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Head CT before Lumbar Puncture in Suspected Meningitis. Craig Brummer MD. Study # 1, 1999. Prospective study to identify which patients could safely undergo lumbar puncture without screening CT
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Head CT before Lumbar Puncture in Suspected Meningitis Craig Brummer MD
Study # 1, 1999 • Prospective study to identify which patients could safely undergo lumbar puncture without screening CT • 113 adults who required urgent LP were studied. Pts were 18 and older, temp, age, and indication for CT scan were recorded. • Physicians evaluated pt based on history including risk factors for HIV, documented HIV, immunocompressive conditions, history of malignant neoplasms, head trauma within the previous 72 hours, history of central nervous system (CNS) mass lesion, report of recent altered mental status, and seizures within the previous 72 hours • Physicians took PE including altered mentation papilledema and focal neuro signs and recorded their perceived likelihood CT would contraindicate LP or disclose new lesion Gopal A J., Whitehouse, James.. Cranial Computed Tomography Before Lumbar Puncture: A Prospective Clinical Evaluation. Archives of Internal Medicine. Vol 159: 22, 1999 Dec 13/27
continued • Radiologists were blinded to the study objectives and not clinical presentation and read CT as “positive, LP contraindicated, positive, LP not contraindicated (new lesions without shift of midline structures, etc) or “completely negative” • 111/113 assessed. Indications for urgent LP was R/O meningitis (36.9%), subarachnoid (42.3%), and other reasons (20.7%). All LP had preceeding CT • 84% had normal or unchanged CT. 17 (15.3%) had new lesions. Only 3 of this group (2.7%) contraindicated LP
Comments • Strengths • Suggests that not all patients require LP before CT. Head CT increased tx time an average of 2.7 hrs • This study suggests that certain items could predict new CT findings • Illustrates that the physician’s clinical impression should be noted in decision to LP • Weakness • Takes into account multiple CNS events other than meningitis • Although no pt with normal findings had a new intracranial lesion, the 95% CI were high (0.63 due to low prevalence) to show conclusively that physical exam can screen for new intracranial lesions
Study # 2, 2001 • Prospective study of 301 adults with suspected meningitis to determine whether clinical characteristics could identify pts likely to have abnormal CT • Base-line characteristic were recorded in ED (sociodemographics, comorbidity, immunocompromise, clinical features, neuologic abnormalities (T4), laboratory results, and management decisions) • Univariate regression analyses of base-line clinical features with respect to abnormal findings on CT. Clinical findings associated with abnormal CT findings were used to identify a subgroup of patients with low likelihood of abnormal findings • Of the 301, 235 had CT read by 2 neuroradiologists (3rd if needed) Hasbun R. Abrahams J. Jekel J. Quagliarello VJ. Computedtomography of theheadbeforelumbarpuncture in adultswithsuspectedmeningitis. New England Journal of Medicine. 345(24):1727-33, 2001 Dec 13
Age over 60 Immunocompromised state History of CNS disease Seizure within 1 week before presentation Neuro findings Abnl level of consciousness 2 questions incorrect 2 commands incorrect Gaze palsy Abnl visual fields Facial palsy Arm drift Leg drift Abnormal languages 4.3 (2.9-6.4) <.001 1.8 (1.1-2.8) .01 4.8 (3.3-6.9) <.001 3.2 (2.1-5.0) <.001 3.8 (2.5-5.8) <.001 3.3 (2.2-4.4) <.001 3.9 (2.6-5.9) <.001 3.2 (1.9-5.4) .003 4.0 (2.7-5.9) <.001 4.9 (3.8-6.3) <.001 4.0 (2.7-5.8) <.001 4.4 (3.0-6.5) <.001 4.3 (2.9-6.5) <.001 Clinical features at baseline associated with abnormal CT were noted Baseline Characteristic Risk ratio / 95%CI P value
Results / Comments • Of the 235 CT, 96 patients had no of the clinical risk factors. • CT scan was normal in 93/96 (-PV of 97%). As of the three misclassified only one had a mild mass effect on CT, and all three subsequently underwent LP • 56 CT were abnormal, 11 with evidence of mass effect, and only 4 had evidence of mass effect that deferred LP . • Strengths: prospective, baseline char are easy to asses • Weakness: single institution, -PV not 100% (97%)
HUP isms • CT scan is not indicated in all cases of suspected meningitis before lumbar puncture • LP without CT in selected cases reduce unnecessary costs and delays in the diagnosis and treatment of infectious meningitis. • Clinical features can guide the physician to proceed with lumbar puncture without CT decreasing time to treatment.