CNS infections 1 Flashcards
Most Common Agents of Congenital Infections
TOxoplasma,
Rubella,
Cytomegalovirus [CMV],
Herpes simplex virus [HSV]) -2 or -1
TORCH test: a series of tests for specific IgM in chord blood
(may be STORCH: syphilis)
one more: Lymphocytic choriomenigitis virus (LCMV)
HSV infections cause infection and morbidity in neonates:
areas ?
Skin, Eye, Mouth
CNS disease
Disseminated disease with or without CNS disease
the leading cause (by far) of infection and morbidity in the neonate
CMV
40,000 neonates born in US/yr affected–>sequelae (hearing loss, vision loss, and cognitive impairment) in 1/5th of cases
nosocomial-acquired meningitis orgs
*half of all meningitis cases in US
Gram-positive cocci:
Staphylococcus aureus
coagulase-negative staphylococci
non-pneumococcal streptococci
Gram-negative rods
Predisposing conditions for Nosocomial-acquired meningitis
recent neurological procedures.
presence of neurological devices.
altered immune status
??? is NOT a portal of entry for viral infection
the brain
Infection in the CNS is usually a secondary infection, occurring days, weeks, months, or years after the initial infection
bacterial meningitis vs. viral meningitis
less common
used to be more but now we vaccinate against mumps?
many not def. ddx
devastating sequelae
bac meningitis neonate orgs
Streptococcus agalactiae, Escherichia coli
K. pneumoniae
bac meningitis infant and young kiddo orgs
N. meningitides
S. pneumoniae
Myobacterium tuberculosis.
bac meningitis adolescents →Elderly orgs
N. meningitides
S. pneumoniae
> 50-y-o: L. monocytogenes
The problem for the physician is to differentiate between bacterial pyogenic/purulent meningitis, which is a ?? and ?? viral meningitis
medical emergency
benign
Symptoms of bacterial meningitis in the older child → adult include acute onset of:
*irritability
*lethargy (altered mental status)
*fever
severe headache
nuchal rigidity
vomiting
opisthotonos
pressure on eyeball
photophobia
the single most important predisposing factor for meningitis in the neonate
Low birth weight
Low birth weight (LBW;
What factors predispose the LBW, VLBW, and ELBW infant to infection?
Impaired innate and adaptive immune functions
if Require nosocomial techniques and devices to keep alive
Incidence of sepsis is much higher
Maternally related events allow agent access to fetus before birth or during parturition
Impaired innate and adaptive immune functions
Antibodies production and PMN (both in number, function) are poor in newborn, especially in prematurely born infants
nosocomial techniques and devices
Are often kept in 80% humidity, an environment where bacteria & fungi flourish. Presence of multiple invasive devices: catheters feeding tubes suction tubes
Maternally related events allow agent access to fetus before birth or during parturition, such as
Premature rupture of membranes, esp. for greater than 24 hours.
Maternal infection during last week of pregnancy, e.g., vaginosis, UTI cervicitis chorioamnionitis
Excessive manipulation during delivery
Use of intrauterine monitoring devices
Sources of etiologic agent:(neonate meningitis)
Infection acquired in utero (Common source):
From infected chorioamnionic and amniotic fluid.
From infected blood – via chord blood – transplacental transmission.
Infection during parturition, aspiration of infected vaginal secretions (Common source).
Infection acquired hours → days post-partum from caregiver(s).
Signs and symptoms of meningitis in the neonate are not the same as the adult and include:
Fever
Lethargy
Poor feeding
GI disturbance (vomiting/diarrhea)/abdominal distension
Respiratory abnormalities (e.g., dyspnea, cyanosis)
Cardiac abnormalities (tachycardia)
Bulging fontanelle
neonatal meningitis px
generally poor, mortality rates vary from 10-60% with survivors showing some permanent defects (neurological sequelae) which may be significant
Streptococcus agalactiae - Group B Streptococci (GBS):
Gram-positive cocci in chains or pairs (AKA streptococci).
β-hemolytic on sheep blood agar via production of the ornithine rhamnolipid pigment or lipid toxin.
Bacitracin-resistant versus GAS, which is bacitracin- sensitive
S. agalactiae group based on ??
cell wall antigen
Lancefield’s serological classification based primarily on cell wall carbohydrate (C carbohydrate, teichoic acids). Groups A→T. Groups A, B, D are clinically important.
S. agalactiae also serologically typed based on ??
capsular polysaccharide:
Major virulence factor –
There are several (9) groups:
Five groups (especially Group III) are most common causes of both early and late onset disease.
S. agalactiae is the leading cause of ?? alone or with ?? within the first 3 months of life
bacteremia
meningitis and/or pneumonia as complications
Incidence is highest in pre-term, but most (75%) cases occur in full-term infants (more of those guys)
1/3 of all invasive GBS disease occurs in ??
pregnant women (Maternal UTI caused by GBS frequently occurs before or just after birth).
adults, esp. elderly can also get GBS
usually with chronic or immunosuppressive disease:
persons > 60 y-o-age is high (4 → 7 cases/100,000 population) with a high (25%) mortality rate.
Diabetes, cirrhosis, malignancy, AIDS.
*Clinical GBS syndromes occur in virtually all tissues/organs
GBS Transmission and Reservoir:
Vertical infection occurs before and/or during birth
Horizontal infection (mother/caregiver → newborn) occurs after birth.
Agent colonizes mother’s pharynx, vagina, and skin via rectal colonization:
- Not all gravid females are colonized by GBS.
- Not all gravid females colonized by GBS pass it to the neonate.
- Not all neonates carrying GBS become infected/diseased.
*no seasonality
Two forms of neonatal disease are recognized:
Early (acute) onset sepsis (bacteremia)
Late (insidious) onset sepsis (bacteremia or focal infection)
Early (acute) onset sepsis (bacteremia):
Occurs within the first 6 days after birth.
Source is mother, infection is acquired in utero or via passage through birth canal.
More common form of disease (80% of cases)
Late (insidious) onset sepsis (bacteremia or focal infection):
Occurs 7 days → 3 months following birth.
Source: associated with postpartum acquisition in the nursery (care givers) or community or mothers.
Focal infections include: meningitis cellulitis osteomyelitis septic arthritis.
Less common form of this disease (20% of cases)
