CT before lumbar puncture: Difference between revisions

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'''LP without CT is likely safe if:<ref>*NEJM 2001; 345; 1727-33</ref>'''
{{CT before LP}}
*History
**Age < 60
**Not immunocompromised
**No history of CNS disease
**No seizure within 1 week of presentation
*Physical Exam
**No ALOC
**Ability to answer two consecutive questions successfully
**Ability to follow two consecutive commands successfully
**Normal [[neurologic exam]]
''If none of the above, chance of normal ct is 97%; none of the patients herniated''
 
'''CT findings that prohibit LP:<ref>Emergency Radiology: Case Studies Schwartz</ref>'''
*Midline shift
**Unequal pressures between the 3 cerebral compartments (left/right supretentorial compartments, posterior fossa)
**Intracerebral masses not causing midline shift
*Obstructive [[Hydrocephalus]]
**Enlargement of ventricles prox to lesions and normal ventricles distal (especially 4th ventricle)
*Basilar cisterns compressed
**Lateral/3rd ventricles may be small due to diffuse cerebral edema or enlarged due to obstr. hydroceph. +/- shift
*Posterior fossa mass
**Displacement/compression of 4th ventricle


==See Also==
==See Also==

Revision as of 22:02, 17 November 2014

LP without CT is likely safe if:[1]

  • History
    • Age < 60
    • Not immunocompromised
    • No history of CNS disease
    • No seizure within 1 week of presentation
  • Physical Exam

If none of the above, chance of normal ct is 97%; none of the patients herniated

CT findings that prohibit LP:[2]

  • Midline shift
    • Unequal pressures between the 3 cerebral compartments (left/right supretentorial compartments, posterior fossa)
    • Intracerebral masses not causing midline shift
  • Obstructive Hydrocephalus
    • Enlargement of ventricles prox to lesions and normal ventricles distal (especially 4th ventricle)
  • Basilar cisterns compressed
    • Lateral/3rd ventricles may be small due to diffuse cerebral edema or enlarged due to obstr. hydroceph. +/- shift
  • Posterior fossa mass
    • Displacement/compression of 4th ventricle

See Also

Source

  1. ↑ Computed Tomography of the Head before Lumbar Puncture in Adults with Suspected Meningitis. NEJM 2001; 345; 1727-33
  2. ↑ Emergency Radiology: Case Studies Schwartz
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