MDs missing, misdiagnosing strokes: study

More education needed to figure out less common variations of devastating incidents

TORONTO — Canadian doctors are missing sometimes-glaring signs of stroke, or overrelying on CT scans alone and skipping physical exams such as “finger-to-nose” testing, a review by the body that defends doctors accused of malpractice shows.

An analysis of 102 medicallegal cases handled by the Canadian Medical Protective Association (CMPA) in 2009-13 shows some strokes were initially misdiagnosed as anxiety attacks, or harmless stomach bugs. Almost half the cases that led to legal actions or complaints to licensing colleges involved some of the most potentially catastrophic strokes.

The review comes as the rate of strokes among younger people is escalating and the health system braces for an increase in stroke as the population ages.

“This is not an easy part of medicine, neurology,” said Dr. Gordon Wallace, managing director of safe medical care at the Ottawa-based CMPA. “The obvious stroke is obvious, but there are many subtle neurological presentations. That’s the challenge here.”

Of the 102 cases, 44 were legal actions, 47 involved regulatory complaints and 11 hospital complaints. Wallace said the purpose of the review is not to embarrass doctors, but to teach — “to understand what the themes are, and how can we frankly alert the physician population as to what to watch for,” he said.

Overall, most of the cases — 63 — ended in a “favourable” outcome for the doctor.

“Patients were harmed here,” Wallace said. “But it was felt that the care that the physician provided in the circumstances was reasonable,” based on expert peer opinion.

The remaining 39 cases were critical of the doctor, including 11 legal cases settled by the CMPA that included a once-healthy woman in her early 40s whose hemorrhagic stroke was misdiagnosed as a migraine by a doctor at a walk-in clinic. She now needs help with daily living.

A hemorrhagic stroke occurs when a weakened blood vessel ruptures or bursts, causing uncontrolled bleeding in the brain. Close to half the cases in the audit involved hemorrhagic strokes, even though they account for only about 10 to 15 per cent of all strokes.

Overall, more than a quarter of the patients in the medical-legal cases reviewed by the CMPA died; another 40 per cent were left permanently disabled.

In some cases, there was nothing to show the doctor performed a complete history or physical exam. Other doctors failed to do neurological testing. Some didn’t consider stroke in patients with clear risk factors, such as smoking or high blood pressure.

The audit also found a worrying tendency to put too much faith in CT scans, which can miss strokes if performed too soon. A stroke is caused by a sudden loss of blood supply to the brain. Most, as many as 85 per cent, are ischemic strokes — a blood clot lodges in a vessel to the brain, starving brain cells of oxygen.

A CT scan measures changes in density in parts of the brain. But damaged and dying brain cells take time — sometimes minutes, others not for hours — to show up as a different shade of grey on the scan, says Dr. Devin Harris, medical adviser for Stroke Services B.C. and an emergency physician in Kelowna.

“It’s a bit of a double-edged sword,” he said. “We can’t not make a diagnosis of stroke — or rule out other things, like a tumour or mass — unless we get a CT scan.”

However, even if a CT scan is read as “normal,” “it doesn’t necessarily mean someone is not having a stroke,” Harris said.

He said it’s crucial doctors also take a full history, including risk factors for stroke, and perform a thorough physical exam.

Strokes affecting the back of the brain — posterior circulation strokes — accounted for a disproportionately high number of cases. Harris said these strokes are harder to diagnose and patients don’t exhibit “classic” symptoms, such as weakness in an arm or a leg, a droopy face or garbled speech, nausea or vomiting. Instead, they often complain of problems swallowing, vertigo, subtle loss of vision or sudden, severe dizziness.

“It’s a bit of a double-edged sword. We can’t not make a diagnosis of stroke—or rule-out other things, like a tumour or mass— unless we get a CT scan.

DR. DEVIN HARRIS STROKE SERVICES B.C.