What is the cause of my persistent internal vibrations, tremors, anxiety, and insomnia, which started after plasma donation and have continued for over a year despite normal electroencephalogram (EEG), electromyography (EMG), brain magnetic resonance imaging (MRI), and bloodwork, including normal thyroid and hormone levels?

Functional Neurological Disorder with Tremor and Anxiety

Your symptoms most likely represent a functional neurological disorder (FND), specifically functional tremor with associated anxiety and insomnia, which requires psychological and behavioral interventions as first-line treatment rather than continued medical workup.

Understanding Your Condition

Your presentation is highly consistent with persistent physical symptoms (PPS) that have evolved into a functional disorder. The key diagnostic features include:

• Multiple negative investigations: Normal EMG, brain MRI, EEG, cardiac workup, and bloodwork effectively rule out structural neurological disease, metabolic disorders, and cardiac pathology 1
• Symptom characteristics: The fine, high-frequency tremor (8-13 Hz) that is inconsistent on testing, worsens with attention/posture, and improves dramatically with benzodiazepines is pathognomonic for functional tremor rather than organic tremor disorders 1
• Temporal pattern: Symptoms persisting beyond one year with multiple body systems involved (tremor, anxiety, insomnia, left-sided sensory symptoms) places you in the "persistent symptom" category with poor prognosis without appropriate intervention 2

Why This Isn't Essential Tremor or Other Organic Disease

Your neurologist correctly identified this is not essential tremor because:

• Essential tremor improves at rest and worsens with action, whereas yours is constant and most noticeable when still 1
• The dramatic response to benzodiazepines (Xanax, Klonopin) but minimal response to propranolol indicates anxiety-mediated symptoms rather than organic tremor 3
• The inconsistent tremor frequency and inability to capture consistent amplitude on tremor apps suggests functional rather than organic pathology 1

The Plasma Donation Connection

While doctors dismiss the plasma donation trigger, the timeline suggests it was a precipitating stressor rather than a direct cause:

• The initial lightheadedness and left-sided symptoms during donation likely represented vasovagal episodes or anxiety responses 1
• These episodes created illness-related anxiety and symptom focusing that perpetuated and amplified symptoms through learned symptom patterns 1
• The persistence of symptoms long after cessation of donations indicates the problem has shifted from the initial trigger to psychological and neurological perpetuating factors 2

Treatment Approach

First-Line: Psychological and Behavioral Interventions

Cognitive behavioral therapy (CBT) should be your primary treatment, as psychological interventions are effective for persistent physical symptoms and should be utilized as initial intervention when conditions permit 4, 1.

Specific components needed:

• Symptom reattribution therapy: Understanding how anxiety creates physical tremor and internal vibrations through heightened autonomic arousal 3, 1
• Sensory grounding techniques: To prevent dissociation and reduce symptom focusing, particularly the 4 AM adrenaline surges 3
• Breathing techniques and progressive muscle relaxation: For acute symptom management 3
• Gradual exposure to feared situations: Addressing avoidance behaviors that maintain disability 1

Exercise Prescription

Begin a structured cardiovascular exercise program, starting with recumbent or semi-recumbent positions for short durations, gradually increasing over time 3. This addresses both the tremor symptoms and anxiety through physiological regulation.

Pharmacological Management

Your current medications need adjustment:

• Continue benzodiazepines short-term only: While Xanax and Klonopin provide relief, they confirm the functional nature of symptoms but create dependency risk with long-term use 3
• Optimize SSRI therapy: Lexapro 20 mg may be insufficient; consider dose increase to 30 mg or switch to a different SSRI, initiated at low doses and titrated slowly given your symptom sensitivity 3
• Consider neuromodulators: For the persistent left-sided sensory symptoms and sleep disturbance, low-dose gabapentin or pregabalin may help 1

Insomnia Management

Implement cognitive behavioral therapy for insomnia (CBT-I) as the primary intervention, as psychological and behavioral interventions are effective and recommended as initial treatment for chronic insomnia 4.

Specific strategies:

• Sleep restriction therapy to consolidate sleep 4
• Stimulus control to reassociate bed with sleep rather than wakefulness 4
• Address the 4 AM adrenaline surges through anxiety management techniques 3
• Maintain sleep diary throughout treatment to track progress 4

What to Avoid

Critical pitfalls that worsen outcomes:

• Stop seeking additional medical workups: Further testing reinforces illness beliefs and delays appropriate treatment 1, 5
• Avoid symptom monitoring apps: Constant tremor measurement increases symptom focusing and perpetuates the problem 1
• Don't wait for a medical explanation: The extensive negative workup IS the diagnosis—functional disorder 2

Prognosis and Follow-Up

Without appropriate psychological intervention, you fall into the 16% of patients with persistent symptoms lasting beyond one year who experience ongoing disability 6. However, with proper treatment:

• Functional tremor responds well to CBT and physiotherapy when patients engage with the biopsychosocial model 1
• Regular reassessment every few weeks initially, then monthly until stable, then every 6 months given high relapse rates 4
• Focus outcome measures on functional improvement and quality of life rather than complete symptom resolution 4

The key to recovery is accepting that these symptoms are real, disabling, but not caused by structural disease—they represent a treatable disorder of nervous system function that responds to psychological and behavioral interventions 1, 5.