Literature suggests a very low rate of clinically significant imaging findings in psychiatric patients without risk factors for organic illness. The yield of a clinically significant finding on a CT of the head in uncomplicated schizophrenia patients with normal vital signs and an otherwise normal physical exam (even if it is a first-time presentation) was published in a Canadian Journal of Emergency Medicine study.¹⁰ From three Ontario hospitals, the yield was one in 300. Another review of five studies from 2009 showed the diagnostic yield to be only 1.3 percent for CTs and 1.1 percent for MRIs in 384 CTs and 184 MRIs of first episode psychosis patients. CT is clinically indicated in psychiatric patients with altered mental status, trauma, immunodeficiency, or focal neurological findings.

Three Main Take-Home Points in Medical Clearance

1. Approach to psychiatric patients should be the same as your approach to any medical patient. An adequate history and physical are essential.
2. Know which patients are at high risk for an organic cause of their behavioral presentation so that you have a heightened awareness for organic pathology in these patients.
3. There is no evidence for benefit of routine diagnostic screening; tests should be ordered just as you would for medical patients, guided by the presenting complaint and findings on a thorough history and physical examination.

Thanks to Howard Ovens, Ian Dawe, and Brian Steinhart for their expert contributions to the EM Cases podcast that inspired this article.

Dr. Helman is an emergency physician at North York General Hospital in Toronto. He is an assistant professor at the University of Toronto, Division of Emergency Medicine, and the education innovation lead at the Schwartz/Reisman Emergency Medicine Institute. He is the founder and host of Emergency Medicine Cases podcast and website.

References

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