Intestine

• What are the symptoms of Atresia ani?


  • Enlarged abdomen
  • Imperforate anus
  • Unable to defecate
  • Possible surgical correction
• What is intestinal atresia?

  It refers to a congenital condition where a portion of the intestine is absent or closed off.
• What is atresia coli characterized by?

  Blind ends of the colon.
• What are the causes of obstruction in structural/functional disorders?

  • Secondary to congenital issues
  • Acquired internal blockage (e.g., worms, foreign bodies)
  • External compression (e.g., neoplasia, granuloma)
  • Functional paralysis

  
• What is paralytic ileus?

  It is a condition where there is a functional paralysis of the intestine, often following surgery or due to other medical conditions.
• What is grass sickness associated with?

  Degeneration of autonomic ganglia.
• What is lethal white foal syndrome?

  • Genetic defect in overo-spotted foals
  • Absence of myenteric ganglia
  • Often results in colic and death within 24 hours
• What does 'accordion pleating' indicate?

  It indicates obstruction in the intestines.
• What are the consequences of obstruction in the intestines?

  • Upper obstruction: acute, severe, rapid onset with complications like haemoconcentration and electrolyte depletion.
  • Lower obstruction: less acute, can be chronic, leading to toxaemia.
  • Simple vs. strangulated: strangulated segments can lead to shock and fluid loss.

  
• What can cause severe shock and death in horses?

  Strangulation due to pedunculated lipoma.
• What are the types of accidents/displacements in structural/functional disorders?

  • Volvulus (mesenteric axis) / torsion (long axis)
  • Intussusception (telescoping)
  • Eventration (surgical wound, umbilical at birth, traumatic)
  • Schistosomus reflexus (foetal anomaly)

  
• What is mesenteric torsion?

  A condition where the mesentery twists, potentially leading to obstruction.
• What is colonic torsion?

  A twisting of the colon that can lead to colic.
• What does intussusception refer to?

  It refers to a condition where a part of the intestine telescopes into another segment.
• What are the types of hernias mentioned in structural/functional disorders?

  • Internal hernia (diaphragmatic, mesenteric tear, epiploic foramen, nephrosplenic space)
  • External hernia (ventral, umbilical, inguinal/scrotal, perineal)
• What causes infarction of the gut?

  Strangulation in a hernia, torsion, or intussusception.
• What are some miscellaneous disorders of the intestine?

  • Intestinal lipofuscinosis ('brown bowel' in dogs)
  • Smooth muscle hypertrophy of terminal ileum (pigs and horses)
  • Diverticulosis (sheep)
  • Intestinal emphysema (pigs)
  • Haemomelasma ilei (horses)
  • Rectal prolapse (pigs, sheep, cattle)
• What is intestinal lipofuscinosis?

  A condition characterized by the presence of brown pigment in the intestinal smooth muscle cells of dogs.
• What is intestinal emphysema?

  An incidental finding in pigs at slaughter where lymphatics become filled with air.
• What is haemomelasma ilei?

  Subserosal haemorrhagic plaques due to migrating strongyle larvae in horses.
• What is iatrogenic rectal perforation in horses?

  It is a very serious condition that must be avoided at all costs.
• What are the normal structures and functions of the intestine?

  • Villi and crypts present
  • Epithelial cell turnover every 36-48 hours
  • Mitoses occur in upper crypts
  • Epithelium contains goblet cells and enterocytes
  • Epithelial cells exfoliate and undergo digestion

  
• How is the functional surface area of the intestine increased?

  • Mucosal folds
  • Villi
  • Microvilli
• What are the types of digestion that occur in the intestine?

  1. Intralumenal digestion (enzymes from exocrine glands and microbes)
  2. Membrane digestion (in glycocalyx on microvillous surface)
  3. Intracellular digestion (following pinocytosis)
• Where does most digestion and absorption occur in the intestine?

  • Digestion and most absorption occur in the small intestine.
  • Na+ and Cl- are absorbed in the colon.
  • Passive absorption of water occurs in the colon.
  • Gut-associated lymphoid tissue (GALT) includes Peyer’s patches.

  
• What are the changes to normal structure/function in enteritis?

  • Irritation leads to increased mucus secretion.
  • Increased exfoliation/desquamation.
  • Increased mitotic rate in crypts.
  • Necrosis of villous epithelium and contraction of lamina propria.
  • Shortening of villi and replacement by less differentiated cells.

  
• What are the results of necrosis of villous epithelium in enteritis?

  • Crypt hyperplasia occurs with necrosis of villous epithelium.
  • Villous denudation occurs with necrosis in crypts.
  • Leads to deficient digestion and absorption, wasting, dehydration, and loss of electrolytes.

  
• What is diarrhea defined as?

  Diarrhea is a relative excess of water compared to fecal dry matter.

  
• What are the types of small bowel diarrhea?

  • Secretory: caused by bacterial enterotoxins (e.g., E. coli).
  • Malabsorptive: due to osmotic retention in lumen or villus atrophy.
  • Effusive: due to hydrostatic/oncotic pressure gradient or inflammation.
• What are the causes of large bowel diarrhea?

  • Loss of absorptive epithelium (e.g., ulcers).
  • Fatty acid production due to bacterial fermentation.
  • Reduction in net absorption (e.g., Johne’s disease).
  • Intestine becomes flaccid and hypomobile.
• What are the types of inflammation of the intestine?

  • Small intestine: enteritis (duodenitis, jejunitis, ileitis)
  • Caecum: typhlitis
  • Ileocaecal valve: typhlodicliditis
  • Colon: colitis
  • Rectum: proctitis

  
• What are the types of enteritis?

  • Lymphoplasmacytic (Inflammatory Bowel Disease)
  • Eosinophilic (Parasites)
  • Granulomatous (Johne’s disease)
  • Pseudomembranous (Salmonella)
  • Necrotic (Parvovirus)
  • Catarrhal (Parasites)
• What are the types of colitis?

  • Lymphoplasmacytic
  • Histiocytic (Boxer colitis)
  • Ulcerative (NHP-Shigella)
  • Pyogranulomatous (Johne’s disease)
  • Dysentery (Swine dysentery)
• What are the chronic conditions associated with enteritis and colitis?

  • Eosinophilic enteritis due to parasites
  • Granulomatous enteritis due to bacterial infections (e.g., Johne’s disease)
  • May follow acute viral enteritis (e.g., BVD)
• What are the viral causes of enteritis?

  • Rotavirus (calves, foals, other species)
  • Coronavirus (calves, pigs, cats, dogs)
  • Parvovirus (cats, dogs)
  • Morbillivirus (rinderpest, distemper in pups)
  • Pestivirus (BVD, Hog Cholera)
  • Herpesvirus (MCF)
• What are the effects of rotavirus on the intestine?

  • Usually affects the upper small intestine.
  • Causes superficial damage to villi and villus atrophy.
  • Leads to osmotic diarrhea and secondary infections.
• What are the effects of coronavirus on the intestine?

  • Affects the lower small intestine and colon.
  • Causes superficial damage to villi and villus atrophy.
  • Leads to osmotic diarrhea.
• What are the effects of coronavirus in pigs?

  • Causes transmissible gastroenteritis (TGE).
  • Leads to epidemic diarrhea, vomiting, and wasting disease.
• What is Feline Infectious Peritonitis (FIP)?

  • Caused by a coronavirus.
  • Characterized by serofibrinous effusion in the peritoneum.
  • Multifocal granulomas on serosal surfaces.
  • Can present in 'wet' and 'dry' forms.
• What are the histopathological features of FIP?

  • Vasculitis and granulomas.
  • Mixed inflammatory infiltrates.
  • Affects multiple organs including kidney, lung, brain, and eye.