A 9-year-old 12-lb spayed female Boston terrier was presented to the emergency service at Angell Animal Medical Center for
evaluation of lethargy and anorexia of one day's duration. The owners also reported progressive hindlimb ataxia.
The owners described the dog's hindlimbs as shaky for a few days, and by the afternoon prior to presentation, the dog could
only take a few steps before collapsing. During the collapsing episodes, the dog vomited and urinated but did not appear to
lose consciousness, according to the owners. The owners reported that there were no clinical signs of neurologic or cardiovascular
disease two days before presentation.
Two weeks before presentation, the dog received its annual examination from its primary care veterinarian and was prescribed
clindamycin (3.1 mg/kg orally twice daily) for treatment of a suspected tooth root abscess. The dog received the drug until
vomiting began the day before presentation.
Long-term medical history included documentation of calculus and periodontal disease by the primary veterinarian, but a dental
procedure was not pursued. A grade II heart murmur was also first diagnosed one year before; however, diagnostic tests, such
as thoracic radiography or an echocardiogram, were not performed at that time to further evaluate and characterize the murmur.
INITIAL EXAMINATION FINDINGS
On presentation, the patient was quiet with slight mental dullness. The dog's temperature was minimally elevated at 102.8
F (39.3 C), and the dog was slightly tachycardic at 138 beats/min. Abnormal physical examination results included about 5%
dehydration, pale mucous membranes, bilateral serous nasal discharge, a grade III/VI left apical systolic heart murmur, and
harsh lung sounds bilaterally.
An oral examination revealed significant periodontal disease with severe dental calculi of the canine, premolar, and molar
teeth as well as erythema of the gingiva characteristic of gingivitis. There was also gingival recession with root exposure
of the maxillary fourth premolars and molars.
Neurologic examination results showed the patient to be mentally dull with a right-sided head tilt. The dog had pelvic limb
ataxia, generalized paresis of the hindlimbs, and conscious proprioceptive deficits to the right pelvic limb. The patient
would also sit with spinal pressure to the cervical and lumbar spine.
Initial diagnostic tests included a complete blood count (CBC), serum chemistry profile, and venous blood gas analysis. The
CBC revealed a normal white blood cell count; however, evaluation of a blood smear by a veterinary pathologist confirmed the
presence of 1+ toxic change. Red blood cell morphology and platelets were adequate on the smear. The patient was also lymphopenic
and anemic (Table 1). Abnormal serum chemistry profile values included elevated alkaline phosphatase activity, hypocalcemia, hyponatremia, hypochloremia,
hypomagnesemia, and increased anion gap (Table 1). All the changes on the serum chemistry profile were considered mild. Despite a low total calcium concentration, the ionized
calcium was within normal limits on the venous blood gas analysis. The only additional information from the venous blood gas
analysis was mild respiratory alkalosis as indicated by the elevated pH and the low partial pressure of CO2 (Table 1).
Table 1: Abnormal Laboratory Results
Thoracic radiography was attempted the evening of presentation but was aborted because of a collapsing episode. During the
episode, the patient vomited and urinated, and its mucous membranes became pale.