Diagnosis
Index of Suspicion
It is important to question owners of geriatric dogs about the characteristic behavior changes. Many owners do not notice or report these behaviors and take it for granted that this “is just normal aging.” I ask owners about sleep-wake cycles by asking if the dog sleeps through the night or is waking them up.
I ask about urination and bowel habits and if the dog is having accidents in the house. If so, then I try to determine if it is incontinence or inappropriate urination and defecation. I also ask about social interactions and behaviors such as tricks and following commands. Some owners are very astute and note changes like the dog going to the wrong side of the door to be let out.Diagnostics
As, these patients are geriatric, other diseases may be present in the same patient. There are many systemic disorders that can make a patient with mild brain dysfunction decompensate and clinically look much worse. I highly recommend screening these patients with a complete blood count, serum chemistry profile, urinalysis, and blood pressure measurement. Inappropriate urination and loss of house training are often seen with CCD, but it is important to culture a sterilely collected urine sample to rule out a bacterial cystitis or pyelonephritis that could induce or worsen these behaviors. Disorders like hypertension, hyperadrenocorticism, anemia, and many others can induce behavior changes or exacerbate preexisting anxiety.
Thoracic radiographs and an abdominal ultrasound are my next steps. With these tests I am looking for significant concurrent
Chronic Disease Managementfor Small Animals, First Edition. Edited by W. Dunbar Gram, Rowan J. Milner and Remo Lobetti.
© 2018 John Wiley & Sons, Inc. Published 2018 by John Wiley & Sons, Inc.
Table 6.1 Canine Dementia Scale (CADES) Frequency: 0 points - abnormal behavior of the dog was never observed, 2 points - abnormal behavior of the dog was detected at least once in the last 6 months, 3 points - abnormal behavior appeared at least once per month, 4 points - abnormal behavior was seen 2-4 times per month, 5 points - abnormal behavior was observed several times a week.
Source: Table adapted from Madari etal. 2015, p. 140. Reproduced with permission of Elsevier.Domain/items
A. Spatial orientation
1, disorientation in a familiar environment (inside/ outside)
2, to recognise familiar people and animals inside or outside the house/apartment
3, abnormally respond to familiar objects (a chair, a wastebasket)
4, aimlessly wandering (motorically restless during day)
5, a reduced ability to do previously learned task
SCORE (0-25)
C. Sleep-wake cycles
11, abnormally responds in night (wandering, vocalization, motorically restless)
12, switch over from insomnia to hypersomnia
Score ? 2(0-20)
B. Social interaction
6, changes in interaction a man/dog, dog/other dog (playing, petting, welcoming)
7, changes in individual behaviour of dog (exploration behaviour, play, performance)
8, response to commands and ability to learn new task
9, irritable
10, expression of aggression
SCORE (0-25)
D. House soiling
13, eliminate at home at random locations
14, eliminate in its kennel or sleeping area
15, changes in signalisation for elimination activity
16, eliminate indoors after a recent walk outside
17, eliminate at uncommon locations (grass, concrete)
SCORE(0-25)
Total score(A + B + C + D)(0-95).
Clinical stage: Normal ageing (Score 0-7), Mild cognitive impairment (8-23), Moderate cognitive impairment (24-44), Severe cognitive impairment (45-95).
Box 6.1
Common signs of CCD include: sleeping during the day and restlessness at night, decreased interaction, disorientation at home, and anxiety.
disease that could explain current signs or significantly alter my treatment and management recommendations.
Definitive diagnosis of CCD is difficult. It is really a diagnosis of exclusion, though there are multiple typical characteristics. Physical examination findings can vary from patient to patient. Neurological examination and behavioral evaluation are more helpful.
Dogs with CCD are not mentally appropriate, ranging from mildly obtunded to demented. They are generally prone to be compulsive and anxious in a foreign environment like an examination room. They also tend to get very anxious and mentally inappropriate when restrained. They also often exhibit inappropriate vocalization. The neurologic examination is generally symmetrical with no overt deficits other than mentation changes and compulsion. If you note lateralizing, asymmetrical abnormalities, then you should be more concerned about an active process.Imaging of the brain by magnetic resonance imaging (MRI) is the most definitive diagnostic test to support your clinical diagnosis as it will rule out a brain tumor, which is your main differential diagnosis. MRI can also show the characteristic imaging changes of canine cognitive dysfunction, which are generalized brain atrophy, enlarged ventricles, and reduced thickness of the interthalamic adhesion. The other supportive test for CCD is to have the owner complete a validated questionnaire for CCD. Table 6.2 shows an example utilizing another scoring method used to help make the diagnosis. This patient's score utilizing the Canine Cognitive Dysfunction Rating Scale (CCDR) exceeded the threshold of 50 points.
Differentials
The main differential diagnosis for a geriatric dog with progressive behavior changes is a brain tumor. Because of this, consultation with a veterinary neurologist and an MRI of the brain should be offered to the owner. A brain tumor is not yet truly curable, but can be managed so as to ensure a good quality of life.