Applied Evidence

Functional neurological disorder: A practical guide to an elusive Dx

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The complexity of this disorder poses a clinical challenge like few others.

PRACTICE RECOMMENDATIONS

› Avoid using stigmatizing terminology (eg, adding the prefix “pseudo” or the adjective “hysterical”) to characterize a suspected functional neurological disorder (FND) or a medically unexplained disorder. C

› Refrain from ordering functional magnetic resonance imaging as part of the routine evaluation of suspected FND. C

› Validate the patient‘s concerns with an appropriate diagnostic label; use layman’s terms to discuss the diagnostic parameters of FND and the cause of symptoms; and emphasize treatment possibilities and plans. C

Strength of recommendation (SOR)

A Good-quality patient-oriented evidence
B Inconsistent or limited-quality patient-oriented evidence
C Consensus, usual practice, opinion, disease-oriented evidence, case series


 

References

CASE

John D,* a 25-year-old patient with an otherwise unremarkable medical history, describes 2 months of daily headache, lower-extremity weakness, and unsteady gait that began fairly suddenly during his first deployment in the US Army. He explains that these symptoms affected his ability to perform his duties and necessitated an early return stateside for evaluation and treatment.

Mr. D denies precipitating trauma or unusual environmental exposures. He reports that, stateside now, symptoms continue to affect his ability to work and attend to personal and family responsibilities.

Asked about stressors, Mr. D notes the birth of his first child approximately 3 months ago, while he was deployed, and marital stressors. He denies suicidal or homicidal ideation.

* The patient’s name has been changed to protect his identity.

The challenge of identifying and managing FND

A functional neurological disorder (FND) is a constellation of psychological, physiological, and neurological symptoms, without an identifiable organic etiology, a conscious decision, or secondary gain for the patient,1 that adversely impacts functioning in 1 or more significant life domains.

Given the high throughput of patients in primary care practices, family physicians can expect to encounter suspected cases of FND in their practices. Regrettably, however, a lack of familiarity with the disorder and its related problems (eg, nonorganic paralysis, sensory loss, nonepileptic seizures, and abnormal movements) can add as much as $20,000 in excess direct and indirect costs of care for every such patient.1 In this article, we synthesize the recent literature on FND so that family physicians can expand their acumen in understanding, identifying, and evaluating patients whose presentation suggests FND.

An underrecognized entity

A precise estimate of the prevalence of FND is difficult to determine because the disorder is underrecognized and misdiagnosed and because it is often accompanied by the confounding of psychological and physiological comorbidities. A 2012 study estimated the annual incidence of FND to be 4 to 12 cases for every 100,000 people2; in primary care and outpatient neurology settings, prevalence is 6% to 22% of all patients.3,4 Stone and colleagues identified functional neurological symptoms as the second most common reason for outpatient neurology consultation,5 with 1 nonepileptic seizure patient seen for every 6 epileptic patients, and functional weakness presenting at the same rate as multiple sclerosis.6

Continue to: Demographics of patients with FND...

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