA
Fecal/oral
Can give first dose until 14w6d of age
Intestinal lactase may be receptor, may be why preemies have less disease
68
When does congenital cutaneous candidiasis occur?
Rare, at birth or within hours
From ascending intrauterine infection
Erythemagous generalized maculopapular rash that CAN involve palms and soles
69
How to treat systemic candida? What’s different if meningitis?
Amphotericin B
| If meningitis, need second agent (amph B CSF penetration is 40-90% plasma levels). Can use fluconazole or flucytosine
70
What is liposomal amphotericin B? Benefits? When not to use?
Less nephrotoxicity, can treat systemic.
| Do NOT use if renal involvement or meningitis (doesnt penetrate well)
71
What is incidence of asymptomatic bacteriuria during pregnancy? Likelihood of developing symptomatic UTI? Most common org?
```
Asymptomatic - 4-7% (25% of those will develop symptomatic UTI)
E coli (80-90%)
```
72
What is most common pathogen in mastitis?
```
S aureus (then coag neg Staph, Strep viridans)
10% develop abscess (esp if S aureus)
```
73
What type of bacteria causes pertussis? How to diagnose?
```
Gram negative pleomorphic bacillus
Bordatella pertussis
Whooping cough
Rx: oral erythromycin (if given after cough presents wont alter illness, only infectivity)
Dx: Bordet-Gengou medium
```
74
What causes tetanus? What is pathophysiology of symptoms? What is treatment?
Clostridium tetani
Gram positive bacillus (anaerobe)
Sx secondary to toxin, decreases acetycholine release
Treatment: tetanus immune globulin, 10-14 days pen G ** still will need vaccine
75
What are differences between maternal mumps vs measles infection?
Mumps: increased risk of abortion (1st tri); no real congenital sx or anomalies. Not transplacental.
Measles: no inc risk of abortions; no anomalies, some inc prematurity. IS transplacental. Worse sx with congenital, pna, encephalitis, koplik spots. Fever, cough, conjuntivitis.
76
What is a bacteriostatic agent in breast milk?
Lactoferrin (also lactoperoxidase but needs hydrogen peroxide and thiocyanate for antibacterial effect)
77
What are examples of bacteriostatic antibiotics?
```
Erythromycin (binds reversibly to 50S subunit of ribosome, inhibits protein synthesis)
Clindamycin
Chloramphenicol
Tetracycline
Sulfonamide
```
78
What are bactericidal antibiotics?
Penicillins (inhibit bacterial enzymes, penicillin binding proteins, block production of peptidoglycan - needed for cell wall)
Cephalosporins (inhibit cell wall synthesis)
Aminoglycosides (bind 30S subunit ribosome, inhibit protein synthesis)
Vancomycin (inhibits peptidoglycan sythesis in cell wall, but enterococcus bacteriostatic)
Quinolones (inhibit DNA gyrase)
79
What does minimal inhibitory concentration (MIC) mean?
Degree of antibiotic activity
Lowest antibiotic concentration that inhibits in vitro visible growth
Does NOT correlate with potency
80
What is the minimal bactericidal concentration (MBC)?
Lowest antibiotic concentration that kills (reduces growth by 99.9%). This is usually equal to MIC in bactericidal, and much higher than MIC in bacteriostatic
81
What is the major component of IVIG?
95% IgG (trace IgA and IgM)
From pooled adult plasma
Give IM for hep A and measles
82
Which diseases have a specific immune globulin?
```
Hep
Rabies
Tetanus
VZV
CMV
RSV
```
83
What is a contraindication to IVIG?
IgA deficiency with antibodies to IgA
84
Where does immune system start?
Yolk sac - 3 weeks GA
Fetal liver 8 weeks
Bone marrow 5 months
85
Are T and B cells part of innate or acquired immune system?
Acquired
| Innate: Neutrophils, monocytes, complement
86
What are sx of Leukocyte adhesion deficiency?
Delayed sep umbilical cord (>21 days)
No pus
High WBCs and neutrophils (cant get out of bloodstream)
87
What is hyper-IgE syndrome?
Aka Jobs syndrome
Disorder of neutrophil chemotaxis
Recurrent infections of skin, course face, broad nose, eczema
88
What is chronic granulomatous disease?
X linked
Abnormal NADPH oxidase and abnl phagocytic ability. Normal B and T cells
Perirectal abscesses, poor wound healing
*diagnosed by nitroblue tetrazolium aka NBT test (negative in CGD, need other persons blood sample)
89
What is Chediak-Higashi?
Abnormal neutrophil degranulation
| Albinism, nystagmus, recurrent infections
90
What disorders cause decreased neutrophil production?
1. Shwachman-Diamond syndrome (AR, steatorrhea, FTT)
2. Kostmann syndrome (severe cong neutropenia, AR, freq infections)
3. Reticular dysgenesis
91
What is the role of the spleen in immunity?
1. Synthesis of Ab against carbohydrate antigens
2. Clears microorganisms from blood
Without, inc risk infection and mortality (usually pneumococcal, also meningococci, e coli, h flu, staph)
92
What is Leiner syndrome?
Complement 5 abnormality
Diarrhea, recurrent infections, FTT
Generalized erythematous desquamative dermatitis
93
What is hereditary angioedema?
Autosomal dominant
| Absence of esterase inhibitor, recurrent swelling
94
What activated natural killer cells?
Interferon- alpha
95
What syndromes causes congenital asplenia?
1. Ivemark syndrome
2. Pearson syndrome
3. Smith Meyers Fineman syndrome
4. Stormorken syndrome
