Tardive Dyskinesia and Related Dyskinesias

Question 1

Classification of acute and chronic dyskinetic disorders

Answer 1

Question 2

Diagnostic criteria for tardive dyskinesia

Answer 2

1. History of at least 1 month of dopamine blocking therapy
2. Presence of involuntary dyskinetic movements
3. Exclusion of other etiologies of dyskinesia

Question 3

What secondary problems are patients with tardive dyskinesia at risk for?

Answer 3

Dental damage/erosion

Poor nutrition

Question 4

Differentiating tardive dyskinesia from idiopathic dystonia syndromes may sometimes be difficult. In these cases, ___ is a useful historical feature that is more specific to tardive dyskinesia.

Answer 4

Differentiating tardive dyskinesia from idiopathic dystonia syndromes may sometimes be difficult. In these cases, presence of arching spasms of the back and neck is a useful historical feature that is more specific to tardive dyskinesia.

Question 5

How to tell apart Tardive dyskinesia involving the limbs and Huntington’s chorea

Answer 5

Chorea tends to be more random while tardive dyskinesia tends to be stereotypic

Note that the two conditions can also coexist! Many Huntington’s patients have psychotic features and may be treated with neuroleptics, which can then cause tardive dyskinesia.

Question 6

If you withdraw the offending medication from someone with tardive dyskinesia, how likely are they to improve?

Answer 6

About 50% reversibility rate

Question 7

If you are treated chronically with a dopamine blocking medication, how likely are you to at some point develop tardive dyskinesia?

Answer 7

About 50%

Question 8

Risk factors for tardive dyskinesia

Answer 8

• Advanced age
• Female biological sex
• Coexistent brain damage

Question 9

Domperidone

Answer 9

Potent dopamine receptor blocker that does not cross the blood brain barrier

As such it is an excellent replacement for metoclopramide for the purpose of improving motility and reducing nausea

Sometimes used in combination with carbidopa/levodopa due to their side effect of slowing motility.

Also prolongs the QT interval.

Question 10

Treatments for tardive dyskinesia

Answer 10

• The best treatment is prevention. Don’t use a dopamine blocking medication chronically unless absolutely necessary.
• Increasing dopamine blockers helps initially, but makes things worse long-term
• Instead, doapmine depleters should be used:
  
  • Alpha methyl-p-tyrosine (a tyrosine hydroxylase inhibitor)
  • Reserpine
  • Tetrabenazine
  • Note: all dopamine depleters may also cause parkinsonism
• Botox injections of affected muscles may also be useful

Question 11

Treatment of an acute dystonic reaction

Answer 11

Anticholinergics given IV can produce resolution of an acute dystonic reaction such as torticollis or retrocollis

Diphenylhydramine (1st generation antihistamine with anticholinergic activity) is a good choice.