Overview
Meningitis is a life-threatening infection of the meninges.
Acute bacterial meningitis: rapid onset of Sx, identified by routine laboratory techniques
Chronic meningitis: ongoing Sx of meningitis for ≥ 4 weeks without clinical improvement
Aseptic meningitis: Sx of meningitis without evidence of bacterial cause by usual laboratory testing methods (includes viruses, Mycobacterium tuberculosis, Borrelia burgdoferi and non-infectious causes)
- Risk factors in neonates
- Preterm
- LBW
- Chorioamnionitis
- Endomeritis
- Maternal GBS colonization
- Prolonged duration of intrauterine monitoring ( > 12 hours)
- PROM
- Traumatic delivery
- Fetal hypoxia
- Galactosemia
- Urinary tract abnormalities
- Dermal sinus tract of the spine
- Risk factors in children
- Asplenia (functional or anatomic)
- Primary immunodeficiency
- HIV infection
- Sickle cell anemia (functional asplenia)
- Cochlear implant
- CSF leak
- Recent URTI
- Day care attendance
- Lack of breastfeeding
- Exposure to a case of meningococcal or HiB meningitis
- Penetrating head trauma
- Dermal sinus tract of the spine
- Travel to an area with endemic meningococcal disease
- Lack of immunization
| Age | Common organisms |
|---|---|
| < 28 days | GBS, Escherichia Coli, Enterobacter, Listeria monocytogenes |
| 28 days – 3 months | Escherichia coli, GBS, S. pneumoniae, H. influenza, N. meningitidis, Listeria monocytogenes |
| 3 months – 18 years | N. meningitidis, S. pneumoniae, H. influenzae |
Clinical Features
Clinical Signs of meningitis may be absent in infants.
When testing for neck stiffness, first rotate the neck from side to side to compare rotation (which should not be stiff) to flexion (which should be stiff in meningitis. Flex the chin until it touches the sternum, or until the patient’s shoulders lift from the bed)
- Signs and symptoms in younger children (non-specific)
- Temperature instability (Fever OR Hypothermia)
- Lethargy OR Irritability (fussy, inconsolable cry, sleepy, weak, or jittery)
- Poor feeding
- Vomiting
- Apnea
- Convulsions (not always present)
- Bulging fontanelle
- Poor tone
- Signs and symptoms in older children
- Fever
- Headache
- Anorexia
- Nausea, Vomiting
- Photophobia
- Confusion
- Physical exam findings due to meningeal irritation (meningism)
- Neck stiffness
- Opisthotonus
- Positive Kernig
- Positive Brudzinski sign
- What do FNDs suggest in a child with (suspected) meningitis?
- Localized infarction
- Subdural collection
- When are cranial nerve palsies commonly seen?
- Tuberculous meningitis
- Cryptococcal meningitis
- Differentials for meningeal irritation (Meningism)
- Strep throat (URTI)
- Pneumonia
- Pyelonephritis
- Intracranial bleeding (Subarachnoid hemorrhage)
- Cerebral infarction
- Vasculitis
Investigations
CSF should ideally be obtained before starting antibiotics. Abx pre-treatment decreases the likelihood of obtaining positive CS culture. Abx pre-treatment does not adversely affect CSF cell count and is associated w/higher CSF glucose and lower protein than would be expected for untreated bacterial meningitis.
- Investigations
- Lumbar Puncture for CSF analysis: WBC count, Differential count, Protein level, Gram stain, Culture
- Blood Culture
- Complete Blood Count
- C-reactive protein: elevated. Serial CRP to monitor clinical response and screen for complications
- Procalcitonin: elevated
- U/E/Cs
- Random Blood Sugar: r/o hypoglycemia
- Urinalysis and Urine Culture
- PCR
- CT scan, MRI: if FNDs
- Cranial ultrasound: for neonates
Management
Treatment aims at sterilization of CSF and adequate maintenance of cerebral and systemic perfusion. Ceftriaxone is not recommended for jaundiced neonates or neonates ≤ 6 days.
- Supportive Treatment
- Treat dehydration (and prevent overhydration, worry about SIADH)
- Manage blood sugar level
- Treat convulsions
- Treat fever and pain
- Monitor vital sx
- Measure head circumference daily for < 18 months (1.5 years)
- Definitive Treatment
- Ceftriaxone 50mg/kg BD (not exceeding 4g/day)
- 14 days (uncomplicated meningitis d/t GBS, L. monocytogenes, or S. pneumoniae)
- 21 days (uncomplicated meningitis d/t Gram negative bacil)
- Dexamethasone for HiB meningitis
- Infants and children < 6 weeks of age and older (considering possible risks vs potential benefits)
- Reduces incidence of hearing loss
- Ceftriaxone 50mg/kg BD (not exceeding 4g/day)
- Preventative Treatment
- Hib vaccine (integrated in Nov 2001)
- Pneumococcal Vaccine (integrated into KEPI 2010, PCV10)
- Meningococcal Vaccine (introduced 2019; Menactra, Nimerix): Turkana, Marsabit, Mandera, West Pokot, and Wajir
Complications
- Suppurative complications
- Subdural empyema
- Pleural empyema
- Arthritis
- Pericarditis
- Ventriculitis
- Brain abscess
- Neurological complications
- Hearing loss (20-30% w/ pneumococcal, 10% w/ meningococcal, 5% with HiB)
- Cognitive and developmental disability
- Hemiparesis
- Quadriparesis
- Cranial nerve palsies
- Epilepsy
- Cortical blindness
- Hydrocephalus
- Diabetes insipidus
- Hypothalamic dysfunction
Prognosis
- What is a decreased level of consciousness at presentation associated with?
- Increased risk of death
- Neurological sequalae
- What is the development of seizures more than 72 hours after starting antibiotics associated with?
- Learning difficulties
- Which causes of meningitis has relatively poorer outcome
- S. pneumoniae (compared to HiB or N. meningitidis)
ETAT+
| Diagnosis | Features |
|---|---|
| Definitive meningitis | Cloudy CSF tap AND/OR, WBC > 10 x 10^6/L; Gram positive diplococci or Gram negative cocco-bacilli |
| Probable Meningitis | Coma, Stiff neck, Bulging fontanelle, Clear CSF |
| Possible meningitis | CSF WBC and Gram stain results not done, No coma/stiff neck/bulging fontanelle/clear CSF |
| Complicated meningitis | Subdural empyema, Ventriculitis, Brain abscess, Suppurative venous sinus thrombosis |
- When do we ABSOLUTELY need to perform LP (unless contraindications)
- Coma
- Inability to drink/feed
- AVPU = ‘P or U’
- Bulging fontanelle
- Convulsions if age < 6 months or > 6 years
- Evidence of partial seizures
- When do we need to perform LP (unless completely normal mental state after febrile convulsion)
- Agitation or Irritability
- Any convulsions
- Absolute contraindications to Lumbar Puncture (CT/MRI findings)
- Midline shift
- Posterior fossa mass (common in HIE)
- Loss of cisterna
- When to defer a Lumbar Puncture (relative contraindications)
- Shock or Cardiovascular instability
- Signs of raised ICP (Bradycardia, Hypertension, irregular respirations)
- Focal neurological deficits (Poor pupillary response to light etc.)
- Focal seizures
- Infection of the skin at the LP site
- Evidence of coagulopathy (esp. in meningococcal septicemia)
