Why Diagnosing Strokes is Complicated | News | Loyola Medicine
Monday, October 29, 2018

Diagnosing Strokes is Complicated by "Mimics" and "Chameleons"

 
MAYWOOD, IL – Stroke specialists often see conditions known as stroke "mimics" and "chameleons" that can complicate accurate diagnoses, Loyola Medicine neurologists report in the November 2018 issue of Neuroimaging Clinics of North America.
 
Stroke mimics are medical conditions that look like strokes, while chameleons are strokes that look like other conditions.
 
Diagnostic accuracy "may be complicated by the abundance of both 'stroke mimics' and 'stroke chameleons,'" neurologists Shannon Hextrum, MD, and José Biller, MD, wrote. Dr. Biller is professor and chair of the department of neurology of Loyola University Chicago Stritch School of Medicine. Dr. Hextrum completed a neurology residency at Loyola.
 
Drs. Biller and Hextrum examined mimics and chameleons associated with ischemic strokes, which account for about 85 percent of all strokes. Ischemic strokes are caused by blood clots that block blood flow to an area of the brain. (The other main type of stroke, hemorrhagic, is caused by bleeding in the brain.)
 
Permanent damage from an ischemic stroke can be minimized by quickly restoring blood flow. This can be done by administering the clot-busting IV drug tPA or by performing a minimally invasive surgery to remove the blood clot. But such treatments can do more harm than good if a patient is incorrectly diagnosed.
 
The exact prevalence of stroke mimics is unknown. According to previous studies, anywhere from 1.4 to 38 percent of patients admitted for suspected ischemic strokes actually have other conditions.
 
For example, Drs. Hextrum and Biller cite the case of a 79-year-old woman who experienced sudden weakness on the right side of her body and difficulty speaking – classic signs of a stroke. But a CT angiogram showed no evidence of stroke, and she later was correctly diagnosed as having viral encephalitis.
 
In another stroke mimic, a 60-year-old man had difficulty walking, speaking and reading. He also had vision problems that were preceded by a headache. The patient earlier had received radiation for a brain tumor. Rather than a stroke, he was experiencing SMART syndrome (stroke-like migraine attacks after radiation therapy).
 
A wide range of other conditions also can mimic ischemic strokes, including seizures, sepsis, low blood sugar, dizziness, vertigo, drug and alcohol toxicity and multiple sclerosis.
 
In treating an ischemic stroke, it's critically important to restore blood flow within the first few hours before brain cells die. But fewer than 10 percent of ischemic stroke patients receive a clot-busting drug and fewer still undergo surgery to remove the clot. One reason may be the prevalence of stroke chameleons.
 
Stroke chameleons with non-specific symptoms, such as nausea, vomiting and decreased mental activity, pose a particular challenge when triaging patients in the emergency room. But often, such patients also have neurologic deficits that can indicate a stroke.
 
Accurately diagnosing an ischemic stroke requires a detailed history and neurologic examination, which should not be rushed in an effort to speed administration of the clot-busting drug, Drs. Hextrum and Biller wrote.
 
They conclude: "Attention to subtleties of the neurologic examination and listening closely to patients remain critical for both diagnostic accuracy and development of sound clinical judgment."
 
Their paper is titled, "Clinical Distinction of Cerebral Ischemia and Triaging of Patients in the Emergency Department."
 

About Loyola Medicine

Loyola Medicine is a quaternary care system based in the western suburbs of Chicago that includes Loyola University Medical Center (LUMC) in Maywood, Gottlieb Memorial Hospital (GMH) in Melrose Park, MacNeal Hospital in Berwyn and convenient locations offering primary and specialty care services from more than 1,772 physicians throughout Cook, Will and DuPage counties. LUMC is a 547-licensed-bed hospital that includes the William G. and Mary A. Ryan Center for Heart & Vascular Medicine, the Cardinal Bernardin Cancer Center, a Level 1 trauma center, Illinois's largest burn center, a certified comprehensive stroke center and a children’s hospital. The medical center campus is also home to Loyola University Chicago Stritch School of Medicine, Loyola University Chicago Marcella Niehoff School of Nursing and the Loyola Center for Fitness. GMH is a 247-licensed-bed community hospital with 150 physician offices, an adult day care program, the Gottlieb Center for Fitness, the Loyola Center for Metabolic Surgery and Bariatric Care and the Loyola Cancer Care & Research at the Marjorie G. Weinberg Cancer Center at Melrose Park. MacNeal Hospital is a 374-bed teaching hospital with advanced inpatient and outpatient medical, surgical and psychiatric services, advanced diagnostics and treatments in a convenient community setting. Loyola Medicine is a member of Trinity Health, one of the nation’s largest health systems with 94 hospitals in 22 states.

About Trinity Health

Trinity Health is one of the largest multi-institutional Catholic health care delivery systems in the nation, serving diverse communities that include more than 30 million people across 22 states. Trinity Health includes 93 hospitals, as well as 122 continuing care programs that include PACE, senior living facilities, and home care and hospice services. Its continuing care programs provide nearly 2.5 million visits annually. Based in Livonia, Mich., and with annual operating revenues of $17.6 billion and assets of $23.4 billion, the organization returns $1.1 billion to its communities annually in the form of charity care and other community benefit programs. Trinity Health employs about 131,000 colleagues, including 7,500 employed physicians and clinicians. Committed to those who are poor and underserved in its communities, Trinity Health is known for its focus on the country's aging population. As a single, unified ministry, the organization is the innovator of Senior Emergency Departments, the largest not-for-profit provider of home health care services — ranked by number of visits — in the nation, as well as the nation’s leading provider of PACE (Program of All Inclusive Care for the Elderly) based on the number of available programs. For more information, visit www.trinity-health.org. You can also follow @TrinityHealthMI on Twitter.