11. Gastrointestinal Disease (Lower) Flashcards
Function of large intestine and rectum
Part of the digestive tract.
Most of digestion and absorption already done by this stage.
Mainly absorbs water and electrolytes to form a solid stool.
Pathology
Inflammation
Cancer
Infection
Acute Appendicitis
Definition - sudden onset inflammation of the appendix
Pathology – obstruction of appendiceal lumen by a fecalith, calculus, tumour or worms causing an increased intraluminal pressure and bacterial invasion
Visceral Vs Parietal Pain
The sensory innervation of abdominal viscera is much less than that of other parts of the body such as the skin, the linings of the abdominal or thoracic cavities (parietal).
Visceral pain is an example of referred pain, as the pain is felt in a different location from where the pathology is.
Parietal pain is much more localised
Clinical Symptoms and Signs
Classically pain begins in the umbilical region of the abdomen which migrates to the right lower abdomen.
On examination there is often tenderness in the right quadrant, with involuntary guarding on palpation, due to localised peritonitis.
Peritonitis: Localised vs Generalised
The peritoneum is the lining of the abdominal cavity and the lining of the organs within the abdominal cavity.
Peritonitis is inflammation of this cavity due to a variety of causes, most commonly infection.
In appendicitis the inflammed appendix on coming in contact with the abdominal wall causes localised peritonitis.
Treatment of Acute Appendicitis
Surgical and/or antibiotics
Anti-biotic Associated Colitis/ Pseudomembraneous Colitis
Acute inflammation of the Colon characterised by the formation of adherent inflammatory pseudomembranes overlying the sites of mucosal injury.
Classically caused by toxins produced by Clostridium difficile that has over grown after competing bowel organism were eliminated by broad spectrum antibiotics
Gastrointestinal Disease (Lower) Pseudomembranous colitis (contd.)-
Typically develops in patients treated with broad spectrum antibiotics
Fever and lower abdominal tenderness
Treatment-
Speak to microbiology! (stop current antibiotic usually and possibly introduce a new antibiotic)
Hydration
Specifical antibacterial therapy
What is Inflammatory Bowel Disease?
Chronic inflammatory conditions of unknown aetiology affecting the gastrointestinal tract
Two main forms of idiopathic IBD
Crohn’s disease
Ulcerative colitis
IDIOPATHIC IBD
Pathogenesis
Genetics
Environment
Constitutional Susceptibility
Crohn’s Disease
Affects from mouth to anus: particularly terminal ileum(30%), colon alone (20%) and ileum and colon (50%)
Skip lesions (not continuous), intervening uninvolved areas
Often perianal skin involvement (75%)
IDIOPATHIC IBD - Crohn’s Disease
Pathology
Transmural inflammation: Active chronic inflammation with non-caseating epithelioid granulomas Can have Fistula formation
IDIOPATHIC IBD - Crohn’s Disease
Complications
Anaemia Malabsorption: fat, vitamins A,D,E,K, bile salts Fistulas Extra-intestinal: skin, eyes, joints) Increased risk of bowel carcinoma Bowel obstruction and perforation
IDIOPATHIC IBD - Ulcerative Colitis
Gross
Colon only Starts in rectum spreads proximally Continuous disease (No skip lesions) Mucosal disease (No transmural involvement) May involve whole colon also appendix
