What is the diagnosis and management for a 22-year-old male with acute epigastric pain, vomiting, periumblical and epigastric tenderness, and obstipation for 24 hours, with stable vital signs?

Differential Diagnosis and Management

Most Likely Diagnosis: Early Acute Appendicitis

This 22-year-old male with 6-hour epigastric pain, vomiting, periumbilical and epigastric tenderness, and 24-hour obstipation most likely has early acute appendicitis, which classically begins with periumbilical/epigastric pain before localizing to the right lower quadrant. 1, 2

Critical Life-Threatening Conditions to Exclude Immediately

Perforated Peptic Ulcer

• Examine for peritoneal signs (rigidity, rebound tenderness, absent bowel sounds) indicating perforation requiring immediate surgical consultation 1, 3
• Perforated peptic ulcer manifests with sudden, severe epigastric pain becoming generalized, accompanied by fever, abdominal rigidity, and absent bowel sounds, with mortality reaching 30% if treatment is delayed 1
• The current presentation shows soft abdomen with tenderness but no rigidity, making perforation less likely but not excluded 1

Acute Pancreatitis

• Order serum amylase (≥4x normal) or lipase (≥2x normal) immediately to exclude acute pancreatitis, which has 80-90% sensitivity and specificity 1, 3
• Acute pancreatitis characteristically presents with epigastric pain radiating to the back, though this patient lacks the classic radiation 1
• Mortality for acute pancreatitis is <10% overall but reaches 30-40% in necrotizing pancreatitis 3

Myocardial Infarction

• Obtain an ECG within 10 minutes of presentation—never rely on a single troponin measurement, obtain serial troponins at 0 and 6 hours 1, 3
• Myocardial infarction presents atypically with epigastric pain as the primary manifestation in women, diabetics, and elderly patients, with mortality rates of 10-20% if missed 1, 4
• While this patient is young, cardiac causes should never be dismissed regardless of age 4

Mesenteric Ischemia

• Mesenteric ischemia must be excluded, particularly in patients with vascular risk factors and pain out of proportion to examination 3
• The stable vitals and soft abdomen make this less likely, but the obstipation warrants consideration 3

Primary Differential Diagnoses

1. Acute Appendicitis (Most Likely)

• The classic presentation of appendicitis consists of periumbilical abdominal pain that migrates to the right lower quadrant, which matches this patient's periumbilical and epigastric tenderness 2
• Acute appendicitis is one of the most frequent causes of acute abdominal pain, and the site of pain can be altered depending upon the anatomical location of the appendix 2
• The 6-hour duration, vomiting, and obstipation are consistent with early appendicitis before right lower quadrant localization occurs 2
• Patients with abdominal pain which is not typical for acute appendicitis should be investigated by abdominal CT if leukocytosis and inflammatory markers are raised 2

2. Small Bowel Obstruction

• The 24-hour history of not passing stools or flatus raises concern for intestinal obstruction 5, 6
• Signs of complete intestinal obstruction and severe abdominal pain require emergency surgical assessment 5
• Bedside ultrasound can show dilated small bowel loops with absent peristalsis, which should be confirmed by CT abdomen 6

3. Peptic Ulcer Disease/Gastritis

• Peptic ulcer disease has an incidence of 0.1-0.3%, with complications occurring in 2-10% of cases 1
• The epigastric location and vomiting are consistent with PUD, though the periumbilical component suggests another process 1
• CT findings suggestive of gastritis or PUD include gastric or duodenal wall thickening, mucosal hyperenhancement, and fat stranding 1

4. Functional Dyspepsia (Unlikely Given Acute Presentation)

• Functional dyspepsia accounts for approximately 80% of patients with epigastric symptoms in the community 1
• However, persistent vomiting is a red flag that excludes functional dyspepsia and mandates investigation for structural disease 3
• Rome IV criteria require symptom onset at least 6 months prior to diagnosis, making this diagnosis inappropriate for a 6-hour presentation 5, 1

Immediate Management Algorithm

Step 1: Vital Signs and Physical Examination

• Check vital signs for tachycardia ≥110 bpm, fever ≥38°C, or hypotension, which predict perforation, anastomotic leak, or sepsis 1, 3, 4
• Re-examine for development of peritoneal signs (rigidity, rebound tenderness, absent bowel sounds) 1, 3
• Assess for right lower quadrant tenderness that may have developed since initial presentation 2

Step 2: Baseline Laboratory Investigations

• Complete blood count to assess for leukocytosis suggesting infection/inflammation 3, 2
• Serum amylase or lipase to exclude acute pancreatitis 1, 3
• Cardiac troponins at 0 and 6 hours if any concern for cardiac etiology 1, 3
• C-reactive protein and serum lactate levels 3
• Liver and renal function tests 3
• Serum electrolytes and glucose 3

Step 3: Immediate Imaging

• CT abdomen and pelvis with IV contrast is the gold standard when diagnosis is unclear, identifying pancreatitis, perforation, appendicitis, and vascular emergencies 1, 6, 2, 7
• CT with IV contrast shows extraluminal gas in 97% of perforations, fluid or fat stranding in 89%, ascites in 89%, and focal wall defect in 84% 1
• Plain abdominal radiography has significant diagnostic limitations and should not delay CT imaging 7
• Point-of-care ultrasound using the ACUTE-ABDOMEN protocol can expedite diagnosis while awaiting CT, evaluating for free fluid, distended bowel loops, and appendicitis 6

Step 4: Initial Treatment While Awaiting Diagnosis

• Maintain NPO status until surgical emergency is excluded 4
• Establish IV access and begin fluid resuscitation 8
• Provide analgesia—pain control does not mask surgical findings and improves patient comfort 8
• Avoid NSAIDs as they worsen PUD and bleeding risk 1, 4
• Consider nasogastric tube placement if bowel obstruction is suspected and patient has recurrent vomiting 8

Step 5: Surgical Consultation

• Obtain immediate surgical consultation given the combination of epigastric/periumbilical tenderness, vomiting, and obstipation 5, 1
• Do not delay surgical evaluation while awaiting imaging if peritoneal signs develop 1, 3

Critical Pitfalls to Avoid

• Never dismiss the possibility of appendicitis based solely on epigastric pain location—the appendix location can vary, and pain migrates over time 2
• Delaying CT imaging in patients with persistent vomiting and obstipation can lead to missed diagnosis of surgical emergencies 3, 6, 2
• Do not attribute symptoms to functional dyspepsia in the setting of acute presentation with vomiting—this represents a red flag for organic disease 3
• Missing cardiac causes of epigastric pain can be fatal, with mortality rates of 10-20%—always obtain ECG and troponins 1, 4
• Do not delay imaging in patients with peritoneal signs, as perforated ulcer mortality increases significantly with delayed diagnosis 1, 4

Disposition

• This patient requires hospital admission for observation, serial examinations, and definitive imaging 1, 3
• If appendicitis is confirmed on CT, proceed to urgent appendectomy 2
• If bowel obstruction is confirmed, surgical intervention may be required depending on etiology and severity 5, 6
• If imaging reveals peptic ulcer disease without perforation, start high-dose PPI therapy (omeprazole 20-40 mg once daily) and admit for observation 1, 4