These words are not uttered by many of us on a regular basis (unless you are studying for boards and talking in your sleep). So, why do you need to know what this is? So that we remember that not all things that twitch have seizures.
Paroxysmal dyskinesia's are one, of a group, of movement disorders characterized by abnormal muscle movements UNRELATED to epileptic discharges. If you take one thing away from this email it is this: movement disorders are not seizures. Not that I suggest you stop reading...
How do I identify a Paroxysmal Dyskinesia (PD)?
This group of movement disorders manifest as sudden cramping in muscles and limbs. It has been identified in several breeds, with increased incidence in Terrier breeds. Notably there is no loss of consciousness, no autonomic signs, and upon recovery from the cramping the dogs return to normal function immediately. These cramping episodes can be triggered with specific activities in some patients (activity or exercise is a common trigger) and may last for minutes to hours. When performed, no EEG abnormalities consistent with epileptic discharges are noted.
What diagnostic testing should I run?
Cramping syndromes may be triggered from metabolic causes as well as genetic causes. A CBC, serum biochemistry and urinalysis are a wonderful way to rule out metabolic causes. If normal, assessment of a video can determine if additional testing for seizure disorder should be pursued.
Are there any treatment options?
Yes! Many movement disorders improve with anticonvulsant drugs such as the benzodiazepine class of drugs. One recent report (reference below) detailed successful treatment of a Welsh Terrier with levetiracetam (20 mg/kg PO q8h) to control signs.
Do you suspect you have a patient with a movement disorder? Please reach out for a consultation - I'm happy to help. I truly love working with you and your staff to help patients live their best lives, with neurologic disease. Keep up the good work!
Stay safe - it's almost spring time and we can make it!
Reference:
Green S, Olby N. Levetiracetam-responsive paroxysmal exertional dyskinesia in a Welsh Terrier. JVIM 2021: https://doi.org/10.1111/jvim.16068