Meningitis Disease

BASICS

DESCRIPTION

Inflammation in response to bacterial infection of the pia-arachnoid and its fluid and the fluid of the ventricles. Meningitis is always cerebrospinal.

System(s) affected: Nervous
Genetics: Navajo Indian and American Eskimo may have genetic or acquired vulnerability to invasive disease
Incidence/Prevalence in USA: 3-10 cases per 100,000 population
Predominant age: Neonates, infants and geriatric aged
Predominant sex: Male = Female

SIGNS AND SYMPTOMS

Antecedent URI
Fever
Headache
Meningismus
Signs of cerebral dysfunction
Vomiting
Photophobia
Seizures
Nausea
Rigors
Profuse sweats
Weakness
Altered mental status
Focal neurologic deficits
Elderly have subtle findings commonly including confusion
Meningococcemia has rash - macular and erythematous at first, then petechial or purpuric

CAUSES

Neonates: Group B or D Streptococcus, Escherichia coli, Listeria monocytogenes and non-group B Streptococcus
Infants/children: H. influenzae (48%), Streptococcus pneumoniae (13%), and Neisseria meningitidis
Adults: Streptococcus pneumoniae (30-50%), Haemophilus influenzae (1-3%), Neisseria meningitidis (10-35%), gram-negative bacilli (1-10%), Staphylococci (5-15%), Streptococci (5%) and Listeria species(5%)

RISK FACTORS

Immunocompromised host
Alcoholism
Neurosurgical procedure or head injury
Abdominal surgery for gram-negative

DIAGNOSIS

LABORATORY

Turbid CSF
Neonates
- > 10 WBC's in CSF
- CSF: blood glucose ratio < 0.6
- CSF protein >150 mg/dL (> 1500 mg/L)
Infants/children
- > 5 WBC's in CSF
- CSF: blood glucose ratio < 0.6
- CSF protein > 50 mg/dL (> 500 mg/L)
Adults
- 1000-100,000 WBC's in CSF (average 5000-20,000)
- CSF: blood glucose ratio < 0.4
- CSF protein > 45 mg/dL (> 450 mg/L) (usually 150-400 mg/dL [1500-4000 mg/L])
- Suspect ruptured brain abscess when WBC count is unusually high (±100,000)
In all age groups:
- CSF opening pressure > 180 mm H2O (1.77 kPa)
- CSF Gram stain + in 75% of untreated patients
- CSF culture + 70-80% of the time
- Blood culture + 40-60% of the time
- CSF bacterial antigen test (sensitivity varies)

Drugs that may alter lab results: N/A
Disorders that may alter lab results: N/A

PATHOLOGICAL FINDINGS

N/A

SPECIAL TESTS

N/A

IMAGING

CT scan of head if concern for increased intracranial pressure (ICP)
Chest x-ray may reveal silent area of pneumonitis or abscess
Sinus/skull x-rays may reveal cranial osteomyelitis, paranasal sinusitis or skull fracture
Later in course, head CT scan, if hydrocephalus, brain abscess, subdural effusions or subdural empyema are considered

DIAGNOSTIC PROCEDURES

Lumbar puncture

TREATMENT

APPROPRIATE HEALTH CARE

Inpatient often with ICU. If diagnosis is suspected, lumbar puncture should be done in office with antimicrobial therapy begun before transfer to hospital.

GENERAL MEASURES

Appropriate antibiotic therapy
Vigorous supportive care with constant nursing to ensure prompt recognition of seizures and prevention of aspiration
Therapy for any coexisting conditions
Measures to prevent hypothermia and dehydration

SURGICAL MEASURES

N/A

ACTIVITY

As tolerated in hospital and on discharge

DIET

Regular as tolerated, except when SIADH complicates course

PATIENT EDUCATION

For patient education materials on this topic, contact: American Academy of Pediatrics, 141 Northwest Point Blvd., P.O. Box 927, Elk Grove Village, IL 60009-0927, (800)433-9016

FOLLOW UP

PREVENTION/AVOIDANCE

Prompt medical treatment for infections
Strict aseptic techniques when treating patients with head wounds or skull fractures
Look for evidence of CSF fistula in patients with recurrent meningitis

POSSIBLE COMPLICATIONS

Seizures (20-30% during course of illness)
Focal neurologic deficit
Cranial nerve palsies (III, VI, VII, VIII) 10-20% of cases, usually disappear within a few weeks
Sensorineural hearing loss (10% in children)
Neurodevelopmental sequelae (subtle learning deficits 30%)
Obstructive hydrocephalus
Subdural effusions

EXPECTED COURSE AND PROGNOSIS

Overall case fatality 14%
- H. influenza 6%
- Neisseria meningitidis 10.3%
- Streptococcus pneumoniae 26.3%

MISCELLANEOUS

ASSOCIATED CONDITIONS

Which worsen prognosis:

Coma
Seizures
Alcoholism
Old age
Infancy
Diabetes mellitus
Multiple myeloma
Head trauma

AGE-RELATED FACTORS

Pediatric: N/A
Geriatric: Several signs and symptoms may be less evident in elderly patients with other disorders (congestive heart failure, pneumonia)
Others: Different etiologic agents, antimicrobials and dosing, and CSF findings as listed above

PREGNANCY

N/A

OTHER NOTES

N/A

ABBREVIATIONS

N/A

Clinical Investigations

ROLE OF HOMOEOPATHY

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