What is the appropriate evaluation and management for a 35-year-old male with 2 months of daily abdominal pain, nausea, and vomiting?

Evaluation and Management of Chronic Abdominal Pain with Nausea and Vomiting in a 35-Year-Old Male

This patient requires urgent CT scan of the abdomen and pelvis with IV contrast to exclude life-threatening surgical emergencies, followed by upper endoscopy to rule out mechanical obstruction, and then gastric emptying scintigraphy if initial imaging is negative. 1

Immediate Diagnostic Priorities

Rule Out Surgical Emergencies First

The combination of 2 months of daily abdominal pain, recurrent vomiting episodes severe enough to cause work absences, and impaired glucose (118 mg/dL suggesting prediabetes/diabetes) creates a clinical picture that demands exclusion of serious pathology before attributing symptoms to functional disorders. 1

CT abdomen and pelvis with IV contrast is the mandatory first test because:

• The severity and chronicity of symptoms with functional impairment (missing work 3 times) indicates potentially significant intra-abdominal pathology 1
• CT has superior sensitivity for detecting mechanical obstruction, bowel wall thickening, mesenteric fat streaking, and other structural abnormalities 2
• While acute mesenteric ischemia classically presents with "pain out of proportion to exam," chronic mesenteric ischemia presents with postprandial abdominal pain, nausea, vomiting, and early satiety—matching this patient's presentation 2
• The impaired fasting glucose (118) raises concern for diabetic gastroparesis, but mechanical obstruction must be excluded first 3

Upper Endoscopy After Negative CT

If CT is negative, proceed immediately to upper endoscopy (EGD) because:

• Endoscopy is the gold standard to exclude mechanical obstruction and structural disease before diagnosing a motility or functional disorder 2, 3
• At age 35, the patient is below the typical age cutoff (45-50 years) for alarm features, but the severity and chronicity of symptoms with vomiting episodes warrant endoscopy 2
• Endoscopy must be performed when symptoms are present and after minimum one month off antisecretory therapy 2

Gastroparesis Evaluation

When to Test for Gastroparesis

If both CT and endoscopy are negative, gastric emptying scintigraphy is the next essential test because:

• The symptom pattern of postprandial nausea, vomiting episodes, and decreased appetite strongly suggests gastroparesis 3
• The impaired fasting glucose (118) indicates prediabetes, a known risk factor for gastroparesis 3
• Gastric emptying scintigraphy is the gold standard diagnostic test 3

Proper Testing Technique

The gastric emptying study must be performed correctly to be valid:

• Test duration must be at least 2 hours, with 4-hour testing providing higher diagnostic yield and accuracy 3
• Use standardized low-fat egg white meal labeled with 99mTc sulfur colloid 3
• Withdraw medications affecting gastric emptying (prokinetics, opioids, anticholinergics) for 48-72 hours prior 3
• Monitor and control blood glucose during testing, as hyperglycemia itself slows gastric emptying 3
• Avoid smoking on test day 3

Critical pitfall: Shorter test durations (<2 hours) are inaccurate and should not be used 3

Symptom Management During Workup

Antiemetic Therapy

Start ondansetron 8 mg three times daily for nausea and vomiting control while diagnostic workup proceeds:

• Ondansetron is indicated for prevention of nausea and vomiting 4
• Dose: 8 mg administered 30 minutes before meals, with subsequent doses every 8 hours 4
• Monitor for QT prolongation, especially if electrolyte abnormalities develop from vomiting 4
• Watch for serotonin syndrome if patient takes other serotonergic medications 4

Important warning: Ondansetron can mask progressive ileus and gastric distension—monitor for decreased bowel activity 4

Avoid Harmful Medications

Do not prescribe opioids for pain management as they worsen gastric emptying and symptoms in gastroparesis patients 3

Differential Diagnosis Considerations

Chronic Mesenteric Ischemia

The clinical triad of postprandial abdominal pain, weight loss (though denied here), and food avoidance classically suggests chronic mesenteric ischemia 2. While this patient denies weight loss, the decreased appetite and nausea after eating could represent early food avoidance behavior. CTA has 95-100% sensitivity and specificity for detecting mesenteric vessel stenosis 2.

Functional Dyspepsia

Functional dyspepsia is defined by bothersome epigastric pain, burning, postprandial fullness, or early satiation without structural disease 3. However, this diagnosis can only be made after excluding structural and motility disorders through appropriate testing 2, 3.

Small Intestinal Dysmotility

The pattern of abdominal pain, distension, nausea, and vomiting without diarrhea or constipation could suggest enteric myopathy or neuropathy 2. However, these conditions are rare and should only be considered after excluding more common causes 2.

Additional Baseline Testing

Obtain the following laboratory tests:

• Complete blood count, comprehensive metabolic panel, liver function tests, lipase 3
• Hemoglobin A1c (given fasting glucose 118) 3
• Thyroid stimulating hormone (hypothyroidism can cause dysmotility) 2
• Celiac disease serologies (tissue transglutaminase IgA with total IgA) 2

Management Algorithm Summary

1. Immediate: CT abdomen/pelvis with IV contrast 1
2. If CT negative: Upper endoscopy 2, 3
3. If endoscopy negative: 4-hour gastric emptying scintigraphy with proper preparation 3
4. Concurrent: Start ondansetron 8 mg TID for symptom control 4
5. Concurrent: Obtain baseline labs including HbA1c, TSH, celiac serologies 2, 3
6. If gastroparesis confirmed: Dietary modifications (small frequent meals, low fat/fiber), maintain hydration ≥1.5 L/day 3

Critical pitfall to avoid: Do not empirically treat with acid suppression or prokinetics before establishing a diagnosis, as this delays potentially life-saving intervention if surgical pathology exists 1.