Study: Reconsider the use of CT scans for patients who present with dizziness

A thorough history and exam can yield more information, save costs

When patients present to the ED with dizziness, oftentimes the provider will order a computed tomography (CT) scan to rule out serious medical problems, such as intracranial bleeding or stroke. However, a new study suggests that such scans may not be worth the expense in the vast majority of cases.

According to researchers at Henry Ford Hospital in Detroit, MI, their findings suggest that it may be much more cost-effective for hospitals to implement stricter guidelines for ordering CT scans of the brain and head for patients who present with dizziness. Such a move would not only cut costs, but also limit radiation exposure to patients from CT scans, say researchers.

Narrow in on a differential diagnosis

The study, which was presented at the annual Triological Society's Combined Sections Meeting in Miami Beach, FL, on January 26, involved a retrospective review of 1,681 patients who were experiencing dizziness or vertigo when they entered a Detroit ED between January 2008 and January 2011. Nearly half of these patients received a CT scan of the brain and head. However, less than 1% of these scans (0.74%) revealed significant underlying conditions requiring intervention, according to researchers. Furthermore, the total cost for the CT scans over the three-year period was $988,200.

Syed Ahsan, MD, the lead author of the study and a neuro-otologist in the Department of Otolaryngology-Head & Neck Surgery at Henry Ford Hospital, explains that while dizziness can be a signal for intracranial bleeding or stroke, it is much more commonly related to dehydration, anemia, a drop in blood pressure with standing, inflammation or other problems of the inner ear, Meniere's disease, or vestibular neuritis. He says a more thorough evaluation can help providers narrow in on a differential diagnosis.

"Proper evaluation should include information such as the duration of dizziness/vertigo, the triggers of the dizziness (positional, activity), and associated symptoms [such as] migraine, headaches, dysarthria, ataxia, unilateral weakness, hearing loss, and tinnitus," explains Ahsan. "Also, in the elderly, we must be aware of polypharmacy (more than four drugs) as a common cause of dizziness and lightheadedness."

In the Henry Ford study, the patients who had some abnormal findings on CT scans had severe headaches or some neurological deficits, notes Ahsan. "It is important to perform a thorough, but directed, physical exam," he says. "Check for orthostatic hypotension, perform an ear exam, evaluate the cranial nerves, look for spontaneous or positional nystagmus, and most importantly, perform a Dix-Hallpike test to assess for BPPV (benign paroxsmal positional vertigo) and a head thrust test or HTT to assess for vestibular deficits."

Ahsan explains that a positive Dix-Hallpike test would suggest BPPV as the cause, and a simple positioning maneuver performed by an otolaryngologist could be employed to treat the problem. Alternatively, he explains that a positive HTT would suggest vestibular neuritis or labyrinthine dysfunction. "Rarely does cerebellar infarction or hematoma cause a positive HTT," says Ahsan.

Consider the probabilities

As a general rule, if a patient presents with isolated dizziness, light-headedness, or positional vertigo without any other symptoms, the likelihood of finding an acute, life-threatening abnormality on a CT scan is quite low, advises Ahsan. "If a patient has a severe, new onset headache, along with dizziness, or if there is ataxia and/or dysarthria, then a CT of the brain may be helpful," he says. "But if the practitioner is concerned with cerebellar stroke or bleed, then an MRI is indicated since CT does not give a good picture of the posterior fossa region."

The bottom line is that a good history and exam will indicate that most cases of dizziness, even when they are coupled with mild headaches, are not urgent, says Ahsan. "In a patient presenting with dizziness after a fall or head injury, and with a physical exam ruling out BPPV or labyrinthine dysfunction, then a CT would be helpful in ruling out an intracranial bleed."

Acting on the results of this study, Henry Ford Hospital plans to implement the use of routine Dix-Hallpike, HTT, and orthostatic BP evaluations, and the evaluation of nystagmus in the ED to see whether these measures decrease the rate of CTs performed while also improving diagnostic accuracy, explains Ahsan. "We hope to decrease the time spent in the ED and the overall cost of evaluation," he says.

Source

Syed Ahsan, MD, Neuro-otologist, Department of Otolaryngology-Head & Neck Surgery, Henry Ford Hospital, Detroit. Phone: 1-800-436-7936.