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Editor’s Note: The TSG course on Stroke Mimics: Pearls and Pitfalls has been updated, one of several stroke/TIA offerings. The following includes a case review and a summary of important issues from that course. Timely and accurate recognition of neurologic deficit and stroke remains at the forefront of emergency medicine risk management and patient safety.

Stroke Mimics: Pearls and Pitfalls

Accurate recognition and management of stroke are critical not only for patient safety but also for minimizing medical-legal risk. Strokes are among the most time-sensitive medical emergencies, and delays in diagnosis can lead to irreversible neurological damage and expose providers to liability. Conversely, mistakenly treating a patient who is experiencing a stroke mimic as though they are having a true ischemic stroke—particularly by administering thrombolytics like IV tPA—can lead to serious complications, including hemorrhage, misdiagnosis, and harm from delayed identification of the actual condition. These situations are also a significant source of malpractice claims, especially when clinical documentation fails to demonstrate thorough reasoning or appropriate caution.

Stroke mimics are non-vascular conditions that present with stroke-like symptoms but are not caused by cerebral infarction. Common mimics include seizures, migraines, metabolic derangements, infections, and psychiatric or functional disorders. They account for roughly 25% to 35% of all acute stroke evaluations. In contrast, stroke chameleons are true strokes that present atypically, such as with confusion, agitation, or movement disorders, and may be missed altogether. Both pose unique challenges: mimics increase the risk of overtreatment, while chameleons heighten the risk of missed diagnoses.

Case Review

A cautionary example involves a patient who presented with sudden right-sided weakness and aphasia. Lacking definitive stroke risk factors and with no clear vascular territory match on exam, she nonetheless received IV tPA based on the acuity of presentation and concern for large vessel occlusion. Shortly after treatment, the patient developed a symptomatic intracranial hemorrhage. Subsequent imaging and neurologic evaluation revealed the true diagnosis: a complex migraine with prolonged aura—a known stroke mimic. This unfortunate outcome underscores the importance of integrating clinical history, physical exam consistency, and diagnostic imaging before administering high-risk interventions. Administering thrombolytics to patients with mimics may be justifiable in some cases but carries the risk of real harm when not adequately supported by clinical evidence.

Stroke chameleons, on the other hand, are actual strokes with misleading presentations, such as transient confusion, bilateral sensory symptoms, or movement disorders. These cases often evade early recognition because their symptoms don’t match typical stroke patterns. For instance, a thalamic or limbic infarct may present with memory disturbance or agitation, mimicking psychiatric illness. Recognizing these subtleties depends on identifying patterns such as sudden onset, negative symptoms (loss of function rather than added sensations), and the presence of stroke risk factors like atrial fibrillation or hypertension.

Clinicians must rely on a combination of diagnostic tools—including glucose testing, non-contrast CT, CT angiography, and, when available, diffusion-weighted MRI—to guide decision-making. While the urgency of stroke treatment often justifies erring on the side of caution, indiscriminate use of thrombolytics without adequate supporting evidence can lead to preventable harm. A well-documented clinical rationale, attention to red flags for mimics, and early involvement of neurology can help reduce both patient risk and legal exposure. In the face of uncertainty, shared decision-making and meticulous assessment are critical safeguards in the high-stakes landscape of stroke care.