The Doctor’s Advocate | First Quarter 2013
TIA Recognition and Management
by David B. Troxel, MD, Medical Director, Board of Governors
On July 23, a 56-year-old male presented to an urgent care center. While working on his computer, he had suddenly experienced a blank stare, his right hand started shaking, and his fingers began moving involuntarily. The episode lasted five minutes, and he was now asymptomatic. However, the history form completed by the patient was nonsensical, a detail not brought to the physician’s attention by office staff. His blood pressure was 140/95. Our insured found no neurological deficits in the upper extremities. His differential diagnosis was absence seizure versus transient ischemic attack (TIA).
What Would You Have Done?
The insured instructed the patient to see his primary care physician (PCP) and a neurologist that same day and to take an aspirin daily. He did not arrange for a referral to a specific neurologist or call the PCP.
The next day, the PCP saw the patient and noted a tremor in his right hand. The patient was told to follow up with a neurologist and, if symptoms recurred, to go to the emergency room (ER). The PCP did not refer him to a specific neurologist.
On July 26, the patient developed slurred speech and went to the ER. A brain CT showed an early left nonhemorrhagic cerebral infarction in the distribution of the middle cerebral artery (MCA). He was seen by a neurologist, who noted right-sided weakness, facial droop, and expressive aphasia. It was determined he was not a candidate for tPA. Magnetic resonance angiography (MRA) revealed occlusion of the left internal carotid artery.
He was discharged to a rehabilitation center on July 28 and was found the next day slumped over with weakness of the right upper extremity. His blood pressure was 145/100. He was taken back to the hospital; a brain CT showed that the infarction was slightly larger. An MRA on July 31 suggested carotid dissection. It was recommended that the patient remain on Lovenox and aspirin for several months. He returned to the rehabilitation center and was discharged two weeks later with use of all extremities, facial weakness, and residual expressive aphasia.
A claim was filed alleging failure to diagnose and treat an acute neurological event and failure to refer to an acute care facility.
Expert Opinion: Plaintiff
Neurologists opined the insured deviated from the standard of care by failing to perform a complete neurological examination, for not recognizing the TIA, and for failing to address the elevated blood pressure.
The patient should have been admitted to the ER by the insured on July 23 and by the PCP on July 24. The ER physicians would have recognized the TIA and arranged for a neurological consultation with testing to include brain and vascular imaging to identify the internal carotid artery occlusion. With heparin and/or stenting or surgery, it’s likely the stroke could have been prevented. By the time the patient presented to the ER, no treatment would have made a difference in outcome. Considering the high risk of stroke within 24 to 48 hours, it was insufficient for both physicians to refer the patient to a neurologist without ensuring he could be seen that day. Furthermore, if the insured suspected absence spells or TIA, he should not have let the patient drive home.
A neurosurgeon testified that when the patient first presented, he was experiencing ischemia from occlusion of the MCA due to a thromboembolism from the internal carotid artery dissection. Had the dissection been diagnosed, the patient would have been anticoagulated. If his signs and symptoms progressed, endovascular angioplasty and stenting could have been performed. If not, anticoagulant therapy would have continued.
Expert Opinion: Defense
Internists opined that TIA is not routinely considered a medical emergency. While the standard of care for TIA requires imaging studies, the insured was not convinced this episode was a TIA because the history that computer work provoked it was consistent with a seizure, and the nonsensical history form was consistent with the postictal phase of a seizure.
If the patient had been referred to the ER initially and was asymptomatic, it is likely physicians would have concluded he’d had a seizure or a TIA and would have obtained a CT scan—which would have been negative at that time. He might not have been admitted for additional studies. Even if the results of a carotid ultrasound showed an occlusion, he was without signs and symptoms and would have been discharged on aspirin with the same outcome.
A neurologist opined that the insured’s differential diagnosis should have included a focal seizure—a more likely explanation for the transient hand shaking. The standard of care for a focal seizure includes referral to a neurologist and a brain scan, because the differential diagnosis includes brain tumor as well as stroke. The insured’s instruction to take aspirin and return to the ER if further events occurred was reasonable. Unfortunately, even if the insured had ordered a brain scan and neurology consult, the stroke probably would not have been averted. If, on the day the patient was seen by the insured, a carotid ultrasound or an MRA had been performed and the diagnosis of carotid occlusion made, it’s unlikely he’d have been hospitalized or received emergency treatment, given his asymptomatic state.
Failure to recognize subtle transient neurologic deficits as a TIA or a harbinger of impending stroke can lead to a claim if a stroke subsequently occurs. The public, increasingly aware of the importance of getting to a stroke center or ER for immediate evaluation and treatment, is likely to be unforgiving with caregivers who fail to act. The following discussion is a summary of the referenced UpToDate review, which I highly recommend.
TIA was originally defined as a sudden onset of a focal neurologic symptom and/or sign lasting less than 24 hours and caused by reversible cerebral ischemia. However, there is risk of infarction even when focal transient neurologic symptoms last less than one hour. Thus, even relatively brief ischemia can cause permanent brain injury.
TIA is now defined as a transient episode of neurologic dysfunction caused by focal brain, spinal cord, or retinal ischemia without acute infarction. Ischemic stroke is defined as infarction of central nervous system tissue.
Of importance is that patients with TIA (or minor stroke) are at increased risk of subsequent (or recurrent) stroke (4 to 10 percent in the first 48 hours) and therefore require urgent evaluation and treatment, which may substantially reduce this risk. Urgent assessment and management are essential regardless of inpatient or outpatient status.
The 2009 American Heart Association and American Stroke Association (AHA/ASA) guidelines for the definition and evaluation of TIA state that it is reasonable to hospitalize patients with TIA who present within 72 hours of symptom onset based on ABCD2 score criteria. The ABCD2 score (Age, Blood pressure, Clinical features, Duration of symptoms, and Diabetes) is a prognostic assessment tool designed to identify patients at high risk of ischemic stroke in the first two days after TIA. They recommend routine noninvasive imaging of the cervicocephalic vessels and, for patients with embolic TIA, cardiac monitoring to exclude atrial fibrillation.
The 2006 National Stroke Association consensus recommendations regarding initial management that follow are based on observational studies and clinical experience:
- Hospitalization should be considered for patients with a first TIA within the past 24 to 48 hours and for patients with the following conditions:
- Crescendo TIAs
- Duration of symptoms >one hour
- Symptomatic internal carotid artery stenosis >50 percent
- Known cardiac source of embolus, such as atrial fibrillation
- Known hypercoagulable state
- High risk of early stroke after TIA
- Patients who need urgent evaluation and are not hospitalized should have rapid access to the following studies:
- Brain imaging with head CT and/or MRI
- Neurovascular studies, such as CT angiography (CTA), MRA, and/or ultrasound
- All patients with a TIA within the past two weeks who are not hospitalized should undergo investigations within 24 to 48 hours to determine the mechanism of ischemia and subsequent preventive therapy.
- Patients who are not admitted should be informed they need to go to an ER immediately if symptoms recur. Brain imaging with CT or MRI as soon as possible is indicated in all patients with suspected TIA or minor stroke.
The most important issue in the initial evaluation of TIA and ischemic stroke is whether there is an obstructive lesion in a larger artery supplying the affected territory. Noninvasive options for evaluation of large vessel occlusive disease include MRA, CTA, carotid duplex ultrasonography, and transcranial Doppler ultrasonography. The choice among these studies depends on local availability and expertise. Early evaluation and intervention for symptomatic carotid artery disease are also important aspects of stroke prevention. These measures should be implemented without delay, preferably within one day of the ischemic event, for patients who present with TIA or minor ischemic stroke.