Pericardiectomia subtotal em cão com linfoma multicêntrico : relato de caso

Abstract

The pericardium is a fibrous sac that surrounds the heart, and the abnormalaccumulation of fluid in this sac is known as pericardial effusion. The removal of part or all ofthe pericardium is called pericardiectomy, a procedure used in cases where pericardiocentesisis not sufficient for clinical improvement. Neoplasms such as lymphoma, mesothelioma, andhemangiosarcoma can cause pericardial effusion in dogs. The aim of this study is todescribethe use of subtotal pericardiectomy as a palliative measure in treating pericardial effusioninadog resulting from lymphoma, as well as to address the methods employed in thesurgicalprocedure. 2. Case: A female Labrador, 6 years old, weighing 21 kg, with a history of anorexia, apathy,and distended abdomen, was attended at the Veterinary Hospital of the Federal UniversityofMato Grosso. On physical examination, the patient presented tachypnea, 7%dehydration,hypochromic mucous membranes, body condition score of 1, sarcopenia, andbulgingabdomen. The hemogram showed anemia and an increase in segmented neutrophils. Initially,chest radiographs revealed images suggestive of marked bilateral pleural effusion. Afterthoracocentesis, a considerable increase in the cardiac silhouette was observed, indicativeofpericardial effusion. After multiple pericardiocenteses for relief of cardiac tamponade, thesurgical approach of subtotal pericardiectomy was chosen. For the start of the procedure, thepatient was placed in the left lateral recumbency, and asepsis was performed with alcohol andalcoholic chlorhexidine. The incision was made in the fifth right intercostal space. Afteropening the thorax, samples of fluid and pericardial tissue were collected for microbiologicaland histological analysis. An incision in the shape of a T was made in the pericardiumfromthe cardiac base to the apex and ventrally to the phrenic nerve at the cardiac base. Aftercompleting the material collection, intercostal closure was performed with Polyester 1threadanchored to the caudal and cranial ribs with simple isolated stitches, followedbythe approximation of the muscular layer in two layers with Polyglactin 910 0 threadinacontinuous simple pattern. Subcutaneous tissue was reduced with Polyglactin 9102-0threadin intradermal zigzag, and dermal closure was performed in a separate simple patternwithNylon 3-0. Cytological analysis of the fluid showed an abundant population of roundor ovalcells compatible with mature lymphocytes, suggestive of lymphoma. In the necropsyexamination, nodules were found in various organs, such as the heart, lungs, stomach, softpalate, and muscle fascia. Microscopic analysis revealed a massive infiltration of roundcells,markedly pleomorphic, and the microscopic diagnosis suggested multisystemic proliferativechanges indicative of large-cell lymphoma. 3. Discussion: Various findings in thoracic radiographs can indicate pericardial effusion, withemphasis on the image of the cardiac silhouette in a globular shape and the bilateral contactbetween the cardiac silhouette and the thoracic wall in dorsoventral and ventrodorsalprojections. Currently, the most recommended diagnostic option is echocardiographyduetoits non-invasive nature, ability to provide a dynamic image, and being a sensitive andspecificexamination. Pericardiocentesis is the main means for the initial stabilization of dogswithpericardial effusion, as it provides immediate relief from cardiac compression byreducingintrapericardial pressure. In cases of successive drainage of pericardial fluidwithoutremission of clinical symptoms, there is a recommendation to opt for the surgical procedureofpericardiectomy, as it tends to provide an extended survival time for patients.