When a TIA Isn’t a TIA

A transient ischemic attack, or TIA, is a "warning stroke" or "mini-stroke" that produces stroke-like symptoms but no lasting damage. It’s important to recognize and treat TIAs, as this can reduce the likelihood of a subsequent full-blown stroke. So emergency room personnel are highly aware of the symptoms of TIAs – perhaps almost too aware, according to a new report given at the American Academy of Neurology meeting. A team working at Rush University Medical Center, headed by Professor Probhakaran, studied the final diagnoses in patients originally admitted to hospital with a TIA diagnosis. They examined records from 100 consecutive patients with transient ischemic episodes lasting less than 24 hours admitted as TIAs, focusing on the final diagnoses made by a stroke neurologist.

Of the 100 patients whose records were selected, 40 were confirmed as TIAs, while the rest had another final diagnosis. The 60 misdiagnosed patients had migraine (14) cases), non-typical seizure (13), toxic effects of a drug, infection, blood pressure or blood glucose abnormality (13), psychiatric disorder (8), compressive neuropathy (7), or unclassifiable (4). The members of this non-TIA group were more likely to be women, Hispanic, and have a history of non-TIA-like neurological symptoms.

Some of the misdiagnosed patients had quite serious conditions, while in others the cause of their symptoms was relatively benign. This shows that ER professionals would do well to try to sharpen their diagnostic skills in this area. Certainly all patients with TIA-like symptoms should be given expert attention, as the risk of a stroke after a TIA is real. But inaccurate TIA diagnosis can cause unnecessary stress for patients.

Once again, here are the symptoms of TIA:

• Sudden numbness or weakness of the face, arm or leg, especially on one side
• Sudden confusion, trouble speaking or understanding
• Sudden trouble seeing in one or both eyes
• Sudden trouble walking, dizziness, loss of balance or coordination
• Sudden, severe headache with no known cause

(Only one in 10 of the true-bill TIAs in the study had a gradual onset of symptoms.)

The short duration of symptoms and lack of permanent brain injury is the main difference between a TIA and a stroke.