Does Dizziness Cause You Diagnostic Disequilibrium?

Although most providers have developed a standardized approach for the evaluation of dizziness, the variation from one provider to the next is likely as vast as the difference in the ways patients report their symptoms.

For several reasons, including improved outcomes, utilization control, operational efficiency, and patient safety, it’s time to narrow the gap in practice variation.

Most cases of vertigo are benign and are not associated with serious pathology or likely to result in bad outcomes no matter what we do. However, the real key is to trim the diagnostic fat without becoming so diagnostically lean that you miss something important. One way, and perhaps the most common, is the shotgun approach (check all the boxes and let the tests guide you), and another is the dartboard approach (random selection of testing combinations based on gestalt). However, a rational approach to dizziness is available with a review of the evidence.

Nine months ago, I started down my evidence-based pathway, evaluating a 67-year-old female patient with new-onset dizziness. I was working at a facility that had easy access to MRI. Despite the fact that brain CT lacks sensitivity for posterior fossa pathology, it is often ordered in the evaluation of dizziness. We do so because MRI frequently isn’t available emergently for this complaint and brain imaging of some kind just seems to make sense. Well, with MRI readily available, I elected not to order the standard CT, which rarely if ever yielded any positive findings, and ordered an MRI, which ultimately was normal as well. This patient led me to challenge whether imaging is necessary at all in patients with dizziness, whether CT has any utility, and in which patients imaging should be obtained. Three studies answered these questions for me, taking care of my diagnostic disequilibrium.

In 2012, Chase et al from Beth Israel Deaconess Medical Center in Boston published a study to determine what clinical factors were associated with stroke in vertiginous patients.¹ MRIs of the brain were obtained during the ED visit or within two weeks. Of the 131 patients, 12 (9.2 percent) experienced a cerebellar or brainstem stroke (posterior fossa). CTs were negative in all five stroke cases in which one was performed. The complaint of gait instability and subtle neurological findings were associated with stroke, with odds ratios (ORs) of 9.3 and 8.7, respectively. Of particular note was that nystagmus was only present in a third of those with stroke and in a fifth of those without stroke.

Also in 2012, Navi et al published a paper reviewing the records of 907 patients presenting to the University of California, San Francisco emergency department between 2007 and 2009. The patients presented with the complaint of dizziness, vertigo, or imbalance for a mean duration of one day.

There was substantial variation in the diagnostic evaluations performed. Laboratory diagnostics were ordered in 72 percent, ECGs were performed on 68 percent, neuroimaging in 35 percent, and neurology consultation in 20 percent of the patients. Serious neurological disease was identified in 5 percent, with stroke being the most common (diagnosed in 3 percent). The independent predictors for serious neurological disease were:

• Focal neurological abnormalities: OR 5.9
• 60 years of age or older: OR 5.7
• Imbalance: OR 5.9
• Isolated dizziness: OR 0.20

Patients older than 60 experiencing imbalance with an identifiable focal neurological abnormality were the most likely to experience serious neurological disease. However, even more helpful is the OR of 0.20 when the patient experienced isolated dizziness. Patients experiencing isolated dizziness and no other symptoms or neurological abnormalities were 80 percent less likely to be experiencing a serious neurological cause.

Finally, in September 2013, Ahsan et al evaluated the costs and utility of neuroimaging of ED patients complaining of dizziness. A total of 1,681 patients seen at Henry Ford Hospital’s ED in Detroit from 2008 to 2011 were included. CTs were performed 48 percent of the time; MRIs, only 5 percent of the time. Overall, 0.74 percent of the CTs were abnormal (6/810), as were 12 percent of the MRIs (11/90). The cost associated with identifying one abnormal CT was $164,700 and $22,058 for a positive MRI. In addition, all patients with a positive CT or MRI had a headache, neurological findings on examination, or ophthalmological complaints along with their dizziness.

Dr. Klauer is the chief medical officer–emergency medicine and chief risk officer for TeamHealth as well as the executive director of the TeamHealth Patient Safety Organization. He is an assistant clinical professor at Michigan State University College of Osteopathic Medicine, speaker of the ACEP Council, and medical editor-in-chief of ACEP Now.

References

1. Chase M, Joyce NR, Carney E, et al. ED patients with vertigo: can we identify clinical factors associated with acute stroke? Am J Emerg Med. 2012;30:587.
2. Navi BB, Kamel H, Shah MP, et al. Rate and predictors of serious neurologic causes of dizziness in the emergency department. Mayo Clin Proc. 2012;87:1080.
3. Ahsan SF, Syamal MN, Yaremchuk K, et al. The costs and utility of imaging in evaluating dizzy patients in the emergency room. Laryngoscope. 2013;123:2250.