Outbreak of thiamine deficiency in cats associated with the feeding of defective dry food

Abstract

Objectives The objective of this study was to determine disease progression, association between neurological signs and magnetic resonance imaging (MRI) findings, and long-term outcome in feline thiamine deficiency associated with defective dry food. Methods The clinical records of 17 cats diagnosed with thiamine deficiency related to a defective dry food were examined and data collected. The thiamine level in the food was analysed by liquid chromatography-tandem mass spectrometry. Results The thiamine level in the food was below the recommendation of the National Research Council. Fifteen cats were fed the food exclusively. Prior to the acute development of neurological signs, most cats displayed non-specific signs such as anorexia, lethargy or vomiting. Vestibular signs of varying severity were observed in 94% of the cats, and all but one of these presented with bilateral dysfunction. Other main neurological signs included altered mentation (76%), blindness (59%) and seizures (59%). Moreover, 80% of the cats with seizures presented with cluster seizures or status epilepticus. MRI abnormalities consistent with findings reported in the previous literature were detected in five cases. MRI was unremarkable in one cat with ongoing severe neurological signs even though thiamine had been administered. Most surviving cats recovered rapidly within 2 weeks of treatment and had either returned to normal or had minimal neurological signs at the 2 month follow-up. One cat recovered slowly over 6 months. Most cats with seizures in the initial stage of the disease remained seizure free at the 24 month follow-up. Conclusions and relevance This study documented the association between feline thiamine deficiency and defective dry food. MRI examination provided valuable information in the diagnosis. However, normal MRI findings do not exclude the diagnosis of feline thiamine deficiency, especially once thiamine has been supplemented. MRI findings also may not always reflect the neurological status or severity. If treated promptly, most cats will recover rapidly with a good outcome. Occasionally, recovery may be slow and take several months.

A real-time reporting system of causes of death or reasons for euthanasia: A model for monitoring mortality in domesticated cats in Taiwan

“…From October 2012 to February 2013, an outbreak of thiamine deficiency in cats due to defective dry food occurred in Taiwan. In severe cases, cats appear to have died from neural disorders (Chang et al, 2016). Based on data collected by our system, a notably higher incidence of neurological disorders attributed to CODs or RFEs occurred during this period as compared to the following two years (data not shown).…”

The Role of Thiamine and Effects of Deficiency in Dogs and Cats

“…The first stage, induction, occurs within one to two weeks of deficiency, and is characterized by a combination of vomiting, lethargy, and hyporexia or anorexia, though the animal’s behaviour may remain otherwise unchanged [ 4 , 28 , 106 , 107 , 108 ]. Few other signs occur at this stage.…”

“…In dogs and cats, these can include ataxia, paraparesis, nystagmus, delayed pupillary light response and blindness, recumbency, and increasingly poor proprioception, as well as seizures [ 4 , 5 , 9 , 28 , 35 , 38 , 106 , 109 ]. Cats may also exhibit cervical ventroflexion [ 106 , 109 ] and dyspnea [ 9 , 106 ]. Cardiovascular signs during chronic deficiency may include arrhythmias and bradycardia [ 110 ].…”

“…Elevated lactate concentrations in urine may occur in dogs with thiamine deficiency [ 28 , 110 ], but these are not always present in cats [ 29 ]. As well, elevated lactate concentrations in plasma and cerebrospinal fluid (CSF) are not always present in dogs during thiamine deficiency [ 100 ], and CSF results can be unremarkable [ 7 , 106 , 109 ]. Blood pyruvate concentrations may be elevated in dogs with thiamine deficiency [ 110 ].…”

“…Lesions may also be present in the cerebral cortex, cerebellar noduli, rostral colliculi, and suprasplenial gyri of the caudal cortex, and the medial vestibular nuclei [ 4 , 5 , 108 , 109 , 114 ]. One report revealed unremarkable MRI findings despite presenting with clinical signs of thiamine deficiency in a cat, though it is unclear if signs reversed due to the cat having received supplemental thiamine for several days prior to MRI, or if no abnormalities had been present prior to supplementation [ 106 ].…”