2027 L7 Gastrointestinal Pathology

Gastritis

Inflammation of the stomach lining, often causing discomfort. With neutrophils present.

Gastropathy

Stomach injury/dysfunction without significant inflammation. Can be caused by NSAIDs, alcohol, bile, stress and blood flow disruption.

Crohn's disease

A chronic inflammatory bowel disease that affects the digestive tract.

Ulcerative colitis

A chronic condition causing inflammation and sores in the colon.

Helicobacter pylori

A bacterium that can cause ulcers and gastritis, associated with gastric cancers. Acute infection goes unnoticed, chronic needs medical attention. Transmitted usually through human reservoirs, higher in older and developing populations.

Diagnosis of H. pylori

Initially gastritis in antrum > duodenal ulcers > spreads to gastric body and fundus, increasing risk of gastric adenocarcinoma > pattern shows if cancers or ulcers more likely. Tested serlogically for antibodies, bacteria in samples, urea breath test on ammonia generation by bacterial urease, or gastric biopsy.

Polyps

Abnormal growths in the colon that may become cancerous.

Colorectal cancer

Cancer that begins in the colon or rectum, significantly impacting global health.

Irritable bowel syndrome (IBS)

A functional disorder causing abdominal pain and changes in bowel habits.

Celiac disease

An autoimmune disorder triggered by gluten, damaging the small intestine.

Mucosa

The innermost layer of the gastrointestinal tract that absorbs nutrients. Epithelium, lamina propria and muscularis mucosa.

Submucosa

Between mucosa and muscularis externa, loose connective tissue layer full of blood vessels, lymphatics, nerves and some mucous secreting glands.

Muscularis externa

Layer between submucosa and adventia, smooth muscle responsible for peristalsis in the GI tract.

Adventia

Outermost layer. Connective tissue covered by serosa aka mesothelium.

Esophageal cardiac glands

Glands in the esophagus that secrete neutral mucus to protect the lining.

chronic Gastro-oesophageal reflux disease (GERD)

A chronic condition where stomach acid frequently flows back into the esophagus, causing irritation and symptoms like heartburn, difficulty swallowing, regurgitation, common in adults over 40. Treat symptoms with proton pump inhib. or H2 histamine antagonists. Can lead to ulcerations, vomitting blood, dark black faeces, narrowing lumen, Barrett oesophagus.

Barrett's Esophagus

Metaplasia of oesophageal cells due to long term acid exposure. Normal squamous cells replaced with columnar cells. GERD primary risk factor, secondary to hiatus hernia. High in male and Western populations.

Hiatal hernia

A condition where part of the stomach pushes through the diaphragm into the chest cavity, often associated with GERD. It can cause symptoms like heartburn and regurgitation.

Stomach’s Layers of Muscle

The stomach has three layers of muscle: the outer longitudinal layer, the middle circular layer, and the inner oblique layer, which work together to churn and mix food, aiding in digestion. Divided by which types of glands are present in each region.

Colorectal adenocarcinoma

Most common malignancy for GIT. Around 2 million cases in 2020, around 1mil deaths worldwide. Occurs higher in Europe, Aus, N. Zealand. Diarrhoea, constipation, blood in stool, stomach pain, fatigue, low iron.

Gall bladder

Stores bile from liver. Has cystic duct forms with hepatic duct to form bile duct. Spiral valve (Heister) ensures bile flow and duct openess. Sphincter of boyden regulates bile entry into duodenum at common bile end, Sphincter of Oddi controls bile AND pancreatic juice release into duodenum.

Cholecystitis

Small solid lumps formed in gallbladder when solid bile precipitates and becomes calcium salt depositions. Cholesterol stones most common, can lead to jaundice. Gallstones can become impacted in cystic duct, causing chronic cholecystitis.

Chronic cholecystitis

Gallbladder contracts more strongly to overcome obstruction, results in thickened muscles. Increases pressure in lumen and pushes mucosa into muscle layer. Bile in gallbladder also causes infection. Pain and fever.

Bowel Cancer Screening

Offered every 2 years to those between 60 and 74. Either FOB or FIT. Blood detection used to identify polyps and bowel cancers.

Pathogenesis of colonic adenomas

KRAS proto oncogene mutations, loss of P53 cancer suppresor genes. Accumulated mutations in genes that regulate growth, differentiation, apoptosis. Methylation-induced gene silencing.

Fecal immunochemical test (FIT)

A screening test that detects traces of blood in stool samples.

Faecal occult blood test (FOB)

A screening test that checks for hidden blood in stool, often used to identify potential bowel cancer.

Sessile polyps

Flat polyps that are harder to detect and have a higher risk of becoming cancerous.

Pedunculated polyps

Polyps attached to the intestinal wall by a stalk, typically easier to detect and generally have a lower risk of becoming cancerous compared to sessile polyps.

Cholecystectomy

Surgical removal of the gallbladder.

Proton pump inhibitors

Medications that reduce stomach acid production.

Colonic adenomas (polyps)

Benign polyps, often show epithelial dysplasia - lead to colorectal cancer. Most are asymptomatic, but big ones can cause anaemia by hidden bleeding or protein and potassium loss, leading to hypoproteinemia hypokalaemia.

Hyperproteinemic hyperkalemia

A condition resulting from polyps causing blood loss and affecting protein and potassium levels.

Alkaline tide

The increase in blood bicarbonate levels following hydrochloric acid secretion.