Fading kitten syndrome: Factors predisposing to 'faders' and treatment options

Fading kitten syndrome is a condition where one or more kittens of a litter are born apparently healthy but gradually become inactive, sick and die; typically faders are considered those that die during the first 2 weeks of life. Fading has many potential aetiologies, including a wide variety of infectious, toxic, traumatic, metabolic and genetic diseases. Regardless of the underlying cause, the approach to a sick neonate is similar, and initiating supportive care is the first priority, followed by a detailed physical examination. Where possible, the cause of disease should be determined, and this may inform adjustments to the treatment protocol.

Most perinatal and neonatal diseases present similarly and a specific cause cannot usually be determined from clinical signs alone, which can make diagnosis challenging. When examining a kitten, it is important to remember that there are distinct physiological differences between adults and neonates. In addition, some procedures can be more difficult to perform than in adults, such as blood collection, and some diagnostic tests are harder to interpret, such as radiography. When treating kittens, differences compared with adults again need to be considered.

The aim of this review is to provide guidance to veterinarians who are presented with a fading kitten. As well as reviewing the potential causes of fading kitten syndrome, the diagnostic approach and treatment options are discussed. Algorithms summarising possible pathways to neonatal mortality in kittens, and diagnostic and therapeutic options in fading kittens, are also provided.

Information provided in this review is based on the published feline literature and papers discussing puppies and/or a range of species including cats, as well as the author's own clinical experience.