Infectious Disease And Immunology Flashcards
(170 cards)
1
Q
Encapsulated organisms
A
SHiNS Salmonella H. Influenzae Neisseria S. Pneumo
2
Q
Which serotype of GBS is most often associated with late onset sepsis?
A
Type 3
3
Q
Disorders associated with congenital asplenia
A
Ivemark
Pearson
Smith-Meyers-Fineman
Stormorken
4
Q
Early onset sepsis preterm infants
A
Gram-negative organisms more likely
5
Q
Early onset sepsis in term infants
A
Gram-positive organisms more likely
6
Q
What can cause early pneumonia in a neonate?
A
Aspiration of infected amniotic fluid
Transplacental transmission (syphilis, listeria, TB)
MCC GBS
7
Q
What can cause late pneumonia in a neonate?
A
Ventilator associated pneumonia (ET tube in place)
Previous bacteremia
Usually colonized with bad bugs - pneumococcus, S. aureus, S. pyogenes, H. influenzae, Enterobacter, pseudomonas
8
Q
How do you diagnose pneumonia In a neonate?
A
Very difficult
Worsening respiratory status
Chest x-ray is not pathognomonic
Tracheal aspirates do not really change management
9
Q
Diagnosis of meningitis in a neonate
A
Abnormal CSF count with neutrophy predominance, increase protein, low glucose
Enteric gram neg 30-40%
10
Q
What percent of infants with GBS bacteremia also have meningitis?
A
5-10%
11
Q
What percent of neonates with listeria bacteremia also have meningitis?
A
5-20%
12
Q
What complication do you worry about if a neonate has Citrobacter meningitis?
A
Brain abscess
13
Q
Are UTIs more common in male or female neonates?
A
Males
14
Q
Pathogenesis of UTIs in neonates
A
Urinary tract abnormality 20-50%
Ascending or hematogenous from bacteremia
E. coli causes 80%
15
Q
How long after infection are the bony changes associated with osteomyelitis typically detectable by x-ray?
A
7-10 days
16
Q
Pathogenesis of osteomyelitis in neonates
A
Majority via hematogenous spread
Typically in the metaphyses of long bones (reduced rate of blood flow)
Caused by S. aureus**, E. coli, GBS (majority S. aureus)
17
Q
What symptoms would make you suspect osteomyelitis in a neonate?
A
Pain with passive positional changes
Lack of extremity use
Joint/limb swelling
18
Q
How do you treat osteomyelitis?
A
Vancomycin + Aminoglycoside or 3rd gen cephalosporin
4-6 weeks and resolution of inflammatory markers
19
Q
Complications of osteomyelitis in neonates?
A
Growth plate damage
Avascular necrosis
Limb length discrepancies
Angular joint deformities
20
Q
What type of conjunctivitis does erythromycin prophylaxis reduce?
A
Gonococcal not chlamydial
21
Q
What special media is needed to isolate gonorrhea?
A
Thayer-Martin media
Sheeps blood +4 antibiotics
22
Q
Gonococcal ophthalmia neonatorum
A
2-5 days of life
Profuse bilateral purulent discharge
Ophthalmic emergency - can lead to corneal ulceration/perforation
Treatment with IV ceftriaxone
23
Q
 Chlamydial conjunctivitis
A
5-14 days of life
Begins as clear discharge and progresses to perulant
Treatment with 14 days of oral erythromycin
24
Q
When does Chlamydia pneumonia Present?
A
2-8 weeks of life
Cough/congestion without fever
25
What percentage of neonates develop gonorrhea conjunctivitis if mother is infected?
30-40%
26
What percentage of neonates will develop chlamydial conjunctivitis if mother is infected?
20%
27
Which organism causing conjunctivitis is an obligate intracellular bacteria?
Chlamydia trachomatis
28
Which organism causing neonatal conjunctivitis is a gram-negative intracellular diplococcus?
Neisseria gonorrhea
29
What are symptoms of omphalitis?
Cellulitis - periumbilical erythema/induration, tenderness
| Purulent drainage from umbilical stump
30
Pathogenesis of omphalitis
Dirty cord
Aggressive cord care disrupts barrier
S. Aureus, GAS, GBS, GN bacilli
31
Which serotype of group B strep causes meningitis?
Type 3
32
IAP prevents which type of GBS infection?
Early onset
| No change in late onset
33
What Percentage of staph aureus infections in the NICU are methicillin-resistant?
25%
34
What kind of infections does S. Aureus cause in the NICU
```
Osteomyelitis
Septic arthritis
Pneumonia
Bacteremia/meningitis
Skin and soft tissue infections (SSTIs)
```
35
What is the most frequent single organism isolated in late onset sepsis?
Coag negative staph
36
How does CONS infection present in neonates?
```
Non-specific all the way to frank sepsis
Embolic phenomena
Line infections
Thrombi
Rarely meningitis
```
37
Which strain Of E. coli causes majority of meningitis?
```
K1 strain (80%)
40% of sepsis
```
38
What bacteria can cause noma neonatorium?
Pseudomonas
| Erosion of the gum/tongue, life-threatening
39
Which pathogens are primarily transmitted transplacentally?
Treponema pallidum
Mycobacterium tuberculosis
Listeria monocytogenes
40
What percentage of neonates will acquire syphilis if mother has untreated primary syphilis during pregnancy?
70-100%
41
In utero transmission of toxoplasmosis
Transmission increases with gestation
| Disease is more severe at earlier gestational ages
42
In utero transmission of syphilis
Transmission can occur at any time during pregnancy
| Disease is more severe at older gestational ages
43
In utero transmission of rubella
Transmission to fetus is most likely in early and late pregnancy (U-shaped distribution)
Disease is more severe at younger gestational ages
44
In utero transmission of CMV
Transmission can occur anytime during pregnancy
| Disease is more severe at younger gestational ages
45
What is the most frequent presentation of late onset sepsis with listeria?
Meningitis
46
What is the most frequent presentation of early onset sepsis with listeria?
Pneumonia and sepsis
47
Immunoglobulin concentrations with age
48
Conjunctivitis in first 24 hours
Chemical following prophylaxis
| Spontaneously resolves within 48 hours
49
Conjunctivitis at 24-48 hrs. of age
```
S aureus - Golden crust around eyelids, MCC
GBS
H. influenzae - dacryocystitis
S. pneumo - dacryocystitis
Pseudomonas
```
50
Most frequent viral etiology of conjunctivitis?
HSV
51
Ocular complications of HSV
Conjunctivitis
Keratitis
Chorioretinitis
Retinal dysplasia
52
When does HSV conjunctivitis occur?
4 days to 3 weeks
53
Presumptive exclusion of HIV infection in neonates
1. 2 neg HIV RNA/DNA from separate specimens both >2 weeks of age and 1 at least >4 weeks of age
2. 1 neg HIV RNA/DNA >8 weeks of age
3. 1 neg HIV antibody test >6 months of age
54
How to definitively rule out HIV infection in a neonate?
1. 2 neg HIV RNA/DNA from separate specimens, both >1 month of age, 1 >4 months of age
2. 2 negative HIV antibody tests from separate specimens >6 months of age
55
How can congenital tuberculosis infection occur?
Hematogenous spread across infected placenta
Aspiration of infected amniotic fluid
Ingestion of infected amniotic fluid
56
Treatment of congenital TB infection
Isoniazid
Rifampin
Pyrazinamide
Aminoglycoside
57
Initial drug of choice for neonatal candidal infections?
Amphotericin B
58
Why is liposomal amphotericin B not used in neonates?
Less penetrance into brain and kidney
| Increased liver toxicity
59
Differences in neutrophils between neonates and adults
Neonatal neutrophils adhere poorly to endothelium
Neonatal neutrophils have impaired chemotactic response
Preterm neutrophils have a developmental defect in phagocytosis that corrects at term
Granule contents and degranulation response are similar to those in adults
60
Preterm infants have ____ B-lymphocyte numbers compared to term infants
Significantly lower
61
At birth the proportion of B cells is ____ to adults, but the absolute number of B cells is ____
Similar
| Significantly higher
62
Which type of HSV is responsible for the majority of neonatal infections?
HSV 2
63
What is the most common route of HSV transmission during pregnancy?
Intrapartum 85%
64
Multinucled giant cells on Tzanck smear
HSV
65
Which form of congenital HSV is most common in neonates?
SEM 45%
66
Cluster of grapes on erythematous base
HSV
67
Ideal timing to perform HSV swabs after birth?
12-24 hrs
68
Can maternal RSV infection transmit to fetus?
No because There is no maternal viremia
69
What kind of virus is RSV?
ssRNA
70
What kind of virus is HSV?
dsDNA
71
Viruses causing severe/fulminant hepatitis
Enterovirus > Adenovirus > HSV > CMV
72
What kind of virus is hepatitis B?
dsDNA
73
Which antigen associated with HBV increases the risk of transmission?
HBeAG
74
Timing of hepatitis B immunoglobulin
<2kg HBIG in 12 hrs
| >2kg HBIG in 7 days
75
What type of virus is hepatitis C virus?
ssRNA
76
Risk of maternal fetal transmission of HCV?
5% if mom positive for hepatitis C at delivery
| 10-20% if HIV coninfected and HCV positive at delivery
77
Diagnosis of neonatal HCV
PCR for HCV RNA at 1-2 months of life
| Antibodies after 18 months
78
What kind of virus is hepatitis A?
ssRNA
79
What kind of virus is parvovirus B19?
ssDNA
80
When is parvovirus B19 infectious?
Before rash onset
| Non-infectious after rash appears
81
When does maternal IgG appear during parvovirus infection?
Day two of rash, persist for life
82
What kind of virus is varicella zoster?
dsDNA
83
When is varicella contagious?
1-2 days before rash until all lesions crusted
84
Congenital VZV
<1%
VZV infected mother during first 20 weeks of gestation
Microcephaly, chorioretinitis, intracranial calcification, scarred skin (cicatricial lesions)
85
Perinatal VZV
Five days before and two days after delivery greatest risk
30% mortality rate due to disseminated varicella
Not enough time for antibodies to cross to fetus
86
When to give VZIG or IVIG if VZV +
Premature <28 weeks regardless of maternal history
When mother develops disease 5d before - 2d after delivery
>28 weeks and mother has exposure without h/o disease
87
What kind of virus is rubella?
ssRNA
88
Precautions for congenital rubella syndrome
Droplet until seven days after onset of rash
Contact until one-year-old or 2 cultures obtained 1 month apart after 3 months of age are negative
89
What type of virus is CMV?
dsDNA
90
Intranuclear giant cells
CMV histology
91
Treatment for symptomatic congenital CMV
Valganciclovir for 6 months (start before 1 month of age)
| Improves developmental/auditory outcomes
92
When are neonates tested for HIV?
If mother HIV +
| 48 hours, 14-21 days, 1-2 months, 4-6 months
93
What type of virus is enterovirus?
ssRNA
94
Examples of enteroviruses
Echovirus - sepsis-like, hepatic necrosis
Coxsackievirus - myocarditis (B)
Polio virus - IUFD
95
What type of virus is influenza?
ssRNA
96
Symptoms of congenital cutaneous candidiasis
Diffusely erythematous papular rash at birth
| Can develop vesicles and bullae or look like a burn
97
Risk factors for invasive candidiasis
```
Extreme prematurity
>2 wks of age
Prolonged antibacterial treatment
NICU site
Empiric 3rd gen cephalosporin (x2 risk)
Central lines
Gut injury
H2 blockers, dexamethasone, ET tube
```
98
Evaluation of babies with candidemia
```
LP and culture
UA and culture
Neuroimaging
Eye exam
Ultrasound kidney/spleen/liver
Echo
```
99
Most common species of Candida?
C. Albicans
Most pathogenic
Sensitive to Ampho B and fluconazole
100
Second most common cause of candida?
C. Parapsilosis
20 to 35%
Decrease sensitivity to ampho B
101
What percentage of neonates with invasive candidiasis have Meningoencephalitis?
More than 15%
102
When to use fluconazole prophylaxis?
Facilities were risk of invasive candidiasis is >5% in VLBWs
103
What maternal exposures lead to toxoplasmosis?
New kittens
| Poorly cooked meat
104
Treatment of congenital toxoplasmosis
Pyrimethamine
Sulfadiazine
Folinic acid
105
What drug do you avoid in cases of botulism?
Aminoglycosides
| Can increase neuromuscular blockade
106
What can lead to neonatal tetanus?
Contamination of the umbilical cord
107
Symptoms of neonatal tetanus
Stiffness, rigidity, spasms
108
Symptoms of botulism
Symmetric, descending, flaccid paralysis
109
Spore forming gram-positive rods that grow anaerobically
Clostridium tetani
| Clostridium botulinum
110
What does the tetanus toxin do?
Binds at neuromuscular junction and blocks GABA release
111
Timing of neonatal tetanus infection
3-12 days of life
112
Timing of botulism infection
3 weeks - 6 months
113
Treatment of neonatal tetanus
Penicillin or metronidazole
| You can give neuromuscular blocking agents
114
What is granulomatosis Infantiseptica associated with?
Listeria infection
115
 What type of bacteria is listeria?
Nonspore forming gram-positive rod
116
What maternal exposures can lead to listeria infection?
Soft/raw cheese
Undercooked meats (bears, goat)
Salads
117
Low ANC + high I/T ratio
Infection, autoimmune destruction
| Increased production of immature forms with ongoing destruction of mature forms (not matched)
118
Low ANC + low I/T ratio
Infection, PIH, SGA
| Suppression of production with/without associated consumption
119
Normal ANC + high I/T ratio
Infection, autoimmune state
| Increase production of immature forms but ongoing destruction of mature forms (matched)
120
Normal ANC + low I/T ratio
Normal
121
What is the innate immune system
Performs nonspecific immune response
Acts within minutes of exposure
Includes barriers, inflammatory response factors, and cells
122
Barriers of the innate immune system
Skin
| G.I. and respiratory mucosa
123
How does pathogen recognition occur?
Pathogen recognition receptors aka Toll-like receptors (TLRs)
124
What inflammatory response mediators lead to vasodilation?
Histamine
Prostaglandin
Nitric oxide
Bradykinin
125
What inflammatory response mediators lead to increased vascular permeability?
```
Histamine
Complement
Bradykinin
Leukotrienes
Nitric oxide
```
126
What inflammatory response mediators lead to leukocyte adhesion?
Cytokines
Complement
Eicosanoids (prostaglandins, leukotrienes)
Selectins
127
What inflammatory response to mediators lead to chemotaxis?
Chemokines
Complement
Eicosanoids
128
What inflammatory response mediators lead to fever?
IL-1
TNF-a
Prostaglandins
129
What inflammatory response mediators lead to tissue necrosis?
Neutrophil granules
| Free radicals
130
What inflammatory response mediators lead to platelet aggregation?
Eicosanoids
131
What are eicosanoids?
Prostaglandins
| Leukotrienes
132
What happens in the classical complement pathway?
Antigen antibody complexes are formed leading to complement activation
133
What happens in the MB-lectin complement pathway?
Lectin binding to pathogen surfaces leading to complement activation
134
What happens in the alternative complement pathway?
Complement binds directly to pathogen surfaces leading to complement activation
135
Outcomes of complement activation
Recruitment of inflammatory cells
Opsonization of pathogens
Killing of pathogens
136
Does complement cross the placenta?
No
137
When do adult level/function of complement system develop?
6-18 months of age
138
Genetics of chronic granulomatous disease
```
X-linked recessive
Xp21.1
gp91phox
65-70% of cases
Deficient or absent function of NADPH oxidase
```
139
Symptoms of chronic granulomatous disease
Severe, recurrent infections with catalase positive bacteria or fungi
Negative nitroblue tetrazolium test (remains colorless)
140
Chediak-Higashi Syndrome
Abnormal degranulation
Albinism
Recurrent infections
Giant intracellular granules
141
Monocytes in newborns
Poor cytokine production and antigen presentation in first year of life
Decreased migration
142
Macrophages in neonates
Poor response to IFN-g
| Decreased activation and migration
143
What is the function of B cells?
Produce antibodies
Sometimes need T cell co-stimulation
Neonatal B cells differentiate into predominantly IgM secreting cells
144
Immunoglobulin levels with age
145
What is the only source of IgA initially in newborns?
Colostrum
146
What are the functions of CD4 T cells?
Helper cells- coordinate immune system
Secrete cytokines
Stimulate besels to make IG
Activate macrophages
147
What are CD4 T cells stimulated by?
Cytokines
| Antigen presenting cells
148
What do CD8 T cells do?
Release preforins, degradative enzymes, cytokines
| Cytotoxic activity is limited in neonates
149
When do Predominant antibody defects become more apparent?
After six months of age
150
X-linked agammaglobulinemia
Profoundly diminished immunoglobulin levels
Tyrosine kinase mutation -> B cells can’t become mature
No plasma cells in G.I. tract
Normal T cell numbers
151
Hyper IgM syndrome
```
Low/absent IgG, IgA, IgE
Normal to elevated levels of IgM
Neutropenia
Perirectal abscesses
Oral ulcers
Infection with PCP, cryptosporidium, salmonella
Associated with congenital rubella
70% X-linked
```
152
What antibodies are low in turner syndrome?
IgG and IgM
153
What antibodies are low in trisomy 21 and trisomy 8?
IgG, IgM, and IgA
154
Syndromes associated with defects in cell mediated immunity
```
DiGeorge
Wiskott-Aldrich syndrome
Perinatal HIV infection
SCID
Ataxia telangiectasia
IPEX syndrome
```
155
Symptoms of cell mediated immune disorders
Opportunistic infections
Macular erythematous rash
Hepatitis
Chronic diarrhea
156
Symptoms of Wiskott-Aldrich syndrome
Eczema, thrombocytopenia, increased infections
Platelets small, defective, abnormally shaped
Decreased lymphocytes
Abnormal T cell function
Elevated IgA and IgE
Decreased IgM
Normal IgG
157
Genetics of Wiskott-Aldrich syndrome
X-linked recessive
Xp11.23
WAS gene
158
Genetics of SCID
X-linked -> due to defects in cellular signal transduction
Abnormal purine salvage pathway -> adenosine deaminase deficiency
Omenn syndrome (RAG1/2)
159
Symptoms of SCID
Deficient antibodies and cell-mediated immunity
Diarrhea, pneumonia, otitis, sepsis, cutaneous infections
Eosinophilia
Graft versus host disease following blood transfusion
160
Levels of T regulatory cells in neonates
High, especially in premature neonates
| Decrease to adult levels by 3-6 years of age
161
Metabolic disorders with neutropenia
```
Isovaleric acidemia
Propionic acidemia
Methylmalonic acidemia
Glycogen storage disease 1B
Orotic aciduria
Hyperglycemia
```
162
Syndromes causing congenital neutropenia
```
Kostmann
Pure white cell aplasia
Reticular dysgenesis
Cartilage-hair hypoplasia
Hyper IgM syndrome
Shwachman-Diamond
Dyskeratosis congenita
```
163
Genetics of IPEX syndrome
X linked
| Forkhead box protein three mutation
164
Symptoms of IPEX syndrome
Immunodysregulation, polyendocrinopathy, enteropathy (IPEX)
Impaired Treg suppressor function
Decreased IL-2 and IFN-g production
Severe watery diarrhea, FTT, dermatitis, type 1 DM
Increased IgE levels
Eosinophilia
165
Electrolyte abnormalities with amphotericin B
Hypomagnesemia
| Hypokalemia
166
Placental findings with listeria infection?
Microabscesses
167
Where are B cells produced in utero?
Start in liver at 8 weeks gestation
| By 30 weeks solely produced in bone marrow
168
Immune deficiency in patients with DiGeorge syndrome
Thymic hypoplasia and mild to moderate peripheral lymphopenia (CD3 cells especially)
169
Leukocyte adhesion deficiency
Recurrent bacterial infections
Delete separation of umbilical cord
Neutrophilia
170
What can be done to breastmilk to reduce CMV transmission?
Freezing
| Pasteurization
