A 6 years old rescued cat fed mainly with canned fish was admitted as an emergency to our Neurology department for severe neurological signs. The cat presented a neck ventroflexion, bilateral ataxia, depression and no menace response with normal pupillary light reflexes.
The MRI of the brain revealed bilateral and symmetrical well defined on T2WI (less obvious but also hyperintense on FLAIR, PD or GRE), rounded strong signal intensities at the lateral geniculate, caudal colliculi, vestibular and fascial nuclei. There was also a patchy ill-defined T2 hyperintensity within the hyppocampus and certebral cortex. (Please see images). The images were consistent with thiamine deficiency.
Thiamine is water-soluble vitamin B1 that acts as an essential cofactor for carbohydrate metabolism. Thiamine-dependent biochemical processes includes the citric acid cycle and pentose phosphate pathway, which are major energy production process in the central nervous system (CNS). Carnivores must obtain thiamine from the environment due to impaired autosynthesis and minimal storage. Causes of thiamine deficiency include consumption of raw fish that often contains thiaminase, cooked food in which the thiamine has been destroyed due to heating, or meats preserved with sulphite that inactivates thiamine (canned food).
Clinical signs of thiamine deficiency include various vestibular signs, vision loss, mydriasis without pupil light reflexes, incoordination, ataxia, and opisthotonus. Clinical resolution is possible if the case is diagnosed early enough. Supplementation with thiamine at 50mg per cat until resolution of the symptoms and further 25mg a day for several weeks until the diet is restored can lead to complete recovery.
T2w transverse- bilateral, symmetrical well defined hyperintensities at lateral geniculate nuclei.
T2w transverse- bilateral, symmetrical well defined hyperintensities at vestibular nuclei.
T2w transverse- bilateral, symmetrical well defined hyperintensities at fascial nuclei.
T2w transverse- bilateral, symmetrical well defined hyperintensities at caudal colliculi nuclei.
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Ane Uriarte, Dip ECVN, MRCVS, DVM
RCVS Recognized & European Specialist in Veterinary Neurology