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Pediatric pyogenic meningitis

pyogenic meningitis

Pyogenic meningitis

•Meningitis is defined as inflammation of membranes surrounding the brain and spinal cord

•Meningoencephalitis is inflammation of meninges and brain cortex

pyogenic meningitis

pyogenic meningitis

Incidence and etiology•Bacterial meningitis is commonest in infancy

•May result in death within hours of onset if not treated

•Responsible for 3% hospital admissions

•More frequent in infant males

•Any organism can cause meningitis

•Great risk during 6-12 months and 95% cases occur between 1month and 5years

pyogenic meningitis

Causative agents for different ages

pyogenic meningitis

Age Causative agents0 – 2 months •Escherichia coli

•Group B streptococci•Staphylococcus aureus•Listeria monocytogenes

2months – 2 years •Haemophilus influenzae type b•Streptococcus pneumoniae•Neisseria meningitides

2 years – 21 years •Neisseria meningitides (serotypes A, B, C, Y and W 135)•Streptococcus pneumoniae (serotype 1, 3, 6, 7, 14, 19, 21, 23)•Haemophilus influenzae

Streptococcus pneumoniae

Pathogenesis•Causative agent enter CNS via blood or direct invasion

•Anatomic or congenital defect can also cause invasion

•Inflammation of meninges initiated when cell elements of organism disrupt blood brain barrier

•Followed by outpouring of polymorphs and fibrin

pyogenic meningitis

•Release of cytokines and chemokines in CNS stimulated by bacteria

•Meninges become swollen, inflamed and covered in exudates

•Early in illness cerebral edema present and ventricles reduced in size

•Pressure on peripheral nerves may lead to motor or sensory deficit

•Communicating hydrocephalus due to adhesive thickening of arachnoid in basal cisterns

pyogenic meningitis pathogenesis

•Obstructive hydrocephalus due to fibrosis blocking aqueduct of sylvius or foraminas

•Affected cranial nerves cause deafness and vestibular problem

•Cerebral vessels and cranial nerves can be involved and may lead to permanent neurologic damage

•Cerebral atrophy by thrombosis of small cortical veins


•Inflammation involving veins crossing subdural space lead to increase in vascular permeability and loss of albumin into subdural space

•Hypoglycorhacia by decreased transport of glucose across the inflamed choroid plexus and increased use by host

•Seizures by electrolyte imbalance ultimately depolarization of neuronal membranes


Clinical features

Meningitis always must be considered in any young infant whose temperature is greater than 100.7°F (38.2°C) and who has no obvious site of infection

pyogenic meningitis

Neonates and infants•Gram negative organisms are commonly responsible

•Infective illness in mother, prolonged rupture of membranes or difficult delivery put the newborn at risk

•Premature infants have low level of antibodies

•Predisposing factor is spina bifida or dermal sinus

pyogenic meningitis

•Initial signs are subtle

•Fever occurs in 50% of cases

•Infant is ill looking and feeds poorly

•May develop vomiting, hypothermia, lethargy, convulsions

•Has bulging anterior fontanelle, head retraction and high pitch cry

pyogenic meningitis neonates and infants

Older children•Classic signs preceded by upper respiratory or GIT symptoms

•High grade fever, head ache and projectile vomiting

•Seizures are common

•Increased CSF pressure leads to bulging fontanelle and diastasis of sutures

pyogenic meningitis

•Neck stiffness, positive kerning's sign and brudzinski’s sign

•Cranial nerve palsies and papilledema

•Hemiplegia in cases late reported, ataxia may also be present

•Patient may be semi comatose or comatose

•Meningococcal meningitis is characterized by the presence features of Waterhouse Friderichsen syndrome

pyogenic meningitis older children

•Otitis media and mastoiditis is likely to lead streptococcal or pneumococcal meningitis

•Staphylococcal infection is likely following surgical procedures, skull fractures or skin infections

•If there is no specific sign between 6months – 2years then H. influenzae is the cause

•Onset of clinical signs is sudden in meningococcal and S. pneumoniae infection

pyogenic meningitis in older children

InvestigationsLumbar puncture•CSF pressure should be noted, fundi checked for papilledema

•Xanthochromia due to jaundice, bilirubin from hemorrhage or increased protein

•If lumbar puncture is traumatic; one leukocyte per 700 RBC in CSF is subtracted and 1 additional mg protein is added in CSF protein for 800 RBC

pyogenic meningitis

•CSF glucose should be compared to blood glucose, CSF glucose is 2/3 of blood glucose

•In CSF of neonates normally there are up to 30 lymphocytes and 150mg/dl protein

•Gram stain is important to recognize the causative agent

pyogenic meningitis investigations LP


CSF findings in various CNS disorders

Conditon Color Leucocytes Protein mg/dl Glucose mg/dl

Normal Clear 0 – 5 60 – 70% lymphocytes

20 – 45 >50 or 75% of blood glucose

Acute bacterial meningitis

Opalescent to purulent

100 – 20000PMN predominate

100 – 500 <40May be none

Tuberculous meningitis

Opalescent 10 – 2000PMN early but lymphocyte later

>50 <40May be none

Viral encephalitis

Clear 5 – 500Mostly lymphocytesPMN early

30 – 150 30 – 70


Gram staining

Meningococci Gram negative intracellular diplococci

Pneumococci Gram positive diplococci

H. Influenzae Gram negative coccobacilli

E. Colli Gram negative bacilli

Contraindications for immediate LP

•Increased ICP especially with focal neurologic deficits

•Severe cardio pulmonary compromises

•Infection of skin overlying the site of LP

•Bleeding or clotting disorder


Recommendation for repeat LP at 24 – 36 hours

•All neonates•Meningitis caused by S. pneumoniae and gram negative enteric bacilli•Lack of cranial improvement in 24 – 36hours after therapy•Prolonged or second fever•Recurrent meningitis•Immunocompromised patients


CSF culture The yield of CSF culture decreases soon after antibiotic therapy has been started. More sensitive technique, polymerase chain reaction may help to diagnose cases of bacterial meningitis in patients treated by antibiotics

Blood culture90% H. influenzae and 80% S. pneumoniae

pyogenic meningitis investigations

Blood countsTotal and differential leukocyte count; generally there is leucocytosis with predominant polymorphs

X – ray chest To rule out TB and pneumonia

CT scan


Indications for CT scan•Newborn except for disease caused by listeria •Prolonged comatose condition•Seizures 72 hours after start of treatment•Continued excessive irritability•Focal neurologic findings•Persistently abnormal CSF findings•Relapse or recurrence


Rapid diagnostic tests•Concurrent immuno electro phoresis•Latex particle agglutination•ELISA to detect bacteria antigen in CSF•CSF lactate level •Enzyme radioisotope to detect activity of ß lactamase in CSF

Gram stainingSmears of petechial or purpuric lesions on skin


Differential diagnosis•Tuberculous meningitis•Aseptic meningitis•Brain abscess•Brain tumor•Cerebral malaria

pyogenic meningitis

Management

Supportive measures•Vitals recorded every 15 – 30 minutes until patient is stable

•Neurologic examinations and seizure evaluation

•Measure head circumference in children <18 months

•Intake and output record

pyogenic meningitis

•Body weight, serum electrolytes monitored 12 hourly

•For fever sponge and give antipyretics

•Feeding continued and give tube feeding if necessary

•Fluid restricted to 60%, not indicated in hypotension

•Care of comatose patient

•IV diazepam for seizures, phenobarbitone for recurrent seizures

pyogenic meningitis management supportive

Specific measures

Antibiotics•Appropriate antibiotic given by culture report

•Term infants in 1st month given combo of ampicillin with gentamicin or cefotaxime

•Low birth weight preterm infants presenting late should be given vancomycin and an aminoglycoside

pyogenic meningitis management

•1 – 2 month infants given ampicillin ad ceftriaxone

•Resistant strains treated with vancomycin alternatively meropenem

•Duration of therapy is 7 – 10 days

Steroids •Dexamethasone for 2 – 4 days

•Given before antibiotic is started for good result

pyogenic meningitis management specific

Treatment of complications

Cerebral edema and raised ICP•Head elevated about 30°

•Steroids for reducing inflammation and brain water content

•Mannitol

Subdural effusion•Symptomatic effusion should be aspirated

pyogenic meningitis management

Subdural effusion

Inappropriate ADH secretion•Hyponatremia, coma, seizures, weight gain, puffiness of face, decreased urine output

•Treated with fluid restriction and diuretics

Waterhouse Friderichsen syndrome•Patient in shock with hypotension petechial rash

•Give normal saline/plasma, steroids and dopamine infusion

pyogenic meningitis management treatment of complications

Waterhouse Friderichsen syndrome

Complications of meningitis

pyogenic meningitis

Increased ICP Cranial nerve palsies

Seizures Stroke

Ataxia Inappropriate ADH

Prolonged fever >10days Rapidly increasing head circumference

Subdural effusions Spastic paraparesis

Blindness Cerebral infarcts

Anemia Cerebral herniation

Long term neurologic abnormality Epilepsy

Deafness Spasticity

Visual handicap Repeated episode

Prognosis

•Worse prognosis in young children with higher bacterial colony counts, intractable seizures, subdural effusion, bacteremia and prolonged fever, thrombocytopenia, low ESR, absence of leukocytosis, DIC, rapidly progressive purpura in 12hours, hypotension or coma

•Mortality rate is 8 – 25%

•35% have permanent deficit

pyogenic meningitis

Prevention

Vaccination•Vaccines available against S. pneumoniae, N. meningitides and H. influenza type b

•Pneumococcal polysaccharide vaccine available

•Meningcoccal vaccine for high risk group and children

•H. influenza vaccine given for all >2months infantspyogenic meningitis

Antibiotic prophylaxis

MeningococcalThe dose of rifampicin recommended is 10mg/kg given 12hourly for 2days

H. InfluenzaeRifampicin 20mg/kg/day for 4 daysFor all house contacts and patient

Streptococcus pneumoniaeNo prophylaxis

pyogenic meningitis

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pyogenic meningitis