Nine Percent to 30% of Strokes Misdiagnosed in ED

However, dizziness less associated with med/mal suits

Diagnostic errors are the most common, most costly, and most deadly medical errors, according to a recent analysis of 25 years of malpractice payouts from the National Practitioner Data Bank.1

Missed strokes and related neurological conditions account for many cases of diagnostic error resulting in serious, permanent disability.1 Patients presenting to an ED with stroke have about a 9% risk that the stroke will be misdiagnosed, compared to less than 2% for patients with heart attacks.2

However, the risk of missed stroke varies widely depending on the patient’s initial manifestations; the risk increases to more than 30% if the patient’s presenting symptom is dizziness or vertigo.1

“Dizziness, though a very common symptom, is very frequently misdiagnosed,” says David E. Newman-Toker, MD, PhD, the study’s senior author and associate professor in the Department of Neurology at Johns Hopkins Hospital in Baltimore, MD. “Strokes causing dizziness look a lot like inner ear conditions causing dizziness if you don’t know what to look for.”

The ED is the highest-risk site for liability claims related to diagnosis, he adds, because the level of illness severity and complexity is as high as any other practice setting, but the timeframe to make a diagnosis is much shorter.

“The ED is probably the toughest place to practice medicine in general because of the high variability of illness manifestations, wide range in illness severity, and heavy patient volume,” he underscores.

Dizziness is among the most common complaints in the ED.3 When The Ottawa Hospital Research Institute surveyed emergency physicians (EPs) about which clinical decision rule they needed most for adults, the number one answer was when to obtain neuroimaging in patients with dizziness or vertigo to exclude stroke.4

“There are four million ED visits for dizziness every year, and we know that clinical practice is not well-aligned with the evidence,” says Newman-Toker. The cases that do end up as lawsuits typically involve very obvious presentations in which the patient presents with additional signs and symptoms, he says. One such case involving a former basketball player who left the ED with neurological complications after a stroke was misdiagnosed as a sinus infection resulted in a $217 million jury verdict.5

“Ironically, dizziness is probably less often associated with malpractice suits because the standard of care is so low,” he says. “It’s more often that suits are brought for headache misdiagnosis because the standard of care is higher.”

Nearly one in four ED patients with dizziness leave with no diagnoses, notes Newman-Toker, and many diagnoses given aren’t correct. In one study, he and colleagues found that more than 80% of ED patients said to have specific benign inner ear conditions causing dizziness were given an incorrect diagnosis.6

Newman-Toker says that ED physicians often focus on the type of dizziness — spinning, fainting, or wobbling — but should instead be focused on whether the dizziness comes in spells and is triggered by particular movements.

“This leads them down a faulty line of diagnostic reasoning that often ends in misdiagnosis and incorrect treatment,” he says. If the patient complains of vertigo, the EP is likely to diagnose an inner ear condition and give the patient a medicine to suppress the symptoms, rather than treat the underlying cause.7

“When a patient is older or has vascular risk factors, ED physicians often rely on CT scans of the head to look for stroke,” he says. “Unfortunately, these scans miss more than 80% of new strokes, and almost all of the new strokes are in the part of the brain that controls balance and present with dizziness.”

More than 40% of all ED patients with dizziness now get CT scans, but most of this imaging is not indicated, adds Newman-Toker. “The test is costly, it exposes the patient to radiation that risks causing cancer, and a normal scan can end up being falsely reassuring that a stroke has been ‘ruled out,’” he says.

William J. Meurer, MD, assistant professor of emergency medicine at University of Michigan Health System in Ann Arbor says these practices can help to prevent stroke misdiagnosis in cases of dizziness:

EPs should check and document visual fields along with coordination and gait testing.

“These additional examination pieces are quite helpful in preventing misdiagnosis in the case of the isolated dizziness presentation,” he says.

EPs should be very cautious when assigning a diagnosis of benign paroxysmal positional vertigo, unless there are objective exam findings such as nystagmus patterns or a positive Dix-Hallpike test that are consistent with those diagnoses.

EPs should document evidence that supports a peripheral cause for the patient’s symptoms.

For instance, the EP’s documentation of “horizontal nystagmus only, completely normal neuro examination otherwise,” can be helpful if someone else is looking at the chart later after a bad outcome.

EPs should not rely on CT scanning to exclude brainstem or cerebellar strokes.

“CT is also relatively inaccurate when obtained early, and in many cases won’t give a clear answer regarding small lacunar stroke anyway,” Meurer says.

“EKG for dizziness”

Newman-Toker and colleagues have developed a new approach to prevent stroke misdiagnosis in patients with dizziness or vertigo. This approach relies on experts examining eye movement physiology at the bedside to differentiate inner ear causes from brain causes of dizziness.

They have shown that this approach picks up more than 99% of all strokes causing dizziness, and is far more accurate than other methods, including what is currently considered the “gold standard” test, brain magnetic resonance imaging.8

Recently, their team has shown that a new device measuring these same eye movements could help non-specialists do the same. The device, recently approved by the Food and Drug Administration, perfectly discriminated between strokes and inner ear disorders, according to a small study led by Newman-Toker.9

Newman-Toker believes this approach will soon transform clinical practice in the evaluation of patients with dizziness.

“It still requires some expertise, but we hope this will soon become the EKG for dizziness,” he says. “In the next couple of years, it will become standard practice in EDs, and will knock out a huge number of these diagnostic errors.” n

References

1. Saber Tehrani AS, Lee H, Mathews SC, et al. 25-year summary of US malpractice claims for diagnostic errors 1986-2010: An analysis from the National Practitioner Data Bank. BMJ Qual Saf. 2013 Apr 22. [Epub ahead of print]

2. Newman-Toker DE, Robinson KA, Edlow JA. Frontline misdiagnosis of cerebrovascular events in the era of modern neuroimaging: A systematic review [abstract]. Ann Neurol. 2008;64(Suppl 12):S17-S18.

3. Tarnutzer AA, Berkowitz AL, Robinson KA, et al. Does my dizzy patient have a stroke? A systematic review of bedside diagnosis in acute vestibular syndrome. CMAJ. 2011;183(9):E571-E592.

4. Eagles D, Stiell IG, Clement CM, et al. International survey of emergency physicians’ priorities for clinical decision rules. Acad Emerg Med. 2008;15(2):177-182.

5. Associated Press. $217 million awarded in malpractice case: A misdiagnosed Tampa man was left brain-damaged and disabled. Florida Times Union 2006.

6. Kerber KA, Morgenstern LB, Meurer WJ, et al. Nystagmus assessments documented by emergency physicians in acute dizziness presentations: A target for decision support? Acad Emerg Med. 2011;18(6):619-626.

7. Newman-Toker DE, Camargo CA, Jr, Hsieh YH, et al. Disconnect between charted vestibular diagnoses and emergency department management decisions: A cross-sectional analysis from a nationally representative sample. Acad Emerg Med. 2009;16(10):970-977.

8. Newman-Toker DE, Kerber KA, Hsieh YH, et al. HINTS outperforms ABCD2 to screen for stroke in acute continuous vertigo and dizziness (in press). Acad Emerg Med. 2013.

9. Newman-Toker DE, Saber Tehrani AS, Mantokoudis G, et al. Quantitative video-oculography to help diagnose stroke in acute vertigo and dizziness: Toward an ECG for the eyes. Stroke 2013;44(4):1158-1161.

Sources

For more information, contact:

  • William J. Meurer, MD, Assistant Professor, Emergency Medicine, University of Michigan Health System, Ann Arbor. Phone: (734) 615-2766. E-mail: wmeurer@medi.umich.edu.
  • David E. Newman-Toker, MD, PhD, Associate Professor, Department of Neurology, Johns Hopkins Hospital, Baltimore, MD. Phone: (410) 502-6270. E-mail: toker@jhu.edu.