Complications
A variety of long‐term postoperative complications have been reported. There are reports of foreign material caught on staples and polypropylene suture material that had extruded into the intestinal lumen at the sites of a previous enterotomy or resection and anastomosis [75, 76]. An obstructive mural intestinal abscess has been reported at an enterotomy site [77]. Foreign body penetration and intra‐abdominal abscess formation have also occurred at sites of enteroplication [78]. In patients with extensive bowel resection, management for short bowel syndrome may be necessary. Loss of the ileocecal valve may lead to reflux of colonic bacteria into the small intestine and subsequent development of diarrhea.
Prognosis
Overall prognosis for dogs and cats with foreign bodies is good. In a review of 208 GI foreign bodies by Hayes, overall survival rate was 91%, with better survival being reported for pets with discrete foreign bodies (94% in dogs and 100% in cats) and than linear (80% in dogs and 63% in cats) foreign bodies [2]. A more recent study evaluating 499 dogs with linear and non‐linear GI foreign bodies found a 96% survival rate overall [55]. Other studies have reported survival rates for linear foreign bodies to be 78–98% in dogs [4, 11, 55] and 84–92% in cats [13, 79]. Increased mortality has also been reported for dogs with fabric and plastic linear foreign bodies [11], pets undergoing multiple GI incisions [2, 30], and those with longer duration of clinical signs (mean 4.6 ± 6.8 days vs. mean 8.7 ± 7.7 days) [4]. The presence of a foreign body for >3 days has also been associated with an increase in the rate of complications [21]. Location of the foreign body and degree of obstruction have not been shown to significantly influence survival [2].
6 Intussusception
Janet Kovak McClaran1 and Yekaterina Buriko2
1 London Vet Specialists, London, UK
2 Veterinary Hospital of the University of Pennsylvania, Philadelphia, PA, USA
Introduction
Intussusception of the digestive tract is the telescoping or invagination of a portion of the viscus into the lumen of an adjacent section of the tract. It occurs in both canine and feline patients. The portion that becomes entrapped is referred to as the intussusceptum, and the portion of bowel that receives the telescoping segment is known as the intussuscipiens. Intussusception may involve most parts of the digestive tract and has been documented to involve the esophagus, the stomach, and the intestinal tract. The most common type of intussusception has been reported as ileocolic [1, 2] in dogs and jejunojejunal in cats [3]. Double intussusception has been reported in dogs [4, 5]. Many conditions have been associated with intussusception, including motility dysfunction, enteritis, infection (viral, bacterial or parasitic), foreign bodies, previous surgery, adhesions, or neoplasia [2, 3, 6]. Often, no predisposing cause can be identified [2, 7]. Gastroesophageal intussusception has been reported to occur most commonly in young German Shepherd dogs (33% dogs in one study) and has been associated with esophageal dilation or megaesophagus [8]. Advanced imaging may be required to confirm a diagnosis and after appropriate emergency stabilization, surgical intervention is usually indicated.
Clinical Presentation
The main clinical signs associated with intussusception in dogs and cats are anorexia, lethargy and vomiting [2, 3, 5, 9]. Less commonly reported signs include diarrhea with or without blood, hematemesis and weight loss [2, 3, 5, 9]. Animals suffering from gastroesophageal intussusception may present with history of regurgitation and dyspnea [8]. The severity and type of clinical signs are partially dependent on patient factors, duration of the intussusception, and whether the obstruction is complete or incomplete.
Common physical exam findings associated with intussusception include dehydration and abnormal findings on abdominal palpation, such as pain, abdominal mass, or intestinal thickening and distention. Hypothermia may be a common finding in cats, as 40% of cats in one study presented with low body temperatures [3]. Some animals with intussusception may present with signs of shock, such as abnormalities in heart rate, pale mucous membrane color, and poor pulse quality [3, 5].
Diagnosis
In animals with a suspicion of intestinal Intussusception, careful abdominal palpation may reveal a tubular structure within the cranial or mid‐abdomen. Commonly reported bloodwork abnormalities include hyponatremia, hypochloremia, and hypokalemia [5, 9]. Other reported relevant clinicopathologic abnormalities in dogs include hemoconcentration, hyperlactatemia, hypoalbuminemia, and leukocytosis with neutrophilia [5, 6, 10]. Clinicopathologic findings will vary with location of the intussusception, duration and severity of clinical signs, as well as any concurrent disease processes at the time of intussusception. Lateral and dorsoventral abdominal radiographic projections may reveal a mass effect and evidence of obstruction (Figure 6.1). Gastroesophageal intussusception may be evident on radiographs as a mass effect in the caudal esophagus. Barium contrast material (orally or via enema) may confirm a diagnosis of intussusception and obstruction [11] but ultrasound provides a superior sensitive and specific method for accurate diagnosis [12, 13]. In transverse section, ultrasonographically the intussusception appears as a target like structure consisting of a hyperechoic or anechoic center surrounded by multiple hyper‐ and hypoechoic concentric rings (Figure 6.2). In longitudinal sections, the segment appears as multiple hyper‐ and hypoechoic parallel lines (Figure 6.3) [12, 13]. Color Doppler may be a useful method for predicting reducibility by detecting venous and arterial blood flow in the mesenteric vessels supplying the affected area, although adhesion formation may preclude reducibility even when blood flow is present [14]. To avoid misdiagnosis, multiplane scanning of the lesion is vital. Identification of a semi‐lunar or G‐shaped hyperechoic center of the target lesion, together with confirmation of an overall width greater than 8–9 mm of the concentric rings appear useful in supporting the diagnosis of intussusception [15].
Figure 6.1 Lateral radiographic projection of a cat with an obstruction and gastric dilation secondary to pylorogastric intussusception.
Figure 6.2 Transverse ultrasound image of small intestinal intussusception.
Figure 6.3 Longitudinal ultrasound image of small intestinal intussusception.
More recently, a report of dual‐phase computed tomography (CT) illustrated the superiority of this modality when compared with ultrasound in confirming the diagnosis of a lead‐point intussusception related to an intestinal carcinoid tumor in a dog [16]. The lead point refers to the abnormality in the intestinal anatomy that incites the intussusception. It might be especially prudent to consider dynamic CT in geriatric patients presenting for an intussusception
