UMEM Educational Pearls

Title: Why Won't It Move? - Functional Neurologic Disorders

Category: Neurology

Keywords: psych, conversion, nonorganic, physical exam (PubMed Search)

Posted: 6/25/2015 by Danya Khoujah, MBBS
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Functional neurologic disorders, also referred to as psychogenic or nonorganic, comprise a significant part of neurological "emergencies", and can be difficult to diagnose in the emergency department, leading to a significant over-utilization of resources.

Accurate diagnosis emphasizes on the presence of positive physical signs that are internally inconsistent or incongruent with recognized disease. The presence of an identifiable stressor is not necessary for diagnosis.

Exam findings may show:

a) Improvement of symptoms temporarily with focused attention on a different body part, such as:

- Hoover sign and hip abductor sign for functional limb weakness

- Entrainment sign for functional tremor

- Improved standing balance with distractions

b) Clinical phenotype that is typical for the diagnosis, such as:

- Eyes tightly shut while "unresponsive"

- Dragging gait with hips internally or externally rotated, with the forefoot remaining in contact with ground

- Fixed dystonic posture with ankle inversion and plantar flexion

- Global weakness, affecting extensors and flexors equally

- Unilateral facial weakness with platysma overactivity, jaw deviation and/or contraction of orbicularis oris.

That being said, functional and organic disease may co-exist in some patients and it may be worthwhile to refer them to a neurology clinic for possible further workup.

The original article has links to multiple videos demonstrating those signs. It can be accessed on h ttp://journals.lww.com/continuum/Abstract/2015/06000/Functional_Neurologic_Disorders.22.aspx

References

Stone J, Carson A. Functional Neurologic Disorders. Continuum 2015;21(3):818 837