Nephrectomy in an Australian Cattle Dog Parasitized by Dioctophyma renale

Abstract

Background: Dioctophyma renale is a globally occurring nematode that parasites the kidneys, and to a lesser extent, can be found in other organs or free in the abdominal cavity. Has the capacity to destroy the renal parenchyma. For the most part, parasitized animals are asymptomatic. The diagnosis is made through urinalysis and ultrasonography. However most the cases are diagnosed only at necropsy. As treatment nephrectomy of the affected kidney is the technique of choice. Therefore, the aim of this work was to report the case of a dog, seven months old, treated surgically by nephrectomy of the right kidney due to the destruction of the renal parenchyma caused by D. renale.Case: A 7-month-old Australian Cattle Dog, with a history of hematuria, was attended in a Florianópolis Veterinary Hospital. At the physical examination of the patient, no change was found, being extremely active. Abdominal ultrasonography, urinalysis, CBC and biochemical profile were requested. Abdominal ultrasonography showed the presence of cylindricaland rounded structures, with a hyperechogenic wall and a hypoechogenic center, compatible with D. renale, located in the right kidney. Urinalysis revealed the presence of D. renale eggs. The erythrogram showed mild anemia and the leukogram showed neutrophilic leukocytosis. Calcium, creatinine, alkaline phosphatase, phosphorus, alanine aminotransferase and urea dosages showed values within normal limits. As treatment, nephrectomy of the right kidney was performed by laparotomy. The kidney was presented with destruction of the renal parenchyma and a single parasite was removed from its interior, measuring 54 cm in length. Histopathological analysis of the affected kidney revealed diffuse pronounced fibrous connective tissue proliferation, increased urinary space with decreased glomerular tuft and increased glomerular to tubule ratio. The nephrectomy was curative and ceased the patient’s hematuria.Discussion: Parasitism by D. renale is closely related to the dietary habits of the patient, since contamination of the animals occurs through the ingestion of fish contaminated by the aquatic annelid Lumbriculus variegates. The reported patient had free access to the beach, where he was frequently used to eat fish. D. renale is popularly known as the giant kidney worm as it can reach up to 100 cm in length. In the present report the parasite was 54 cm long. The great majority of the parasitized animals are asymptomatic or present pictures of haematuria, dysuria and abdominal pain. However, only the hematuria was observed at the present report. Ultrasound examination and urinalysis confirmed the diagnosis, and these tests were adequate to diagnose parasitism by D. renale. The helminth was found in the right kidney, and especially in dogs, the parasite is mainly located in the right kidney, due to its proximity to the duodenum. Abdominal ultrasonography showed the left kidney measuring 7.08 cm in diameter, which justified the compensatory activity of the same. The patient presented parasitism with only seven months of life, which indicates that the ingestion of the infecting stage of the parasite may have occurred at four months of age or less, since the pre patent period is approximately 155 days, and the cycle has a slow evolution. In cases of only one affected kidney, the recommended surgical treatment is nephrectomy, and this procedure was performed in this patient, which showed excellent results.Keywords: canine dioctophymosis, parasite, surgery.