Functional neurological symptoms in children — branching viva

Stem

The examiner opens with a young person who has an abnormal gait and a normal scan, then branches into the PNES distinction, iatrogenic harm, the diagnosis conversation and the management plan. [2] [13]

Branch 1 — Positive diagnosis

Examiner: The MRI is normal. Is this "medically unexplained", or have you made a diagnosis? [13]

Strong answer: I have made a positive diagnosis. Functional neurological disorder is diagnosed from internally inconsistent or incongruent signs, not by exclusion. Here I have a positive Hoover sign, non-dermatomal midline-split sensory loss, and a gait that improves with distraction — that is a defensible, positive diagnosis of motor FND. "Medically unexplained" is a term I avoid; it defines the problem by what it is not and sounds dismissive. [2] [13]

Examiner: Take me through the Hoover sign. [2]

Strong answer: I test hip extension on the affected side by asking the child to push that leg down into the bed; it appears weak. I then ask the child to press the good leg outwards against my hand, recruiting the contralateral hip extensor — and the previously weak hip extension returns. That return of power with contralateral recruitment is the positive Hoover sign. [2] [5]

Branch 2 — The PNES distinction

Examiner: Now picture a child with seizure-like events. How do you tell dissociative from epileptic seizures? [10]

Strong answer: Dissociative seizures tend to have gradual onset, eyes that are closed and resist opening, non-rhythmic or out-of-phase movements, variable duration, and recall afterwards; injuries, incontinence and postictal confusion are less common than in epilepsy. Epileptic seizures are stereotyped, abrupt, with eyes typically open, a clear postictal state, no recall, and an electrographic correlate. [10] [11]

Examiner: How do you confirm it? [11]

Strong answer: Video-EEG capturing a typical event showing no electrographic change during the semiology is the gold standard. A routine interictal EEG does not confirm or refute PNES. [10]

Branch 3 — Iatrogenic harm and formulation

Examiner: This child has been immobilised, catheterised and given morphine. What is going wrong? [2]

Strong answer: These are iatrogenic perpetuators. Immobilisation causes deconditioning, catheterisation is unnecessary in a continent child and reinforces the sick role, and opioids reinforce functional pain. I would remove each, begin graded functional rehabilitation, and agree an explicit investigation stop-point so the family stops doctor-shopping. [2] [3]

Examiner: Build me a formulation. [7]

Strong answer: I use a biopsychosocial 3-Ps framework: predisposing factors (female adolescent, anxiety, possible neurodevelopmental difference, family illness), precipitating factors (a minor injury or stressor, sleep deprivation), and perpetuating factors (diagnostic delay, deconditioning, school absence, family symptom-focus). The mechanism is disrupted self-agency and attention networks — abnormal predictive priors overriding sensory input. The formulation guides treatment of the modifiable perpetuators. [13]

Branch 4 — Communication and management

Examiner: What exactly do you say to the family? [2]

Strong answer: I say the symptoms are real, the signals between brain and body have become disrupted, the nervous system is structurally intact with no damage, this is a recognised condition called functional neurological disorder, and it improves with rehabilitation. I do not say "all in your head", "fake", or "psychosomatic". [2] [13]

Examiner: Give me the management plan. [3]

Strong answer: A named coordinator — usually me as the general paediatrician — holds a single written plan shared with neurology, physiotherapy, psychology, the school and the family. First-line for motor FND is physiotherapy-led functional rehabilitation; for PNES I add CBT and family therapy with reframed seizure first-aid. I treat comorbid mood, sleep and pain in parallel, withdraw unnecessary medication and investigation, plan a graded school return with a relapse strategy, and review in two to four weeks. No drug treats FND itself. [3] [5] [10]