CT before lumbar puncture: Difference between revisions
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##Look for unequal pressures between the 3 cerebral compartments (left/right supretentorial compartments, posterior fossa) | ##Look for unequal pressures between the 3 cerebral compartments (left/right supretentorial compartments, posterior fossa) | ||
##Look for intracerebral masses not causing midline shift | ##Look for intracerebral masses not causing midline shift | ||
# | #Obstructive [[Hydrocephalus]] | ||
##Look for enlargement of ventricles prox to lesions and normal ventricles distal (especially 4th ventricle) | ##Look for enlargement of ventricles prox to lesions and normal ventricles distal (especially 4th ventricle) | ||
#Basilar cisterns compressed | #Basilar cisterns compressed |
Revision as of 02:02, 10 October 2014
LP without CT is likely safe if
- History
- Age < 60
- Not immunocompromised
- No history of CNS disease
- No seizure within 1 week of presentation
- Physical Exam
- No ALOC
- No inability to answer two consecutive questions successfully
- No inability to follow two consecutive commands successfully
- No gaze palsy
- No abnormal visual fields
- No facial palsy
- No arm drift
- No leg drift
- No abnormal language
If none of the above, chance of normal ct is 97%; none of the patients herniated
CT findings that prohibit LP
- Midline shift
- Look for unequal pressures between the 3 cerebral compartments (left/right supretentorial compartments, posterior fossa)
- Look for intracerebral masses not causing midline shift
- Obstructive Hydrocephalus
- Look for 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
- Look for displacement/compression of 4th ventricle
See Also
Source
- NEJM 2001; 345; 1727-33
- Emergency Radiology: Case Studies Schwartz