Pathology of Intestinal Obstruction Dr. M. Madhavan, MBBS., MD., MIAC, Professor of Pathology Saveetha Medical College
Pathology of Intestinal Obstruction Objectives list the causes of intestinal obstruction discuss their morphology, aetiopathogenesis correlate with the clinical features Intestinal obstruction 2
Intestinal Obstruction - Causes Mechanical Lumen Wall External Paralytic Intestinal obstruction 3
Mechanical - Causes Intraluminal gall stones, faecolith, foreign bodies worms meconium Intestinal obstruction 4
Mechanical - Causes Intramural intussusception inflammatory stricture tumours atresia imperforate anus Intestinal obstruction 5
Mechanical - Causes Extramural Adhesion volvulus hernia congenital bands large intra abdominal tumour Intestinal obstruction 6
Paralytic - Causes paralytic ileus bowel infarction myopathy & neuropathy Hirschsprung disease Intestinal obstruction 7
Intestinal obstruction Incidence tumour & infarction 15 to 20% adhesion, volvulus, hernia & intussusception 80% Intestinal obstruction 8
Clinical features acute colicky abdominal pain vomiting abdominal distension absolute constipation Intestinal obstruction 9
Pathophysiology Proximal Vigorous peristalsis Days Flabby & toneless Gas & Fluid Distension Distal Intestinal obstruction 10
Gas swallowed air diffusion from blood products of digestion Fluid Distension Secretion Drinking 2 L Saliva 1 L Reabsorption Jejunum 3 to 5 L Gastric juice 2 L Bile 1 L Ileum 2 to 4 L Pancreatic juice 2 L Intestinal secretion 1 L Colon 1 L Intestinal obstruction 11
Hernia protrusion of viscera thro weakness / defect in the wall of the peritoneal cavity inguinal canal femoral canal periumbilical hernial sac S. bowel, omentum, L. bowel its vessels Intestinal obstruction 13
Hernia - pressure at the neck of the sac intestinal obstruction venous obstruction arterial obstruction infarction (strangulation) diffusion of toxin & bacteria leading to shock Intestinal obstruction 14
Adhesion Causes surgical procedure infection (e.g., tuberculosis) endometriosis Intestinal obstruction 15
Pathophysiology Injury Inflammation (Peritonitis) Healing (Fibrosis) Adhesion (Closed loops) Intestinal obstruction Internal herniation Intestinal obstruction 16
Adhesion intestinal obstruction Intestinal obstruction 17
Intussusception Telescoping of one segment of intestine into the adjacent distal intestine Sites ileo-colic colo-colic ileo-ileal Intestinal obstruction 18
Intussusception - components intussuscepiens intussusceptum traction (leading) point rotavirus infection (children) tumour (adults) Intestinal obstruction 19
Intussusception - sequalae intestinal obstruction obstruction to vessels infarction (gangrene). Intestinal obstruction 20
Volvulus complete twisting of a loop of bowel around its mesentery Sites: sigmoid caecum small bowel (all / portion) stomach transverse colon Effects: intestinal obstruction & infarction. Intestinal obstruction 21
Volvulus - infarction Intestinal obstruction 22
Atresia & Stenosis a segment of bowel is not (under) developed complete occlusion atresia incomplete occlusion stenosis congenital anomaly; uncommon Sites: duodenum jejunum, ileum (NOT colon) imperforate anus. Intestinal obstruction 23
Atresia & Stenosis Pathology imperforate mucosal diaphragm string like segment single / multiple. Intestinal obstruction 24
Normal Diaphragm String Discontinuous Intestinal obstruction 25
Meckel diverticulum Congenital Failure of involution of vitelline duct 2% of population Intestinal obstruction 26
Meckel diverticulum - Pathology single within 2 feet from ileocaecal valve antimesenteric border true diverticulum (all 4 layers +) mucosa S. bowel, ectopic gastric, pancreas Intestinal obstruction 27
Meckel diverticulum Clinical features usually asymptomatic peptic ulceration of adj. small intestine mucosa intestinal bleeding intestinal obstruction intussusception fibrous persistent band Intestinal obstruction 28
Hirschsprung disease congenital megacolon aganglionosis absence of Meissner & Auerbach plexus distal part of large intestine rectum & sigmoid colon (short segment lesion) proximal colon of variable length (long segment lesion) Intestinal obstruction 29
Hirschsprung disease - Pathology affected part is narrow proximal (NORMAL) part is dilated Meissner & Auerbach plexus absent Acetyl cholinesterase stain positive Intestinal obstruction 30
Hirschsprung disease - pathogenesis mutation in RET gene inactivation of kinase activity of its receptor arrest of migration of neural crest cells mutation of endothelin & endothelin receptor system Intestinal obstruction 31
Hirschsprung disease clinical features 1 in 5000 live births in siblings M:F = 4:1 10% associated with Down syndrome failure to pass meconium obstructive constipation complications enterocolitis perforation of the colon Intestinal obstruction 32
hardened meconium in the gut mucoviscidosis of pancreas born with intestinal obstruction Meconium ileus Intestinal obstruction 33
Inflammatory stricture inflammatory bowel disease intestinal tuberculosis ulcerative tuberculosis hyperplastic tuberculosis Intestinal obstruction 34
Ulcerative tuberculosis 2 to pulmonary TB swallowing of TB bacilli ulcers in the terminal ileum transverse (along the lymphatics) stricture due to fibrosis Intestinal obstruction 35
Intestinal obstruction 36
Hyperplastic tuberculosis usually due to primary TB most often in the ileocaecal region (caecum) fibrous tissue & fatty tissue mesenteric lymphnodes enlarged Intestinal obstruction 37
Summary intestinal obstructions are surgical emergency should be diagnosed early Intestinal obstruction 38
Thank you Ref: Robbin & Cortan Pathologic Basis of Disease 8 th edition (2010) Intestinal obstruction 39