
Pediatrics TUCOM Dr.Bahaa
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MENINGITIS
Q1- What are the
most
common signs and symptoms of
meningitis in infants <2 months old?
In general, the findings among neonates and young infants with meningitis are
minimal and often subtle.
1-Temperature instability (fever or hypothermia) occurs in approximately
60% of infected infants;
2-Increasing irritability is present in about 60%,
3-Poor feeding or vomiting in roughly 50%,
4-Seizures in about 40%.
5-Lethargy, respiratory distress, and diarrhea are frequent nonspecific
manifestations of meningitis in this patient group.
On physical examination,
1- 25% of newborns and young infants have bulging fontanels,
2- Only 13% have nuchal rigidity.
The diagnosis of meningitis cannot be excluded based on the absence of these
physical findings in infants.
Q2- What is the percentage of neonates with bacterial sepsis and
positive blood cultures have meningitis.
Up to 25% of infants <28 days old with bacterial sepsis and positive blood
cultures will have culture-confirmed meningitis.
Q3-What is the most common cause of aseptic meningitis?
Aseptic meningitis is defined as clinical and laboratory evidence of
inflammation of the meninges (e.g., CSF pleocytosis and increased protein)
without evidence of bacterial infection on Gram stain or culture.
More than 80% of cases are caused by enteroviruses (i.e., coxsackievirus,
enterovirus, echovirus, and, rarely, poliovirus). West Nile virus is an increasingly
common cause of aseptic meningitis, especially in the late summer and early fall.
Q4- What is the diagnostic test of choice for enteroviral
meningitis?
PCR is highly sensitive and specific, and it is more rapid than viral cultures,
which typically take 2-5 days to become positive.

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Q5-Is intracranial pressure elevated in patients with meningitis?
In acute bacterial meningitis, pressure is elevated in up to 95% of cases.
Elevation is also common among patients with tuberculous or fungal meningitis.
The frequency of elevation in patients with viral meningitis is less well studied.
Q6. Should CT scans be performed before a lumbar puncture
(LP) during the evaluation of possible meningitis?
CT scans are not routinely indicated before an LP, unless one of the following is
present:
1-Signs of herniation (rapid alteration of consciousness, abnormalities of
pupillary size and reaction, absence of oculocephalic response, fixed oculomotor
deviation of eyes) 2-2-Papilledema
3-Abnormalities in posture or respiration
4-Generalized seizures (especially tonic), which are often associated with
impending cerebral herniation
5-Overwhelming shock or sepsis
6-Concern about a condition mimicking bacterial meningitis (e.g., intracranial
mass, lead intoxication, tuberculous meningitis, Reye's syndrome)
Q6. What is the range of values found in CSF of infants and
children who do not have meningitis?
Preterm newborn infants: WBC count, 0-29/mm
3
; protein, 65-150
mg/dL; blood glucose, 55-105 mg/dl
Term newborn infants: WBC count, 0-32/mm
3
; protein, 20-170 mg/dL;
glucose, 44-248
Infants and children: WBC count, 0-6/mm
3
; protein, 15-45 mg/dL;
glucose, 60-90
Q7. If bloody CSF is collected during a lumbar puncture, how is
CNS hemorrhage distinguished from a traumatic artifact?
Most often, the blood is a result of the traumatic rupture of small venous plexuses
that surround the subarachnoid space, but pathologic bloody fluid can be seen in
multiple settings (e.g.,
subarachnoid hemorrhage, herpes simplex encephalitis
).
Distinguishing features that suggest pathologic bleeding include the following:
1-Bleeding that does not lessen during the collection of multiple tubes.
2-Xanthochromia of the CNS supernatant
3-Crenated RBCs noted microscopically

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Q8. How do the CSF findings vary in bacterial, viral, fungal, and
tuberculous meningitis in children beyond the neonatal period?
Although a large overlap is possible (e.g., bacterial meningitis can be associated
with a
low WBC count early in the illness, or viral meningitis can often be
associated with a predominance of neutrophils
early or even persistently in the
illness).
Q9. How is a traumatic lumbar puncture interpreted?
To interpret the number of WBCs in the CSF after a traumatic lumbar puncture,
the following correction factor can be applied. It is important to emphasize that
the corrected WBC count is an estimate and should be considered in the context
of other clinical information.
Table 11-5. TYPICAL FINDINGS IN BACTERIAL, VIRAL, FUNGAL, AND
TUBERCULOUS MENINGITIS
Cerebrospinal fluid findings Bacterial
Viral
Fungal/tuberculous
White blood cells per mm
3
>500
<500
<500
Polymorphonuclear
neutrophils
>80%
<50%
<50%
Glucose (mg/dL)
<40
>40
<40
Cerebrospinal fluid to blood
ratio
<30%
>50%
<30%
Protein (mg/dL)
>100
<100
>100
Q10. When is the best time to obtain a serum glucose level in an
infant with suspected meningitis?
Because the stress of a lumbar puncture can elevate serum glucose, the serum
sample is ideally obtained just before the lumbar puncture. When the blood
glucose level is elevated acutely, it can take at least
30 minutes
before there is
equilibration with the CSF.

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Q11. How often does bacterial meningitis appear in younger
patients with normal findings on the initial CSF examination?
In up to 3% of cases in children between the ages of
3 weeks and 18 months
with
positive bacterial cultures of the CSF, the initial CSF evaluation (i.e.,
cell count,
protein and glucose concentrations, and Gram stain
) can be normal. Of note is
that, in almost all of these cases, physical examination reveals evidence of
meningitis or suggests serious illness and the need for empiric antibiotics.
Q12. Does antibiotic therapy before lumbar puncture affect CSF
indices?
In most cases, shortly after the initiation of antibiotics, the CSF Gram stain still
demonstrates bacteria with typical staining properties, and chemistry values and
cell counts are abnormal. Even when children have received appropriate
antibiotic therapy for
44-68 hours
, chemical and cytologic analysis of the CSF
generally still reflects a bacterial process. In earlier studies of patients with
Haemophilus influenzae meningitis who received oral antibiotic therapy before
lumbar puncture, CSF cultures often grew the organism.
By contrast, there is a
tendency for oral therapy to sterilize the CSF of children with meningococcal
disease or with meningitis because of sensitive Streptococcus pneumoniae.
Q13. What are the most common organisms responsible for
bacterial meningitis in the United States?
0-1month old :
Group B streptococci
Escherichia coli
Listeria monocytogenes
Streptococcus pneumoniae
Miscellaneous Enterobacteriaceae
Haemophilus influenzae (especially other than type b)
Coagulase-negative staphylococci (in hospitalized preterm infants)
1-23Months old
Streptococcus pneumoniae
Neisseria meningitidis
Group B streptococci
2-18 Years old
Neisseria meningitidis
Streptococcus pneumoniae

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KEY POINTS: MINIMAL DURATION OF THERAPY
FOR BACTERIAL MENINGITIS
1.
Five days of therapy for
meningococcal meningitis
2.
Between 7 and 10 days for
Haemophilus influenzae
meningitis
3. Ten days for
pneumococcal meningitis
4.
Between 14 and 21 days for
group B streptococcal or
Listeria monocytogenes meningitis
5. Twenty-one days or more for
gram-negative enteric
bacilli
(after the cerebrospinal fluid has become sterile)
6. Among patients with complications
(e.g., brain abscess,
subdural empyema, delayed CSF sterilization,
persistence of meningeal signs, prolonged fever)
, the
duration of therapy should be individualized and may
need to be extended
Q15. Why are Haemophilus influenzae type B strains more
virulent than nontypeable Haemophilus strains?
H. influenzae type b expresses the type b polysaccharide capsule, which is a
polymer of ribose and ribitol-5 phosphate.
In the absence of type-specific antibody, the type b capsule promotes
intravascular survival by preventing phagocytosis and complement-mediated
bactericidal activity. It is likely that other factors also contribute to the unique
virulence of H. influenzae type b.
Q16. What are the drugs of choice for the empirical treatment of
bacterial meningitis in children >1 month old?
In cases of suspected bacterial meningitis, both
vancomycin and a third-
generation cephalosporin are recommended for empirical therapy
because
resistance to penicillin and cephalosporins is present in
10-30% of Streptococcus
pneumoniae isolates
. The exception is when the Gram stain suggests another
etiology (e.g., gram-negative diplococci). Treatment failures have been reported
when the dosage of vancomycin is
<60 mg/kg/day
. Vancomycin should not be
used alone to treat S. pneumoniae meningitis because data from animal models
indicate that bactericidal levels may be difficult to maintain. The combination of
vancomycin plus cefotaxime or ceftriaxone
has been shown to produce a
synergistic effect in vitro, in animal models, and in the CSF of children with
meningitis.

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Q17. How quickly is the CSF sterilized in children with
meningitis?
In successful therapy, the CSF is usually sterile within 36-48 hours of the
initiation of antibiotics. In patients with meningococcal meningitis, CSF is
typically completely sterile in no longer than 2 hours after starting treatment.
With other organisms, the time until sterilization is generally at least 4 hours.
Q18. How long after treatment has been initiated, must
individuals with meningitis remain in respiratory isolation?
Respiratory isolation is recommended for patients with suspected Haemophilus
influenzae type b or meningococcal meningitis, but it can be discontinued after
24 hours of therapy
.
Q19. What is the accepted duration of treatment for bacterial
meningitis?
The duration of antibiotic treatment is based on the causative agent and clinical
course. In general, a minimum of 5 days of therapy is required for meningococcal
meningitis, 7-10 days for Haemophilus influenzae meningitis, and 10 days for
pneumococcal meningitis. Disease as a result of group B streptococci or Listeria
monocytogenes should be treated for 14-21 days, and meningitis caused by gram-
negative enteric bacilli should be treated for a minimum of 21 days after the CSF
has become sterile. Among patients with complications such as brain abscess,
subdural empyema, delayed CSF sterilization, persistence of meningeal signs, or
prolonged fever, the duration of therapy may need to be extended and should be
individualized.

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Q20. What is the role of corticosteroids in the treatment of
bacterial meningitis?
The inflammatory response plays a critical role in producing the CNS pathology
and resultant sequelae of bacterial meningitis. Several studies have demonstrated
that treatment with dexamethasone
reduces the incidence of hearing loss and
other neurologic sequelae in infants and children with Haemophilus
influenzae meningitis
. For cases of meningitis caused by pathogens other than
H. influenzae, the current recommendations by the American Academy of
Pediatrics are to consider the use of dexamethasone. The role of steroids in
meningitis caused by other bacterial pathogens (particularly Streptococcus
pneumoniae) remains controversial.
Tuberculous meningitis
Generally occurs within
6-8
weeks of primary pulmonary infection or during
miliary tuberculosis (TB).
Commonest in age range
6 months to 3 years
.
Leads to basal arteritis, which may cause hydrocephalus and cranial
neuropathies.
Symptoms:
otherwise are often non-specific, lethargy, fever, headache.
CSF - high white cell count,
predominantly lymphocytes
, raised protein often > 2
g/dl, low glucose, tuberculous cultures may be positive.
Treatment:
1-Antituberculous chemotherapy
2-Optimal treatment not determined
3-Usually triple therapy (rifampicin, isoniazid, pyrazinamide) for at least 6
months but
4-Many authorities suggest a fourth drug for the first 2 months
5-The place of corticosteriods in treatment is unclear but these are often used in
the first few months to reduce inflammation
6-
Mortality and morbidity remain high despite treatment.

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Encephalitis
Numerous viruses may lead to inflammation of the brain: herpes viruses,
adenoviruses, arboviruses and enteroviruses for example.
The underlying causative agent in undiagnosed encephalitis may remain
obscure. It is therefore usual practice to treat with
cefotaxime/ ceftriaxone,
acyclovir and erythromycin/azithromycin until results are available.
Clinical features:
Confusion, coma, seizures, motor abnormalities
Infection usually starts to resolve 7-14 days after the onset. However, recovery
may be delayed for
several months.
Herpes simplex encephalitis: is Common, often-focal
brain inflammation,
located in temporal lobes
. High mortality, high morbidity
(50%)
. Specific
treatment is acyclovir.
Investigations for encephalitis
1-CSF examination/cultures
2-Electroencephalogram
3-Brain imaging
4-Occasionally, brain biopsy
Treatment
1-Supportive (fluid management/ventilation if necessary)
2-Acyclovir

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Immune-mediated and other infectious disorders
1-Sydenham's chorea
Main neurological feature of rheumatic fever
Chorea results from immune reaction triggered by Croup A streptococcal
infection
May be associated with emotional liability
Probably overlaps with PANDAS (psychiatric and neurological diseases
associated with streptococcal infection)
In about
75%
of cases the chorea resolves
within 6 months.
2-Subacute sclerosing panencephalitis:
A slow viral infection, caused by an atypical response to measles infection.
Exposure to measles virus is usually in the
first 2 years
. Risk is higher after
contracting' natural measles, compared with that after measles immunization.
Median interval between measles and subacute sclerosing panencephalitis is
8
years.
Clinical features:
1-Subtle deficits initially
2-Increasing memory difficulties
3-Worsening disabilities - seizures, motor difficulties, learning disability
3-Mycoplasma encephalitis
Mycoplasma pneumoniae is the
commonest cause of community-acquired
pneumonia in adults and commonly leads to infection in the pediatric age
range
. It may cause encephalitis, predominantly through immune-mediated
mechanisms, which may respond to steroid administration. The evidence base is
small.
4-Acquired immune deficiency syndrome
Caused by human immunodeficiency virus, an RNA retrovirus which eventually
leads to the death of its host cell
CD4-positive T lymphocyte.
Neurological features include:
1-Neurological features of opportunistic infection such as meningitis or
encephalitis
2-Dementia
GOOD LUCK