Primary Myopathic Chronic Intestinal Pseudo-Obstruction in a Maltese Dog

An 11-year-old castrated male Maltese had vomiting, diarrhea, and abdominal distension for over two weeks and weight loss for several months. Clinical laboratory studies were not remarkable. Abdominal radiographs showed severe dilated intestine with a gravel sign. Colon was empty with normal diameter in the pneumocolon study. On ultrasonographs, most small bowel loops were dilated without normal peristalsis and showed abnormal thin wall. Barium contrast study revealed remarkably delayed gastric emptying and transit time up to $6^{th}$ day. On exploratory laparotomy, there were no mechanical obstruction and extra-intestinal abnormalities except severe dilated small intestine. Chronic fibrosing lymphohistiocytic leiomyositis with atrophy of tunica muscularis in the small intestines and colon was identified through full thickness biopsy and histopathology. Therefore, primary myopathic chronic intestinal pseudo-obstruction was diagnosed. This dog is survival with symptomatic treatments for eight months.