CNS infections

Question 1

List 10 infectious causes of meningitis

Answer 1

INFECTIOUS:
Bacterial:
§ Pneumococcus
§ Meningococcus
§ Listeria
§ H. flu
§ Staph aureus
§ E. coli
§ Borrelia (LYME)
§ Treponema (SYPHILIS)
§ Mycoplasma

Viral:
§ Enteroviruses: coxsachi, echo, polio
§ Herpes virus: HSV, EBV, CMV, VZV
§ Arboviruses: WEE, EEE, Japaneses, St. Louis, WNV
§ Other: rabies, HIV, HTLV, measles, mumps

Fungal
§ Cryptococcus
§ Coccidiomyocosis
§ Candida
§ Histoplasma
§ Blastomyces

Parsites
§ Toxoplasma
§ Cysticercosis
§ Amoeba

Rickettsia
§ Rocky mountain spotted fever

Question 2

List 5 categories, with 2 examples from each, of non-infectious meningitis (aseptic meningitis)

Answer 2

- Inflammatory
		o SLE
		o RA
		o Sarcoidosis
		o Serum sickness
		o Bechet’s
		o Kawasaki
	- Post-infectious / post vaccination:
		o Rubella
		o Varicella
		o Influenza
		o Rabies
		o Pertussis
	- Neoplastic
		o Carcinomatous meningitis
		o Leukemia
	- Drugs – “SIN”
		o Septra, sulfasalazine
		o Isoniazid, IVIG
		o NSAIDS 
	- Infection in neighbouring structures
		o Brain abscess
		o Epidural abscess
	
	What are the classic signs and Sx of meningitis?
	- Fever, headache, photophobia, nuchal rigidity, lethargy, malaise, altered LOC, seizures, vomiting, chills
		o May be more subtle in elderly, immunocompromised à LOC may be only sign
		o Fungal/TB very subtle with headache and B Sx
		o Kernig/Brudzinski + in 50% of adults
	- Systemic signs:
		o Endocarditis stigmata
		o Petichiae/purpura, shock
		o Arthritis à N. meningitidis
	- Absence of fever, neck stiffness, altered LOC virtually eliminates dx
Fever most sensitive at 85% (no single s/s very sensitive)

Question 3

What are 8 immediate and 8 delayed complications of bacterial meningitis (Box 109-3)?

Answer 3

Immediate:
- Coma
- Loss of airway reflexes
- Sz
- Cerebral edema
- Shock
- DIC
- Respiratory arrest
- Volume depletion
- Pericardial effusion
Death

Delayed:

• Sz disorder
• Sensorineural hearing impairment
• Blindness
• Cognitive impairment
• Focal paralysis
• Hydrocephalus
• Ataxia
• Bilateral adrenal hemorrhage
• CVT
• Death

Question 4

What is Waterhouse-Friedrichsen syndrome?

Answer 4

• Hemorrhagic adrenalitis causing acute adrenal insufficiency and contributing to shock.
  
  • More common with meningococcemia

Question 5

What are 5 indications to CT before LP?

Answer 5

• Immunocomprimised
  
  • Hx of à Stroke, mass lesion, focal trauma, head trauma
  • Sz last 7 days
  • Altered LOC
  • Inability to answer questions
  • Focal neurologic abnormalities à motor, speech, abnormal gaze or VF
  • Signs raised ICP

Question 6

What is normal CSF?

Answer 6

- Cell count:
		o WBC <5
		o <1PMN
		o <1 eosinophil
	- CSF:serum glucose: 0.6:1 (abnormal if CSF is less than ½ the value of serum glc)
	- Protein: 15-45mg/dL

Question 7

What are CSF characteristics in bacterial and viral meningitis?

Answer 7

· WBC
o Bacterial: WBC GT 500 and PMN GT 80% (often will be ++ elevated, 10,000)
o Viral: WBC LT 500, nearly 100% monocytes
o Early on may have non-specific pleiocytosis that can resemble bacterial meningitis
· Glucose CSF:serum ratio LT 0.4
· Protein GT (>1g/L)
· CSF lactate >3.5mmol/L (although ++non-specific)

Question 8

What are the indications, and regimes, for chemoprophylaxis for meningitis?

Answer 8

• Confirmed meningococcemia: Household contacts: Rifampin
  o Adults 600mg po bid x 2 days
  o Children GT 1 month – 10mg/kg po bid x 2 days
  o Children LT 1 month – 5 mg/kg po bid x 2 days
  o Watch for fever, sore throat, or meningitis symptoms
• Confirmed meningococcemia: Healthcare workers : require prophylaxis if direct mucosal contact with patient’s secretions (mouth to mouth, intubation, suctioning):
  o Adults, children GT 15yo: Ciprofloxacin 500mg po x 1 AND ceftriaxone 250mg IM x 1
  o Children LT 15yo: ceftriaxone 125mg IM x 1 dose
• Pneumococcal meningitis: No chemoprophylaxis

- H. Flu type b
o Pregnant women
o Non-pregnant household contacts when there are children <4 yo in the house
	o Rifampin
		§ Adults 600mg po od x 4 days
		§ Children 20mg/kg po od x 4 days

• No prophylaxis for S. pneumoniae

Question 9

What are the signs and Sx of encephalitis?

Answer 9

• Altered LOC
  
  • Fever
  • Headache
  • Personality change / hallucinations / bizarre behavior
  • Meningeal irritation
  • Focal motor deficits, seizures

Question 10

What are the signs and symptoms of CNS abscess?

Answer 10

• May be indistinguishable from meningitis/encephalitis
  
  • Usually subacute presentation w/ Sx for 2 weeks
  • Focal motor deficits, papilledema, abrupt ¯ LOC if herniation