How should I initially manage a typical adult presenting with acute gastritis?

Acute Gastritis Management

Critical First Step: Distinguish True Gastritis from Gastroenteritis

Acute gastritis is a histological diagnosis requiring endoscopic biopsy confirmation, not a clinical syndrome you can diagnose at the bedside. 1, 2 Most patients presenting with acute epigastric pain, nausea, and vomiting actually have acute gastroenteritis (viral or bacterial infection) or functional dyspepsia, not true gastritis. 2

Initial Assessment & Red Flags

Immediately evaluate for life-threatening conditions requiring urgent intervention:

• Hemorrhagic gastritis with active bleeding: Look for hematemesis, melena, tachycardia >90 bpm, hypotension, or hemoglobin <105 g/L—these patients need urgent endoscopy and ICU-level care. 3
• Acute phlegmonous gastritis (rare but lethal): Suspect if severe epigastric pain with high fever, septic shock, rebound tenderness, and CT showing diffuse gastric wall thickening with edema/gas—requires immediate broad-spectrum antibiotics and surgical consultation. 4, 5
• Perforated viscus: Bilious vomiting, absent bowel sounds, or peritoneal signs mandate immediate surgical evaluation. 6

Supportive Management for Presumed Acute Gastritis

For stable patients with epigastric pain, nausea, and vomiting without alarm features:

Acid Suppression

• Start high-dose proton pump inhibitor therapy immediately: Omeprazole 40 mg twice daily or equivalent PPI is first-line treatment for ulcer-like dyspepsia and presumed acid-related gastric mucosal injury. 1
• This approach confirms the acid-related nature of symptoms and ensures healing of any underlying erosions or ulcers. 1

Identify & Remove Offending Agents

• Stop NSAIDs, aspirin, and alcohol immediately—these are the most common causes of acute hemorrhagic gastritis and erosive mucosal damage. 3, 7
• Aspirin damages the gastric mucosal barrier, lowers gastric potential difference, and causes microerosions that can progress to chronic ulceration. 7
• Patients on chronic NSAIDs have a 50% incidence of gastric erosions and 20% incidence of gastric ulcer. 7

Nutritional Support

• Resume normal oral intake as tolerated—there is no evidence that fasting benefits gastric mucosal healing. 6
• Avoid foods high in simple sugars, high-fat foods, and caffeinated beverages, which can exacerbate symptoms. 6

When to Pursue Endoscopy

Obtain urgent upper endoscopy with topographical biopsies if:

• Symptoms persist beyond 2–3 weeks despite PPI therapy. 1
• Any alarm features: age >55 years, unintentional weight loss, dysphagia, odynophagia, persistent vomiting, evidence of GI bleeding, or palpable abdominal mass. 1
• Suspected H. pylori infection (test and treat if positive). 1, 2

Endoscopy provides definitive diagnosis: biopsies from body and antrum/incisura (in separate jars) confirm histological gastritis, identify H. pylori, and rule out malignancy. 1, 2

H. Pylori Testing & Eradication

• All patients with confirmed gastritis must be assessed for H. pylori using non-serological testing (stool antigen, urea breath test, or biopsy urease test). 1, 2
• If H. pylori-positive, treat with standard triple or quadruple therapy and confirm eradication 4–6 weeks after completing antibiotics. 2, 8
• H. pylori acute gastritis can mimic gastric carcinoma or lymphoma endoscopically—histology is essential. 8

Common Pitfalls to Avoid

• Do not delay acid suppression while awaiting endoscopy—start PPI therapy immediately in stable patients. 1
• Do not use antimotility agents (loperamide) if diarrhea is present—these are contraindicated in inflammatory conditions and can worsen outcomes. 6
• Do not assume "gastritis" based on symptoms alone—true gastritis requires histological confirmation; most cases are actually gastroenteritis or functional dyspepsia. 1, 2
• Do not miss phlegmonous gastritis—this rare entity progresses rapidly to septic shock and requires immediate antibiotics plus surgery if conservative treatment fails within 24–48 hours. 4, 5

Disposition & Follow-Up

• Discharge stable patients on high-dose PPI with 2–3 week follow-up: If symptoms resolve, consider trial of PPI withdrawal or on-demand therapy. 1
• Refer for endoscopy if symptoms persist or alarm features develop. 1
• Admit patients with severe dehydration, hemodynamic instability, suspected perforation, or sepsis. 6, 4