The stomach and duodenum stay healthy when aggressive factors (acid, pepsin) are balanced by protective factors (mucus, bicarbonate, mucosal blood flow, prostaglandins). Disease follows when aggression rises or protection falls.

Gastritis

• Acute gastritis: NSAIDs, alcohol, physiologic stress (burns, sepsis, critical illness), corrosive ingestion; epigastric pain, nausea, vomiting, sometimes bleeding
• Chronic gastritis: most often Helicobacter pylori; autoimmune gastritis destroys parietal cells, causing loss of intrinsic factor and vitamin B12 deficiency (pernicious anemia)

Peptic ulcer disease (PUD) — a break in the mucosa that extends deeper than an erosion.

• Main causes: H. pylori (urease produces ammonia, damages the mucus layer) and NSAIDs, including low-dose aspirin (block prostaglandin synthesis)
• Risk rises sharply when NSAIDs are combined with corticosteroids, anticoagulants, antiplatelet agents, or SSRIs, and with older age and prior ulcer
• Smoking delays healing; stress and spicy foods do not cause ulcers but may worsen symptoms

Gastric cancer — mostly adenocarcinoma. Risk factors: H. pylori, diets high in salted, smoked, or pickled foods, smoking, family history, pernicious anemia, prior partial gastrectomy. Early disease is silent; late signs include early satiety, weight loss, epigastric pain, anemia, and a palpable left supraclavicular node (Virchow node).

Subjective

• Location, character, and timing of epigastric pain in relation to meals; nausea, bloating, early satiety
• Medication history: NSAIDs, aspirin, corticosteroids, anticoagulants, SSRIs, bisphosphonates
• Alcohol and smoking; family history of gastric cancer
• Use open, specific questions: "Where exactly is the pain? What makes it better or worse?"

Objective

• Signs of bleeding: hematemesis (bright red or coffee-ground), melena (black, tarry stool), orthostatic dizziness, pallor
• Hemodynamic status: tachycardia and hypotension signal significant blood loss — a heart rate of 110/min with BP 90/60 mmHg indicates hemorrhagic shock risk
• Perforation: sudden severe epigastric pain spreading across the abdomen, board-like rigidity, rebound tenderness, absent bowel sounds, pain referred to the shoulder
• Gastric outlet obstruction: vomiting of undigested food, fullness, visible distension, weight loss, metabolic alkalosis

Acid suppression and mucosal protection

H. pylori eradication — current guidance (ACG 2024)

• First-line for treatment-naive clients: optimized bismuth quadruple therapy for 14 days — a PPI twice daily + bismuth + tetracycline + metronidazole
• Clarithromycin-based triple therapy is no longer recommended as empiric first-line therapy because of widespread clarithromycin resistance; use it only when testing shows the strain is clarithromycin-susceptible
• Alternatives: vonoprazan (a potassium-competitive acid blocker) with amoxicillin, or rifabutin-based triple therapy. Levofloxacin-containing regimens are generally reserved for rescue therapy
• Test of cure is required in every treated client: at least 4 weeks after antibiotics and after PPIs have been stopped for 2 weeks

Upper GI bleeding

• Two large-bore IV lines, isotonic crystalloid, type and crossmatch
• Restrictive transfusion: commonly when hemoglobin is below 7 g/dL (70 g/L), with a higher threshold (about 8 g/dL, 80 g/L) in cardiovascular disease
• IV PPI; endoscopy within 24 hours for hemostasis (clips, thermal therapy, epinephrine injection)
• Hold NSAIDs, aspirin (discuss with prescriber if needed for heart disease), and anticoagulants as ordered; iced saline lavage is not used

Perforation: NPO, NG suction, IV fluids, IV antibiotics, emergency surgical repair (laparoscopic patch). Gastric outlet obstruction: NG decompression, endoscopic dilation, or surgery.

Gastric cancer: subtotal or total gastrectomy with lymph node dissection, perioperative chemotherapy; palliative stenting or feeding tubes for advanced disease. After total gastrectomy, intrinsic factor is lost — lifelong vitamin B12 injections (or high-dose oral per prescriber) are required, along with iron, calcium, and vitamin D monitoring.

Listed in priority order.

1. Upper GI bleeding / shock
   • Continuous monitoring of vital signs and level of consciousness; orthostatic changes
   • Two large-bore IVs, fluids and blood as ordered; NPO; position to protect the airway during hematemesis
   • Monitor hemoglobin, hematocrit, urine output (at least 0.5 mL/kg/h), stool and emesis for blood
2. Perforation — sudden severe pain with rigidity is an emergency: keep NPO, notify the provider, prepare for surgery
3. After gastric surgery
   • Maintain NG tube patency; do not reposition or irrigate without an order (suture line)
   • Drainage is bloody for the first hours, then dark brown to greenish; report bright red bleeding after the early period or unusually high output — large NG losses cause hypokalemia, hypochloremia, and metabolic alkalosis
   • Semi-Fowler's position, deep breathing, early ambulation (high upper-abdominal incision)
   • Advance diet slowly; watch for dumping syndrome
4. Pain and medication safety — give acid suppressants on schedule; review all NSAID and corticosteroid use
5. Nutrition — small frequent meals; weight monitoring; B12 and iron replacement as ordered
6. After bariatric surgery (Roux-en-Y gastric bypass, sleeve gastrectomy, adjustable band)
   • Anastomotic leak: a new, sustained pulse above 120/min lasting more than 4 hours, tachypnea, hypoxia, or fever must be reported at once. A water-soluble contrast study or CT may be used, and surgery may proceed despite a negative study when suspicion is high
   • Venous thromboembolism prevention: sequential compression devices, subcutaneous heparin or low-molecular-weight heparin within 24 hours as ordered, and early ambulation
   • Diet progression: low-sugar clear liquids usually start within 24 hours, then a staged meal progression set by the surgical team
   • Protein at least 60 g/day (up to 1.5 g/kg ideal body weight); 3 small meals a day, small bites chewed thoroughly
   • Report persistent vomiting: it is a risk factor for thiamine deficiency, which is treated with IV thiamine when severe

Dumping syndrome (after gastrectomy, gastric bypass, pyloroplasty)

Management: diet changes first (below). Refractory cases may receive acarbose (for late dumping) or octreotide (injection-site pain, gallstones, glucose changes).

Ulcer prevention and healing

• Avoid NSAIDs and aspirin unless prescribed; use acetaminophen for pain as advised
• Stop smoking; limit alcohol; eat regular meals — no special bland diet is required
• Report black or tarry stools, vomiting blood or coffee-ground material, dizziness, or sudden severe abdominal pain

H. pylori therapy

• Take every dose for the full course, even after symptoms improve — stopping early promotes resistance and failure
• Expect black stools with bismuth; avoid alcohol with metronidazole; separate tetracycline from dairy and antacids
• Return for a test of cure; household members with symptoms may need testing per provider

Dumping syndrome diet

• Small, frequent meals (about 6 per day)
• Avoid simple sugars and sweets; choose complex carbohydrates, protein, moderate fat, and soluble fiber
• Drink fluids 30 minutes before or after meals, not with them
• Lie down (semi-recumbent or on the side) for about 20–30 minutes after meals to slow emptying
• For late dumping, carry a quick source of glucose and eat regularly

After total gastrectomy — lifelong B12 replacement; watch for anemia, weight loss, and bone loss.

After bariatric surgery

• Eat 3 small meals and chew small bites well; sip fluids slowly and wait at least 30 minutes after a meal before drinking
• After gastric bypass, avoid concentrated sweets to prevent dumping syndrome
• Take daily supplements long term and keep follow-up labs; do not stop them without the bariatric team. Minimum after gastric bypass or sleeve gastrectomy: 2 adult multivitamin-mineral tablets (with iron, folic acid, and thiamine), 1,200–1,500 mg elemental calcium (diet plus supplement, in divided doses), at least 3,000 IU vitamin D, total iron 45–60 mg, and vitamin B12 to keep levels normal (oral 350–1,000 mcg daily, intranasal, or IM/subcutaneous 1,000 mcg monthly if oral or nasal routes fail) (AACE/TOS/ASMBS 2019 update). After an adjustable band, 1 multivitamin-mineral tablet plus the same calcium and vitamin D
• Avoid pregnancy for 12–18 months after surgery

• Main causes of PUD: H. pylori and NSAIDs; NSAID + corticosteroid (or anticoagulant) sharply raises ulcer and bleeding risk
• Duodenal ulcer pain improves with food; gastric ulcer pain worsens with food
• Upper GI bleed with tachycardia and hypotension: monitor vital signs continuously, large-bore IVs, fluids — then endoscopy
• Perforation: sudden severe pain + board-like abdomen
• H. pylori first-line: bismuth quadruple therapy for 14 days; clarithromycin triple therapy only if the strain is known to be susceptible
• Always confirm cure (breath or stool test) at least 4 weeks after therapy, off PPIs for 2 weeks
• Complete the full antibiotic course even when symptoms resolve
• Long-term PPI → B12 deficiency, low magnesium, fractures, C. difficile
• Early dumping 10–30 min (vasomotor); late dumping 1–3 h (hypoglycemia)
• Dumping diet: small meals, no simple sugars, fluids between meals, lie down after eating
• Total gastrectomy → lifelong vitamin B12
• After bariatric surgery: sustained pulse > 120/min for > 4 hours suggests anastomotic leak; protein ≥ 60 g/day; daily multivitamin, calcium, vitamin D, iron, and B12