AVMA 2017: Behavioral Problems in Senior Dogs

Senior dogs represent a special class of behavioral patients for veterinarians, according to Marsha Reich, DVM, DACVB, from Maryland-Virginia Veterinary Behavior Consulting in Silver Spring, Maryland. Presenting at the American Veterinary Medical Association Convention in Indianapolis, Indiana, Dr. Reich discussed the proper approach to evaluating behavioral problems in older dogs.

She explained that behavioral problems in seniors can be sorted into 3 categories: true primary behavioral changes, behavioral problems that arise secondary to a medical issue, and problems related to cognitive decline.

True Primary Behavioral Problems

In senior dogs, primary behavioral problems are similar to those seen in younger animals and may include problems such as separation anxiety, aggression, and phobias. However, according to Dr. Reich, except for problems that existed at a younger age, true primary behavioral diagnoses occur less frequently than behavioral problems secondary to a medical condition. “A new behavioral problem in a senior dog is usually a result of a medical problem,” she said.

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Behavioral Problems Secondary to a Medical Problem

Because a change in behavior is frequently the first indication of an underlying medical problem, Dr. Reich emphasized the importance of reviewing all medical records relating to the dog’s clinical history. And, because many medical conditions may have nonspecific or similar causes, Dr. Reich highlighted the need for clinicians to perform a thorough clinical examination, as well as baseline laboratory testing (complete blood count, biochemistry profile with electrolytes, thyroid profile, and urinalysis), to help identify underlying metabolic or endocrine abnormalities in senior dogs with behavioral problems. She advised that the findings of the clinical examination and baseline laboratory testing should then inform the clinician’s decisions regarding additional diagnostic testing.

Any medical problem can potentially contribute to a dog’s developing behavioral problems, said Dr. Reich. For example, discomfort or pain can lead to behavioral changes such as pacing, restlessness, night waking, and aggression. Dr. Reich noted that the most common sources of pain she encounters in senior dogs are of musculoskeletal and gastrointestinal (GI) origin.

Dogs with underlying musculoskeletal problems may show behaviors such as aggression when they are lying down and forced off furniture, excessive licking of their feet or joints, and aggression toward other dogs in the family that occurs outside. To help identify musculoskeletal problems, clinicians should question owners about whether their dog slides on smooth flooring, is slow to rise after lying down, or has become less active and maybe gradually gained weight as a result.

GI problems may cause food aggression. In particular, new cases of food aggression directed toward people should prompt questions from the clinician to obtain information to help rule in or rule out the possibility of underlying GI disease—for example, if a dog is refusing to eat but does not want the owner to remove the food bowl. Dogs with GI disease may also have nausea, which may cause anxiety that manifests as chewing of various objects. This can be difficult to differentiate from the destructive chewing associated with separation anxiety, said Dr. Reich. However, dogs with GI disease typically show other signs as well, such as excessive swallowing or picky eating.

Endocrinopathies can also affect a senior dog’s behavior. Hyperadrenocorticism may cause irritability, lethargy, and polyuria/ polydipsia and may even contribute to food aggression, said Dr. Reich. Hypothyroidism may be associated with behavioral changes ranging from lethargy to aggression. “Cushing’s disease is one of the most common endocrine disorders that I have seen associated with behavioral problems,” she said. “However, although hypothyroidism is a common endocrine disease in dogs, I rarely see it associated with behavioral problems.”

In all cases of behavioral problems, Dr. Reich stressed the importance of carefully questioning the owner to obtain as much specific information as possible about the dog’s behavior. Clients may be unaware that certain observations or information about their pet could be useful to the veterinarian and thus may not mention some things. Clients also frequently become accustomed to some behavioral changes in their pet and may not think to discuss the problems, she said.

Additionally, “what the owner calls a problem may affect its diagnostic path,” she cautioned. For example, an owner may describe a dog’s abnormal urination behavior as marking, whereas it may in fact be pollakiuria.

Dr. Reich also stressed the importance of performing urinalysis on any dog that is urinating in the house. She requests this of referring veterinarians before they refer a dog to see her. “I want to rule out urinary tract infection,” she said.

However, regarding any diagnostic testing in senior dogs with behavioral problems, Dr. Reich reminded clinicians that “failure to find an abnormality does not mean nothing is wrong—it just means nothing was found.” Problems Related to Cognitive Decline

Because many medical conditions in older dogs have signs that mimic those of cognitive decline, when evaluating senior dogs with behavioral problems, Dr. Reich noted that “the possibility of cognitive dysfunction always looms in the background, but it’s really a diagnosis of exclusion.”

The acronym DISHA can help clinicians recognize the signs of cognitive dysfunction in senior dogs:

• Disorientation: Dogs may walk aimlessly, stare at walls, or lose balance and fall.
• Interactions: Dogs may begin to interact differently with people or other pets in the home.
• Sleep: Dogs that previously slept through the night may now be restless during the night or wake frequently.
• House soiling: Dogs may no longer alert the owner to the need to go outside and may urinate indoors or be incontinent.
• Activity level changes: Dogs may be restless, agitated, or show other signs of anxiety such as separation anxiety; they may stop grooming or may have a decreased appetite.

Treating Behvaioral Problems

Treatment of behavioral problems in senior dogs varies depending on whether the problem is a true primary behavioral problem, secondary to a medical problem, or cognitive dysfunction, said Dr. Reich. She stressed that clinicians should treat any underlying medical issues first. Treatment plans may also require medications or changes in how the owner manages the dog.

Managing Undesired Behaviors

Some behavioral problems—including separation anxiety—are managed the same way in older dogs as in younger dogs, said Dr. Reich. Behavioral modification techniques are also the same in older and younger dogs, but Dr. Reich stressed that such techniques may not be as effective in seniors. She discussed using treats or rewards to redirect or facilitate desired behaviors; in addition, although clinicians can use desensitization and counterconditioning to help dogs that fear noises, scary stimuli, and being alone, Dr. Reich noted that these techniques may be difficult to implement in seniors. “Dogs have limited learning ability as they age,” she said.

Owners may also need to implement various management changes, depending on the dog’s behavioral problem. For example, in cases involving food aggression, owners should feed the dog where it cannot be disturbed. In cases involving house soiling, owners should take the dog outside more frequently to urinate, including as late as possible before bedtime. Owners may also wish to teach their dog a cue for elimination if the dog is easily distracted when outside. They can also train their dog to urinate on pads or paper indoors.

Supplements and Drug Therapy

Dr. Reich discussed various supplements that have been used to treat senior dogs with behavioral problems, including S-adenosylmethionine (SAMe), apoaequorin, alpha-casozepine, and omega-3 fatty acids.

Although Dr. Reich said that many of the medications used to treat young dogs with behavioral problems can also be used in seniors, she stressed that drugs with fewer adverse effects are preferred—for example, selective serotonin reuptake inhibitors such as fluoxetine and sertraline.

For dogs with poor liver function, Dr. Reich advises that clinicians avoid using diazepam and instead choose other benzodiazepines, such as lorazepam and clonazepam, because metabolism of these drugs is minimally affected by age and liver disease. She also recommends that clinicians perform bloodwork regularly—once or twice each year—on dogs receiving long-term medications for behavioral problems to ensure that the drugs are not adversely affecting the animal’s metabolism.

For dogs with cognitive dysfunction, in particular, Dr. Reich favors using SAMe supplements. “I try to treat as many senior dogs as possible with SAMe,” she said. It stimulates brain glutathione and decreases oxidative stress, which is implicated in cognitive dysfunction, she explained. Many dogs that receive SAMe supplementation show clinical improvement, she said.

In contrast, Dr. Reich noted that she does not typically use selegiline, a monoamine oxidase-B inhibitor, for dogs with cognitive dysfunction because of its potential to interact with other products or drugs such as amitraz and fluoxetine.

Combination Therapy

For managing senior dogs with behavioral problems, Dr. Reich recommends using an approach that combines medical, behavioral, and environmental management strategies, with drug therapy as needed. This approach can help to improve quality of life for both the dog and the owner.

Dr. Parry, a board-certified veterinary pathologist, graduated from the University of Liverpool in 1997. After 13 years in academia, she founded Midwest Veterinary Pathology, LLC, where she now works as a private consultant. Dr. Parry writes regularly for veterinary organizations and publications.