Differentiating Strokes from Mimics

Upon initial assessment by emergency medical professionals, a patient may show signs of a "possible stroke," and display common symptoms associated with acute stroke. However, symptoms that appear to be characteristic of stroke may actually be indicative of another condition whose symptoms can mimic that of a stroke. Common conditions with symptoms mimicking that of stroke include head and neck trauma, hypoglycemia, seizure, migraine, drug overdose or toxic exposure. Stroke rehabilitation assessment and prescribed treatment protocol depends on correct diagnosis, making accuracy of stroke assessment by prehospital stroke care providers and stroke hospital professionals increasingly critical.

History

The incidence of stroke mimics has been well-documented in medical literature. A landmark study in the 1990s reviewed over 800 consecutive patients admitted to a Canadian stroke hospital from an emergency department, and found the initial diagnosis of stroke to be incorrect in 13 percent of patients. A two-year investigation by Libman et al found that of 400 consecutive patients admitted to an emergency department with an initial diagnosis of stroke,19 percent were found to have mimics following stroke assessment. More recently, Kothari et al compared the admitting diagnosis of stroke to and discharge diagnosis in over 400 patients, and found agreement in 96 percent of cases.

Because stroke-like symptoms can be common in a number of conditions, stroke certification can help healthcare providers conduct effective stroke assessment and help differentiate stroke from other conditions.

Consider the following scenario: A 43-year-old man with an unknown medical history was brought to the emergency room after being found lying in a parking lot. He was confused, mumbling, and incontinent, although his condition improved during transport to the hospital. His neurologic exam was notable for left arm weakness and facial droop, both of which were resolving. There were no other dramatically abnormal vital signs and his blood glucose and oxyhemoglobin levels were normal.

While the patient's symptoms, particularly arm drift and facial droop, may have appeared to be indicative of acute stroke, these symptoms were ultimately found to be caused by a phenomenon called Todd's paralysis, a focal neurologic deficit that follows a seizure and rarely lasts more than 24 hours before resolving completely.

Consider another scenario: A 60-year old Hispanic man is brought to the emergency room as a possible stroke patient. He is diaphoretic, tachycardic, and tachypneic, is moderately confused and responds slowly. The neurologic exam reveals slurred speech, his left arm and leg seem weaker than the right, and when questioned, the patient reports feeling weak and light-headed. He is wearing a medical ID bracelet that indicates that he has insulin-dependent diabetes mellitus and end-stage renal disease.

Again, while the patient’s initial symptoms suggest acute stroke, the cause of these mimicking symptoms was actually found to be hypoglycemia resulting in decreased level of consciousness and left-sided weakness. Like stroke, hypoglycemia must be considered in every patient with focal neurologic deficits, as the condition can produce symptoms that may mimic signs of acute stroke but represent problems that are generally easy to correct.

Stroke rehabilitation assessment today

Both of these examples demonstrate the importance of considering several causes for abnormal vital signs mirroring acute stroke symptoms, such as seizures or hypoglycemia. Stroke mimics may be discovered at different points in clinical investigation, including following admission to a stroke hospital and after extensive evaluation through physical exams, neuroimaging and laboratory work. However, distinguishing stroke mimics from actual strokes is increasingly important in this era of advanced stroke rehabilitation assessment and interventional stroke therapies with potential adverse effects.

For more information on acute stroke certification, visit the overview of stroke courses offered online.

The information included in this article is based on the 2020 guidelines for CPR, first aid and advanced cardiovascular care.