Some key points on Meningitis...

Hi everyone,

We recently covered our approach to meningitis, and I wanted to highlight some of the discussion points.

Epidemiology: Major causes of Community-Acquired bacterial meningitis in adults in developed nations include Streptococcus pneumoniae (gram positive diplococci) & Neisseria meningitidis (gram negative diplococci). In those >50 years, or those with immune deficiencies consider Listeria monocytogenes (gram positive rods & cocco-bacilli).

History: Classic triad includes fever, nuchal rigidity, & altered mental status (AMS). In patients with meningitis, 99% of patients have 1 of the 3 components. Fever is the most sensitive of the triad. Thus, if the patient does not have fever, neck stiffness or AMS on examà meningitis is virtually ruled out! Other things to inquire about include nausea, vomiting, photophobia, headache, lethargy, recent URTI, inner ear infection (i.e. OM), sinus infection, or mastoiditis. Focal neurological deficits (i.e. cranial nerve palsies) typically occur later in the course. Inquire about dermatological manifestations (i.e. N. meningiditis can cause petechiae, palpable purpura). Ask about arthralgia or any active joints.

Physical Exam Pearls-Review of Meningeal Signs:

Kernig’s sign: patient laying supine, with hips flexed >90 degrees; extension of knees from this position elicits resistance or pain in low back or posterior thigh

Brudzinksi’s sign: passive neck flexion in the supine patient results in flexion of the knees and hips

NOTE: these signs are specific, but have a low sensitivity! 

Article: Thomas K, et al. The diagnostic accuracy of Kernig’s sign, Brudzinski’s sign, and nuchal rigidity in adults with suspected meningitis. Clin Infect Dis 2002; 35: 46-52. 

Link:

http://cid.oxfordjournals.org/content/35/1/46.full.pdf+html

Jolt Accentuation of headache: patient turns their head horizontally at a frequency of 2-3 rotations per second. Worsening h/a = +ve sign, sensitivity 97%, specificity 60%. Note that this was only evaluated in a single study, which had an N of 34 patients!

CT head prior to LP

CT head: may demonstrate structural abnormalities (ICH, brain abscess, tumor); risk of herniation in performing an LP when the patient has a mass/increased ICP. Evidence suggests that those without findings on history or physical to suggest increase ICP, can safely undergo an LP without a prior head CT

2004 IDSA Guidelines: A CT head is indicated before LP if 1 or more of:

Age >60, history of CNS disease, new onset seizures within 1 week, focal neurological deficits/abnormalities, papilledema, obtunded/AMS, & immune-compromised state (i.e. HIV infection, immune-suppressive therapy, solid organ/hematopoietic stem cell transplantation)

Article:  

Hasbun R, et al. Computed tomography of the head before lumbar puncture in adults with suspected meningitis. N Engl J Med 2001; 345: 1727-33

http://www.nejm.org/doi/pdf/10.1056/NEJMoa010399

Lumbar Puncture Pearls

If LP is delayed (i.e. d/t CT head), draw blood cultures and administer empiric antibiotics, consider dexamethasone 0.15 mg/kg IV q6h. Appreciate that administration of antibiotics will reduce the yield of the gram stain (untreated cases: gram stain is 60-80% sensitive, versus 40-60% in cases of partially treated meningitis).

Mortality: Higher for S. pneumoniae meningitis (19-26%) versus N. meningididis (3-13%)

Management: ABC, IV, O2, Intubation is severe deterioration in LOC and not protecting the airway

-Droplet precautions: H. influenza & N. meningiditis , until 24h of Abx therapy has been given

-Empiric Antibiotics “CVA”

-Give Dexamethasone for acute bacterial meningitis 15-20 minutes before 1^st dose of Abx if suspicion for S. pneumoniae (0.15 mg/kg or 10 mg IV q6h x4 days)à some literature to suggest it may reduce mortality and reduce adverse sequelae (i.e. sensorineural hearing loss) in meningitis, specifically S. pneumoniae

-Ceftriaxone 2g IV q12h (or Cefotaxmine)

- Vancomycin 1-1.5 g IV q12h: to cover resistant S. pneumoniae (penicillin-resistant Pneumococci coverage until sensitivities are known!)

-Ampicilin 2g IV q4h if: age >50, immune-compromised (to cover Listeria)

-If concern for HSV encephalitis: acyclovir 10 mg/kg IV q8h

NOTE: If culture comes back with N. meningiditisà prophylaxis to household and intimate contact. Prophylaxis for health care workers only if they were in direct contact with respiratory secretions *(should have been on droplet!)

More information on use of corticosteroid administration:

Article:  Assiri M, et al. Corticosteroid administration and outcome of adolescents and adults with acute bacterial meningitis: a meta-analysis. Mayo Clin Proc 2009; 84: 403-9.

http://www.mayoclinicproceedings.org/article/S0025-6196(11)60558-2/abstract