Source
Espinoza J, Espadas I, Karpozilou A, et al. Paroxysmal dyskinesia associated with hyperthyroidism in 7 cats: a novel manifestation of a metabolic encephalopathy. J Vet Intern Med. 2026;40(1):aalaf007. doi:10.1093/jvimsj/aalaf007
Research Note
Paroxysmal dyskinesia (PD), a subtype of movement disorder characterized by transient episodes of involuntary, sustained muscle contractions, is associated with hyperthyroidism in humans but has not been reported in cats with hyperthyroidism. Specific neurologic signs attributable to this disease are rare in cats.
This retrospective study reported on a small cohort of cats with hyperthyroidism (n = 7) presented with clinical signs consistent with PD, including diagnostic findings, treatment, and outcomes. All cats were initially presented for episodes consistent with PD; none were diagnosed with hyperthyroidism prior to the onset of these episodes.
Common features of PD episodes in all cats were impaired balance, stiffness, dystonic movements of all limbs, bradykinesia, and dystonic postures with varying degrees of trunk kyphosis or twisting. Physical examination revealed a low BCS, palpable goiter, and heart murmur in 4 cats; 3 cats had no significant findings on physical examination. MRI in 2 cats revealed no abnormalities. Hyperthyroidism was treated with thiamazole (ie, methimazole) in 6 cats and with carbimazole in 1 cat; 3 cats later received radioiodine therapy.
A euthyroid state was confirmed in 6 cats; posttherapy thyroxine measurements were unavailable for the remaining cat. PD episodes resolved in all cats.
This case series suggested that hyperthyroidism should be a differential in cats presented with PD.
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