Originally published September 2015
Advances in the management of stroke promise to significantly improve outcomes for patients. Often the benefits of these advances are best realized if stroke is promptly recognized. Yet stroke can be challenging to diagnose.
It is not surprising then that the biggest issue identified in a review of the CMPA’s medical-legal cases involving stroke was diagnosis. In the cases with diagnostic issues, most patients first presented to an emergency department, but many visited their family physician or a walk-in-clinic. Patients were evenly distributed among all age groups up to 70 years, with only a few over the age of 70. There were slightly more men than women. More than a quarter of the patients died and another 40% were left with a permanent disability. While hemorrhagic strokes make up only 10–15% of strokes overall in the clinical arena,1 close to half of the CMPA cases involved this type of stroke.
Research suggests that nearly 10% of strokes are not recognized at initial presentation.2 The symptoms may be non-specific and may vary by subtype and location.
In the reviewed CMPA cases, the common symptoms were headache, dizziness, and nausea and vomiting. Delayed presentation with longer symptom duration (i.e. days to weeks) was also seen. Peer experts were often supportive of physicians’ management of the care in the cases where there was atypical presentation of stroke, provided there was evidence that an adequate general and neurologic assessment had been made and appropriate instructions had been provided to the patient.
Experts were, however, critical of physicians who:
- failed to recognize the seriousness of the patient’s condition, including red flags such as a new or severe headache, or focal neurological signs;
- did not perform a complete physical examination with vital signs; assess orientation, speech, gait, and neck stiffness; complete a neurological examination of the cranial nerves; assess motor and sensory function in all four extremities; perform cerebellar testing (i.e. finger to nose); and complete a visual fields assessment as appropriate;
- developed an inadequate differential diagnosis; or
- did not repeat the neurological exam if a patient’s condition persisted or evolved.
The experts were especially disapproving when physicians did not consider the possibility of stroke in patients with obvious risk factors such as smoking, obesity, and hypertension. Some patients with recurrent subarachnoid hemorrhage (SAH) were not sufficiently assessed despite having had a history of the condition.
In some cases, physicians relied too heavily on the sensitivity of CT scanning to detect stroke. Experts state that CT scans are often normal in ischemic stroke or may have only subtle findings for approximately the first 24 hours. For SAH, CT scanning at this time is likely to be positive within six hours of headache, but is only about 85% sensitive for SAH after six hours.
Many cases of misdiagnosis involved system issues such as communication problems between providers; equipment not being available; delayed reporting or failure to directly contact a treating physician with diagnostic imaging results, including reporting discrepant findings from earlier interpretations; and not following appropriate clinical practice guidelines.
Anchoring on a specific diagnosis — most often migraine or psychiatric disorders, but also gastrointestinal, sinus, or musculoskeletal issues — often impeded the final diagnosis of stroke.
Case example: Subarachnoid hemorrhage misdiagnosed as a first migraine
A previously well woman in her early forties presents to a busy walk-in clinic with a new severe headache that has lasted for five days and has been accompanied by vomiting. She does not have a history of recurrent headaches. The pain is more intense around her right eye, but she has not noticed any visual changes. The family physician who examines the patient observes that her pupils are equal and reactive, and notes that her blood pressure is 95/60 mm Hg. The physician suspects migraine and prescribes medication for pain. He tells the patient that he will be on call in the emergency department in two days, and advises her to attend for reassessment and a CT scan if her symptoms do not improve.
Two days later the patient is still experiencing symptoms and presents to the emergency department requesting the scan. The triage nurse informs the patient that the scanner is undergoing maintenance. The nurse advises the physician of the situation over the phone, and he agrees that the scan can wait until the following day.
The next day the patient collapses and is taken to hospital. Imaging studies suggest an infarct in the middle cerebral artery territory. The patient is transferred to a tertiary hospital, where she is ultimately diagnosed with an ischemic stroke due to vasospasm following SAH from a ruptured aneurysm of the posterior communicating cerebral artery. After treatment and rehabilitation, she continues to have significant residual symptoms that prevent her from living independently.
The patient and her family pursue a legal action against the family doctor and hospital. Experts in the case are critical of the physician, as his notes do not reflect a complete history and physical exam. The experts suggest that a more thorough questioning of the patient about her symptoms would have uncovered the fact that she had a SAH. The details and rapidity of onset of the headache were not recorded. They are also critical that neither the physician nor the nurse examined the patient when she first presented to the hospital. The patient receives a settlement, paid jointly by the CMPA (on behalf of the physician member) and the hospital.
Stroke subtypes and special considerations
Many presenting symptoms in the reviewed cases were similar whether the stroke was ischemic or hemorrhagic; however, patients with hemorrhagic stroke were more likely to have normal neurological exam findings on initial assessment. In some cases of suspected subarachnoid hemorrhage, physicians were criticized when appropriate testing was not performed.
While failing to treat ischemic stroke with thrombolytics such as tPA was often alleged, it was rarely the subject of expert criticism, as most patients were found to have been outside the treatment window timeframe at the time of initial assessment or were not candidates for this treatment.
Posterior circulation strokes
Strokes affecting the posterior circulation brain structures often cause a range of symptoms and carry a high mortality rate. These strokes were seen in a large percentage of CMPA cases despite making up only about 20% of strokes overall in clinical practice. Presenting symptoms of posterior circulation strokes in CMPA cases were headache, dizziness, and nausea and vomiting. Focal neurological signs were not apparent in some of these cases. Risk management experts, recognizing the challenges of diagnosing these events, recommend that physicians facing unusual neurological symptom complexes expand their differential diagnoses to include the possibility of a posterior circulation stroke.3 Patients with swallowing difficulties, facial pain with vertigo or numbness, or gait disturbance may have a posterior circulation event.
Risk management considerations
To reduce risk and improve care when assessing patients with symptoms or signs that could be related to stroke, physicians may consider the following, which are based on the expert opinions in the reviewed CMPA cases:
- As the treatments available for stroke continue to improve, maintain your knowledge of appropriate clinical practice guidelines. Recognize the urgency of thoroughly assessing patients presenting with a possible stroke.
- Be familiar with the types of stroke and the characteristic presenting symptoms or signs.
- Obtain an adequate history, including co-morbidities and current medications, and conduct an appropriate systematic physical examination with vital signs.
- Perform a detailed neurological exam.
- Incorporate clinical pathways, guidelines, or decision tools for suspected stroke (such as the Ottawa SAH Rule4) or TIA and the evaluation and management of related conditions (e.g. headache, vertigo).
- Be cautious when ascribing a patient’s symptoms to a psychological condition without appropriate supportive or collateral information.
- Pause and reflect on the differential diagnosis, being careful to consider possibilities that may be serious or life-threatening.
- Determine which investigations and treatments are necessary.
- Record relevant information in patients’ medical records to reflect the medical history (including symptoms and co-morbidities), the physical examination, the differential diagnosis, the investigation and treatment plan, discharge instructions, and follow-up.
- Confirm there is a system for appropriate follow-up of suspicious, indeterminate, or discrepant diagnostic imaging findings.
- When patients return with the same or worsening symptoms, re-evaluate the diagnostic assumption and repeat the physical and neurological examinations.
- Flaherty, M.L., Woo, D., Broderick, J.P. 2010. “The epidemiology of intracerebral hemorrhage.” In Intracerebral hemorrhage, edited by J.R. Carhuapoma, S.A. Mayer, and D.F. Hanley, 1-10, Cambridge, UK: Cambridge University Press
- Newman-Toker, D.E., Robinson, K.A., Edlow, J.A., “Frontline misdiagnosis of cerebrovascular events in the era of modern neuroimaging: a systematic review [abstract],” Annals of Neurology (2008) Vol. 64, p.S17–S8
- Risk Management Foundation of the Harvard Medical Institutions, AMC PSO Patient Safety Alerts, “Diagnosis and treatment of ischemic stroke,” Issue 20, 2014
- Perry, J..J., Stiell, I.G., Siviolotti, M.L., et al., "Clinical Decision Rules to Rule out Subarachnoid Hemorrhage for Acute Headache." Journal of the American Medical Association (2013) Vol.310, p.1248-55