Misdiagnosis of a neurologic emergency such as stroke can lead to serious morbidity or mortality. Using a large multi-state database, this study examined the likelihood of readmission or inpatient mortality among patients who were initially discharged with nonspecific diagnoses of headache or back pain and found that 0.5% of headache and 0.2% of back pain patients experienced an inpatient death or serious neurological event after ED discharge. Extrapolated to a national level, this translates to over 55,000 patients with adverse outcomes due to a missed diagnosis for headache or back pain.