Today’s case is a 10 year old FS domestic shorthaired cat presenting to you with episodic “trouble walking”. The owners have noticed the cat appearing to occasionally writhe when she walks, sticking out one leg, then moving her back oddly, and possibly sticking out another leg as she moves. It is slow motion. The events can last up to 30 minutes after which time she is completely normal. She can walk and jump normally for a few days and then another event will be seen. Does this sound like anything you’ve seen before? The episodic nature of the history suggests either a movement disorder or a seizure disorder.

How do you differentiate between a movement disorder and a seizure?
Cats with seizures are expected to have autonomic signs (salivation, urination, defecation, vomiting), as well as a post ictal period. The post ictal period could be very short (e.g.: she is dazed for a few moments before returning to normal) or can last up to a day. The owners in this case did not identify any autonomic or post ictal signs therefore a movement disorder was suspected. There are many different types of movement disorders, ranging from hiccups to Parkinson’s movements. That’s a pretty wide range! Where do you start?

Causes of paroxysmal dyskinesia in cats
A recent article published in JVIM (2026) identified 7 cats with a movement disorder, called a paroxysmal dyskinesia ( AKA occasional weird movement) secondary to hyperthyroidism. Six of 7 cats had an undiagnosed hyperthyroidism meaning that the movement disorder was the FIRST sign of hyperthyroidism! All 7 cats underwent treatment (6: thiamazole; 1: carbimazole) and abnormal movements ceased in all cats! There was a complete cessation in 4 of 7 cats and a gradual reduction in signs in the remaining 3 cats. If you’re wondering what the movement looks like visit the supplementary data in the article to see the videos (https://doi.org/10.1093/jvimsj/aalaf007). Other than hyperthyroidism, one other article suggested a genetic cause in a cohort of Sphynx cats with a paroxysmal dyskinesia. The current article was the first study identifying hyperthyroidism as a cause.

Take away:
If you see a cat with a writhing-type muscle movement (especially slow moving) and NO autonomic signs, consider a paroxysmal dyskinesia.
If you see a cat with a suspected paroxysmal dyskinesia consider hyperthyroidism.

Thanks for reading! I hope you have a great week, and I look forward to working with you soon. March might be out like a lion instead of a lamb this week so stay safe, warm and dry in this upcoming weather!