Common Kock Pouch and BCIR-Related Complications: Clinical Endoscopic, Histologic, and Radiographic Characterization

ABBREVIATIONS

BCIR

Barnett Continent Intestinal Reservoir

CI

continent ileostomy

CD

Crohn’s disease

CTE

computed tomography enterography

CMV

cytomegalovirus

MRE

magnetic resonance enterography

ECF

enterocutaneious fistula

FAP

familial adenomatous polyposis

FPC

floppy pouch complex

IBD

inflammatory bowel disease

IPAA

ileal pouch-anal anastomosis

NSAID

nonsteroidal antiinflammatory drugs

PDAI

Pouchitis Disease Activity Index

QoL

quality of life

UC

ulcerative colitis

VCE

video capsule endoscopy

INTRODUCTION

Colectomy is performed in patients with refractory ulcerative colitis (UC), colitis-associated neoplasia, or familial adenomatous polyposis (FAP). Some patients may not be candidates for restorative proctocolectomy with ileal pouch-anal anastomosis (IPAA), mainly due to structural or functional anal sphincter. These patients along with those who had failed IPAA may get a second choice by having a continent ileostomy (CI). ^, Kock (K) pouch and less Barnett Continent Intestinal Reservoir (BCIR) are two primary configurations of CI. ^, The reconstructive nature of the surgery for those with underlying disease processes (such as systemic and local inflammation in UC and desmoid reactions in FAP) makes structural complications common. In addition, inflammatory, functional, systemic, or metabolic adverse sequelae can occur. Diagnosis and classification of the structural, inflammatory, functional, and metabolic complications often require a combined assessment of clinical, laboratory, endoscopic, histopathological, and radiographic features. ^, The endoscopic treatment of these complications is discussed in a separate chapter ( Chapter 38 : Endoscopic Corrective Procedures for Kock Pouch and Barnett Pouch).

DISORDERS OF THE CONTINENT ILEOSTOMY

A consensus guideline on the endoscopic evaluation of surgically altered bowel in IBD, continent ileostomies was published by the Global Interventional IBD Group. In addition, a consensus guideline for the diagnosis and classification was proposed by the International Ileal Pouch Consortium. Disorders of the ileal pouch, including K pouch and BCIR are classified into five main categories: (1) structural disorders, including intrinsic and extrinsic strictures, primary and anastomotic strictures, acute and chronic anastomotic leaks (with or without fistulas, sinuses, and abscesses), and floppy pouch complex (FPC); (2) inflammatory disorders, including acute and chronic pouchitis and inflammatory, fibrostenotic, or penetrating Crohn’s disease (CD) of the pouch; (3) functional disorders of the pouch, such as irritable pouch syndrome; (4) neoplastic disorders, such as pouch dysplasia; and (5) systemic or metabolic complications, such as chronic anemia, vitamin D deficiency, and nephrolithiasis. Disorders unique to CI include nipple valve prolapse, disruption, or retraction. Bezoars are more commonly seen in the CI than in IPAA.

CLINICAL AND LABORATORY EVALUATION

Common presentations of disorders in the CI are difficulty in catheter intubation or oral intake, abdominal cramps or pain, bloating, nausea, loose or watery bowel movements, and the need for frequent intubation. Patients may have peristomal dermatitis, peristomal cellulitis ( Fig. 37.1 ), and prolapse with incontinence ( Fig. 37.2 ). Nipple valve dysfunction is probably the most common presentation with symptoms of slippage or difficult intubation of the valve. Nipple valve slippage can be partial or total, leading to difficult intubation or pouch incontinence. Obesity gain is a common risk factor for nipple valve slippage. Patients may experience difficulty in intubation resulting from extrinsic compression (e.g., mesh at the fascia [ Fig. 37.3 ]), angulation of the nipple valve and exit conduit ( Fig. 37.4 ), and valve prolapse ( Fig. 37.5 ).

The base of the valve ( Fig. 37.6 ) and the junction between the valve and exit conduit ( Fig. 37.7 ) are prone to the development of ischemia-associated enterocutaneous fistula. Patients with pathogen-associated (such as Clostridium difficile and cytomegalovirus [CMV]) infection pouchitis or CD of the pouch (especially in penetrating CD with fistulas and abscesses) may present with fever, night sweats, weight loss, leukocytosis, and failure to thrive. Patients with CI may also have nephrolithiasis, develop nutritional deficiencies, including iron, calcium, vitamin D, and vitamin B978-0-323-83439-1. For all patients with CI as well as IPAA, we recommend clinical and laboratory (such as complete blood counts, comprehensive metabolic panel, iron panel, calcium, and vitamin D) evaluation at least once a year. For patients suspected of pouchitis or CD of the pouch, we routinely check Clostridium difficile in the stool and CMV in the blood and tissue biopsy. For patients with chronic diarrhea, we check the celiac disease panel.

ENDOSCOPIC EVALUATION

Endoscopy plays a key role in the diagnosis, differential diagnosis, disease monitoring, surveillance, and treatment of pouch disorders. For patients with CI for underlying IBD, routine surveillance pouchoscopy is not recommended, as the neoplasia in the CI is extremely Rare. However, for patients with CI for FAP, yearly surveillance pouchoscopy is recommended.

Pouchoscopy for CI is usually performed with a gastroscope or ultra-thin scope in the office (without sedation) or in the endoscopy suite (with conscience sedation or monitored anesthesiology care). Anatomic landmarks of a K-pouch are the exit conduit, nipple valve ( Figs. 37.8 and 38.1 ), pouch body, vertical staple line, pouch inlet, and prepouch ileum or afferent limb. In patients with a history of diverting ileostomy, there may be an end-to-end or side-to-side stoma closure site. In patients with BCIR, we can usually identify the orifice of the intestinal collar close to the nipple valve in a retroflex view ( Fig. 38.2 ).

Structural disorders in CI which can be identified with pouchoscopy include stoma stenosis ( Fig. 37.1 ), slippage ( Fig. 37.9 ), prolapse ( Fig. 37.5 ), stenosis, angulation ( Fig. 37.4 ), and fistula at or around the valve ( Figs. 37.6 and 37.7 ), strictures in the pouch body, inlet ( Figs. 37.10 – 37.13 ), and prepouch ileum, inflammatory polyps ( Figs. 37.11 and 37.12 ), bezoars ( Figs. 37.14 and 37.15 ), foreign bodies, retained video capsule endoscope (VCE). ^, Intubation of the pouch inlet of a Kock pouch may require putting the patient in a right-lateral position ( Figs. 37.13 and 37.16 ). The endoscopist may find it difficult to identify and intubate pouch inlet in patients whose K pouches are converted from pelvic pouches. The inlet in the converted K pouch is located near the base of the nipple valve, which can be visualized in a retroflex view ( Fig. 37.17 ), and stricture in the area can also be treated endoscopically ( Fig. 37.18 ). Patients with staged restorative proctocolectomy with IPAA or CI undergo temporary diverting end or loop ileostomy. The stoma closure site which is usually located within 20 cm of pouch inlet is also prone to the development of anastomotic stricture ( Fig. 37.19 ). Therefore, a careful review of prior operative reports and endoscopy reports before pouchoscopy is important.