Lethargy & Anxiety in a Dog

Amara H. Estrada, DVM, DACVIM (Cardiology), University of Florida

ArticleLast Updated May 20223 min readPeer Reviewed
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Bentley, an 8-year-old, 57-lb (26-kg) neutered male crossbreed dog, is presented for lethargy, panting, and anxious behavior of 2-days’ duration. His owner reports he was previously healthy.


Bentley is fed a commercial diet. Vaccinations are current, but his owner reports administration of flea, tick, and heartworm preventives is inconsistent and often forgotten for 1 to 2 months at a time. 

Bentley has no travel history, lives in Florida, and is an active dog that swims in the family pool and goes on nightly walks. Two nights prior to presentation, he resisted going on his regular walk. On the next night, he was again reluctant to go on a walk and woke his owners up several times by whining and pacing. He was taken outside multiple times during the night and urinated normally each time.

Physical Examination

On physical examination, Bentley’s temperature is 99.7°F (37.6°C). Respiratory rate is 36 breaths per minute at rest, heart rate is 180 bpm, and capillary refill time is 3.5 seconds. BCS is 8/10. 

It is difficult to auscultate the heart because of Bentley’s constant panting, but no murmurs or arrhythmias are identified. Lung sounds are normal over all lung fields. Pulses are weak and synchronous with the heartbeat. There is a palpable fluid wave in the abdomen and a positive hepatojugular reflux. All extremities feel warm to the touch. The remainder of the physical examination is normal. 

There is no evidence of trauma, and Bentley gets up a couple of times to reposition himself in the examination room. He does not seem anxious but appears uncomfortable when lying down, similar to the behavior that prompted presentation to the clinic.

How would you diagnose and treat this patient?

Treatment & Outcome

Focused cage-side ultrasonography was performed on the abdomen and thorax. A large amount of both free abdominal fluid and pericardial effusion was identified. There was also evidence of cardiac tamponade. 

A peripheral catheter was placed for fluid, and possible lidocaine, administration. Pericardiocentesis was performed, and 450 mL of serosanguineous fluid was removed. Fluid packed cell volume was 11% and total solids was 2.3 mg/dL compared with peripheral blood packed cell volume of 43% and total solids of 8.2 mg/dL. Bentley did well during pericardiocentesis but remained uncomfortable. 

Abdominocentesis was then performed, and 3.1 L of serosanguineous fluid was removed. Bentley was visibly more comfortable afterward and slept the rest of the day while being monitored for increases in heart rate or unusual behavior. His heart rate was 40 to 60 bpm while he was asleep and 100 to 120 bpm when he was awake. 

Bentley was hospitalized for 24 hours, and a recheck thoracic-focused assessment with sonography for trauma was performed to ensure there was no further fluid accumulation. He was discharged the next day, and a full cardiac evaluation was scheduled for the 2-week recheck. 

At the recheck, there was recurrent pericardial effusion without evidence of tamponade; no masses were visualized. Repeat pericardiocentesis was performed at that time and 2 months later, at which time a pericardiectomy was also performed to prevent further episodes of tamponade. Histopathologic evaluation of the pericardium showed changes consistent with chronic inflammation and mesothelial proliferation.