Differential Diagnosis for Neck Shaking

The patient reports new and constant neck shaking that is non-painful and without a history of injury. Here's a structured approach to the differential diagnosis:

• Single Most Likely Diagnosis

  • Essential Tremor: This is a common movement disorder characterized by tremors during action or with posture, which can affect the neck (cervical dystonia when it involves involuntary, patterned, and often repetitive muscle contractions). The lack of pain and absence of injury make this a plausible initial consideration.

• Other Likely Diagnoses

  • Dystonic Tremor: A type of tremor that occurs in conjunction with dystonia, which could manifest as neck shaking. It's less common than essential tremor but should be considered, especially if the tremor is accompanied by abnormal postures.
  • Parkinson's Disease: Although less common, Parkinson's disease can cause tremors, and while it typically involves other symptoms like bradykinesia, rigidity, and postural instability, a tremor can be an early or isolated symptom.
  • Anxiety or Stress-related Tremor: Tremors can be exacerbated or caused by anxiety and stress. If the patient is experiencing significant stress or anxiety, this could contribute to or cause the neck shaking.

• Do Not Miss Diagnoses

  • Multiple Sclerosis: Although less likely, multiple sclerosis (MS) can cause tremors due to lesions in the brainstem or cerebellum. MS is a "do not miss" diagnosis because of its significant implications for treatment and prognosis.
  • Stroke or Transient Ischemic Attack (TIA): A stroke or TIA can cause sudden onset of tremor, among other symptoms. While the patient reports no injury, a stroke could cause neurological deficits without a clear history of trauma.
  • Wilson's Disease: A rare genetic disorder that leads to copper accumulation in the body, causing neurological symptoms including tremors. It's crucial to diagnose early due to the availability of treatment that can prevent progression.

• Rare Diagnoses

  • Huntington's Disease: An inherited disorder that causes progressive damage to the brain, leading to cognitive, motor, and psychiatric symptoms, including chorea (involuntary, abrupt movements that can resemble tremors).
  • Creutzfeldt-Jakob Disease: A rare, degenerative, fatal brain disorder that can cause a variety of neurological symptoms, including tremors and myoclonus (sudden, involuntary jerks of a muscle or a group of muscles).
  • Neurosyphilis: A complication of untreated syphilis infection that can cause a wide range of neurological symptoms, including tremors. It's rare in the modern era due to the availability of effective antibiotic treatments.

Recommendations for Workup

• Clinical Examination: A thorough neurological examination to assess for other signs of neurological disease.
• Imaging: Consider MRI of the brain to rule out structural lesions, MS, or other abnormalities.
• Laboratory Tests: Blood tests to rule out Wilson's disease, syphilis, and other metabolic or infectious causes.
• Psychological Evaluation: If anxiety or stress is suspected as a contributing factor.

Possible Treatment

Treatment will depend on the diagnosis. For example, essential tremor may be treated with beta-blockers or primidone, while dystonic tremor might require botulinum toxin injections or oral medications like anticholinergics. Parkinson's disease is managed with dopaminergic medications. Anxiety-related tremors may respond to anxiolytics or cognitive-behavioral therapy.