Bacterial Meningitis

Athit Wutthisanwatthana

Acute purulent infection within the subarachnoid space

Etiology

50

25

15

10

Streptococcus pneumoniae

Neisseria meningitidis

Group B streptococci

Listeria monocytogenes

Community-Acquired Bacterial Meningitis

#1 in age > 20 years Predisposing conditions

#1 Streptococcal pneumonia Acute/chronic pneumococcal sinusitis/otitis media Alchoholism Diabetes Complement deficiency Head trauma with basilar skull fracture and CSF

rhinorrhea Mortality ~20%

Streptococcus pneumoniae

Petechial or purpuric lesion is important clue Some is fulminant Initiated by nasopharyngeal colonization

Asymptomatic carrier Invasive meningococcal disease

Neisseria meningitidis

Enteric Gram-Negative Bacilli

Diabetes mellitus Cirrhosis Alcoholism Chronic urinary tract

infection Craniotomy

Group B Streptococcus

Streptococcus agalactiae

Neonates Age > 50 years

Listeria monocytogenes

Acquired by food ingestion

Cause of meningitis in Neonate Pregnant woman Age > 60 year Immunocompromis

ed patient

Haemophilus influenzae

Unvaccinated children and adults

Staphylococcus aureus and Coagulase-Negative

staphylococci

Invasive neurological procedures

Pathophysiology

Clinical Manifestation

Fever Headache Nuchal rigidity Decreased level of consciousness Nausea Vomiting Photophobia Seizures

Clinical Manifestation

Increase intracranial pressure

Deceased level of consciousness Papilledema Dilated poorly reactive pupils Sixth nerve palsies Decerebrate posturing Cushing reflex

Rash of meningococcemia

Diffuse erythematous maculopapular rash Petechiae

Trunk Lower extremities Mucous membranes Conjuctivae Palms Soles

Management

Management Algorithm for Adults with Suspected Bacterial

Meningitis

Indication Antibiotic

Immunocompetent children > 3 and adults < 55

Cefotaxime/ceftriaxone + vancomycin

Adults > 55 and adult of any age with alcholism or other debilitating illness

Cefotaxime/ceftriaxone + vancomycin +Ampicillin

Empical Antibiotic

Antimicrobial agent

Ampicillin 2 g IV q 6 h

Cefotaxime 2 g IV q 6 h

Ceftriaxone 2 g IV q 12 h

Vancomycin 1 g IV q 12 h

Total Daily Dose and Dosing Interval

Contraindication for LP

Absolute Signs of raised intracranial pressure Local skin infection Evidence of obstructive hydrocephalus, cerebral

edema or herniation in CT/MR scan

Relative

Sepsis/hypotension (BP <100/<60 mmHg) Coagulation disorder (DIC, platelet < 50,000,

warfarin) Neurological deficit GCS ≤ 8 Epileptic seizure

Contraindication for LP

Cerebrospinal Fluid Abnormalities in Bacterial

Meningitis

Comparison of CSF of Meningitis

Antibiotic Based on Positive Gram Stain

Duration of Treatment (A-III)

Decrease inflammatory response Dexamethasone therapy for bacterial

meningitis. N Engl J Med 2002 301 cases Unfavorable outcome (15% vs. 25%, p = 0.03) Death (7% vs. 15%, p = 0.04)

Role of Dexamethasone

Benefit in pneumococcal meningitis subgroup

Unfavorable outcome (26% vs. 52%, p = 0.006) Death (14% vs. 34%, p = 0.02)

Most beneficial in patient with moderate-severe disease on the Glasgow Coma Scale

Dexamethasone 0.15 mg/kg q6h for 2-4 days Suspected/proven pneumococcal meningitis

(A-I) First dose administered 10-20 min before

antibiotic

Recommendation by IDSA

Concerns in highly penicillin- / cephalosporin-

resistant strain Dexamethasone diminishes inflammatory

response

Dexamethasone be administered to all (B-III) Addition of rifampin (B-III)

Dexamethasone and Pneumococcal Meningitis

Any patient who has not responded clinically

after 48 h (A-III)

Indications for Repeated Lumbar Puncture