Understanding Behavior Feline Hyperesthesia Syndrome*
About This Column ❯❯ John Ciribassi, DVM, DACVB Behavior problems are a signifi- Chicagoland Veterinary Behavior Consultants Carol Stream, Illinois cant cause of death (euthanasia) in companion animals. While most eline hyperesthesia syndrome (FHS) is known by several names, including veterinary practices are necessarily rolling skin disease, neurodermatitis, neuritis, psychomotor epilepsy, and pru- geared toward the medical aspect F ritic dermatitis of Siamese.1,2 As evidenced by these names and by the use of of care, there are many opportuni- the term syndrome, FHS is not characterized as having a single etiology. In fact, ties to bring behavior awareness it is often a diagnosis of exclusion. The differential diagnosis for FHS includes into the clinic for the benefit of diseases related to the fields of dermatology, neurology, and behavior. Only after the pet, the owner, and ourselves. conditions relating to skin and the nervous system have been ruled out can this This column acknowledges the condition be labeled a behavior disorder. importance of behavior as part of veterinary medicine and speaks Signalment FHS can occur in cats of any age, but it is commonly seen in cats aged 1 to 5 practically about using it effectively years. Males and females are equally affected. While all breeds can be affected, in daily practice. Siamese, Burmese, Persian, and Abyssinian cats are more commonly afflicted.3
Clinical Signs As indicated by the name rolling skin disease, affected cats often show rippling or rolling skin along the lum- bar spine. Palpation of the lumbar musculature may elicit signs of pain. Mydriasis is common during bouts of FHS. Affected cats commonly stare at their tail, then attack QuickNotes the tail and/or flanks. Biting of the tail base, forelegs, and FHS can occur in cats paws is common. These cats of any age, but it is often run wildly around the commonly seen in home, vocalizing at the same cats aged 1 to 5 years. time. Normally calm cats may display aggression toward people or other cats in the household, while aggressive cats may display increased affection. The behavior may be induced by pet- ting or stroking the cat’s fur and most commonly occurs in the morning or later in the evening.2
Diagnosis The differential diagnosis for FHS *Adapted with permission from John Ciribassi, DVM, and the Veterinary can be categorized by the type of Information Network (VIN). clinical signs displayed:
116 CompendiumVet.com | March 2009 ©2009 Kelpfish/Shutterstock.com Understanding Behavior Dermatologic: Flea allergy dermatitis, food unrelated, behavior such as grooming. If this allergy, atopy, infectious dermatitis conflicting situation persists over a prolonged Neurologic: Epilepsy, brain tumors, spinal period, the cat may engage in the displace- disease (disk disease, neoplasia, infectious ment behavior even when the competing myelitis) motivations are no longer present. This is Musculoskeletal: Myositis, myopathy then defined as a compulsive behavior. Behavioral: Compulsive disorder, displace- The environmental factors that trigger ment behavior compulsive behaviors exert their influence by stimulating the hypothalamus and the limbic A minimum database to aid in diagnos- system, which in turn activate motor activity ing FHS should include a physical exami- through the basal ganglia. Three types of neu- nation, neurologic examination, complete rotransmitters are reported to be involved: blood count, serum chemistry profile (espe- cially hepatic and renal function), urinalysis, Dopamine. Increased dopamine levels can and spinal radiography. Depending on these result in increased frequency of compulsive results, further diagnostics might include skin behaviors. scraping, fungal culture, skin and/or muscle Opiates. One theory is that when animals biopsy, spinal or cranial imaging (computed engage in compulsive behaviors, levels of QuickNotes tomography or magnetic resonance imaging), opiates in the brain are elevated, and the electromyography, food trials, and pharma- pleasurable effects that opiates promote Successful therapy is ceutical trials (flea control, corticosteroids, reinforce the behaviors. Another theory is based on reasonable antiseizure medication). The decision of that opiates initiate stereotypic behavior. owner expectations which tests to run and in what order depends This theory is based on the observation that and the ability to on the patience and financial situation of the administration of opioids enhances the dis- monitor the degree owner and the severity of the clinical signs. play of amphetamine-induced stereotypic of improvement. While running the gamut of tests is ideal, it behaviors, but these behaviors are blocked may be more practical to use pharmaceuti- when narcotic antagonists (such as nalox- cal trials once the baseline database has been one) are administered.4 collected. I typically suggest a trial of flea Serotonin. Serotonin is produced in the dor- control medication and, if there is no change, sal raphe nucleus, and its influence on the treatment with corticosteroids at antiinflam- basal ganglia and frontal cortex affects behav- matory doses. If the patient does not respond iors such as compulsive disorders. Higher to steroid treatment, treatment with an anti- levels of serotonin reduce the incidence of seizure medication is indicated. Phenobarbital compulsive disorders, which is the rationale is my initial antiseizure drug of choice; some for the use of selective serotonin reuptake practitioners also use gabapentin. inhibitors (SSRIs) to treat these disorders. If none of the above approaches results in an improvement in the cat’s condition, then a Treatment presumed diagnosis of behavioral FHS can be Successful therapy is based on reasonable made. owner expectations and the ability to moni- tor the degree of improvement. This can be Pathophysiology accomplished by recording the frequency and FHS is commonly considered to be a com- severity of signs of FHS during the treatment pulsive disorder resulting in self-injurious period. behavior. One proposed trigger of FHS is displacement behavior. Displacement behav- Behavior Modification ior occurs as an alternative to two other con- As with many behavior problems in compan- flicting behaviors. An example might be a cat ion animals, the treatment of FHS combines that wants to eat but is being prevented from behavior modification protocols and the use doing so by an aggressive cat in the house- of psychoactive pharmaceuticals. Behaviorally, hold. The competing motivations, hunger and the goal is to create a stable and consistent fear, cause the affected cat to want to simulta- environment for the cat. This can be accom- neously perform the conflicting behaviors of plished in the following ways: eating and escaping. As a consequence, the Institute a regular feeding schedule to pro- cat might perform a species-appropriate, but vide a more predictable source of food. ©2009 Dr. Margorius/Shutterstock.com ©2009 Dr.
118 Compendium: Continuing Education for Veterinarians® | March 2009 | CompendiumVet.com Understanding Maintain consistency in interactions with the administration of the medication. If the patient Behavior cat. When managing dogs with a compulsive is receiving combination therapy (an SSRI or disorder, one common recommendation is TCA with a benzodiazepine), the medications for the owners to use a command–response– should be weaned one at a time to determine reward technique for all interactions. For which drug is responsible if signs return as the example, the owner asks the dog to sit and, dose is reduced. after the dog obeys, gives it a treat. The same technique can be used with cats. Selective Serotonin Reuptake Inhibitors Provide regular play sessions using target- The following dosages are recommended for type toys (e.g., feather toys). cats with FHS6: Anticipate situations that trigger the behavior. When the behavior is likely to occur, redirect Fluoxetine: 0.5 to 2.0 mg/kg PO q24h the cat’s activity to more appropriate behav- Paroxetine: 0.5 to 1.0 mg/kg PO q12–24h iors, such as training exercises or play.3,5 The adverse effects of SSRIs include seda- FHS behaviors should not be punished tion, anorexia, irritability, vomiting, and diar- because punishment will increase the cat’s con- rhea. In addition, SSRIs inhibit the function of QuickNotes flict and stress, resulting in a likely increase in the liver cytochrome P450 enzymes CYP2C9, FHS behaviors should the problem behaviors. CYP2D6, CYP2C19, and CYP3A4. As a conse- quence, care should be taken when prescrib- not be punished Pharmaceutical Intervention ing concurrent medications that rely on these because punishment There are no US Food and Drug Administration– enzymes for their metabolism (e.g., pheno- will increase the cat’s approved medications for treating FHS or barbital, carbamazepine, benzodiazepines, conflict and stress, any other compulsive disorder in pets. Con TCAs). SSRIs should not be used in combina- resulting in a likely sequently, owners should be informed of the tion with each other or with other drugs that increase in the potential risks as well as the possible benefits increase serotonin levels, such as monoam- problem behaviors. of the use of behavior medications. It is always ine oxidase inhibitors (e.g., selegiline), other wise to conduct appropriate laboratory testing SSRIs (e.g., paroxetine, sertraline), or TCAs to confirm normal hepatic and renal function (e.g., amitriptyline, imipramine, doxepin). before prescribing these medications, which are metabolized and eliminated by the liver Tricyclic Antidepressants and kidneys. It is also helpful to repeat test- Of the TCAs, clomipramine (0.5 to 1.0 mg/kg ing approximately 4 weeks after instituting PO q24h)7 can be used to treat FHS. Adverse therapy to evaluate the medication’s effect on effects associated with this drug include organ (particularly hepatic) function. sedation, anticholinergic effects, potentiation The three main classes of medications used of arrhythmias in predisposed patients, and to treat FHS are SSRIs, tricyclic antidepressants lowering of the seizure threshold in patients (TCAs), and benzodiazepines. When using any with seizure disorders. of these medications in cats, it is best to begin at the lower end of the dose range, then titrate Benzodiazepines upward as needed to achieve the desired The following dosages8 are recom- response. This approach minimizes the poten- mended for cats with FHS. These tial for serious side effects such as prolonged benzodiazepines are recommended anorexia or excessive sedation. in cats because they do not have active Once the frequency of the behavior metabolites. Diazepam has been impli- reaches an acceptable level, treatment should cated in cases of hepatic necrosis in cats. be maintained for 4 to 6 months. The dose Lorazepam: 0.125 to 0.50 mg PO q8–24h can then be gradually reduced (25% reduction Oxazepam: 0.20 to 0.50 mg/kg PO q12–24h every 1 to 2 weeks) until the patient has been weaned off the drug. If the behavior recurs The potential adverse effects of these drugs or increases in frequency during the weaning include sedation, ataxia, and temperament process, the previously effective dose should changes. Combination therapy with an SSRI or be reinstituted. Another reduction may be a TCA is acceptable with either of these drugs attempted after another 4 to 6 months of ther- if no agent alone provides sufficient response.
apy; however, some patients require lifelong CONTINUEs ON page 132 Koval/Shutterstock.com Vasiliy ©2009
CompendiumVet.com | March 2009 | Compendium: Continuing Education for Veterinarians® 121 Understanding CONTINUED FROM page 121 FHS can be controlled but is not likely to be Behavior cured. By developing a clear diagnostic plan Conclusion and following it closely, veterinarians can FHS has multiple possible etiologies. It requires avoid confusion for the owner and foster a patience and close communication with the sense of cooperation between the owner and pet’s owner in order to arrive at the correct themselves. Overall, this is the true measure diagnosis. As with most behavior disorders, of success.
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