Newly discovered feline muscle disease

From Cat

A newly diagnosed potassium-aggravated myopathy has recently been reported in cats.

Twelve shorthair cats in Europe (6 males and 6 females; age range, 2 months to 3 years) from one household were assessed for clinical signs of episodic muscle spasticity. Familial relationships among the cats were suspected but not known. A functional channel disease, especially a sodium channelopathy similar to potassium-aggravated myotonia, was considered likely[1].

Clinical signs

Clinical signs are characterized by a hypermetric, ataxic gait that appeared to be induced by exercise. The physical examination of all the cats demonstrated a thin to mildly emaciated body condition and signs of suppurative rhinitis. The results of hematologic and CSF analysis, diagnostic imaging, electromyography, motor nerve conduction tests, screening for metabolic storage diseases, provocation tests via exercise in a cold environment, and gross pathological and histologic examination revealed no abnormalities that could explain the clinical signs.


Potassium restriction appears to alleviate clinical signs in affected cats.

Offering consumption of a potassium-enriched diet resulted in severe aggravation of clinical signs in 7 of 7 tested cats. These developments lead to a diagnosis of potassium-aggravated muscle stiffness.


  1. Kiesewetter IS et al (2011) Potassium-aggravated muscle stiffness in 12 cats. J Am Vet Med Assoc 238:1026-1031