Atraumatic Headache in US Emergency Departments
Atraumatic Headache in US Emergency Departments
Objectives To estimate recent trends in CT/MRI utilisation among patients seeking emergency care for atraumatic headache in the USA and to identify factors associated with a diagnosis of significant intracranial pathology (ICP) in these patients.
Design/setting/participants Data were obtained from the USA National Hospital Ambulatory Medical Care Survey of emergency department (ED) visits between 1998 and 2008. A cohort of atraumatic headache-related visits were identified using preassigned 'reason-for-visit' codes. Sample visits were weighted to provide national estimates.
Results Between 1998 and 2008 the percentage of patients presenting to the ED with atraumatic headache who underwent imaging increased from 12.5% to 31.0% (p<0.01) while the prevalence of ICP among those visits decreased from 10.1% to 3.5% (p<0.05). The length of stay in the ED was 4.6 h (95% CI 4.4 to 4.8) for patients with headache who received imaging compared with 2.7 (95% CI 2.6 to 2.9) for those who did not. Of 18 factors evaluated in patients with headache, 10 were associated with a significantly increased odds of an ICP diagnosis: age ≥50 years, arrival by ambulance, triage immediacy <15 min, systolic blood pressure Hg or diastolic blood ≥160 mm Hg and disturbance in sensation, vision, speech or pressure ≥100 mm motor function including neurological weakness.
Conclusions The use of CT/MRI for evaluation of atraumatic headache increased dramatically in EDs in the USA between 1998 and 2008. The prevalence of ICP among patients who received CT/MRI declined concurrently, suggesting a role for clinical decision support to guide more judicious use of imaging.
Headache is one of the most common complaints in the emergency department (ED), accounting for approximately 1–3% of all visits. While the majority of headaches are benign and self-limited, a subset are associated with potentially life-threatening intracranial pathology (ICP). These patients may present with unremarkable symptoms and physical findings, impeding timely diagnosis. Owing to lack of high-quality data, clinical guidelines for imaging in atraumatic headache remain unclear; for example, current recommendations of the American College of Emergency Physicians (ACEP) and American College of Radiology (ACR) are ambiguous for patients with a non-focal neurological examination without red flags such as history of trauma or 'thunderclap' headache.
Multiple studies have shown that neuroimaging for ED patients who lack any red flags is unlikely to lead to discovery of significant ICP. An ACR expert panel review of CT use in patients with atraumatic headache but normal neurological examination reported a diagnostic yield of 0.4% in 897 studies of patients with migraine and 2.4% in 1825 patients with unspecified headache. Despite the low yield of imaging, nearly half of the respondents in an international survey of 2100 emergency physicians stated that every patient who presents to the ED with acute headache should categorically receive CT. Several studies indicate that the overall use of CT/MRI in EDs is increasing, including neuroimaging. Increased use of CT/MRI is associated with both monetary and non-monetary costs including increased exposure to ionising radiation.
A recent study evaluating national trends for the use of CT/MRI in EDs for injury-related conditions found that use of these procedures is increasing without a comparable increase in the prevalence of life-threatening diagnoses. No study to date has analysed comparable trends over the past decade among ED visits for atraumatic headache. The goals of this investigation are to describe national trends in utilisation of CT/MRI among ED patients with atraumatic headache between 1998 and 2008. We hypothesised that the use of CT/MRI has increased without a commensurate increase in the frequency of diagnosis of ICP. We also aimed to identify independent factors associated with an ICP diagnosis, underscoring the need for future prospective development of a clinical decision aid to guide more judicious use of imaging.
Abstract and Introduction
Abstract
Objectives To estimate recent trends in CT/MRI utilisation among patients seeking emergency care for atraumatic headache in the USA and to identify factors associated with a diagnosis of significant intracranial pathology (ICP) in these patients.
Design/setting/participants Data were obtained from the USA National Hospital Ambulatory Medical Care Survey of emergency department (ED) visits between 1998 and 2008. A cohort of atraumatic headache-related visits were identified using preassigned 'reason-for-visit' codes. Sample visits were weighted to provide national estimates.
Results Between 1998 and 2008 the percentage of patients presenting to the ED with atraumatic headache who underwent imaging increased from 12.5% to 31.0% (p<0.01) while the prevalence of ICP among those visits decreased from 10.1% to 3.5% (p<0.05). The length of stay in the ED was 4.6 h (95% CI 4.4 to 4.8) for patients with headache who received imaging compared with 2.7 (95% CI 2.6 to 2.9) for those who did not. Of 18 factors evaluated in patients with headache, 10 were associated with a significantly increased odds of an ICP diagnosis: age ≥50 years, arrival by ambulance, triage immediacy <15 min, systolic blood pressure Hg or diastolic blood ≥160 mm Hg and disturbance in sensation, vision, speech or pressure ≥100 mm motor function including neurological weakness.
Conclusions The use of CT/MRI for evaluation of atraumatic headache increased dramatically in EDs in the USA between 1998 and 2008. The prevalence of ICP among patients who received CT/MRI declined concurrently, suggesting a role for clinical decision support to guide more judicious use of imaging.
Introduction
Headache is one of the most common complaints in the emergency department (ED), accounting for approximately 1–3% of all visits. While the majority of headaches are benign and self-limited, a subset are associated with potentially life-threatening intracranial pathology (ICP). These patients may present with unremarkable symptoms and physical findings, impeding timely diagnosis. Owing to lack of high-quality data, clinical guidelines for imaging in atraumatic headache remain unclear; for example, current recommendations of the American College of Emergency Physicians (ACEP) and American College of Radiology (ACR) are ambiguous for patients with a non-focal neurological examination without red flags such as history of trauma or 'thunderclap' headache.
Multiple studies have shown that neuroimaging for ED patients who lack any red flags is unlikely to lead to discovery of significant ICP. An ACR expert panel review of CT use in patients with atraumatic headache but normal neurological examination reported a diagnostic yield of 0.4% in 897 studies of patients with migraine and 2.4% in 1825 patients with unspecified headache. Despite the low yield of imaging, nearly half of the respondents in an international survey of 2100 emergency physicians stated that every patient who presents to the ED with acute headache should categorically receive CT. Several studies indicate that the overall use of CT/MRI in EDs is increasing, including neuroimaging. Increased use of CT/MRI is associated with both monetary and non-monetary costs including increased exposure to ionising radiation.
A recent study evaluating national trends for the use of CT/MRI in EDs for injury-related conditions found that use of these procedures is increasing without a comparable increase in the prevalence of life-threatening diagnoses. No study to date has analysed comparable trends over the past decade among ED visits for atraumatic headache. The goals of this investigation are to describe national trends in utilisation of CT/MRI among ED patients with atraumatic headache between 1998 and 2008. We hypothesised that the use of CT/MRI has increased without a commensurate increase in the frequency of diagnosis of ICP. We also aimed to identify independent factors associated with an ICP diagnosis, underscoring the need for future prospective development of a clinical decision aid to guide more judicious use of imaging.
