%0 Journal Article
%T Nonconcordance between Clinical and Head CT Findings: The Specter of Overdiagnosis
%A Kelli N. O'Laughlin
%A Jerome R. Hoffman
%A Steven Go
%A Gelareh Z. Gabayan
%A Erum Iqbal
%A Guy Merchant
%A Roberto A. Lopez-Freeman
%A Michael I. Zucker
%A William R. Mower
%J Emergency Medicine International
%D 2013
%I Hindawi Publishing Corporation
%R 10.1155/2013/314948
%X Background. It is unclear whether history and physical examination findings can predict abnormalities on head computed tomography (CT) believed to indicate increased risk of lumbar-puncture- (LP-) induced brain herniation. The objectives of this study were to (1) identify head CT findings felt to be associated with increased risk of brain herniation and (2) to assess the ability of history and physical examination to predict those findings. Methods. Using a modified Delphi survey technique, an expert panel defined CT abnormalities felt to predict increased risk of LP-induced brain herniation. Presence of such findings on CT was compared with history and physical examination (H&P) variables in 47 patients. Results. No H&P variable predicted ˇ°high-riskˇ± CT; combining H&P variables to improve sensitivity led to extremely low specificity and still failed to identify all patients with high-risk CT. Conclusions. ˇ°High-riskˇ± CT is not uncommon in patients with clinical characteristics known to predict an absence of actual risk from LP, and thus it may not be clinically relevant. ˇ°Overdiagnosisˇ± will be increasingly problematic as technological advances identify increasingly subtle deviations from ˇ°normal.ˇ± 1. Introduction There is substantial evidence in the medical literature that lumbar puncture (LP) is extremely safe [1¨C3], particularly in the setting of patients who are immunologically normal and who do not manifest abnormal mental status, papilledema, or focal neurological deficit [3¨C5]. Nevertheless, many clinicians are concerned that LP could lead to tonsillar herniation [6¨C11] in patients with increased intracranial pressure (ICP), by decreasing cerebrospinal fluid pressure in the subarachnoid space, and thus creating a pressure gradient that could displace cerebral and brainstem structures [7, 12]. There are only a small number of reports, however, suggesting catastrophic deterioration related to LP [9, 13, 14], and even the validity of these observations has been questioned [15¨C17]. Nevertheless, despite the substantial evidence that few, if any patients, are at risk from LP, many clinicians worry about potential harm, and it has been suggested that head computed tomography (CT) be obtained prior to LP, in the hope that it might be able to identify the few patients in whom the procedure would purportedly be dangerous [5, 18]. There are no studies, however, which define what if any findings on head CT actually do predict increased risk of tonsillar herniation following LP [3, 4, 19]. We designed this study to assess the prevalence of ˇ°high-riskˇ± CT
%U http://www.hindawi.com/journals/emi/2013/314948/