Use of tamoxifen in a German shepherd dog with sclerosing encapsulating peritonitis

Abstract

A German shepherd dog was diagnosed with sclerosing encapsulating peritonitis after an episode of peritonitis caused by a free intra-abdominal foreign body (stick). The foreign body had initially been treated by surgical removal and abdominal lavage. Postoperatively, peritoneal effusion persisted despite the use of methylprednisolone for 1 month and a second surgical exploration and abdominal lavage. After a third surgery at our institution (to breakdown abdominal adhesions) followed by open abdominal drainage, treatment with tamoxifen orally was initiated and within 2 weeks the dog's condition improved dramatically. Two months later, no fluid was present in the abdomen. The only apparent adverse reaction to tamoxifen therapy was swelling of the vulva. In humans, sclerosing encapsulating peritonitis is a known life-threatening complication following peritoneal dialysis. In veterinary medicine, most animals with sclerosing encapsulating peritonitis die because of chronic weight loss, peritoneal effusion and progression of concurrent disease. This dog's condition was unresponsive to methylprednisolone alone but was successfully treated with aggressive surgery including enterolysis and open abdominal lavage and the addition of tamoxifen.

Imaging Diagnosis–sclerosing Encapsulating Peritonitis in a Dog

“…11,13,14 Clinical signs reported in dogs include vomiting, abdominal pain and/or distension, peritoneal effusion, excessive borborygmi, and anorexia. 2,[5][6][7] Our patient had similar signs, with addition of decreased urination and defecation.…”

“…Sclerosing encapsulating peritonitis (also known as encapsulating peritoneal sclerosis) is characterized by the formation of sheets of fibrous tissue covering the abdominal organs as a result of the proliferation of fibrous connective tissue. [1][2][3] In humans, this condition may develop secondary to long-term ambulatory peritoneal dialysis, bacterial or fungal peritonitis, chronic infections, blunt abdominal trauma, and exposure to asbestos. The idiopathic form is most commonly diagnosed in young adolescent girls but can occur at any age or gender.…”

What Is Your Diagnosis?

“…Histologic evaluation of the adhesions revealed granulation tissue, fibrinous peritonitis, and chronic hemorrhage (consistent with a diagnosis of SEP). [1][2][3] The patient remained stable after surgery and was discharged from the hospital several days later. The dog began a treatment course of prednisone and tamoxifen after consultation with an oncologist.…”

“…The abdominal fluid and encapsulation of abdominal organs are suggestive of sclerosing encapsulating peritonitis (SEP). [1][2][3] …”

“…Tamoxifen is a nonsteroidal antiestrogen drug that has been used in conjunction with surgery to successfully control a case of SEP in a German Shepherd Dog. 2 This medication promotes degradation of collagen through production of transforming growth factor-β and synthesis of metalloproteinase. Serial abdominal imaging studies (eg, ultrasonography) can then be used to monitor progression of disease.…”