Bacterial Meningitis Flashcards

1
Q

Common causative organisms for bacterial meningitis

A

N. Meningitis
H. Influenza
L.monocytogenes
Group B strep
Streptococcus pneumonia

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2
Q

Risk factors for bacterial meningitis

A

Age- infants particularly those younger than 1 month
Settings of high population and contact with peers
Weakened immune system- cancer , DM, HIV/AIDs
Head trauma
Cochlear implants or CSF shunts
Medical conditions- sinusitis, otitis media, pneumonia, meningococcal disease
Endemic areas

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3
Q

Signs and symptoms

A

Fever
N/V
Photophobia
Altered mental status
Positive kernig or brudzinski signs
Young children- purpuric rash, convulsion, bulging fontanelle

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4
Q

Pathophysiology of BM

A

Nasopharyngeal colonization
Bacteria then phagocytized into hosts bloodstream some CNS bacterial pathogen have extensive capsules resistant to neutrophil phagocytosis.
Activation of host inflammatory response ie macrophage release cytokines , TNF, IL-1 . The release of macrophages trigger proteolytic products and toxic o2 radicals cuz alterations BBB. Platelets activating factor activate coagulation and arachidonic acid metabolites stimulate vasodilation.
Finally we see increased intracranial pressure, decrease cerebral blood flow, cerebral edema and ischemia

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5
Q

Bacterial meningitis score

A

Parameters
Positive CSF gram stain
Presence of seizures
Serum absolute neutrophil count >10 x 10^9 /L
CSF protein > 80mg/dL
CSF neutrophil count > 1000cells/mm^3

Treat if score more than 1

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6
Q

CSF fluid analysis do BM

A

WBC less than 5
Differential : bacterial( neutrophil)
Protein; less than <0.5g\L
CSF:blood glucose ratio between 0.5-0.6

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7
Q

Diagnostic tools

A

Gram stain and culture of CSF
PCR for S. Pneumonia , N. Meningitis, H influenza type B
Rapid antigen test when gram stain is negative

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8
Q

Use of dexamethasons for BM

A

Acts as anti-inflammatory agent
Prevents complications such as hearing loss , neurological deficits of death
Preferred IV/IM for duration of 4 days

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9
Q

For infants if S. Pneumonia, N meningitis and H. Influenza give recommended therapy with alternative

A

S. Pneumonia-vancomycin +3rd gen cephalosporins. alternative ~FQ and meropenem
N. Meningitis- 3rd gen ceph. Alternative-PenG, ampicillin ,FQs
H. Influenza- 3rd gen ceph alternative- chloramphenicol, cefepime and FQs

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