Walle is a seven-year-old neutered male Boxer dog initially presented to our Emergency/Critical Care services on 12/26/16 for acute onset vomiting, diarrhea, and weakness. He was ambulatory but dull on presentation. He was evaluated by Merrilee Small, DVM, DACVIM (Cardiology), who found WHT 25.7kg/56.5#, HR 180bpm, RR 60bpm, Temp 97.9, muffled heart sounds, and oscillometric BP 54mmHg mean. FAST thoracic ultrasound revealed a moderate amount of pericardial effusion with evidence of cardiac tamponade and a mass effect near the heart. A FAST revealed scant free fluid, edematous gall bladder wall, and no obvious abnormalities on the spleen. Thoracic radiographs revealed a "tall" cardiac silhouette, prominent caudal vena cava, and no evidence of metastasis. Significant pericardial effusion was confirmed, and a moderate-sized echoic mass was identified at the heart base adjacent to the bifurcation of the pulmonary arteries, presumed to originate from the base of the heart although right atrial origin was also considered. Other workup included CBC (Hct 47%), Chemistry (BUN 28mg/dL, Creat 1.9mg/dL, ALT 220U/L), PT/PTT (16.5/98.1 seconds), and Cardiac Troponin (I 0.5ng/dL, N < 0.2ng/dL)      

   

Pericardiocentesis was performed, and a small amount of non-clotting hemorrhagic effusion was obtained. Following centesis, the pericardial sac was noted to be essentially evacuated and cardiac filling improved. A moderate amount of pleural effusion was then identified, likely leaked from the pericardial space. Referral for further investigation of the mass was discussed and deferred at the time. Yunnan Baiyao (1 capsule every 12 hours) and I'm-Yunity (2,400mg/day) were recommended, and the Yunnan Baiyao was implemented.

 

Dr. Small reevaluated Walle on 1/3/17 and 2/16/17. No pericardial, pleural, or abdominal fluid was noted, and the cardiac mass appeared unchanged. Walle was released with instructions to have him evaluated promptly if signs recurred.

 

Walle presented to the ER Service on 6/21/17 following an episode of acute collapse, and a large volume of pericardial fluid with echoic material suggestive of blood clots was identified. Pericardiocentesis was again performed and 240ml nonclotting hemorrhagic effusion was obtained.

 

He was evaluated on 7/10/17 by the Cardiology and Soft Tissue Surgery services at North Carolina State University, where a moderate-sized heart base mass was confirmed and observed to somewhat compress the right proximal pulmonary artery. He underwent thoracoscopic subtotal pericardectomy the next day. Histopathology of the pericardium revealed moderate arteriovenous hyperplasia with wall thickening and moderate parietal mesothelial erosion with mild mesothelial hypertrophy, consistent with chronic effusion. There was no evidence of metastatic disease. The heart base mass is most likely a chemodectoma-a benign, slow-growing tumor that can be associated with effusive processes.

 

Since the procedure, Walle is a new dog! He is scheduled to undergo a course of stereotactic radiation therapy in September in hopes of reducing the tumor mass to prevent future compromise of thoracic structures.