Functional neurological symptoms in children — formative SAQs

SAQ 1 — Making a positive diagnosis and avoiding the investigation cascade (10 marks)

A 13-year-old presents with three weeks of a fluctuating, abnormal gait. Examination shows internally inconsistent weakness with a positive Hoover sign, non-dermatomal sensory loss split at the midline, and a gait that improves with distraction. An MRI brain and spine are normal. The family is anxious and asking for "more scans". ^{[2] [13]}

Questions

1. State the diagnostic principle at work and name three positive clinical signs that support the diagnosis. (3 marks) ^{[2] [5]}
2. Outline how you would communicate the diagnosis to the family, giving an example of validating and an example of harmful language. (3 marks) ^{[2] [13]}
3. Describe the definitive stepped management, naming first-line therapy and the role of investigation. (4 marks) ^{[3] [5]}

Model answer

Diagnostic principle (3). Functional neurological disorder is a positive diagnosis made from internally inconsistent or incongruent signs that are not better explained by another disorder — not a diagnosis of exclusion. Positive signs here include the Hoover sign (hip extension weakness resolving with contralateral hip adduction against resistance), non-dermatomal midline-split sensory loss, and a gait that improves with distraction. FND may coexist with organic disease, but here the signs and intact neuroanatomy make FND defensible. ^{[2] [13]}

Communication (3). Use validating language: "These symptoms are real. The signals between your brain and body have become disrupted, the nervous system is structurally intact, and this improves with rehabilitation." Name the diagnosis explicitly as functional neurological disorder. Avoid harmful language — "it's all in your head", "medically unexplained", "psychosomatic", "fake", "attention-seeking" — which fractures the alliance. Offer family plan and a named coordinator. ^{[2] [13]}

Stepped management (4). Step 1: communicate the positive diagnosis. Step 2: triage acuity, safety and comorbidity (mood, sleep, pain, safeguarding, school). Step 3: treat in parallel — physiotherapy-led functional rehabilitation is first-line for motor FND (retrain normal movement, graded activity, distraction, confidence), with psychological therapy for comorbid mood/anxiety. Step 4: graded, structured return to school with a written plan and relapse strategy. Step 5: follow up at two to four weeks then as needed, with a clear safety-net. Investigations are directed at specific differentials with an agreed stop-point — a repeated normal scan perpetuates harm. No drug treats FND itself. ^{[3] [5] [9]}