Differential Diagnosis for a 15-year-old boy with episodes of excessive blinking and dysarthria when scared or anxious

• Single most likely diagnosis:
  • Tourette Syndrome: Characterized by repetitive, stereotyped, involuntary movements and vocalizations called tics. The tics can be exacerbated by stress, anxiety, or excitement, which fits the scenario of the boy's symptoms worsening when he is scared or anxious. The normalcy between episodes also aligns with the typical presentation of Tourette Syndrome.
• Other Likely diagnoses:
  • Anxiety Disorder: While not directly causing the physical symptoms, severe anxiety can trigger or worsen tics in conditions like Tourette Syndrome or even lead to anxiety-induced physical symptoms that might mimic tics.
  • Stress-induced Movement Disorder: This can include a variety of movement disorders that are triggered or worsened by stress, including dystonic movements or tics.
• Do Not Miss (ddxs that may not be likely, but would be deadly if missed.):
  • Neurodegenerative Disorders (e.g., Huntington's Disease): Although rare in a 15-year-old, these disorders can present with movement abnormalities and psychiatric symptoms. Early diagnosis is crucial for management and genetic counseling.
  • Wilson's Disease: A genetic disorder leading to copper accumulation in the body, which can cause neurological symptoms including movement disorders, psychiatric symptoms, and can be fatal if not treated.
• Rare diagnoses:
  • Sydenham's Chorea: A rare neurological disorder occurring in some cases of rheumatic fever, characterized by rapid, involuntary, purposeless movements, primarily of the face and limbs. It can also include vocalizations and is often associated with emotional disturbances.
  • Tardive Dyskinesia: Although more commonly associated with long-term use of neuroleptic drugs, it could be considered in the differential if the patient has been exposed to such medications, presenting with involuntary, repetitive body movements.