Evaluation of outcomes following subtotal colectomy for the treatment of idiopathic megacolon in cats.

OBJECTIVE: To evaluate outcomes in cats undergoing subtotal colectomy for the treatment of idiopathic megacolon and to determine whether removal versus nonremoval of the ileocecocolic junction (ICJ) was associated with differences in outcome. ANIMALS: 166 client-owned cats. PROCEDURES: For this retrospective cohort study, medical records databases of 18 participating veterinary hospitals were searched to identify records of cats with idiopathic megacolon treated by subtotal colectomy from January 2000 to December 2018. Data collection included perioperative and surgical variables, complications, outcome, and owner perception of the procedure. Data were analyzed for associations with outcomes of interest, and Kaplan-Meier survival time analysis was performed. RESULTS: Major perioperative complications occurred in 9.9% (15/151) of cats, and 14% (12/87) of cats died as a direct result of treatment or complications of megacolon. The median survival time was not reached. Cats with (vs without) a body condition score < 4/9 (hazard ratio [HR], 5.97), preexisting heart disease (HR, 3.21), major perioperative complications (HR, 27.8), or long-term postoperative liquid feces (HR, 10.4) had greater hazard of shorter survival time. Constipation recurrence occurred in 32% (24/74) of cats at a median time of 344 days and was not associated with retention versus removal of the ICJ; however, ICJ removal was associated with long-term liquid feces (OR, 3.45), and a fair or poor outcome on owner assessment (OR, 3.6). CONCLUSIONS AND CLINICAL RELEVANCE: Results indicated that subtotal colectomy was associated with long survival times and a high rate of owner satisfaction. Removal of the ICJ was associated with less favorable outcomes in cats of the present study.

Colonic impaction in dogs: a retrospective study of 58 cases (1996 to 2014).

OBJECTIVES: To describe the clinical findings, management and outcome of colonic impaction in dogs and report the effectiveness of medical treatment. MATERIALS AND METHODS: Case records of 58 dogs with colonic impaction were reviewed. Telephone contact with the owners was used to obtain long-term outcome. RESULTS: Twenty-nine dogs (50%) were mixed-breed, and 45 (78%) were entire males. Median age at presentation was 7 years, and median bodyweight was 22 kg. The degree of radiographic colonic distension did not appear to be related to long-term outcome. Fifty-five dogs (95%) received medical treatment including enemas alone, hyperosmotic and/or bulk-forming and/or lubricant laxatives, enemas combined with laxatives or enemas and/or laxatives combined with manual evacuation of faecal material under anaesthesia. Median survival time of the 58 dogs was 2 years. Overall, 36 of 41 dogs with available long-term follow-up had a favourable outcome. CLINICAL SIGNIFICANCE: Medical treatment of colonic impaction in dogs with a single agent or a combination of agents has a high success rate. Marked colonic dilation is not necessarily indicative of megacolon in dogs.

Closure of gastrointestinal incisions using skin staples alone and in combination with suture in 29 cats.

OBJECTIVE: To report the use of skin staples alone, and in combination with sutures, for closure of gastrointestinal incisions in cats and to describe outcomes. MATERIALS AND METHODS: Retrospective study of cats that underwent gastrotomy, jejunotomy, jejunal or colonic anastomosis using skin staples alone or in combination with sutures to close the enteric wounds at one referral hospital between 2001 and 2016. Data regarding patient signalment, duration of clinical signs, indication for surgery, diagnosis, haematological and biochemical values, surgical time, procedure, complications and outcome were collected. All the gastrotomies and some of the large intestine incisions were closed in a hybrid technique using two layers (monofilament suture and skin staples). All the small intestine and some of the large intestinal incisions were closed in a single layer using skin staples. RESULTS: Twenty-nine cats were included in the study. Indications for surgery included foreign body (14/29), neoplasia (6/29) and idiopathic megacolon (9/29). Overall, 26 of 29 (~90%) of cases survived to discharge. One cat had postoperative cardiopulmonary arrest, and 2/29 cats were euthanased at the owner's request. There was no evidence of incisional dehiscence in any case. CLINICAL SIGNIFICANCE: Skin staplers are safe, reliable, affordable and effective for closure of gastrointestinal incisions in cats. We found skin staples can be a useful tool in closure of gastrotomies and large intestinal resection and anastomosis procedures in cats.

Effects of a probiotic (SLAB51™) on clinical and histologic variables and microbiota of cats with chronic constipation/megacolon: a pilot study.

Chronic constipation (CC) and idiopathic megacolon (IMC) occur frequently in cats. The aim of the study was to investigate the effects of a multi-strain probiotic (SLAB51™) in constipated cats (n=7) and in patients with megacolon and constipation (n=3). Ten pet cats with a diagnosis of chronic constipation, non-responsive to medical management received orally 2×1011 bacteria daily for 90 days. For microbiota analysis, selected bacterial groups were analysed by qPCR. Histological samples in megacolons were evaluated for interstitial cells of Cajal (ICC), enteric neurons, and neuronal apoptosis. Biopsies were compared at baseline (T0) and after the end of treatment (T1), and with those obtained from healthy control tissues (archived material from five healthy cats). Constipated cats displayed significantly lower ICC, and cats with idiopathic megacolon had significantly more apoptotic enteric neurons than controls. After treatment with SLAB51™, significant decreases were observed for feline chronic enteropathy activity index (FCEAI) (P=0.006), faecal consistency score, and mucosal histology scores (P<0.001). In contrast, a significant increase of ICC was observed after probiotic therapy. Lactobacillus spp. and Bacteroidetes were increased significantly after treatment (comparing constipated cats before and after treatment, and control healthy cats to constipated cats after treatment), but no other differences in microbiota were found between healthy controls and constipated cats. Treatment with SLAB51™ in cats with chronic constipation and idiopathic megacolon showed significant clinical improvement after treatment, and histological parameters suggest a potential anti-inflammatory effect of SLAB51™, associated with a reduction of mucosal infiltration, and restoration of the number of interstitial cells of Cajal.

Perianal neuroendocrine tumor with suspected lymph node metastasis causing colonic compression and subsequent megacolon.

An 8-year-old spayed female domestic shorthair cat was presented with a 4- to 5-month history of a progressively growing mass above her anus and an inability to defecate for 3 to 4 wk. External perianal and internal regional masses were subsequently identified and diagnosed as tumors of neuroendocrine origin through surgical excision and histopathologic evaluation. The cat was treated with 2 courses of chemotherapy and radiation therapy.

Tumeur neuroendocrinienne périanale avec une métastase suspectée des ganglions lymphatiques causant une compression du côlon et un mégacôlon subséquent. Une chatte commune domestique stérilisée âgée de 8 ans a été présentée avec une anamnèse de 4 ou 5 mois d'une masse à croissance progressive au-dessus de l'anus et l'incapacité de déféquer depuis 3 ou 4 semaines. Les masses périanales externes et régionales internes ont été subséquemment identifiées et diagnostiquées comme des tumeurs d'origine neuro-endocrinienne suite à l'excision chirurgicale et une évaluation histopathologique. La chatte a été traitée à l'aide de deux séries de traitement et d'une radiothérapie.(Traduit par Isabelle Vallières).

Subtotal colectomy by rectal pull-through for treatment of idiopathic megacolon in 2 cats.

Surgical management of idiopathic megacolon is described in 2 cats by a rectal pull-through with subtotal colectomy performed outside of the abdomen. This newly described technique facilitates access to the rectum for suturing an anastamosis without the need for pubic osteotomy and with minimal risk of abdominal contamination.

Radiographic diameter of the colon in normal and constipated cats and in cats with megacolon.

Radiographs of 50 cats with no history of gastrointestinal disease were evaluated to establish a normal reference range for radiographic diameter of the feline colon. Thirteen cats with constipation and 26 with megacolon were also evaluated and compared with the normal cats to characterize the accuracy of the reference range and to identify a cutoff to distinguish constipation from megacolon. A ratio of maximal diameter of the colon to L5 length was the most repeatable and accurate measurement. A ratio <1.28 is a strong indicator of a normal colon (sensitivity 96%, specificity 87%). A value >1.48 is a good indicator of megacolon (sensitivity 77%, specificity 85%).

Long-term results of subtotal colectomy for acquired hypertrophic megacolon in eight dogs.

OBJECTIVES: To evaluate the long-term results of subtotal colectomy for acquired hypertrophic megacolon in the dog. METHODS: Eight dogs with acquired hypertrophic megacolon underwent subtotal colectomy with preservation of the ileocolic junction. Long-term follow-up was obtained by clinical records and telephone interviews with the owners. RESULTS: Eight large-breed dogs (age range: 6 to 12 years; mean age: 10.75 years) were enrolled. The use of bone meal, low levels of exercise, chronic constipation with dyschesia and tenesmus refractory to medical management were factors predisposing dogs to acquired hypertrophic megacolon. The diagnosis was confirmed in all animals by abdominal palpation, plain radiography and postoperative histopathological findings. There were no intraoperative complications. One dog died as a result of septic peritonitis. The clinical conditions (that is, resolution of obstipation and stool consistency) of the remaining seven dogs were improved at discharge; all animals returned to normal defecation in five to 10 weeks (mean: 7.3 weeks) and were alive 11 to 48 months (mean: 40.5 months) after surgery. CLINICAL SIGNIFICANCE: Predominantly bony diet and/or low levels of physical activity may predispose dogs to acquired hypertrophic megacolon. Our results emphasise the long-term effectiveness of subtotal colectomy with preservation of the ileocolic junction in this condition.

Comparison of biofragmentable anastomosis ring and sutured anastomoses for subtotal colectomy in cats with idiopathic megacolon.

OBJECTIVE: To report use of a biofragmentable anastomosis ring (BAR) device in cats with idiopathic megacolon (FIM) and compare outcome after subtotal colectomy with sutured colocolic anastomosis. STUDY DESIGN: Retrospective study. ANIMALS: Nineteen cats with megacolon. METHODS: Medical records (January 1990-January 2004) of cats treated surgically for idiopathic megacolon with sutured (SUT) or BAR anastomosis were retrieved and reviewed. Operative, short- and long-term complications, and survival times were recorded and Kaplan-Meier survival analysis used to assess outcome. RESULTS: There were 11 SUT and 8 BAR cats. One BAR cat had anastomotic dehiscence 36 hours after surgery. Mild serosal tearing during BAR insertion in 6 cats was corrected by suture reinforcement. One SUT cat developed anastomotic stricture at 32 days. Short-term complication rates at 3 and 7 days were 18% and 45% in the SUT group and 25% and 87.5% in the BAR group, respectively (P=.058). Two SUT cats had persistent loose stool consistency and were euthanatized 254 and 1661 days after surgery. One BAR cat had recurrence of constipation which was managed medically. Long-term complication rates were not significantly different between SUT and BAR (P=.61). The 1 and 4-year survival rates were 90% for SUT and 100% for BAR (P=.29). CONCLUSIONS: No difference was detected for short and long-term complication rates and survival times between SUT and BAR groups. CLINICAL RELEVANCE: The BAR device can be used for colocolic anastomosis in cats with idiopathic megacolon. Serosal tearing during BAR insertion was a common intraoperative complication. Regardless of anastomotic technique, survival outcome after colonic resection is excellent for cats with FIM.

Surgical management of constipation.

There are many recognised causes of constipation in the cat and the management of the condition depends on the clinician's ability to recognise the appropriate aetiology in each case. Most surgery therapies for constipation in the cat are related to the management of idiopathic megacolon, although causes such as pelvic outlet obstruction, complications of neutering surgery, perineal herniation, and malunion pelvic fractures may also require surgical intervention. Currently, the surgical management of megacolon consists of subtotal colectomy with the recommendation that the ileocolic junction be preserved. The procedure, in general, is associated with few life-threatening complications although the majority of individuals will experience a transient period of loose stool formation in the immediate post-operative period. In the majority of cases, the long-term outcome following subtotal colectomy is considered excellent.

Megacolon in the cat.

Megacolon is a condition that is not uncommon in the cat. Most cases are idiopathic (a cause cannot be determined), and these seem to be a result of colonic inertia. Pelvic fracture malunions are the next most common cause and result in a pelvic outlet obstruction. Total or subtotal colectomy offers good long-term results in cases of idiopathic megacolon and chronic cases of pelvic fracture malunion, and the technique is described in detail.

Gastrointestinal obstruction.

For cats that present with signs of gastrointestinal disease, obstruction is a primary differential. There are numerous reasons of gastrointestinal obstruction in small animals, yet there are several specific causes that are more commonly associated with the cat. These include linear foreign bodies, trichobezoars, focal intestinal neoplasia, feline infectious peritonitis, and megacolon. Clinical signs related to gastrointestinal obstruction consist of vomiting, diarrhea, constipation, tenesmus, anorexia, or weight loss. The course and onset of disease depends on the rate at which the obstruction develops and whether the obstruction is partial and complete. The diagnosis of obstruction is typically suspected based on clinical presentation and palpation of an abdominal mass. Diagnostics tools are used for definite diagnosis and determination of location within the gastrointestinal tract. Surgical treatment is dependent on the etiology of the obstruction and various techniques are employed to remove the obstruction and prevent recurrence.

Pathogenesis, diagnosis, and therapy of feline idiopathic megacolon.

Many cats have one or two episodes of constipation without further recurrence, although others progress to complete colonic failure. Middle-aged male cats are particularly at risk for the clinical continuum of constipation, obstipation, and dilated megacolon. Pelvic canal stenosis and nerve injury are minor causes in the development of this syndrome. In most affected cats, the underlying pathogenesis appears to involve colonic smooth muscle dysfunction. In this group of cats, it is not yet clear whether this disorder represents a primary or secondary (resulting from long-standing constipation and colonic distension) abnormality. Many cats with mild to moderate constipation respond to conservative medical management (e.g., dietary fiber supplementation, emollient or hyperosmotic laxatives, colonic prokinetic agents). Indeed, early use of colonic prokinetic agents is likely to prevent the progression of constipation of obstipation and dilated megacolon in many cats. Some cats may become refractory to these therapies, however, as they progress through moderate or recurrent constipation to obstipation and dilated megacolon. These cats eventually require colectomy. Cats have a generally favorable prognosis for recovery following colectomy, although mild to moderate diarrhea may persist for 4 to 6 weeks postoperatively in some cases.

Subtotal colectomy and ileocolonic anastomosis in a Vietnamese pot-bellied pig with idiopathic megacolon.

A 7-month-old sexually intact female Vietnamese pot-bellied pig was evaluated because of constipation. On abdominal palpation, a hard tubular structure was palpated in the middle of the abdomen. Abdominal radiography revealed loops of intestine that were markedly distended with ingesta, consistent with obstructive intestinal disease. On exploratory celiotomy, a massively distended cecum and spiral colon were found. A subtotal colectomy, with a side-to-side ileocolonic anastomosis, was performed. The cause of the megacolon was not discovered. The pig did well following surgery and eventually defecated normally following an initial period of diarrhea. To our knowledge, this is the first report of therapeutic removal of a substantial portion of the large intestine in swine. Our decisions concerning the pig of this report were based largely on our knowledge of megacolon in cats. The outcome for this pig indicates that subtotal colectomy along with removal of the cecum and ileocecal valve can be used to successfully treat idiopathic megacolon in Vietnamese pot-bellied pigs.

Cisapride stimulates contraction of idiopathic megacolonic smooth muscle in cats.

We have previously shown that cisapride, a substituted piperidinyl benzamide, stimulates contraction of healthy feline colonic smooth muscle. The purpose of the present investigation was to determine the effect of cisapride on feline idiopathic megacolonic smooth muscle function. Longitudinal smooth muscle strips from ascending and descending colon were obtained from cats with idiopathic megacolon, suspended in a 1.5 mM Ca(2+)-HEPES buffer solution (37 degrees C, 100% O2, pH 7.4), attached to isometric force transducers, and stretched to optimal muscle length (Lo). Control responses were obtained at each muscle site with acetylcholine (10(-8) to 10(-4) M), substance P (10(-11) to 10(-7) M), or potassium chloride (10 to 80 mM). Muscles were then stimulated with cumulative (10(-9) to 10(-6) M) doses of cisapride in the absence or presence of tetrodotoxin (10(-6) M) and atropine (10(-6) M), or in a 0 calcium HEPES buffer solution. In cats with idiopathic megacolon, cisapride stimulated contractions of longitudinal smooth muscle from both the ascending and the descending colon. Cisapride-induced contractions were similar in magnitude to those induced by substance P and acetylcholine in the ascending colon, but were less than those observed in the descending colon. Cisapride-induced contractions in megacolonic smooth muscle were only partially inhibited by tetrodotoxin and atropine, but were virtually abolished by removal of extracellular calcium. We concluded that cisapride-induced contractions of feline megacolonic smooth muscle are largely smooth muscle mediated and dependent on influx of extracellular calcium. Cisapride-induced contractions in megacolonic smooth muscle are only partially dependent on enteric cholinergic nerves. Thus, cisapride may be useful in the treatment of cats with idiopathic megacolon.

Alterations in colonic smooth muscle function in cats with idiopathic megacolon.

OBJECTIVE: To determine whether colonic smooth muscle dysfunction is involved in the pathogenesis of idiopathic megacolon in cats. DESIGN: In vitro smooth muscle mechanical measurements. ANIMALS: Colon from healthy cats and cats with idiopathic megacolon. PROCEDURE: Colonic smooth muscle strips were suspended in physiologic buffer solution, attached to isometric force transducers, and contracted with acetylcholine (ACh; 10(-9) to 10(-4)M), substance P (SP; 10(-10) to 10(-6)M), cholecystokinin (CCK; 10(-11) to 10(-8)M), potassium chloride (KCl; 10 to 80 mM), or electrical field stimulation (EFS; 25 V, 1 to 30 Hz, 0.5-millisecond duration). Isometric stress responses were compared with those obtained from healthy controls. Colonic smooth muscle strips were also evaluated histologically for neuronal and smooth muscle cell morphology. RESULTS: Passive isometric stress was not altered, but the active isometric stress responses of megacolon smooth muscle to ACh, SP, CCK, KCl, and EFS were significantly (P < 0.05) diminished, compared with healthy controls. Differences were observed in longitudinal and circular smooth muscle from proximal and distal portions of the colon. Histologic evaluation revealed few abnormalities of smooth muscle cells or of myenteric or submucosal plexus neurons. The contractile response of megacolon smooth muscle to EFS, and the inhibition of this response by tetrodotoxin, suggest that myenteric and submucosal plexus neurons in megacolon smooth muscle are functional. CONCLUSIONS: Idiopathic megacolon is a generalized dysfunction of colonic smooth muscle in cats. The diminished isometric stress responses to receptor occupancy (ACh, SP, and CCK) and membrane depolarization (KCl) further suggest that the disorder involves disturbance in the activation of smooth muscle myofilaments.