Clinical Case Challenge

Anxious Greyhound

Greyhound with Anxiety

History
An 8-year-old neutered male Greyhound was evaluated at the Tufts Animal Behavior Service for intermittent episodes of extreme anxiety. The first anxiety attack occurred in late October of 2008 and lasted for 3 days. Physical examination, CBC and serum biochemistry analysis performed by the referring veterinarian were within reference limits.

The dog had no history of cardiovascular or neurological signs. About a year prior, the referring veterinarian had diagnosed the dog with a form of epilepsy and had treated him with 1/2 grain of phenobarbital twice a day. There were no further episodes until early May the following year, when the dog began having similar acute anxiety episodes. Each lasted about five hours, each after one-mile walks in woods with the owner. He would pace, pant, look around the house, and seemed to want to go back outside.

The owner had taken the dog to his veterinarian several times over the two weeks prior to the appointment here. The intermittent acute anxiety episodes were increasing in frequency and duration. On the days that the dog did not have the episodes, he looked anxious and had a mildly decreased appetite.  The referring veterinarian performed an EKG and referred the dog to the Foster Hospital for Small Animals, located at the Cummings School of Veterinary Medicine, because he suspected a cardiac dysrhythmia.

Initial findings

  • Echocardiographic examination
    Mild concentric left ventricular hypertrophy and slight aortic regurgitation were detected, but these were subtle and could have been a consequence of normal aging.
  • Chest radiographs
    Normal
  • Blood work
    CBC and serum biochemistry analysis were within reference limits.
    Phenobarbital level was 10.4 mcg/ml – below therapeutic range (15-40 mcg/ml).

Potential causes for anxiety episodes:

  • Hormone-secreting tumor, such as pheochromocytoma
  • Neurological problem
  • Behavioral problem

What additional examinations or information be required to make a diagnosis?

1.  Abdominal ultrasound
A slightly enlarged spleen was found, and the remainder of the abdomen was unremarkable.

2. Neurological consultation
Neurological examination was unremarkable. Since the current phenobarbital blood level was not within the therapeutic range and the dog did not suffer from epilepsy, weaning off of phenobarbital was recommended.

3. Behavior consultation
Additional questioning of the owner revealed that the first episode occurred after the dog had been stung by a huge bee in the house. From that point forward, the dog hesitated to go into the sunroom, where he had encountered the bee. There were no anxiety attacks over the winter, but the attacks started to occur again in May.

Diagnosis and prognosis

The differential diagnosis for anxiety resulting from behavioral causes includes attention-seeking behavior and phobias.  Phobias may be related to living or inanimate objects, or noises.

Since this dog had anxiety attacks while separated from his owners, attention seeking behavior was unlikely. A bee phobia was presumptively diagnosed based on the history, the dog’s behavior and exclusion of other possible causes. Treatment involved avoiding exposure of the dog to buzzing sounds and flying insects as best as possible. Liberal use of a bug spray was recommended. Buspirone (10 mg TID) and propranolol (20 mg BID to TID) were recommended to reduce anxiety.  These medications were prescribed during the warm weather months from spring to late fall. The dog’s anxiety was managed well for one year of available follow up.