Functional Neurological Disorder with Post-Traumatic Cervical Spine Injury
This constellation of symptoms—full-body tremors/vibrations, anxiety, insomnia, progressive left-sided neurological symptoms following whiplash injury with C5-C6 disc bulge, and normal extensive workup—is most consistent with functional neurological disorder (FND), and should be managed with occupational/physical therapy using FND-specific techniques, cognitive behavioral therapy for insomnia (CBT-I), and low-dose gabapentin continuation for muscle jerks, while avoiding further diagnostic testing that reinforces symptom focus. 1
Clinical Reasoning and Diagnosis
The key diagnostic features pointing toward FND include:
Extensive negative workup despite prominent symptoms: Normal brain MRI, EEG, EMG, EKG, muscle conduction studies, and cardiac evaluation effectively rule out structural neurological disease, stroke, seizure disorder, primary muscle disease, and cardiac pathology 1
Symptom characteristics inconsistent with organic disease: Full-body tremors affecting hands, head, torso, tongue, and eyelids simultaneously, with vibrations that worsen at night or don't improve with lying down, are atypical for any single neurological lesion 1
Temporal dissociation: The 8-month gap between injury resolution (after physiotherapy successfully treated pain/inflammation) and onset of new symptom constellation suggests functional rather than structural etiology 1
Anxiety and insomnia as prominent features: Sudden onset anxiety with insomnia commonly accompanies FND and may represent both contributing factors and manifestations of the disorder 1
The C5-C6 bulging disc is a common incidental finding and, given that the original pain resolved with physiotherapy, is unlikely to explain the current widespread symptoms 1
Management Algorithm
Phase 1: Establish Diagnosis and Patient Education (Weeks 1-2)
Provide positive diagnosis of FND rather than diagnosis of exclusion: Explain that this is a genuine neurological condition where the nervous system is functioning incorrectly, not damaged structurally 1
Reframe symptoms: Help patient understand that tremors/vibrations represent reversible nervous system dysfunction, not progressive neurological disease 1
Address plasma donation history: While unlikely the primary cause, frequent plasma donation may have contributed to physiological stress; discontinuation was appropriate 1
Phase 2: Functional Symptom Management (Weeks 2-12)
Occupational/Physical Therapy with FND-Specific Techniques:
For tremor/vibrations: Engage in tasks promoting normal movement patterns with distraction techniques; video recording (with consent) can demonstrate symptom changeability and build confidence 1
For left-sided symptoms: Encourage bilateral functional tasks with even weight distribution; avoid "nursing" the affected side which promotes learned non-use 1
Graded activity progression: Gradually increase time using affected limb within functional activities using normal movement techniques 1
Avoid reinforcing behaviors: Do not use splinting or adaptive aids that increase attention to symptoms, prevent normal movement, or risk learned non-use 1
Sensory grounding strategies: Use techniques like noticing environmental details (sounds, sights, smells), feeling textured items, or cognitive distractors during symptom episodes 1
Phase 3: Insomnia Management (Concurrent with Phase 2)
First-line treatment is CBT-I, which should include:
- Cognitive therapy to address distorted beliefs about sleep 1, 2
- Stimulus control to strengthen bed-sleep association 1, 2
- Sleep restriction therapy to improve sleep efficiency 1, 2
- Sleep hygiene education and relaxation techniques 1, 2
If insufficient improvement after 2-4 weeks of CBT-I:
- Continue CBT-I and add low-dose trazodone (25-50mg) or doxepin (3-6mg) at bedtime 2
- Continue current low-dose gabapentin as it has shown benefit for muscle jerks and can help with insomnia in anxiety-related conditions 2
Avoid benzodiazepines due to dependence risk, abuse potential, cognitive impairment, and potential worsening of FND symptoms 1, 2
Phase 4: Anxiety Management (Concurrent with Phases 2-3)
Diaphragmatic breathing and progressive muscle relaxation as part of FND management 1
Consider "slow" movement activities like yoga or tai chi to regain movement control and redirect attention from symptoms 1
Address cognitive symptoms: Discuss how anxiety, poor sleep, and symptom focus compete for cognitive resources, normalizing these experiences as part of FND rather than additional pathology 1
Critical Pitfalls to Avoid
Do not order additional neuroimaging or testing unless new objective findings emerge on examination. Repeated testing reinforces illness beliefs and symptom focus, potentially worsening FND 1
Do not attribute symptoms to the C5-C6 disc bulge given the resolved pain, normal EMG/nerve conduction studies, and symptom pattern inconsistent with single-level radiculopathy 1
Avoid medications that increase sedation or attention to symptoms: Serial casting or rigid splinting for dystonic posturing has been associated with worsening symptoms and complex regional pain syndrome 1
Monitor for symptom evolution: While FND is the most likely diagnosis, document any new objective neurological signs (not subjective symptoms) that might warrant reassessment 1
Expected Trajectory and Follow-up
Regular monitoring during therapy to assess response and adjust strategies 1
Reassess sleep patterns every 2-4 weeks to evaluate insomnia treatment efficacy 1, 2
Gradual medication weaning: Once symptoms stabilize with therapy, consider tapering gabapentin to lowest effective dose 1
Long-term management: FND often requires ongoing symptom management strategies rather than cure-focused approach; emphasize functional improvement over complete symptom resolution 1
The combination of normal extensive workup, symptom characteristics, temporal pattern, and response to low-dose gabapentin strongly supports FND as the unifying diagnosis, making rehabilitation-focused treatment the most appropriate path forward 1