DIAGNOSTIC INVESTIGATION IN 13 CATS WITH SUSPECTED FELINE HYPERESTHESIA SYNDROME

Feline hyperesthesia syndrome (FHS) was first reported in 1979
and described as an accentuation of an otherwise normal behavior
in cats consisting in episodes of tail chasing, biting or licking the
lumbar area, flank, anal area or tail; skin rippling and muscle
spasms; excessive and unusual vocalizations, wild and uncontrolled
jumping and running and presumed hallucinations. FHS has been
anecdotally reported in association with dermatological, behavioural,
orthopaedic and neurological conditions. Treatment with
phenobarbital, gabapentin, prednisolone, amitriptyline, fluoxetine,
clomipramine and multivitamin supplements have been used with
inconsistent responses. However, we are not aware of any clinical
scientific investigation on Feline Hyperesthesia Syndrome.
We retrospectively collected data on the history, signalment,
diagnostic workup and treatment from three referral veterinary
centers. The inclusion criteria were a history of attacking or overgrooming
the tail, flank or perineal area associated with either
vocalization or lumbar hyperesthesia, manifested as rippling of the
thoracolumbar skin occurring spontaneously or induced by gentle
touch. Information on physical and neurological examination, and
diagnostic work up were also necessary for inclusion in the study.
Thirteen cats were included in the study. The median age of
presentation was 1 year (1–7 years). Eleven cats were attacking or
over-grooming their tails and two cats their flank or perineal area.
Tail mutilation was reported in 9/13 cats, rippling of the thoracolumbar
skin in 10/13 cats and 6 cats presented with unusual
vocalization during the episodes. The episodes occurred multiple
times per day in 12/13 of the cases, and multiple times per week in
1/13. No consistent triggers were reported. Results of CBC and
biochemistry were available for 12/13 cats, spinal radiographs for
7/13, magnetic resonance imaging for 6/13, cerebrospinal fluid
analysis for 3/13, electromyography for 3/13, dermatological
assessment for 7/13, and joint fluid analysis for one cat. The diagnostic
work up led to the diagnosis of allergic dermatitis in 2 cases
and immune-mediated polyarthritis in one case, but a definitive
diagnosis was not reached in the remaining 10 cases. Treatment
included corticosteroids in 7/13 of the cats, gabapentin in 8/13,
clomipramine in 4/13, topiramate in 2/13, phenobarbital in 2/13
and cyclosporine in 6/13. The majority of the cases (10/13)
received a combination of 2 or more drugs.
Our study confirmed previous anecdotal reports of FHS affecting
young cats and the possibility of that FHS signs are secondary
to inflammatory skin conditions. A definitive diagnosis was not
reached in 10 cases. However, not all the cases had the same
diagnostic work up and not all had a full behavioral and dermatological
assessment. Based on the results of this retrospective
study, specialists in neurology, behavior and dermatology have
formulated a standardized questionnaire and proposed a rational
diagnostic approach for investigation and treatment of this constellation
of clinical signs in cats and as a platform for future
prospective studies.