Meet "Harry": a spunky 12-year-old male cat that overtly looks like he is in good health and my physical examination confirms this. He has minimal dental tarter, in good body condition, abdomen palpates normally, no heart murmur heard and no orthopedic pain elicited when I flexed his joints. His blood work and urinalysis results were all within the normal range. Why, then, are his parents upset with Harry? Well, Harry is keeping them up at night howling and roaming the halls. At times, his parents report that he seems a little disoriented. Sometimes he screams to be fed even though his food bowl is full. Occasionally, he forgets where his litter box is and urinates in the closet. What do I think is wrong with Harry? After a complete diagnostic work up, I believe that "Harry" is suffering from Cognitive Dysfunction Syndrome.
Cognitive Dysfunction Syndrome (CDS) is a disease that involves the degeneration and loss of nerve cells within the brain of older pets resulting in behavioral changes. These changes are not the result of any other medical condition, like brain cancer, thyroid, liver or kidney disease.
The brain is made up of over 100 billion nerve cells with an intricate circuit pathway. Each nerve cell communicates with the adjacent nerve cell by a releasing a substance that stimulates the next cell. This communication process can be disrupted or tangled when abnormal substances accumulate in spaces between nerve cells, called amyloid plaques, and within nerve cells, called tau proteins. Both of these substances increase in concentration when nerve cells begin to die. The initiation of this degenerative process is thought to be due to a dysfunction of the mitochondria and accumulation of toxic substances in the brain. (The mitochondria are the structures within all cells that provide cells with energy. Cells will die without an ample energy supply.) The reason why mitochondria fail is still under investigation, and the answer may lead to a remarkable treatment plan for CDS patients.
Although age is the greatest risk factor for developing CDS, it is not the only factor involved. With neurologic signs that mimic Alzheimer's disease in humans, pets as young as eight years of age may present with signs of CDS. In one study, 28 percent of 11 to 12-year-old dogs and 68 percent of 15 to 16 year-old dogs had a least one sign consistent with CDS.
The clinical signs of CDS in pets may include one or more of the following signs:
- Spatial Disorientation and Confusion -- wandering, staring, going to abnormal places or difficulties navigating stairs.
- Altered memory or learning -- forgetfulness (which may include house soiling or lack of response to previously learned command).
- Increased vocalization
- Altered social relationships -- inability to recognize familiar people, withdrawal from family members, aggression.
- Altered sleep-wake cycle
- Decreased interest in every day activities or irritability
- Decreased interest in food.
Regrettably there is no cure yet for CDS. Frequently, I will approach this syndrome with multiple treatment modalities to try to improve the pet's quality of life. My treatment plan may include one or more of the following elements:Environment:
- Sleeping area should be convenient for the pet and litter box should be easily accessible.
- Keep the pet awake during the day as much as possible to encourage sleeping at night.
- Increase mental stimulation, which includes food puzzle and interactive toys, massage therapy, acupuncture, brushings, having pets do tricks they know and encourage learning new ones.
- Exercise with your pet at least 15-30 minutes twice daily.
- Teach pets with decreased hearing and vision to respond to hand and touch cues.
- Provide a diet enriched with essential fatty acids, Vitamin E and anti-oxidants. Hill's prescription B/D is a diet made exclusively for brain health.
- Maintain good body condition by watching caloric intake.
- Selegiline (Anipryl) may prolong the dopamine activity in the brain and help reduce the amount of free radicals that are toxic to nerve cells.
- Minocycline -- may decrease nerve inflammation and nerve degeneration.
- Acepromazine -- a tranquilizer to reduce night waking and encourage a good night sleep.
- SAMe -- a naturally occurring substance that helps increase neurotransmitter levels of dopamine and protect cells against free radicals.
- Melatonin -- a hormone that helps promote normal wake-sleep cycle and reduce cell death.
- Fish Oil -- Omega three and six -- decreases inflammation
- Vitamin E and Selenium -- antioxidant benefit
- Steroids -- like prednisolone or dexamethasone.
- Diazepam (valium)
- Iron supplements
Please contact your veterinarian if your pet is showing any of the above clinical signs of CDS. The clinical signs present in CDS may also be present in other disease processes. It is imperative that your veterinarian performs a complete physical examination, blood work, urinalysis, and other diagnostic testing (like radiographs or MRI) to confirm this diagnosis. Although there is no present cure for CDS, talk to your veterinarian about therapeutic options available to help your forgetful pet live its best life possible. With continued research, hopefully, we will soon find a cure for pets with CDS and people with Alzheimer Disease.