Case history

The dog had initially begun to have diarrhoea 4 months prior to presentation. The diarrhoea had become progressively more haemorrhagic and increased in frequency and urgency to defecate. At presentation the dog strained to defecate almost continuously when taken on walks. He produced small amounts of soft to liquid faeces and large amounts of blood when defecating. The dog only rarely vomited. The owner said the dog had lost about 7 kg during the last 4 months.

His current diet was a restricted protein dry diet, with no snacks or treats. The dog’s vaccinations were current and he had recently been treated with 50 mg/kg fenbendazole for 5 days.

He was on meloxicam for discomfort due to hip dysplasia. This had been stopped for a month 2 months earlier and there had been no resolution of clinical signs of diarrhoea or haematochezia. Other than the hip dysplasia, he had been a healthy dog until the onset of the diarrhoea.

Physical examination

The dog was bright, alert and responsive (Fig 38.1) although he was quite thin (body condition score 3/9) with muscle loss over the lumbar area (Fig 38.2). His mucous membranes were pink and moist with a capillary refill time of <2 seconds and hydration appeared adequate. No abnormalities were noted on thoracic auscultation. His heart rate was 82 beats per minute with good matched pulses and respiratory rate was 32 breaths per minute. Peripheral lymph nodes were normal in size. Due to the history of haematochezia, taking the rectal temperature was delayed until analgesia (e.g. topical lignocaine) could be used. When taken later it was 38.2° C.

Fig 38.1 Dog showing bright and alert attitude

Fig 38.2 Dog showing loss of muscle mass

On abdominal palpation several large firm masses were identified. One of these was especially prominent in the caudal abdomen and was felt to be at least 4 to 5 cm in diameter. The masses were not attached to the body wall and could be moved fairly freely. A tubular mass was present in the ventral abdomen, which was thought to be either a ventrally displaced colon or an enlarged loop of small intestine. The dog appeared uncomfortable during abdominal palpation.

Problem list and discussion of problems

The dog’s primary problems were haematochezia and tenesmus consistent with large intestinal disease. The frequency and urgency of the diarrhoea was also consistent with disease of the colon and/or rectum, although weight loss is less common in large intestinal disease.

Severe acute pancreatitis can cause melaena and haematochezia, but this dog was too bright to have severe acute pancreatitis. The dog had been given an adequate dose of fenbendazole, making gastrointestinal parasites less likely. While he had previously been on meloxicam, there had been a period of about a month where it had not been given and there had been no change in clinical signs.

The other problem was the presence of masses or thickened areas found during palpation of the abdomen. The most likely causes of these were thought to be neoplasia, lymph node enlargement or intussusception(s).