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Meningitis

Posted on 24. Apr, 2009 by admin in Infectious diseases, Neurology

Meningitis is inflammation of the protective membranes covering the brain and spinal cord.

Here is a  quick overview of meningitis. Click for a larger view.

We will focus on Septic or Bacterial meningitis. It can be broken down in to:

1. Community-acquired

2. Nosocomial (hospital acquired)

3. Recurrent

 

Definition of Nosocomial meningitis: Meningitis after 48 hours or within a week after discharge.

 

Predispositions for community acquired meningitis

• Usually none → N. Meningitis
• Conditions predisposing to S. Pneumococci infection (fractured cribriform plate) → S. Pneumococci
• Cell mediated immunity defects → Listeria
• Humoral  immunity defects → H. Influenza

Predispositions for nosocomial meningitis

• Surgery & foreign body (ventricular shunt) → Coagulase –negative Staph
• Surgery & endocarditis → Staph. Aureus
• Advanced medical illness, neurosurgery → Gram negative rods

 

Causes of community acquired meningitis

Use the following mnemonic to remember the common organisms responsible in different age groups:

Here is the mnemonic explained:

Ages <1 month (neonate):  “coil-strip-l”

• E. Coli
• Strep. agalactiae
• Listeria

Ages between 1 month and 15 years: “M comes before P”

• Meningococcus
• Pneumococcus

Ages beyond 15 years: “MP reversed”

• Pneumococcus
• Meningococcus

 

THE most common cause of meningitis seen in hospitals:

• Community acquired  -  Strep. Pneumoniae making up 60% of all cases of meningitis.
• Nosocomial -  Gram negative bacilli making up 33% of nosocomial cases
• Recurrent -  Strep. Pneumoniae

 

MENINGITIS Treatment:

1) Important.. NEVER delay Antibiotics, they can be given even before a LP

                        (organisms can still be identified in LP)

 

EMPIRICAL Treatment:

        1) THIRD Gen Cephalosporin

                                a) Cefotaxime

                                b) Ceftriaxone

if penicillin-Resistance and pneumococcus suspected, give VANCOMYCIN.

SUPPORTIVE Treatment:

                DEXAMETHASONE = Decreases rate of Hearing

                                                Loss and Neurological

                                                complications

 

Here’s the mnemonic for empirical treatment for meningitis:

 

 

Empirical = Imperial (fit for a king) treatment!

Trident = cefTRIaxone

Golden Taxi Van = cefoTAXIme and VANcomycin

King is buff = he uses “steroids” = Dexamethasone

 

 

Suspect:

        if culture shows:

                        1) GRAM POSITIVE COCCI = S. Pneumo.

                        2) GRAM POSITIVE BACILLI = LISTERIA

                        3) GRAM NEGATIVE COCCI = N. MENINGITIS

                        4) GRAM NELGATIVE BACILLI = Enterobact.

 

 

If History of

• Neurosurgery (within one Month)
• Head trauma  (within one Month)
• Neurosurgical device
• CSF Leak with Gram

Think   = Pseuodomonas or Acinotobacter

          Give Ceftazidime, not Ceftriaxone

 

if History of travel to sub Saharan AFRICA,

        Suspect Epidemic meningococcal Meningitis

follow Protocol!

1) chloramphenicol

2) Ceftriaxone as Second line

 

SPECIFIC TREATMENT:

        when clinical presentation and CSF GRAM STAIN

        are Unequivocal or POSITIVE culture:

        for..

1) S. Pneumo = CefTRIaxone and VANCOMYCIN for 2 Weeks

         VANCO (‘if Beta-lactam resistance is noted locally]

 

RIFAMPIN can be given instead of or in addition to VANCOMYCIN..

                – RIFAMPIN is synergistic with Ceftriaxone against S. pneumo.

 

Mnemonic: “Rule with a TRIdent”

R = Rifampin

TRI = cefTRIaxone

 

- Penicillin or cephalosporin allergy?

                                give CHLORAMPHENICOL

Mnemonic: Like the king pictured above- “Rule with a Trident”

 

 

2) N. MENINGITIS = Penicillin G

         4 million units every 4 hours

               

Mnemonic: a “G” made of meningococci for “penicillin G”

3) H. Influenza = THIRD Generation Cephalosporin

                                                        – Cefotaxime

                                                        – ceftriaxone

               

4) LISTERIA = Ampicillin or Penicillin G

                  GENTAMYCIN (for synergy)

                  Penicillin allergy? BACTRIM

 

Mnemonic: follow the “listeria links”

AmP –> Pen G –> Genta

Ampicillin –> Penicillin G –> Gentamycin

 

5) GRAM Negative enteric meningitis =  E. coli or Klebsieka

Cefotaxime

Mnemonic: imagine a taxi racing down the intestines “enteric” tract

 

-admin

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Tags: mind map, mnemonic, USMLE