Peptic Ulcer Disease (PUD)

•    Ulceration of gastric or duodenal mucosa due to acid/pepsin imbalance

•    Common causes:

o    H. pylori infection (duodenal > gastric)

o    NSAIDs (gastric > duodenal)

•    Duodenal ulcers: pain relieved by food, more common

•    Gastric ulcers: pain worsened by food, higher malignancy risk

•    Complications: bleeding, perforation, gastric outlet obstruction

•    Diagnosis: OGD + biopsy (especially for gastric ulcers to exclude malignancy)

•    Treatment:

o    PPI

o    H. pylori eradication: triple therapy (PPI + clarithromycin + amoxicillin/metronidazole)

Zollinger–Ellison Syndrome (ZES)

•    Gastrin-secreting tumour (gastrinoma) → excess gastric acid

•    Location: pancreas or duodenum

•    Features: refractory peptic ulcers, diarrhoea, multiple ulcers

•    Associated with MEN1

•    Diagnosis:

o    ↑ fasting gastrin

o    Confirm with secretin stimulation test

o    Localise with somatostatin receptor imaging

•    Treatment: high-dose PPI ± surgical resection

Gastric Cancer

•    Most commonly adenocarcinoma

•    Risk factors: H. pylori, smoking, high salt/nitrate diet, atrophic gastritis, pernicious anaemia

•    Features: weight loss, epigastric pain, early satiety, Virchow’s node (left supraclavicular), acanthosis nigricans

•    Diagnosis: OGD + biopsy

•    Staging: CT, endoscopic ultrasound, laparoscopy

•    Treatment: surgery ± chemotherapy

Gastritis

•    H. pylori gastritis: chronic active inflammation; risk of ulcers, cancer

•    Autoimmune gastritis:

o    Antibodies against parietal cells and intrinsic factor

o    Leads to B12 deficiency (pernicious anaemia)

o    Associated with ↑ risk of gastric cancer

•    Chemical gastritis: alcohol, NSAIDs, bile reflux

Dumping Syndrome

•    Rapid gastric emptying post-gastrectomy or vagotomy

•    Early dumping: fluid shift → abdominal pain, diarrhoea, hypotension

•    Late dumping: reactive hypoglycaemia due to insulin surge

•    Treatment: dietary changes (small, frequent meals, avoid high-sugar foods)

Post-Gastrectomy Complications

•    Vitamin B12 deficiency: loss of intrinsic factor → megaloblastic anaemia

•    Iron deficiency: ↓ acid affects iron absorption

•    Small bowel bacterial overgrowth (SIBO): due to altered motility/anatomy

o    Features: bloating, diarrhoea, malabsorption

o    Dx: breath test

o    Rx: antibiotics (e.g. rifaximin)