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Three Part Question

In [adults with suspected meningitis with no neurological abnormality] is [CT head] necessary to exclude [contraindication to lumbar puncture]?

Clinical Scenario

A previously well 40 year old female is admitted with fever, headache, neck stiffness & photophobia. No neurological deficit is found on examination, you wonder whether LP can be safely performed without the need for a CT scan?

Search Strategy

Search Terms: (CT.TI. OR Computed tomography.TI.) AND (lumbar puncture.TI. OR spinal puncture.TI. OR LP.TI.)
Limited to Abstracts
Medline 1950 to date (MEZZ)

Search Outcome

20 results, 6 useful papers - 3 relevant to 3 part question

Relevant Paper(s)

Author, date and country	Patient group	Study type (level of evidence)	Outcomes	Key results	Study Weaknesses
Hasbun R et al 2001 USA	301 adults (over 16) with suspected meningitis in the Emergency department Mean age = 40 (range 18-93)	Prospective Cohort	Incidence of CT results that prevented LP	1.7% (4/235)	Confidence intervals not provided Information on complications not available on 8 patients *clinical features include:immuncompromised/history of CNS disease/seizures
			Probability of normal CT in a patient with no abnormal clinical features* (Negative Predictive Value)	0.97 (93/96)
			Estimated potential reduction in CTs	41% (96/235)
Gopal AK et al 1999 USA	111 Adults (over 18) requiring urgent LP in the Emergency department Mean age = 42 (range 19-77)	Prospective Cohort	Incidence of CT results that prevented LP	2.7% (3/111)	Only 36.9% of LPs performed to rule out Meningitis (n=41) Large Confidence Intervals - may only suggest a minimal decrease in the likelihood of disease Radiographers not blinded & scans not independently reviewed. Neurological examination not defined.
			Likelihood of no contraindication on CT when neuro exam normal (Negative Likelihood ratio)	0 (0-0.63)
			Estimated potential reduction in CTs	31.5% (35/111)
Greig PR & Goroszeniuk 2005 UK	64 Adults (over 16) considered for LP in 6 Month period Mean age = 42 (range 16-83)	Retrospective Case note review	Incidence of CT results that prevented LP	9.4% (6/64)	Only 35.9% of LPs considered to rule out Meningitis (n=23). CT/Neuro examination criteria not defined. Scans not independently reviewed
			Probability of normal CT given a normal neurological examination (Negative Predictive Value) [Excluded ?SAH cases]	0.93 (0.79-1)

Comment(s)

CT criteria for predicting patients at risk of herniation with LP are not well established. 7 patients in the prospective studies received LP despite mild to moderate mass effect on CT – none experienced significant ill-effect. Only 2 patients herniated, neither had received a Lumbar Puncture. None of the patients with normal clinical features had severe mass effect on CT, and none experienced fatal complications of LP. A delay was demonstrated in time to LP by first CT scanning but no statistically significant delay in time to treatment was shown – this has been suggested elsewhere and that such a delay increases mortaility(a) (a) Proulx, N. Frechette, D. Toye, B. Chan, J. Kravcik, S. Delays in the administration of antibiotics are associated with mortality from adult acute bacterial meningitis. QJM 2005 98(4):291-298

Clinical Bottom Line

In cases of suspected meningitis it is very unlikely that patients without clinical risk factors (immunocompromise/ history of CNS disease/seizures) or positive neurological findings will have a contraindication to lumbar puncture on their CT scan If CT scan is deemed to be necessary, administration of antibiotics should not be delayed.

References

1. Hasbun-R, Abrahams-J, Jekel-J, Quagliarello-V-J. Computed tomography of the head before lumbar puncture in adults with suspected meningitis The New England journal of medicine 13 Dec 2001, vol. 345, no. 24, p. 1727-33
2. Gopal-A-K, Whitehouse-J-D, Simel-D-L, Corey-G-R. Cranial computed tomography before lumbar puncture: a prospective clinical evaluation Archives of internal medicine Dec 13-27 1999, vol. 159, no. 22, p. 2681-5
3. Greig-P-R, Goroszeniuk-D Role of computed tomography before lumbar puncture: a survey of clinical practice Postgraduate medical journal Mar 2006, vol. 82, no. 965, p. 162-5