This case highlights the recommendation that all patients with transient neurologic symptoms should have brain imaging not only to look for ischemia but also to look for other causes of transient neurologic symptoms.
Hemorrhage is a rare, but important, cause of transient neurologic symptoms. Many different mimics of transient ischemic attack exist, as in this case. He was referred for neurosurgical assessment.Ĭomment. Urgent brain CT showed a left-sided chronic subdural hematoma. He had no significant past medical history and was on no medications. 10,11Ī 75-year-old man presented to the emergency department after experiencing a 10-minute episode of right hand weakness 2 hours earlier, after which he completely returned to normal. 10 Although the proportion of patients with true ischemia is lower in those without motor or speech symptoms, it is important not to miss patients with true TIAs and minor ischemic strokes. Posterior circulation ischemia can pose an additional diagnostic challenge as symptoms are more variable than those that occur with hemispheric ischemia. 9 This is likely related to the higher probability of a nonischemic cause of symptoms in these patients. 8 However, patients who present with symptoms other than motor and speech symptoms (eg, sensory symptoms or dizziness) have a more uncertain etiology. Motor and speech symptoms may have a higher likelihood of brain ischemia as the cause of the symptoms because the differential diagnosis for such clinical presentations is much narrower, and patients who present with motor or speech symptoms are known to be at high risk for recurrent stroke. The prevalence of these mimics is higher among clinical presentations without motor and speech symptoms. Some have, indeed, had an ischemic event, but others have had symptoms related to a stroke or TIA mimic, such as migraine, epilepsy, multiple sclerosis, or peripheral nerve entrapment ( Case 4-2). One of the problems with assessment is that half of all patients presenting to emergency departments and physicians’ offices in North America with transient or mild neurologic deficits have symptoms with an uncertain diagnosis or prognosis. Even experts do not agree about which clinical events are in fact TIAs. Because patients vary in reliability in reporting the events they have experienced, even an astute physician may find it challenging to make a certain diagnosis based on the history and physical examination alone. Symptoms are attributed to ischemia based mainly on the time course of the deficits (an acute deficit is more consistent with ischemia), the distribution of the deficits, and background risk factors for ischemia in the patient. A limitation of the clinical definitions of stroke and TIA is that they rely on the presumed cause of the symptoms: ischemia. The main criteria used are the clinical history or objective findings on neurologic examination consistent with focal neurologic dysfunction at some point of the evaluation and imaging of the brain. The diagnosis of TIA depends on the quality and quantity of information available and the time of assessment. Very early assessment of these patients also makes the distinction between TIA and minor ischemic stroke difficult.
Treatment to prevent ischemic stroke following TIA and treatment to prevent recurrent stroke following minor ischemic stroke are also similar. Although this article focuses primarily on TIA, a significant difference in the outcome of TIA compared to minor ischemic stroke has not been demonstrated by compelling evidence. 3,4 It is also relevant that the diagnoses of TIA and minor stroke are commonly used interchangeably and recorded as such in medical records. The time-based definition has been debated in light of diffusion-weighted MRI demonstrating relevant ischemic lesions in 30% to 50% of patients fulfilling the time-based definition of TIA ( Case 4-1).
The historical time-based definition of TIA was based on full resolution of all symptoms within 24 hours of onset. It is important to note that TIA and stroke represent different ends of an ischemic continuum from the physiologic perspective, but clinical management is similar. The clinical definitions of TIA and ischemic stroke are based on focal neurologic signs or symptoms referable to known cerebral arterial distributions without direct measurement of blood flow or cerebral infarction.