Pathology Lecture 2024 - Pathology (Macroscopic and Microscopic) of Inflammatory Diseases of the Bowel 1.pdf

COLITIS-ASSOCIATED NEOPLASIA Risk is related to: – Duration: 10 years after onset (20X risk after 10 years) – Extent of the disease: Pan colitis > left-sided – Inflammation: Frequency and severity of active inflammation Surveillance: regular endoscopy with biopsy COMPLICATIONS OF UC...

COLITIS-ASSOCIATED NEOPLASIA Risk is related to: – Duration: 10 years after onset (20X risk after 10 years) – Extent of the disease: Pan colitis > left-sided – Inflammation: Frequency and severity of active inflammation Surveillance: regular endoscopy with biopsy COMPLICATIONS OF UC Toxic megacolon: acute dilatation of the colon due to toxic damage to muscularis propria and neural plexus with shutdown of neuromuscular function Markedly increased cancer risk related to the extent of colonic involvement and duration of the disease Preceded by dysplasia  esp. if duration >10 years (20X risk after 10 years)  Regular endoscopy with biopsy DYSPLASIA IN ULCERATIVE COLITIS SYSTEMIC MANIFESTATIONS OF UC Joint Migratory polyarthritis Sacroiliitis Ankylosing spondylitis Skin Erythema nodosum Necrotising skin lesion- pyoderma gangrenosum Clubbing Liver Primary sclerosing cholangitis Uveitis ERYTHEMA NODOSUM DIVERTICULAR DISEASE Diverticulum- blind pouch leading off the alimentary tract communicating with the lumen In the colon, there are defects in the muscle wall where nerves and vessels penetrate (where vasa recta travers muscular is propria) The prevalence of diverticular disease approaches 50% in adults over 60, in western countries! PATHOGENESIS Related to wall stress – Associated with constipation, straining and low fibre diet – Arise in where the vasa recta traverse the muscularis propria (Focal weakness of the bowel wall) PATHOGENESIS OF DIVERTICULAR DISEASE Low fibre diet   stool bulk  peristaltic contractions   intraluminal pressure  herniation of the bowel wall through the anatomic points of weakness (where vessels penetrate the muscularis propria)  diverticula Outpouching of the mucosa and submucosa (pseudo diverticulum) Almost always in sigmoid colon CLINICAL FEATURES OF DIVERTICULAR DISEASE Usually asymptomatic In about 20% of cases, patients have cramping or lower abdominal pain Constipation Sensation of never being able to empty the rectum completely Treatment  High fibre diet (may prevent progression)  Surgical intervention for obstructive or inflammatory complications COMPLICATIONS OF DIVERTICULOSIS Inflammation of the diverticulum (diverticulitis)  May be caused by obstruction of the narrow neck of the herniated diverticulum, impaction of faecal material, constriction of the blood supply and infection Perforation Adhesions Fistula formation (e.g. bladder) Pericolic abscess formation Inflammatory mass formation Haemorrhage- rectal bleeding Obstruction  INTESTINAL OBSTRUCTION More common in the small bowel (small lumen) Mechanical  Congenital – atresia, imperforate anus, etc.  Acquired  Volvulus  Adhesions  Hernia  Intussusception  Stenosis: (e.g. CD, ischaemia, diverticular disease)  Mass Functional  Paralytic ileus (post op)  Myopathy, neuropathy and Hirschsprung’s disease HERNIA Weakness in wall of peritoneal cavity, permitting protrusion of serosa-lined sac of peritoneum  Inguinal & femoral canals, umbilicus, scars Organs may get trapped in the hernial sac  Bowel or omentum May lead to incarceration and strangulation ADHESIONS Due to previous surgery, peritonitis, endometriosis Fibrous bands may develop between loops of bowel, or between organs and abdominal wall Can create closed loops and strictures INTUSSUSCEPTION Telescoping of proximal segment of bowel into distal segment resulting in obstruction and ischaemia  In elderly adults, almost always a tumour at the leading edge  In children, most common cause is lymphoid hyperplasia (TI to caecum) VOLVULUS Twisting of a loop of bowel along its mesentery, cutting of the blood supply and resulting in obstruction and acute ischaemia Common locations:  Sigmoid colon (elderly)  Caecum (young adults)