Can Patients with Brain Herniation on Cranial Computed Tomography Have a Normal Neurologic Exam?

Objectives:  Herniation of the brain outside of its normal intracranial spaces is assumed to be accompanied by clinically apparent neurologic dysfunction. The authors sought to determine if some patients with brain herniation or significant brain shift diagnosed by cranial computed tomography (CT) might have a normal neurologic examination.
Methods:  This is a secondary analysis of the National Emergency X-Radiography Utilization Study (NEXUS) II cranial CT database compiled from a multicenter, prospective, observational study of all patients for whom cranial CT scanning was ordered in the emergency department (ED). Clinical information including neurologic examination was prospectively collected on all patients prior to CT scanning. Using the final cranial CT radiology reports from participating centers, all CT scans were classified into three categories: frank herniation, significant shift without frank herniation, and minimal or no shift, based on predetermined explicit criteria. These reports were concatenated with clinical information to form the final study database.
Results:  A total of 161 patients had CT-diagnosed frank herniation; 3 (1.9%) had no neurologic deficit. Of 91 patients with significant brain shift but no herniation, 4 (4.4%) had no neurologic deficit.
Conclusions:  A small number of patients may have normal neurologic status while harboring significant brain shift or brain herniation on cranial CT.     

Lumbar Puncture First: An Alternative Model for the Investigation of Lone Acute Sudden Headache

Subarachnoid hemorrhage (SAH) is a diagnosis often considered in patients presenting to the ED with acute sudden headaches, but with normal physical examinations. Standard of care today is for these patients to be investigated by noncontrast CT scan followed by lumbar puncture (LP) for negative CTs. However, given that most investigated patients have benign headaches, most of the CT and LP results are normal. The authors studied, by means of a theoretical analysis, the impact of an alternative diagnostic model, in which LP would be the first (and, in most cases, only) diagnostic test for patients suspected of SAH who met lone acute sudden headache (LASH) criteria. Given reasonable assumptions, for every 100 patients investigated, the "LP-first" model would result in 79 to 83 fewer CT scans and only seven to 11 additional LPs, as compared with traditional strategies. Among ED headache patients meeting LASH criteria, the authors believe use of this model could result in more efficient use of resources, minimal additional morbidity, and equal diagnostic accuracy for SAH.     

Can Computed Tomography Angiography of the Brain Replace Lumbar Puncture in the Evaluation of Acute‐onset Headache After a Negative Noncontrast Cranial Computed Tomography Scan?

Objectives: The primary goal of evaluation for acute‐onset headache is to exclude aneurysmal subarachnoid hemorrhage (SAH). Noncontrast cranial computed tomography (CT), followed by lumbar puncture (LP) if the CT is negative, is the current standard of care. Computed tomography angiography (CTA) of the brain has become more available and more sensitive for the detection of cerebral aneurysms. This study addresses the role of CT/CTA versus CT/LP in the diagnostic workup of acute‐onset headache. Methods: This article reviews the recent literature for the prevalence of SAH in emergency department (ED) headache patients, the sensitivity of CT for diagnosing acute SAH, and the sensitivity and specificity of CTA for cerebral aneurysms. An equivalence study comparing CT/LP and CT/CTA would require 3,000 + subjects. As an alternative, the authors constructed a mathematical probability model to determine the posttest probability of excluding aneurysmal or arterial venous malformation (AVM) SAH with a CT/CTA strategy. Results: SAH prevalence in ED headache patients was conservatively estimated at 15%. Representative studies reported CT sensitivity for SAH to be 91% (95% confidence interval [CI] = 82% to 97%) and sensitivity of CTA for aneurysm to be 97.9% (95% CI = 88.9% to 99.9%). Based on these data, the posttest probability of excluding aneurysmal SAH after a negative CT/CTA was 99.43% (95% CI = 98.86% to 99.81%). Conclusions: CT followed by CTA can exclude SAH with a greater than 99% posttest probability. In ED patients complaining of acute‐onset headache without significant SAH risk factors, CT/CTA may offer a less invasive and more specific diagnostic paradigm. If one chooses to offer LP after CT/CTA, informed consent for LP should put the pretest risk of a missed aneurysmal SAH at less than 1%. ACADEMIC EMERGENCY MEDICINE 2010; 17:444–451 © 2010 by the Society for Academic Emergency Medicine     

Attitudes and Judgment of Emergency Physicians in the Management of Patients with Acute Headache

OBJECTIVES: There is little evidence guiding physicians in the evaluation of acute headache to rule out nontraumatic subarachnoid hemorrhage (SAH). The authors assessed emergency physicians in: 1) their pretest accuracy for predicting SAH, 2) their comfort with not ordering either head computed tomography (CT) or lumbar puncture (LP) in patients with acute headache, and 3) their comfort with not ordering head CT before performing LP in patients with acute headache. METHODS: This two-and-a-half-year prospective cohort study was conducted in three tertiary care university emergency departments with 51 emergency physicians. Consecutive patients more than 15 years of age with a nontraumatic, acute headache (onset to peak headache less than one hour) and normal results on neurologic examination were enrolled. Patients known to have cerebrospinal fluid shunt, aneurysm, or brain neoplasm, and patients with recurrent headaches of the same intensity/character as their current headache were excluded. Physicians recorded their pretest probability for SAH and their comfort with performing either no tests or an LP without first obtaining head CT. RESULTS: The authors enrolled 747 patients (mean age 42.8 years; 60.1% female; 77.0% their worst headache; 83.4% had CT and/or LP), including 50 (6.7%) with SAHs. Physicians reported being "uncomfortable" or "very uncomfortable" with performing no test in 75.4% of cases and being "uncomfortable" or "very uncomfortable" with performing LP without CT in 49.6% of cases. The area under the receiver operating characteristic (ROC) curve for SAH was 0.85 (95% CI = 0.80 to 0.91). CONCLUSIONS: Physicians were able to moderately discriminate SAH from other causes of headache before diagnostic testing.     

Computed Tomographic Angiography for the Evaluation of Aneurysmal Subarachnoid Hemorrhage

Objectives: Computed tomography (CT) followed by lumbar puncture (LP) is currently the criterion standard for diagnosing subarachnoid hemorrhage (SAH) in the emergency department (ED); however, this is based on studies involving a limited number of patients. The authors sought to assess the ability of CT angiography (CTA), a new diagnostic modality, in conjunction with CT/LP to detect SAH. Methods: Consecutive patients presenting to the ED with symptoms concerning for SAH were approached. All patients had an intravenous catheter placed and underwent a noncontrast head CT followed by CTA. Patients whose CT did not reveal evidence of SAH or other pathology underwent LP in the ED. CTAs were read within 24 hours by a neuroradiologist blinded to the patient's history. Results: A total of 131 patients were approached, 116 were enrolled, and 106 completed the study. In six of 116 patients (5.1%), aneurysm was found on CTA with normal CT and positive findings on LP; three had a positive CTA with normal CT and LP findings (one of which had a negative cerebral angiogram), and there was one false‐positive CTA. Follow‐up of all 131 patients showed no previously undiagnosed intracranial pathology. In this patient population, 4.3% (5/116) were ultimately found to have an SAH and/or aneurysm. Conclusions: In this pilot study, CTA was found to be useful in the detection of cerebral aneurysms and may be useful in the diagnosis of aneurysmal SAH. A larger multicenter study would be useful to confirm these results.     

Subarachnoid hemorrhage diagnosis by computed tomography and lumbar puncture: Are fifth generation CT scanners better at identifying subarachnoid hemorrhage?

This study sought to determine the sensitivity and specificity of modern computed tomography (CT) scans for the diagnosis of subarachnoid hemorrhage (SAH). No studies have been done recently with fifth generation CT scanners to look at the diagnosis of SAH. A retrospective chart review was done of Emergency Department (ED), laboratory, and hospital records at Pitt County Memorial Hospital in Greenville, North Carolina over 1 year from January 1, 2002 to December 31, 2002. Patients presented with headache and had a CT scan of the head with a fifth generation multi-detector CT scanner followed by a lumbar puncture (LP) to rule out SAH. There were 177 patients who presented to the ED with headache and went on to have a CT scan and an LP to rule out SAH. No patients who had a negative CT were found to have a subarachoid hemorrhage. It is concluded that fifth generation CT scanners are probably more sensitive than earlier scanners at detecting SAH.     

Sensitivity of newer-generation computed tomography scanners for subarachnoid hemorrhage: a Bayesian analysis

Background

Subarachnoid hemorrhage (SAH) is a life-threatening condition considered in patients presenting to the emergency department (ED) with acute and severe-onset headache. Currently, the practice pattern for suspected SAH is to perform a non-contrasted computed tomography (CT) scan of the head, followed by lumbar puncture (LP) if the CT is negative. Newer-generation 16-slice CT scanners have been shown in one study to be very sensitive for SAH.

Objective

We sought to validate these findings at our institution by retrospectively analyzing the sensitivity of our 16-slice or better CT scanner and performing a bayesian analysis with the results.

Methods

We utilized ED electronic medical records and the Department of Neurosurgery research database to search for patients admitted from the ED with a diagnosis of SAH from January 1, 2005 to December 31, 2008. We found a total of 134 patients admitted with SAH during this time frame.

Results

Average age was 53.8 years; 62% were female. Presenting complaint was headache in 57%, paresthesia or weakness in 7%, unresponsive in 10%, confusion or altered mental status in 5%, and “other” in 10%. Sensitivity of 16-slice or better CT scanner in our study was 131/134, or 97.8% (95% confidence interval 93.1–99.4%). No patient with a negative CT had a lesion requiring intervention.

Conclusion

Our study confirms the high sensitivity of 16-slice or better CT scanners for SAH. This calls into question the need for LP after negative head CT when 16-slice CT or better is used.     

A Decision Guideline for Emergency Department Utilization of Noncontrast Head Computed Tomography in HIV-infected Patients

OBJECTIVE: To determine which neurologic signs or symptoms are predictive of new focal lesions on head CT in HIV-infected patients. METHODS: Prospective study with convenience sample enrollment of HIV-infected patients who presented to a large inner-city university-based ED over an 11-month period. Patients were assessed using a standardized neurologic evaluation to ascertain whether they had developed new or changed neurologic signs or symptoms. Patients with any new or changed neurologic findings had a head CT scan in the ED. The association between individual complaints or findings and new focal lesions on head CT was assessed by univariate analysis, and sensitivity, specificity, and positive predictive values were calculated. Stepwise logistic regression analysis was then carried out to estimate the relative risk for those variables independently associated with new focal lesions on CT scans. A decision guideline was developed incorporating those variables. RESULTS: One hundred ten patients were identified as having new or changed neurologic signs or symptoms and had a head CT done in the ED. Twenty-seven patients (24%) had focal lesions on head CT, of which 19 (18%) were identified as new focal lesions; eight of these (7%) demonstrated a mass effect. Clinical findings most strongly associated with new focal findings on head CT were: 1) new seizure, relative risk (RR) = 73.5, 95% CI = 6.2 to 873.0; 2) depressed or altered orientation, RR = 39.1, 95% CI = 4.6 to 330.0; and 3) headache, different in quality, RR = 27.0, 95% CI = 3.2 to 230.1. Use of these three findings as a screen for ordering head CT in the ED would have identified 95% (18/19) of the patients with new focal intracranial lesions, and resulted in a 53% reduction in the number of head CTs ordered in the ED. Inclusion of one additional parameter (prolonged headache, > or =3 days), would have resulted in identification of 100% of all new focal lesions, with a 37% reduction in the number of head CTs ordered. Among those patients with new focal findings, 74% required emergent management (i.e., seizure control, IV antibiotics, IV steroids or surgery). The most common intracranial lesion among patients with CD4 counts less than 200 cells/microL was toxoplasmosis, while cerebrovascular accidents (ischemic or hemorrhagic) were most common in those with CD4 counts greater than 200 cells/microL. CONCLUSION: Specific clinical signs and symptoms were associated with the presence of new intracranial lesions in a group of HIV-infected patients who presented to the ED with neurologic complaints. These clinical findings can be incorporated into guidelines for determining the need for emergent head CT. Validation and widespread application of these guidelines could result in limiting the use of emergent neuroimaging to a more well-defined HIV-infected patient population.     

Mastoid bone fracture presenting as unusual delayed onset of facial nerve palsy

Delayed-onset facial nerve paralysis is a rather uncommon complication of a mastoid bone fracture for children younger than 10 years. We routinely arrange a cranial computed tomography (CT) for patients encountering initial loss of consciousness, severe headache, intractable vomiting, and/or any neurologic deficit arising from trauma to the head. However, minor symptomatic cranial nerve damage may be missed and the presenting symptom diagnosed as being a peripheral nerve problem. Herein, we report a case of a young boy who presented at our emergency department (ED) 3 days subsequent to his accident, complaining of hearing loss in the right ear and paralysis of the ipsilateral face. Unpredictably, we observed his cranial CT scan revealing a linear fracture of the skull over the right temporal bone involving the right mastoid air cells. The patient was treated conservatively and recovered well without any adverse neurologic consequences. We emphasize that ED physicians should arrange a cranial CT scan for a head-injured child with symptomatic facial nerve palsy, even if there are no symptoms such as severe headache, vomiting, Battle sign, and/or initial loss of consciousness.     

动脉瘤性蛛网膜下腔出血后头痛病因学分析

目的分析动脉瘤性蛛网膜下腔出血(SAH)后头痛的病因。方法对107例发病后24h内CT诊断为SAH,并经全脑动脉造影(DSA)明确存在颅内动脉瘤的患者,分别在出血后1、2、3、5、7、10、14d行头痛数字评分(NRS),对中、重度头痛患者行头颅CT和经颅三维多普勒(TCD)检查,分析头痛发生原因,观察不同类型头痛的临床特点。结果86.9%(93/107)的动脉瘤性SAH患者病程中存在中、重度头痛,其中9.7%(9/93)源自动脉瘤再出血,其临床特点是突然出现剧烈头痛或原有头痛骤然加重,常伴有意识障碍或其他神经系统阳性体征;16.1%(15/93)的头痛患者CT显示继发性脑积水,且头痛多持续性加重,但有时可突然自行缓解;TCD检查显示12.9%(12/93)的头痛患者存在颅内血管痉挛,并可因病情持续加重出现局灶性神经功能缺损及意识障碍,61.3%(57/93)的患者无阳性发现,但临床表现类似。结论大多数动脉瘤性SAH患者存在中、重度头痛。     

The role of lumbar puncture in the diagnosis of subarachnoid hemorrhage when computed tomography is unavailable

Subarachnoid hemorrhage (SAH) is an important but uncommon condition in the differential diagnosis of acute headache. Most authorities recommend that patients with suspected SAH undergo noncontrast computed tomography (CT) as a first diagnostic intervention. If the results of the CT scan are negative, a lumbar puncture should be performed. Many nonurban Canadian hospitals do not have CT scanners and must either transfer patients or consider performing lumbar puncture prior to CT. In selected patients, performing lumbar puncture first may be an option, but timing of the procedure and the interpretation of results is important.     

Diagnosis of subarachnoid hemorrhage in the emergency department

To decide which patients with headache ought to be evaluated for SAH, physicians should focus on specific elements of the patient history, such as onset, severity, and quality of the headache and associated symptoms. These questions should be asked and the responses documented for every patient with a headache. The physical examination should be compulsive with regard to vital signs, HEENT. and neurologic signs. Then, the physician should form an explicit differential diagnosis and have reasons for diagnosing migraine, tension, or sinus headache and other benign causes. If there is no clear-cut alternative hypothesis, the patient should be evaluated by CT and LP (if the CT is negative, equivocal, or technically inadequate). Physicians should understand the limitations of this diagnostic algorithm. In addition, the CSF should be carefully analyzed, including measuring the opening pressure. In patients whose CT scans and CSF analyses are normal, further testing is rarely indicated.     

Findings of Chronic Sinusitis on Brain Computed Tomography Are Not Associated with Acute Headaches

Background

Headache is a common complaint in emergency department (ED) patients. Nearly 15% of ED headache patients will have brain computed tomography (CT) done. One frequent finding on these scans is “chronic sinusitis.” Assuming that “chronic sinusitis” is the cause of the patient's headache is a potential source of mis-diagnosis.

Study Objective

We hypothesized that CT findings of chronic sinusitis occur with equal frequency in patients with atraumatic headache as in control patients with minor head injury.

Methods

This is a retrospective, single-center medical record review of consecutive discharged patients who received noncontrast head CT scans in an urban ED for either minor closed head injury or atraumatic headache. Each patient's head CT radiologic report was reviewed for findings of sinusitis and classified as chronic sinusitis, indeterminate for sinusitis, air-fluid levels, or no findings of sinusitis.

Results

We enrolled 500 patients (234 in the atraumatic headache group, 266 in the minor head injury group). The two groups were similar except that more women were enrolled in the atraumatic headache group. CT findings of chronic sinusitis in the atraumatic headache group (22.2%) and the minor head injury group (17.7%; difference 4.5%; 95% confidence interval of −2.5–11.6%).

Conclusion

Prevalence of CT findings of sinusitis in ED patients with atraumatic headaches and mild head injury are similar. This strongly suggests that CT findings of chronic sinusitis in patients with atraumatic headache may be incidental, and are rarely the cause of a patient's acute headache.     

The Risk of Intra‐abdominal Injuries in Pediatric Patients with Stable Blunt Abdominal Trauma and Negative Abdominal Computed Tomography

Objectives: This review examines the prevalence of intra‐abdominal injuries (IAI) and the negative predictive value (NPV) of an abdominal computed tomography (CT) in children who present with blunt abdominal trauma. Methods: MEDLINE, EMBASE, and Cochrane Library databases were searched. Studies were selected if they enrolled children with blunt abdominal trauma from the emergency department (ED) with significant mechanism of injury requiring an abdominal CT. The primary outcome measure was the rate of IAI in patients with negative initial abdominal CT. The secondary outcome measure was the number of laparotomies, angiographic embolizations, or repeat abdominal CTs in those with negative initial abdominal CTs. Results: Three studies met the inclusion criteria, comprising a total of 2,596 patients. The overall rate of IAI after a negative abdominal CT was 0.19% (95% confidence interval [CI] = 0.08% to 0.44%). The overall NPV of abdominal CT was 99.8% (95% CI = 99.6% to 99.9%). There were five patients (0.19%, 95% CI = 0.08% to 0.45%) who required additional intervention despite their initial negative CTs: one therapeutic laparotomy for bowel rupture, one diagnostic laparotomy for mesenteric hematoma and serosal tear, and three repeat abdominal CTs (one splenic and two renal injuries). None of the patients in the latter group required surgery or blood transfusion. Conclusions: The rate of IAI after blunt abdominal trauma with negative CT in children is low. Abdominal CT has a high NPV. The review shows that it might be safe to discharge a stable child home after a negative abdominal CT. ACADEMIC EMERGENCY MEDICINE 2010; 17:469–475 © 2010 by the Society for Academic Emergency Medicine     

The Ottawa subarachnoid hemorrhage clinical decision rule for classifying emergency department headache patients

BackgroundSubarachnoid hemorrhage (SAH) is a serious cause of headaches. The Ottawa subarachnoid hemorrhage (OSAH) rule helps identify SAH in patients with acute nontraumatic headache with high sensitivity, but provides limited information for identifying other intracranial pathology (ICP).ObjectivesTo assess the performance of the OSAH rule in emergency department (ED) headache patients and evaluate its impact on the diagnosis of intracranial hemorrhage (ICH) and other ICP.MethodWe conducted a retrospective cohort study from January 2016 to March 2017. Patients with acute headache with onset within 14 days of the ED visit, were included. We excluded patients with head trauma that occurred in the previous 7 days, new onset of abnormal neurologic findings, or consciousness disturbance. According to the OSAH rule, patients with any included predictors required further investigation.ResultsOf 913 patients were included, 15 of them were diagnosed with SAH. The OSAH rule had 100% (95% CI, 78.2%–100%) sensitivity and 37.0% (95% CI, 33.8–40.2%) specificity for identifying SAH. Twenty-two cases were identified as SAH or ICH with 100% sensitivity (95% CI, 84.6%–100%) and 37.3% (95% CI, 34.1%–40.5%) specificity. As for non-hemorrhagic ICP, both the sensitivity and negative predictive values (NPV) decreased to 75.0% (95% CI, 53.3%–90.2%) and 98.2% (95% CI, 96.1%–99.3%), respectively.ConclusionsThe OSAH rule had 100% sensitivity and NPV for diagnosing SAH and ICH with acute headache. The sensitivity and specificity were lower for non-hemorrhagic ICP. The OSAH rule may be an effective tool to exclude acute ICH and SAH in our setting.     

Sensitivity of New-generation Computed Tomography in Subarachnoid Hemorrhage

Objective: To determine the sensitivity of the initial new-generation CT (NGCT) scan interpretation for detection of acute nontraumatic subarachnoid hemorrhage (SAH) and to decide whether lumbar puncture (LP) should follow a "normal" NGCT scan.
Methods: A retrospective chart review was performed of patients admitted between March 1988 and July 1994 with proven SAH. Exclusion criteria were age <2 years, diagnosis other than acute SAH, history of head trauma within 24 hours before symptom onset, NGCT scan not done before diagnosis, and records not available. Patients were placed into two groups: symptom duration <24 hours (group 1) and >24 hours (group 2) prior to CT scan. The resolution of each NGCT scanner was recorded. An NGCT sceinner was defined as a third-generation scanner or more recent.
Results: Of 349 SAH patients, 181 met inclusion criteria. The sensitivity of NGCT scans for SAH was 93.1% for the group 1 patients ( n = 144) and 83.8% for the group 2 patients ( n = 37). The overall sensitivity was 91.2%. All the patients who had SAH not detected by NGCT scans were diagnosed by LP. There was no significant relationship between NGCT scanner resolution and sensitivity for SAH.
Conclusion: Initial interpretation of NGCT scans to detect SAH does not approach 100% sensitivity. A "normal" NGCT scan does not reliably exclude the need for LP in patients who have symptoms suggestive of SAH.     

The diagnostic and prognostic value of the optic nerve sheath diameter on CT for diagnosis spontaneous subarachnoid hemorrhage

Introduction

The aim of this study was to investigate the relationship between the optic nerve sheath diameter (ONSD) measured on non-contrast head computed tomography (CT) and the diagnosis and prognosis of spontaneous subarachnoid hemorrhage (SAH) on emergency department (ED) patients.

Sudden onset headache: a prospective study of features,incidence and causes

Sudden onset headache is a common condition that sometimes indicates a life-threatening subarachnoid haemorrhage (SAH) but is mostly harmless. We have performed a prospective study of 137 consecutive patients with this kind of headache (thunderclap headache=TCH). The examination included a CT scan, CSF examination and follow-up of patients with no SAH during the period between 2 days and 12 months after the headache attack. The incidence was 43 per 100 000 inhabitants >18 years of age per year; 11.3% of the patients with TCH had SAH. Findings in other patients indicated cerebral infarction (five), intracerebral haematoma (three), aseptic meningitis (four), cerebral oedema (one) and sinus thrombosis (one). Thus no specific finding indicating the underlying cause of the TCH attack was found in the majority of the patients. A slightly increased prevalence of migraine was found in the non-SAH patients (28%). The attacks occurred in 11 cases (8%) during sexual activity and two of these had an SAH. Nausea, neck stiffness, occipital location and impaired consciousness were significantly more frequent with SAH but did not occur in all cases. Location in the temporal region and pressing headache quality were the only features that were more common in non-SAH patients. Recurrent attacks of TCH occurred in 24% of the non-SAH patients. No SAH occurred later in this group, nor in any of the other patients. It was concluded that attacks caused by a SAH cannot be distinguished from non-SAH attacks on clinical grounds. It is important that patients with their first TCH attack are investigated with CT and CSF examination to exclude SAH, meningitis or cerebral infarction. The results from this and previous studies indicate that it is not necessary to perform angiography in patients with a TCH attack, provided that no symptoms or signs indicate a possible brain lesion and a CT scan and CSF examination have not indicated SAH.     

Cranial Computed Tomography in the Emergency Evaluation of Adult Patients without a Recent History of Head Trauma: A Prospective Analysis

Objectives: To examine the pattern of nontrauma cranial CT use in an urban ED, to identify the rate of significant CT abnormalities in this setting, and to develop criteria for restricting the ordering of CT scans. Methods: A prospective, observational study of a case series of adults who underwent cranial CT scanning for nontraumatic cases was performed at the EDs of an urban teaching hospital and an affiliated community hospital with a combined annual census of 110,000. Clinically significant CT scans were defined as: 1) acute stroke, 2) CNS malignancy, 3) acute hydrocephalus, 4) intracranial bleeding, or 5) intracranial infection, χ² recursive partitioning was used to derive a decision rule to restrict ordering of CT scans. Results: Only 61 (8%) of 806 CT scans revealed clinically significant abnormalities. The presence of any of the following: age ≥60 years, focal neurologic deficit, headache with vomiting, or altered mental status, was 100% sensitive (95% CI: 94–100%) and 31% specific (95% CI: 28–33%) in detecting clinically significant CT scans. This set of features had positive and negative predictive values of 11% (95% CI: 8–13%) and 100% (95% CI: 98–100%), respectively. If these criteria had been used to restrict cranial CT use, 229 fewer patients (28%) would have had CT scans obtained and no clinically significant abnormalities would have been missed.
Conclusion: Clinically significant CT abnormalities were uncommon in this study population, suggesting that current criteria for ordering nontrauma cranial CT scans may be too liberal. In this study, a set of clinical criteria was derived that may be useful at separating patients into high- and low-risk categories for clinically significant cranial CT abnormalities. Before these results are applied clinically, these criteria should be validated in larger, prospective studies.     

Evaluation of acute headaches in adults

Classifying headaches as primary (migraine, tension-type or cluster) or secondary can facilitate evaluation and management A detailed headache history helps to distinguish among the primary headache disorders. "Red flags" for secondary disorders include sudden onset of headache, onset of headache after 50 years of age, increased frequency or severity of headache, new onset of headache with an underlying medical condition, headache with concomitant systemic illness, focal neurologic signs or symptoms, papilledema and headache subsequent to head trauma. A thorough neurologic examination should be performed, with abnormal findings warranting neuroimaging to rule out intracranial pathology. The preferred imaging modality to rule out hemorrhage is noncontrast computed tomographic (CT) scanning followed by lumbar puncture if the CT scan is normal. Magnetic resonance imaging (MRI) is more expensive than CT scanning and less widely available; however, MRI reveals more detail and is necessary for imaging the posterior fossa. Cerebrospinal fluid (CSF) analysis can help to confirm or rule out hemorrhage, infection, tumor and disorders related to CSF hypertension or hypotension. Referral is appropriate for patients with headaches that are difficult to diagnose, or that worsen or fail to respond to management