Aug. 11, 9 p.m.
Episode: "Mother's Day"
Shirley Riddle, an elderly woman, collapses, shaking, outside the emergency room. Her daughter, Maureen (Erinn Hayes), tells Dr. Brenda Marshall (Anne Ramsay), the doctor on duty, that her mother's apparent seizure was preceded by an episode in which she slurred her words, started shaking and became unconscious as she was getting out of the car. Marshall believes that the woman may be having a stroke.
Maureen tells Marshall that her mother has no history of migraines, seizures, smoking or drug or alcohol use. A CT scan of the brain is negative, so Marshall starts Shirley on a clot-dissolving drug, tPA (Tissue Plasminogen Activator), to treat the stroke. But nurse Kelly Epson (Vanessa Lengies) elicits further history from Maureen, who discloses that her mother was actually sick from the day before -- speaking gibberish, dropping her coffee cup and appearing disoriented. Kelly believes that the tPA should be stopped, as it is only effective within a three-hour window after the onset of symptoms and can make the stroke worse by causing intracranial bleeding, especially if given too late. At first, Marshall ignores Kelly. But Kelly repeats the story to other doctors in the ER, and the tPA is stopped. Shirley is moved to the intensive care unit.
The medical questions
Is the timetable of symptoms important in determining immediate treatment for a stroke? Can a seizure be a feature of one? Why must tPA be given within a three-hour period to be effective? Are the risks of bleeding much greater if tPA is given later? Should a doctor accept input from a nurse in obtaining an accurate history?
The drug tPA increases production of the clot-dissolving enzyme plasmin at the site of the clot. It is FDA-approved for use within three hours of the onset of symptoms of an ischemic stroke (one caused by a blood clot). Most studies don't show benefit beyond that time frame, says Dr. David Liebeskind, associate neurology director at the UCLA Stroke Center. But recent data suggest that there may be some benefit for up to four and a half hours, adds Dr. Larry B. Goldstein, director of the stroke center at Duke University Medical Center.
Goldstein and Liebeskind agree that if the original symptoms the day before were temporary (suggesting a patient experienced a transient ischemic attack, in which a cutoff of oxygen to part of the brain is only temporary), it may still be legitimate to consider tPA. That would especially be the case if there were no signs yet of permanent damage on the CT scan. So Nurse Kelly would be right in saying the tPA treatment should stop if the stroke really began the day before. But given the normal CT scan, it is more likely that she is wrong and the earlier symptoms were just a transient ischemic attack and a warning that a stroke may be imminent.
There is a narrow window for the effectiveness of tPA because the longer brain cells are deprived of blood and oxygen, the more likely that the injury will be irreversible, Goldstein says.
The bleeding that can occur during a stroke is made more likely by underlying structural damage to the brain from the insufficient blood flow, or ischemia. The risk of bleeding is 10 times higher with tPA treatment, both experts say, and the risk increases if there is a delay in tPA treatment, especially beyond six hours.
An acute stroke can cause a seizure. "Seizures occur in approximately 5% of ischemic, nonbleeding strokes, typically at the onset," Liebeskind says. He adds that the lack of seizure history in this elderly patient makes stroke the most likely cause of the seizure.
In recording a patient's history, a good physician would be open to a nurse's contribution. "Nurses may be less intimidating than physicians, allowing them to elicit sensitive information," says Sandy Summers, executive director of the Truth About Nursing, an advocacy group for nurses' roles. "Nurses provide a double-check on physicians to prevent errors."
Siegel is an associate professor of medicine at New York University's School of Medicine.