CT before lumbar puncture: Difference between revisions

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5% had mass effect on ct
{{CT before LP}}


- pts with abnormal cts:
==See Also==
*[[Lumbar Puncture]]


--- age >60,immunecompromised, cns dz, sz within one wk, aloc, unable to answer questions, unable to follow
==References==
<references/>


commands, gaze palsy, abnrm visual fields, arm/ leg
[[Category:Neurology]]
 
[[Category:Procedures]]
drift, abnrml speech.
[[Category:Radiology]]
 
- features not assoc with abnormal ct- race,
 
insurance, htn, h/o parameningeal dz like otitis/
 
sinusitis
 
- if none of the above, chance of normal ct is 97%
 
- even if do lp with mildly abnormal ct, none had
 
brain herniation
 
- ct before lp resulted in longer ER stay and delay in
 
abx
 
- if no abnormal findings, neg predictive value is 97% - so don't need ct routinely
 
- if have abnormal finding, abx first, then ct then lp
 
 
7/2/09 PANI
 
 
 
 
[[Category:Neuro]]

Latest revision as of 16:50, 25 June 2016

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

References

  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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