Serotonin Syndrome

 

Dogs suffering from compulsive behaviors, separation anxiety, chronic pain and other conditions may benefit from medications that affect the level of serotonin in the body. Serotonin is a neurotransmitter, a chemical that works in the brain, and is found in the nervous system. It regulates behavior, awareness of pain, appetite, movement, body temperature, and function of the heart and lungs.

 

If a dog is taking more than one type of medication that causes levels of serotonin to increase in the body, a condition known as serotonin syndrome (SS) can result, and if not caught in time, can lead to death.

 

Symptoms and Types

 

As seen in humans, serotonin syndrome may cause:

 

• Altered mental state (confusion, depression, or hyperactivity)
• Difficulty walking
• Trembling and seizures
• Vomiting
• Diarrhea
• Rapid breathing (tachypnea)
• Rapid heart rate (tachycardia)
• Increased body temperature (hyperthermia)

 

Causes

 

Drugs prescribed as antidepressants in humans are becoming more common for use in animals. These medications alter the body’s levels of serotonin, and thus alter mood and behaviors. Some commonly used antidepressant drugs in dogs include buspirone, fluoxetine, and clomipramine.

 

Serotonin syndrome can be triggered when:

 

• Antidepressant drugs are given in excess
• Other drugs which affect serotonin levels are also ingested (e.g., amphetamines, chlorpheniramine, fentanyl, lithium, LSD)
• Individuals with a system more sensitive to the chemical ingest these medications
• Certain foods are ingested along with medications (e.g., cheese, anything containing L-tryptophan)

 

Signs of serotonin syndrome usually come on rapidly in dogs; anywhere from 10 minutes up to four hours after ingestion. 

 

Diagnosis

 

Your veterinarian will conduct blood tests to figure out if your dog could have an infection, as well as to determine what substances the dog might have eaten. Neurological testing (measuring reflexes and coordination) will also be done to pinpoint a specific area of the nervous system that might be affected, like the brain or spinal cord. There is not a specific test that can be run to tell your veterinarian that serotonin syndrome is to blame. The history of drug ingestion and the signs your dog is showing should lead to the proper diagnosis.

 

 

Cognitive Dysfunction Syndrome  in Dogs

 

Cognitive dysfunction syndrome is a condition related to the aging of a dog’s brain, which ultimately leads to changes in awareness, deficits in learning and memory, and decreased responsiveness to stimuli. Although the initial symptoms of the disorder are mild, they gradually worsen over time, also known as “cognitive decline.” In fact, clinical signs of cognitive dysfunction syndrome are found in 50 percent of dogs over the age of 11, and by the age of 15, 68 percent of dogs display at least one sign.

 

Symptoms and Types

 

• Disorientation/confusion
• Anxiety/restlessness
• Extreme irritability
• Decreased desire to play
• Excessive licking
• Seeming disregard for previously learned training or house rules
• Slow to learn new tasks
• Inability to follow familiar routes
• Lack of self-grooming
• Fecal and urinary incontinence
• Loss of appetite (anorexia)
• Changes in sleep cycle (i.e, night waking, sleeping during the day)

 

Causes

 

Although the exact cause of cognitive dysfunction syndrome is currently unknown, genetic factors may predispose an animal to develop the condition.

 

Diagnosis

 

You will need to give a thorough history of your dog’s health to your veterinarian, including the onset and nature of the symptoms and possible incidents that might have precipitated the unusual behaviors or complications. He or she will then perform a complete physical examination to evaluate the overall health status and cognitive functions of the dog. Routine blood tests, ultrasounds, and X-rays are also employed to rule out other diseases that may lead to behavioral changes associated with cognitive dysfunction syndrome.