History

A 5-year-old spayed female Greyhound was examined for an iliopsoas muscle strain of the right hind limb. On physical examination, a grade 1 of 6 intermittent left basilar systolic murmur was auscultated and the heart sounds were mildly muffled on auscultation. The results of a CBC, serum biochemical analysis, and urinalysis as well as prothrombin time and activated partial thromboplastin time were within reference limits. Radiographs of the thorax were obtained to investigate the muffled heart sounds (Figure 1).

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Right lateral (A) and dorsoventral (B) radiographic views of the thorax of a 5-year-old spayed female Greyhound evaluated for a grade 1 of 6 systolic left basilar murmur and muffled heart sounds on auscultation.

Citation: Journal of the American Veterinary Medical Association 238, 7; 10.2460/javma.238.7.847

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Determine whether additional imaging studies are required, or make your diagnosis from Figure 1—then turn the page →

Radiographic Findings and Interpretation

The cardiac silhouette is enlarged, occupying 4 intercostal spaces on the lateral view and greater than two-thirds of the width of the thorax on the dorsoventral view (Figure 2). The cardiac silhouette has a figure-eight appearance on the dorsoventral view. The caudal border of the cardiac silhouette and the cranioventral diaphragmatic border are adjacent to and indistinguishable from each other. On the right lateral view, 2 fat opacity linear structures are present in the cardiac silhouette at the sixth intercostal space extending in dorsoventral and craniocaudal directions. Cranial displacement of the pylorus is present. On the basis of these findings, a diagnosis of peritoneopericardial diaphragmatic hernia (PPDH) was made. Cranial displacement of the pylorus is suggestive of right liver lobe herniation.

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Same radiographic images as in Figure 1. Notice that enlargement of the cardiac silhouette can be seen on both views. Linear fat opacity structures (thin arrows), silhouetting of the caudal aspect of the cardiac silhouette with the cranioventral diaphragmatic outlines (arrowheads), and cranial displacement of the pylorus (thick arrows) can be visualized on the lateral view. On the dorsoventral view, there is a figure-eight appearance of the cardiac silhouette (arrowheads).

Citation: Journal of the American Veterinary Medical Association 238, 7; 10.2460/javma.238.7.847

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Comments

Echocardiography confirmed the presence of a portion of the liver and mesenteric fat within the pericardial space. Cardiac 2-D imaging revealed chamber sizes and wall thickness to be within reference limits. Color flow Doppler echocardiography revealed no abnormal blood flow patterns, and the murmur was determined to be physiologic in nature. An abdominal exploratory surgery revealed a communication between the peritoneal cavity and pericardial sac; the right medial liver lobe, quadrate lobe, and gallbladder were herniated into the pericardial sac, and an adhesion had formed between the gallbladder and the pericardial sac. The adhesion was divided by blunt dissection, and the liver lobes and gallbladder were replaced in the abdomen. The edges of the diaphragmatic defect were débrided and sutured with a simple continuous pattern. The dog recovered well from surgery, and the owner reported that the dog was doing well 9 months after surgery.

The diagnosis of congenital PPDH is made when abdominal structures are present in the pericardial sac. The most commonly herniated organs are the liver and gallbladder, followed by small intestine, spleen, stomach, and occasionally mesentery, omentum, and falciform ligament.¹ All PPDHs in dogs and cats are congenital and nontraumatic in origin. During embryogenesis, a defect arises in the ventral portion of the diaphragm, the septum transversum, preventing the union of the paired pleuropericardial membranes and consequently creating an abnormal communication between the pericardium and peritoneal cavity.² Although PPDH is most frequently diagnosed in young animals, it can be seen in a dog or cat³ of any age with Weimaraners overrepresented.¹ Common radiographic changes include enlarged or abnormally shaped cardiac silhouette, dorsally displaced trachea, overlapping diaphragmatic and caudal heart borders, and opacities indicative of either gas or abnormal fat within the pericardial sac.¹ In PPDH, the enlarged cardiac silhouette commonly appears globoid. In the dog in the present report, we believe that the adhesion of the pericardium caused the atypical figure-eight appearance of the cardiac silhouette on the dorsoventral view. Abdominal radiography may reveal cranial displacement of the stomach, absent or diminished liver, or few intestinal loops. Some affected animals have had concurrent sternal abnormalities¹ that may indicate a common defect during embryogenesis.

In 60% of dogs and cats with PPDH, PPDH was an incidental finding,³ as in the dog in the present report. However, clinical signs consistent with gastrointestinal, respiratory, cardiac, or hepatic disease are possible. Surgical correction of PPDH in asymptomatic patients is controversial because mixed results of herniorrhaphy have been reported.^3,4 Because acute decompensation with life-threatening cardiac tamponade,⁵ strangulation of intestinal loops, and liver incarceration causing hepatic ischemia have been reported,¹ preemptive surgical correction of the abnormality was elected by the owner.