Head CT is poor screening tool for ED

CT scans may not be the most effective tool for examining emergency department (ED) patients complaining of dizziness or fainting, according to a study published online this month in the American Journal of Roentgenology.

According to study authors Myles M. Mitsunaga, MD, of the John A. Burns School of Medicine at the University of Honolulu, and Hyo-Chun Yoon, MD, of the Kaiser Foundation Hospital in Honolulu, more than 3 percent of all ED visits annually are due to dizziness while 1.9 percent are due to fainting or near fainting spells.

The authors contend that despite warnings to avoid head CT scans unless fainting is not suspected to the reason for loss of consciousness, these types of scans seem to be a common way to evaluate patients complaining of syncope.

“We analyzed consecutive patients who underwent head CT from the ED for a primary complaint of dizziness, near-syncope, or syncope,” Mitsunaga and Yoon wrote.  “Our objectives were: first, to determine the yield of acute findings on head CT in patients presenting to the ED with dizziness, near-syncope, or syncope; and, second, to determine the clinical factors that potentially predicted acutely abnormal head CT findings and subsequent hospital admission in these patients.”

The study focused on 489 patients who were seen in the ED for dizziness or fainting (or near-fainting) and who also underwent a head CT scan.

A total of 253 patients were seen for dizziness and of these, only 7.1 percent had an acutely abnormal head CT finding. The abnormal findings included possible acute infarct, intracranial hemorrhage, intercranial masses, hydrocephalus and skull fracture.

Of the 236 patients with fainting or near-fainting, 6.4 percent had acutely abnormal head CT findings. These findings included intracranial hemorrhage, possible acute infarct, intracranial masses and skull fracture.

Additionally, the researchers found the following three clinical factors were correlated with abnormal findings: a focal neurologic deficit, patient age greater than 60 years and acute head trauma.

“The ED physician also faces two seemingly conflicting challenges—first, rapidly identifying cases that require emergent care and, ideally, alleviating the symptoms or triaging the patient to a specialist, and second, using resources appropriately,” Mitsunaga and Yoon wrote.

 They contend that in an effort to quickly identify true emergencies, emergency physicians may rely on head CT scans despite their low diagnostic yields. Head CT, the authors wrote, should be used as a diagnostic test and not a screening exam.

“Our results suggest that most patients presenting with syncope or dizziness to the emergency department may not benefit from head CT unless they are older, have a focal neurologic deficit, or have a history of recent head trauma,” Mitsunanga and Yoon wrote.