Feline Hyperesthesia (FHS)
Ever since the earliest days of human-cat interactions, cats have had a reputation for being mystical, spiritual beings, either divine or possessed. It isn't hard to understand why. Cats have the propensity to gaze unblinking in peoples' eyes, to appear to see things that aren't there, to run crazily around for no apparent reason, and to go from quiet to ferocious in a moment.
Some of these attributes, in an extreme form, are components of the syndrome known as feline hyperesthesia. Cats affected by this syndrome show the most bizarre character changes, sometimes appearing to hallucinate, act manic, schizophrenic, or even "possessed."
Clinical Signs of Feline Hyperesthesia Syndrome (FHS)
Sudden bouts of bizarre hyperactive or aggressive behavior
Frenetic self-directed grooming directed along the flank or tail (possibly leading to hair loss)
Tail swishing, fixation with tail, tail chasing, or vicious attacks directed toward the tail
Large pupils/strange look to the eyes
Skin rippling/rolling (this disorder is sometimes referred to as "Rolling Skin Disease.")
Apparent hallucinations – seemingly following the movement of things that are not there or running away from some unseen adversary.
Vocalization, crying, loud meowing
Exquisite sensitivity to touch ("hyperesthesia") along the spine – stroking can precipitate a bout of the behavior.
Sudden mood swings – e.g. from extremely affectionate to aggressive
Any or all of the above signs progressing to seizures [falling over, legs paddling, salivating)
Bouts occurring almost constantly, all day, every day, or once every few days
FHS tends to arise for the first time in mature cats. No one really knows what causes FHS but there are a few possibilities.
Because some cats display grand mal seizures during or following a bout of FHS, it is possible that the condition arises as a result of aberrant electrical activity in areas of the brain that control emotions, grooming, and/or predatory behavior (i.e. there may be partial seizure activity). In support of this explanation, some affected cats respond to anticonvulsant (anti-epileptic) therapy.
FHS could be a form of feline obsessive-compulsive disorder (OCD) in which the obsession relates to grooming, and/or aggression, plus concerns for personal safety. The apparently compulsive nature of self-directed grooming and a positive response to anti-obsessional medication supports this etiology.
Seizure activity leading to obsessive-compulsive manifestations (almost half of human bulimics have abnormal brain waves). This hypothesis provides a way of unifying the seemingly disparate etiologies described above.
An inherited tendency for mania precipitated by stress. Certain (oriental) breeds are more susceptible to FHS and its expression does seem to be stress-linked.
Some affected cats have been reported to have pathological lesions in the muscles along their spine. It is assumed that the lesions may cause local irritation, altered sensitivity, and/or pain.
There is no definitive "rule in" test that confirms FHS. If the clinical picture fits the description above, the diagnosis is confirmed by exclusion of possible medical causes and by a positive response to treatment for FHS. To this end, your veterinarian should obtain a careful behavioral history regarding your cat, perform a thorough physical examination, and take a blood sample for complete blood count, chemistry profile, and thyroid hormone level (T4). Medical conditions that may be confused with FHS include hyperthyroidism [thyroid gland overactivity], brain infections, brain trauma, brain tumors, some poisonings (e.g. lead, strychnine), heavy parasitic infestations of the skin, nutritional deficits (e.g. thiamine), and severe allergy.
Optimize the affected cat's environment to minimize stress (stress could be – probably is – a factor in every expression of the syndrome). Recommendations include:
Provide daily aerobic exercise for the cat by playing with the cat using a feather wand toy or toys dragged along on a string.
Feed the cat frequently and on a regular schedule to minimize stress over food.
Train the cat to perform one new trick each month (come for food, sit for food, jump up, jump down). Click and treat training is the best way to accomplish this goal.
Consider getting a friendly cat for your cat. You should probably arrange a "trial marriage" first.
Address any infighting between existing cats in the home.
Arrange predatory play activities to allow the cat to "blow off steam" and dissipate any unvented prey drive. The feather wand type of toys mentioned above are appropriate for this purpose as are "laser mice" toys, ping-pong balls kicked or dragged around, Cat Dancer toys, and so on.
Make life interesting for your cat: spend more quality time with him and make the environment more "cat friendly." Provide a three dimensional environment by adding cat perches strategically placed so that he can sit up on high and have a good view of the world. Buy a fish tank or get some birds in a cage but make sure the little ones are always safe and secure. Get a window bird feeder. Provide an assortment of cat toys – moving interactive toys are best. Catnip mice appeal to some cats.