Emergency departments at two hospitals - one in Montgomery County - initially missed a stroke diagnosis in more than a fifth of patients later found to have had strokes, according to a study published this month in the journal Stroke.
Rather than an indictment of poor diagnostic skills, the study shows how difficult it can be to identify certain kinds of strokes, said David Weisman, one of the report's authors and a neurologist at Abington Neurological Associates, a private physician group. Weisman practices at Abington Hospital-Jefferson Health, the source of some of the data. The other members of the research team were from the Yale University School of Medicine.
While many of us are aware of common stroke symptoms such as sudden drooping in part of the face, weakness in one arm or trouble speaking, the patients whose strokes were missed often had less obvious symptoms, particularly nausea and dizziness. Their strokes more often were caused by blockages to vessels in the back of the brain than in the front. Such posterior strokes account for about 20 percent of strokes.
Nausea and dizziness are very common symptoms. "The ER is swamped with people like this," Weisman said. "For every dizzy or vertiginous patient having a problem, very few of them have strokes. It's a very difficult problem."
While it is well known that these strokes are harder to diagnose, Weisman said researchers have not studied how many strokes are missed and why.
The study examined records for 465 patients with strokes caused by blocked vessels at a large academic hospital (Yale-New Haven Medical Center) and a community hospital (Abington). Both are certified as stroke centers, a designation for hospitals with special expertise in stroke care. The question was whether doctors in the emergency department had recognized that the patients might have strokes. All were eventually diagnosed properly.
The study found that 22 percent of the strokes were initially misdiagnosed. The rate was 26 percent at Abington and 20 percent at Yale.
A third of the misdiagnosed patients had come to the hospital quickly enough to be eligible for a clot-busting drug.
The missed strokes were generally small, Weisman said, but some of the patients might have benefitted from a clot-buster.
Surprisingly, one of the factors that made it harder to diagnose the strokes was a history of a previous stroke. While that is a risk factor for more strokes, it also makes it hard to know whether a stroke symptom is from new or old brain damage, Weisman said. Plus, an infection like pneumonia can make old stroke symptoms worse.
While you can have nausea and dizziness for lots of reasons, Weisman said it's important for doctors to look at the company these symptoms keep. Nausea with gastrointestinal distress isn't a stroke. But nausea accompanied by mild double vision or speech changes is cause for concern. Doctors also should look for clumsiness on one side of the body, difficulty walking or a wide gait. High blood pressure also was a clue.
Weisman said he thinks it is helpful for doctors to be reminded to consider stroke in patients with posterior stroke symptoms. He and his fellow researchers are also interested in how evaluation procedures can be changed to catch more of these challenging strokes.
Larry Goldstein, chairman of the department of neurology at the University of Kentucky, agreed that posterior strokes can be challenging. Patients may come to the emergency department complaining of vertigo, or a sense that the room is spinning. Often, that's an inner ear problem.
The symptoms are more of a problem if combined with weakness or speech problems, he said. "Those are all very signficant warning signs that it's not just an inner ear problem," he said.
Ryna Then, a stroke neurologist at Cooper University Hospital, said those other symptoms can be very subtle. At Cooper, emergency room physicians are encouraged to call for stroke team evaluation for any suspicious cases of vertigo.
Then said proper diagnosis is important because doctors need to know what caused the stroke so they can prevent another one. The patient may have clogged blood vessels or an undiagnosed heart problem.
She thinks patients are wise to have vertigo checked by a doctor, but is especially concerned about smokers, or those with diabetes or high blood pressure. "Those are the patients that should rush to the emergency department when they have sudden onset of vertigo," she said.
Signs of a stroke usually come on quickly. Common symptoms include:
- Numbness or weakness, especially on one side
- of the face or body.
- Confusion, trouble speaking or understanding speech
- Trouble seeing
- Trouble walking, dizziness
- Sudden severe headache
Symptoms of posterior stroke include:
- Limb weakness on one side
- Nausea or vomiting
- Staggering, uncoordinated gait
SOURCES: National Institute of Neurological Disorders and Stroke, Archives of Neurology