MENINGITIS

Dr. Opiro Keneth

• Definition:- Inflammation of the leptomeninges

• Importance:- Significant cause of morbidity and mortality among children. 426,000 children are affected annually, with 85,000 deaths.

Overall mortality rate is 5 – 10%: 15 – 20% in neonates, 3 -10% in older children.

Mortality rate from S.pneumoniae is 26.3 – 30%, H. influenza type B is 7.7 – 10.3, N. meningitidis is 3.5 – 10.3%

- High frequency of neurologic sequelae: up to 30%, highest with S pneumonia.

- Classical symptoms and signs may not be present in neonates and infants

- The most important causes are preventable through immunisation (S. pneumonia, Hib, N. meningitidis, Mtb, and some viral causes e.g Measles, Rubella)

Aetiology• Bacterial:

a) 0 - 2 months

- Escherichia coli

- Group B streptococci

- Listeria monocytogenes

- Others: Klebsiella, Salmonella

b) 2 months – 2 years

- Streptococcus pneumoniae

- Haemophilus influenza type b

- Neisseria meningitidis

c) 3 years and above

- S. pneumonia

- N. meningitis

- Hib

- Mycobacterium tuberculosis

d) Unusual bacteria

- Staphylococcus aureus

- Pasteurella multocida

- Mycoplasma

• Viruses:

- Enterovirus

- Paramyxoviruses

- Herpes simplex

- Cytomegalovirus

- Influenza

- Rubella

- Adenovirus

- Polio

• Fungal

- Cryptococcus neoformans

- Candida albicans

• Drugs and Chemicals

- NSAIDs

- IVIG

- Antibiotics

Predisposing/ Risk factors• Age: prematures, neonates• Intrauterine infection• Maternal infection and pyrexia at delivery• Open head trauma (with skull fracture or CSF leakage)• Contiguous focus of infection e.g. sinusitis, otitis media,

mastoiditis, osteomyelitis of skull, periorbital and facial cellulitis, septic arthritis,

• Open neural tube defects• Neurosurgical procedures and patients with ventriculoperitoneal

shunts• Immune deficiency (primary or secondary)• Sickle cell anaemia or asplenia• Overcrowding• Immunisation status

Pathogenesis• Acquisition:

Aerosol or droplet, nasopharyngeal colonisation, replication and invasion

• Spread:- Haematogenous: from nasopharynx, skin, or

following pneumonia, infective endocarditis; bacteremia then meningeal seeding

- Direct: Otitis media, mastoiditis, sinusitis, open head injury

• Local immune response

• Endothelial cells, macrophages, neutrophils

• Inflammation, increased blood brain barrier permeability, cerebral edema, increased ICP

• Local thrombosis, infarction

Clinical features• History: Brief & fulminant Vs slow gradual

a) Bacterial meningitis:

Neonate:

- Maternal infection or pyrexia at delivery

- Non specific symptoms: change in feeding or sleeping habits, irritability, lethargy, vomiting, high pitched cry, seizures, paradoxical irritability (quiet at rest, cries when moved or comforted)

Infants:

- Fever, lethargy, irritability, change in behaviour, restlessness, seizures, coma

After 2 - 3 years:

- Headache, irritability, nausea, vomiting, anorexia, nuchal rigidity, photophobia, confusion, back pain, seizures, coma

b) Viral:

- Onset variable; fever, general malaise, anorexia, vomiting

- features of pharyngitis, conjunctivitis, myositis

- seizures and evidence of encephalitis

c) Tuberculous meningitis- occurs 3 – 6 months following primary infection- sudden or insiduous presentation- 3 stages:

- First stage: 1 -2 weeks of fever, headache, malaise, irritability

- Second stage: typical meningeal signs- Third stage: worsening neurological

condition, coma and deathd) Fungal meningitis:- Immunesuppressed patients, variable presentation

Physical Examination• Young infant:

- Irritable, unconscious

- Febrile, hypothermic

- Bulging fontanelle

- Diastasis of the sutures

- +/- Nuchal rigidity

• Older child:

- Meningeal signs: Neck stiffness, +ve Kernig and Brudzinski signs,

- Bulging fontanelle

- Ptosis, Sixth nerve palsy, diplopia

- Bradycardia, hypertension and apnea = Cushing’s triad – brain herniation

- Focal neurological signs in 15% of patients

- Seizures in up to 30% patients

- Altered consciousness and coma 15 – 20%

Signs and Symptoms of Bacterial MeningitisSigns and Symptoms of Bacterial Meningitis

Hemi paresis, ptosis, deafness, facial nerve palsy, optic neuritis

Hemiparesis, ptosis, facial nerve palsy

Focal Focal neurologic neurologic signssigns

Headache, bulging fontanel, diastasis of sutures in infants, papilledema, mental confusion, altered state of consciousness

Bulging fontanel, diastasis of sutures, convulsions, opisthotonus

Increased Increased intracranial intracranial pressurepressure

Neck rigidity, Kernig and Brudzinski sign

Neck rigidity, Meningeal Meningeal inflammationinflammation

Fever, anorexia, confusion, irritability, photophobia, nausea, vomiting, headache, seizure

Fever or hypothermia, abnormally sleepy or lethargic, disinterest in feeding, poor feeding, cyanosis, grunting, apneic episodes, vomiting

NonspecificNonspecific

Older infants and childrenOlder infants and childrenNeonatesNeonatesSigns and Signs and symptomssymptoms

Investigations• Blood:

- Complete blood count

- Blood cultures

- Blood glucose

- Serum electrolytes

- Bacterial antigen studies

- Coagulation studies

- Sickle cell screening test

• CSF examination:- Most important- Lumbar puncture: anatomical markings, opening and closing pressures- Analysis:

- Cell counts; total and differential, - Gram stain (- ZN stain- Indian ink stain- Glucose- Protein- Antigen tests

- Culture and sensitivity (even with ‘normal csf’)

- Latex agglutination tests

• Contraindications to LP:- Infection at LP site- Signs of increased ICP (other than a bulging fontanelle)- Suspicion of a mass lesion- Extreme patient instability

CSF findings in various conditions are attached;Interpretation of CSF from a traumatic LP

• Imaging studies:

- Rarely required

- May be needed to rule out other pathology before LP, or when focal nerological signs are present

- Helpful in abscesses, subdural effusions, empyema, hydrocephalus

- CT Scan, MRI: Normal findings do not rule out increased ICP

- Cranial Ultrasound Scan

DDx: Bacterial Meningitis• Tuberculous meningitis

• Fungal meningitis

• Brain abscess

• Intracranial or spinal epidural abscesses

• Encephalitis

• Bacterial endocarditis with embolism

• Subdural empyema

• Subarachnoid hemorrhage

• Brain tumors

Management• Airway, Breathing, Circulation

• Management of seizures

• Empiric and specific antibiotic therapy

• Supportive treatment

- ABC

- Fluid: 2/3 of maintenance

- Feeding

- Antipyretics

- Physiotherapy, occupational therapy

- Counseling and support to attendants

Empiric Therapy for Bacterial Empiric Therapy for Bacterial MeningitisMeningitis

Bacterial meningitis is a medical emergency, delay in treatment may lead to increased sequelae or deathDrug of choice must be bactericidal for pathogen involvedMust achieve adequate levels in the CSFInitial regimen should cover most likely pathogens for specific age groups, and reach bactericidal levels in the CSFKnowledge of local susceptibility patterns is essential

Empiric Therapy for Bacterial MeningitisEmpiric Therapy for Bacterial Meningitis

Cefotaxime or Chloramphenicol

Benzyl penicillin & Ceftriaxone

H. influenzaeS. pneumoniaeN. meningitidis

2mos – 5 yrs

ChloramphenicolOr Ceftriaxone

Penicillin GS. pneumoniaeN. meningitidis

>5 yrs

Ampicillin + Cefotaxime or Ceftriaxone

Ampicillin or Penicillin + Aminoglycoside

E. coliGram (-) bacilliS. pneumoniae

0-2 mos

AlternativePrimary

Antimicrobial choiceLikely etiologyPatient group

Duration of Therapy of Bacterial Meningitis*

Pathogen Suggested duration of therapy (days)

H. influenzae 10 - 14S. pneumoniae 10 -14N. meningitidis 10 - 14Grp. B. streptococci 14-21

G(-) bacilli 21

*Quagliarello, et al, NEJM 1997, 336(10):708-716

Supportive management

IV Fluids and hydration

maintain normal blood pressure, watch out for SIADH

Control of increased intracranial pressure

Nutritional support

Prevention- chemoprophylaxis, immunizations, infection control

Complications• Fits/ Epilepsy• Hydrocephalus• Cranial nerve palsies: CN 3 – 6• Subdural effusions ( common with Hib)• Brain abscess• Encephalitis/ Cerebritis• Hearing loss• Blindness• Cognitive dysfunction• SIADH secretion• Ventriculitis• Cerebral edema• Learning disabilities• Cerebral palsy• Paresis, ataxia

Persistent fever• Inadequate drug doses

• Organism not sensitive to drug

• Drug fever

• Complications: cerebral abscess, ventriculitis, subdural effusion

• Another focus of infection

• Hib infection

• Pericardial or joint effusions

Poor prognosis• Young age: Prematures, neonates• Long duration of illness prior to effective

antibiotic therapy• Late onset seizures• Coma and other coplications at presentation• Shock• Low or absent CSF WBC count in the presence

of visible bacteria on CSF Gram stain• Immunocompromised status• Positive CSF culture• Organism: Strep pneumoniae

Look out for:• Role of immunisation in the prevention and

control of meningitis

• Role of steroids in the management of meningitis

• TB and fungal meningitis

and