What is the appropriate management for a patient presenting with 2 days of intermittent fever, epigastric pain, and vomiting?

Management of 2 Days Intermittent Fever with Epigastric Pain and Vomiting

Immediately initiate IV fluid resuscitation with 500-1000 mL bolus of normal saline or lactated Ringer's solution, obtain urgent laboratory testing including complete blood count, comprehensive metabolic panel, lipase, and liver function tests, and administer ondansetron 8 mg IV or sublingual as first-line antiemetic therapy. 1, 2

Immediate Stabilization and Initial Assessment

• Fluid resuscitation is the priority given 2 days of vomiting, which causes hypokalemia, hypochloremia, and metabolic alkalosis 1, 2
• Administer maintenance fluids after initial bolus, adding dextrose-containing fluids if prolonged fasting or hypoglycemia is suspected 2
• Check and correct electrolyte abnormalities and glucose levels before initiating antiemetic therapy, as addressing hypokalemia and hypomagnesemia is crucial 1, 2

Essential Laboratory Evaluation

Obtain the following tests to exclude metabolic causes and assess severity 1:

• Complete blood count
• Serum electrolytes, glucose, BUN, creatinine
• Liver function tests (AST, ALT, bilirubin)
• Serum lipase (to evaluate for pancreatitis given epigastric pain)
• Urinalysis
• Consider hypercalcemia testing if clinically indicated 1

Critical pitfall: Low serum bicarbonate combined with clinical parameters predicts significant dehydration 3

Differential Diagnosis Considerations

The combination of fever, epigastric pain, and vomiting requires consideration of 4, 1:

• Acute gastroenteritis (most common)
• Acute pancreatitis (lipase elevation confirms)
• Peptic ulcer disease or gastritis
• Cholecystitis or biliary pathology
• Infectious causes including pneumonia, urinary tract infection 4

Important: Fever with change in consciousness should raise suspicion for infection 4. COVID-19 can present with GI symptoms preceding respiratory symptoms, with up to 61% experiencing nausea, vomiting, or diarrhea 4

Imaging Strategy

• CT abdomen/pelvis is indicated to exclude bowel obstruction, tumor infiltration, pancreatitis, or other structural abnormalities 2, 5
• One-time esophagogastroduodenoscopy (EGD) or upper GI imaging is recommended to exclude obstructive lesions if symptoms persist beyond acute management 1
• Avoid repeated endoscopy or imaging studies unless new symptoms develop 1

Stepwise Pharmacologic Management Algorithm

First-Line Therapy (Immediate)

• Ondansetron 8 mg IV bolus or sublingual tablet (sublingual may have superior absorption in actively vomiting patients) 1, 2, 5
• Administer around-the-clock rather than PRN dosing for persistent symptoms 2
• Monitor for QTc prolongation, especially when combined with other QT-prolonging agents 1

Second-Line Therapy (If vomiting persists after 24 hours)

• Add metoclopramide 10 mg IV/IM as a dopamine antagonist from a different drug class 1, 2, 5
• Metoclopramide is particularly effective for gastroparesis-related vomiting and promotes gastric emptying 1, 5
• Monitor for extrapyramidal side effects, particularly in young males 1, 2
• Note black box warning for tardive dyskinesia with prolonged use 2, 5

Third-Line Therapy (For refractory symptoms)

• Add dexamethasone 10-20 mg IV/PO for synergistic antiemetic effect 2
• Consider adding proton pump inhibitor or H2 receptor antagonist if gastritis or GERD suspected 1, 5

Key principle: Add agents from different drug classes rather than replacing one antiemetic with another, as different neuroreceptors are involved in the emetic response 5

Route of Administration Considerations

• Avoid oral route during active vomiting; use IV, IM, sublingual, or rectal routes 2, 5
• Sublingual ondansetron may have superior absorption compared to oral tablets 5
• Rectal suppositories (promethazine or prochlorperazine) are effective alternatives when IV access unavailable 2, 5

Treatment of Specific Underlying Causes

If Acute Gastroenteritis Suspected

• Ondansetron reduces rate of vomiting, improves tolerance of oral rehydration, and reduces need for IV rehydration 6, 3
• Obtain stool culture and C. difficile testing if bloody diarrhea, leukocytosis, or recent antibiotic use 4
• Empiric antibiotics should be considered only for severe illness with fever ≥38.5°C and/or signs of sepsis 4

If Pancreatitis Confirmed (Elevated Lipase)

• Continue aggressive IV hydration
• NPO status initially
• Pain control as needed
• Monitor for complications

If Peptic Ulcer Disease or Gastritis

• Initiate proton pump inhibitor therapy 1, 5
• Continue metoclopramide as it promotes gastric emptying 1

Critical Pitfalls to Avoid

• Never use antiemetics if mechanical bowel obstruction is suspected until surgical evaluation is completed, as this can mask progressive ileus and gastric distension 1, 2, 5
• Do not rely solely on oral temperature measurement; core temperatures should be utilized if concern for fever is present 7
• Fever may not always be present in true infection, especially in elderly and immunocompromised patients 7
• Avoid repeated endoscopy or imaging unless new symptoms develop 1
• Monitor for extrapyramidal symptoms with dopamine antagonists 1, 2, 5

Supportive Care Measures

• Ensure adequate fluid intake of at least 1.5 L/day once tolerating oral intake 1
• Dietary modifications including small, frequent meals when resuming oral intake 1
• Consider thiamin supplementation to prevent Wernicke's encephalopathy in patients with persistent vomiting 1

Disposition Considerations

• Most patients with mild to moderate dehydration can be treated successfully with oral rehydration therapy after initial stabilization 3
• Admission criteria include inability to tolerate oral intake, severe electrolyte abnormalities, evidence of severe underlying pathology (pancreatitis, bowel obstruction), or sepsis 4