Bacterial meningitis: Difference between revisions
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= Bacterial meningitis = |
= Bacterial meningitis = |
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| − | + | = Definition = |
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* Bacterial infection of meninges |
* Bacterial infection of meninges |
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| − | + | = Etiology = |
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* Adults |
* Adults |
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** Gram-negatives |
** Gram-negatives |
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| − | + | = Risk factors = |
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* Immunosuppression |
* Immunosuppression |
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* Chronic otitis media |
* Chronic otitis media |
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| − | + | = Presentation = |
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* Typically, an acute onset of headache with fever and vomiting after viral prodrome |
* Typically, an acute onset of headache with fever and vomiting after viral prodrome |
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* Ask about recent travel and sick contacts |
* Ask about recent travel and sick contacts |
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| − | + | = Investigations = |
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* Lab |
* Lab |
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** Lumbar puncture after CT head |
** Lumbar puncture after CT head |
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| − | + | == CSF Interpretation == |
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* Gram stain positive |
* Gram stain positive |
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* PMNs >1180 |
* PMNs >1180 |
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| − | + | = Management = |
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* Blood cultures before antibiotics |
* Blood cultures before antibiotics |
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* Adjust antibiotics based on Gram stain and cultures |
* Adjust antibiotics based on Gram stain and cultures |
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| − | + | = Complications = |
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* Cerebral edema with raised ICP |
* Cerebral edema with raised ICP |
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* Venous sinus thrombosis |
* Venous sinus thrombosis |
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* Cranial nerve palsies, especially deafness |
* Cranial nerve palsies, especially deafness |
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| + | [[Category:CNS infections]] |
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Revision as of 13:32, 12 August 2019
Bacterial meningitis
Definition
- Bacterial infection of meninges
Etiology
- Adults
- Streptococcus pneumoniae
- Neisseria meningitidis
- Listeria monocytogenes in immunocompromised, elderly, alcoholics, adn diabetes
- Haemophilus influenzae
- Infants:
- Group B Streptococcus
- Escherichia coli
- Haemophilus influenza
- Listeria monocytogenes
- Head trauma or neurosurgery
- Staphylococcus aureus
- Gram-negatives
Risk factors
- Immunosuppression
- Diabetes
- Splenic dysfunction or splenectomy (e.g. sickle cell)
- Alcoholism
- Recent neurosurgery
- CSF leak
- Shunt infections
- Head trauma
- Chronic otitis media
Presentation
- Typically, an acute onset of headache with fever and vomiting after viral prodrome
- Bacterial vs. aseptic/viral meningitis
- Headache or neck pain (70-80%)
- Fever (75%)
- Altered level of consciousness (70%)
- Clinical signs
- Brudzinski's sign (unhelpful)
- Kernig's sign (may be specific)
- Jolt test (very sensitive)
- Seizures or focal neurological deficits (rare, poor prognosis)
- Rash (purpuric with Neisseria)
- Ask about recent travel and sick contacts
Investigations
- Lab
- CBC with differential
- Electrolytes
- Liver enzymes
- Blood cultures
- Imaging
- CT head to rule out abscess or increased ICP
- MRI head if suspicion for herpes encephalitis
- Temporal lobe enhancement (usually unilateral)
- Other
- Lumbar puncture after CT head
CSF Interpretation
- Gram stain positive
- Glucose <1.0
- CSF:blood glucose <0.23
- Protein >2.2
- WBC >2000
- PMNs >1180
Management
- Blood cultures before antibiotics
- Start empiric antibiotics and dexamethasone
- Infants
- Children
- Adults
- Ceftriaxone 2g bid
- vancomycin 1g q12h
- +/- ampicillin 2g 14h if >50
- Dexamethasone 10mg q6h x72h
- +/- acyclovir
- >65 years old
- Treat like immunocompromised
- CT head if reduced or altered level of consciousness
- Lumbar puncture
- Adjust antibiotics based on Gram stain and cultures
Complications
- Cerebral edema with raised ICP
- Hydrocephalus
- Seizures
- Arterial ischemia or infarction
- SIADH
- Subdural effusion or subdural empyema
- Venous sinus thrombosis
- Cranial nerve palsies, especially deafness
