How should I evaluate and manage a patient presenting with fever and gastritis symptoms?

Evaluation and Management of Gastritis with Fever

For a patient presenting with fever and gastritis symptoms, immediately assess for severe inflammatory colitis or phlegmonous gastritis—both life-threatening conditions requiring urgent intervention—then systematically exclude infectious causes, particularly C. difficile if recent antibiotics were used, before attributing symptoms to simple gastritis.

Initial Risk Stratification and Red Flags

Phlegmonous gastritis is a surgical emergency that presents with acute epigastric pain, purulent vomiting, fever, and leukocytosis, carrying mortality exceeding any other nonmalignant gastric condition 1, 2. This diagnosis must be considered in patients with:

• Large alcohol intake history 2
• Recent upper respiratory infection 2
• Acute upper abdominal pain with peritonitis 2
• Purulent ascitic fluid 2

Immediate hospitalization criteria include hypotension, altered mental status, respiratory distress, tachycardia, or signs of end-organ dysfunction 3.

Focused Clinical Assessment

Critical History Elements

Assess for colitis symptoms (severe fever, abdominal cramps, diarrhea with or without blood/WBCs in stool), which require different management than simple gastritis 4.

Document all medications from the past 30 days, as:

• Recent antibiotic use mandates C. difficile testing 4
• Drug-induced fever has a mean lag time of 21 days after initiation 3
• PPI therapy (omeprazole) is associated with increased C. difficile risk 5

Identify predisposing conditions including diabetes, COPD, poor swallowing, indwelling catheters (39-fold increased bacteremia risk), alcohol abuse, NSAID use, or ICU-level physiologic stress 4, 3, 6.

Physical Examination Priorities

• Respiratory rate >25 breaths/min (90% sensitivity, 95% specificity for pneumonia in older adults) 4
• Signs of volume depletion: tachycardia, orthostatic hypotension, decreased skin turgor, altered mental status, reduced urine output 7
• Abdominal examination for peritonitis 2
• Mental status changes 4

Diagnostic Algorithm

Essential Laboratory Testing

Obtain immediately:

• Complete blood count with differential: WBC ≥14,000 cells/mm³ or left shift (band neutrophils ≥6% or ≥1,500 cells/mm³) warrants careful bacterial infection assessment 4
• C-reactive protein (highly specific for organic pathology) 8
• Comprehensive metabolic panel 8
• Blood cultures (2-3 sets before antibiotics if bacteremia suspected, though low yield in stable long-term care residents) 4, 3

Stool Studies Based on Clinical Presentation

For symptoms of colitis (fever + abdominal cramps + diarrhea ± blood/WBCs):

1. If antibiotics within past 30 days: Submit single diarrheal stool specimen for C. difficile toxin assay; if diarrhea persists with negative result, submit 1-2 additional specimens 4

2. If no recent antibiotics and/or negative C. difficile: Submit stool culture for Campylobacter jejuni, Salmonella, Shigella, and E. coli O157:H7 4

3. If symptoms persist >7 days or patient severely ill: Examine stool for Giardia and other protozoa 4

For stable gastroenteritis without colitis features: No laboratory evaluation required unless severely ill or symptoms persist beyond 7 days 4

Advanced Imaging Considerations

Abdominal imaging (CT or ultrasound) should be performed if intra-abdominal abscess suspected, as these complications carry substantial morbidity and mortality requiring acute care evaluation 4.

Gastroscopy with biopsy and culture of gastric contents may establish diagnosis of phlegmonous gastritis preoperatively 2.

Management Strategy

Hydration and Supportive Care

Initiate oral rehydration solution (sodium 90 mM, potassium 20 mM, chloride 80 mM, bicarbonate 30 mM, glucose 111 mM) for mild-moderate dehydration 7.

Replace ongoing losses: 10 mL/kg ORS per watery stool, 2 mL/kg per vomiting episode 7.

Reserve IV fluids for severe dehydration, shock, altered mental status, or inability to tolerate oral intake 7.

Ondansetron facilitates oral rehydration tolerance in adults with severe vomiting 7.

Antimotility Agent Precautions

Avoid loperamide until infectious causes excluded, particularly with leukocytosis suggesting inflammatory process 7. Contraindications include bloody diarrhea, fever, suspected C. difficile, or age <18 years 7.

Antibiotic Decision Algorithm

Do NOT give empiric antibiotics for simple gastroenteritis 7.

Initiate empiric antibiotics if:

• Severe inflammatory diarrhea with fever and bloody stools 7
• Immunocompromised status with persistent symptoms 7
• Signs of sepsis 7
• Neutropenia (ANC <500 cells/mm³) 3
• Suspected phlegmonous gastritis 1, 2

For suspected C. difficile: Start metronidazole or vancomycin immediately based on recent antibiotic exposure and leukocytosis 7.

For phlegmonous gastritis: Large doses of systemic penicillin combined with surgical resection or drainage (medical mortality 100% vs. surgical mortality 18.2%) 2.

PPI Considerations

Discontinue omeprazole if acute tubulointerstitial nephritis suspected (malaise, nausea, anorexia with decreased renal function) 5.

Consider C. difficile-associated diarrhea in patients on PPI therapy, especially hospitalized patients; use lowest dose and shortest duration appropriate 5.

Transfer and Escalation Criteria

Transfer to acute care facility for:

• Suspected intra-abdominal abscess or phlegmonous gastritis 4, 2
• Severe dehydration despite oral rehydration 7
• Hemodynamic instability 7
• WBC >30,000 cells/mm³ 7
• Signs of sepsis 7
• Neutropenia with diarrhea 7
• Inability to tolerate oral fluids 7

Public Health Notification

Contact local public health authorities if gastroenteritis rates exceed baseline thresholds, 2 cases occur simultaneously in same unit, or reportable pathogen isolated 4.

Common Pitfalls to Avoid

• Missing phlegmonous gastritis: Easily confused radiologically with infiltrating gastric carcinoma; requires high index of suspicion in elderly or those with preexisting gastric abnormalities 1
• Premature antimotility agents: Can worsen inflammatory/infectious colitis 7
• Inadequate C. difficile testing: Single negative test insufficient if diarrhea persists 4
• Overlooking intra-abdominal complications: Uncommon but associated with substantial mortality 4