Gastrointestinal Pathology Flashcards

Question

What is the most common cause of Duodenum peptic ulcer?

Answer 1

Most commonly caused by hypersecretion of stomach acid into the duodenal mucosa.

Answer 2

Usually develop from areas of erosive gastritis Have the same risk factors / predisposing factors as acute & erosive gastritis: NSAID’s, Alcohol, stress, shock.. etc. Acute Peptic ulcers may: Cause severe bleeding Heal completely without scarring, or progress to form a chronic peptic ulcer.

Answer 3

If Damaging stimulus persists: Necrosis - organisation - repair all occur concurrently PLUS specific immune system defences are activated around the damaged area (macrophages & lymphoid cells) and therefore this state is termed chronic inflammation The gastric mucosa is normally protected from adverse effects of HCL & proteolytic enzymes If the mechanisms are broken down, the acid & enzymes destroy the epithelium & supporting stroma. This damaging stimulus is persistent  As acid & enzymes are constantly produced Tissue damage stimulates an active inflammatory response, with the formation of exudate close the damaging acid in the stomach. In the depths of the ulcer ,furthest away from the acid, attempts are made to organise the exudate and granulation tissue forms, which then progresses to a collagenous scar. In an established ulcer, these processes occur all at once (therefore is a chronic inflammatory process).

Answer 4

Haemorrhage Penetration The Ulcer penetrates the full thickness of the stomach or duodenal wall and progresses into underlying local tissue  in particular the liver or pancreas. Penetration of the pancreas manifests clinically as severe back pain. Perforation Which leads to peritonitis Fibrous Stricture Mostly seen in oesophageal peptic ulcers. Fibrous thickening caused by healing leads to scarring of the eosophagus and obstruction

Answer 5

1. The Pancreas: secretes digestive enzymes into the gut lumen which breakdown macromolecules 2. The Liver Secretes bile acids needed for solubilisation and absorption of fats 3. The Mucosa Specialised for absorption: including transverse mucosal fold and villi 4. Mucosal Enzymes Located on the brush border. These hydrolyse large molecules such as complex sugars (sucrase / lactase)

Answer 6

The important cause of small intestine malabsorption (in the developed world) is celiac disease. Celiac Disease is caused by hypersensitivity to a component of gluten. Autoimmune response to the protein gliadin (a component of gluten) which causes atrophy of small intestinal villi Diagnosis made by biopsy of small bowel mucosa. Histologically, the immune mediated damage causes heavy lymphocyte infiltration of lamina propria, significant loss of villous architecture. A common cause of failure to thrive in infants and children. Complete withdrawal of gliadin from the diet leads to gradual recovery of villus structure .

Answer 7

There are to main types of inflammatory bowel disease of no known cause (autoimmune): Crohn’s Disease Granulomatous inflammation of the bowel wall, most common in the terminal ileus. Ulcerative Colitis Chronic inflammatory disease of the rectal mucosa, which may extend to involve the whole of the colon. Both types are associated with systemic manifestation outside of the intestine .

Answer 8

Women > Men Terminal Ileum most affected Early stage of the disease shows marked swelling of the submucosa and mucosa This leads to loss of normal pattern of transverse folds Small focal haemorrhagic ulceration occurs which over time develop into fissures In establish Crohn’s this is termed cobblestone pattern due to deep interconnecting fissures. Strictures can cause obstruction.

Answer 9

Affects the rectum and may extend into the colon (in extensive disease, it can affect the whole colon mucosa). Patients develop diarrhoea: with the faeces being mixed with blood, mucus and pus. There are 3 clinical patterns of the disease: Active Acute – show areas of ulceration & inflammation in the mucosa & lamina propria Chronic Quiescent – no prominent ulceration, mucosa appears red, granular and thinned – evidence of chronic inflammation Fulminant active disease – extensive inflammation and ulceration Stress is believe to exacerbate the disease in some people 10% of patients require surgery 10% have persistent active disease despite treatment 80% have chronic quiescent colitis with infrequent episodes of relapse. Systemic Complications of Ulcerative Colitis: Erythema Nodosum Iritis Arthropathy of large joints Sacroiliitis Ankylosing Spondylitis

Answer 10

Emboli from intracardiac thrombosis - thrombus formation following an MI or from mitral / atrial valve stents. The embolus can lodge in the superior mesenteric artery which supplies the entire small intestine. Thrombosis in a severely atherosclerotic mesenteric artery Venous infarction due to strangulation -usually due to a strangulated bowel loop

Answer 11

common cause of abdominal pain Can be caused by obstruction of the lumen of the appendix, usually by faeces Complications of appendicitis include: peritonitis and subsequent spread of infection involvement of adjacent bowel loops causing perforation of small bowel