What is the appropriate management for a patient with mononucleosis presenting with left abdominal pain, suspected splenomegaly, and risk of splenic rupture?

Management of Mononucleosis with Left Abdominal Pain

In a patient with infectious mononucleosis presenting with left abdominal pain, immediately obtain urgent abdominal imaging (ultrasound or CT scan) to evaluate for splenic rupture or subcapsular hematoma, as this represents a life-threatening complication requiring emergent splenectomy if the patient is hemodynamically unstable or has evidence of active bleeding. 1, 2, 3

Immediate Assessment

Clinical Evaluation

• Check hemodynamic stability immediately: measure blood pressure, heart rate, capillary refill, mental status, and shock index 1
• Assess for Kehr's sign (left shoulder pain from diaphragmatic irritation), which indicates splenic capsule irritation or rupture 4
• Examine for peritoneal signs: guarding, rebound tenderness, and progressive abdominal distension 3, 4
• Monitor for progressive anemia: obtain serial hematocrit measurements every 4-6 hours 1

Urgent Imaging

• Obtain abdominal ultrasound or CT scan with IV contrast immediately when left upper quadrant pain occurs in infectious mononucleosis, as splenic rupture should be strongly considered whenever abdominal pain develops 1, 2, 3
• CT scan is the gold standard with 90-95% sensitivity and specificity for detecting splenic pathology 1, 5
• Look for: subcapsular hematoma, splenic enlargement, free peritoneal fluid, or active bleeding 3, 4

Risk Stratification and Management Algorithm

Hemodynamically Unstable Patients

• Proceed immediately to emergent splenectomy if the patient has hypotension, tachycardia, progressive anemia requiring continuous transfusions, or signs of active intraperitoneal bleeding 1, 3, 6
• Mortality approaches 30% if diagnosis and treatment are delayed in cases of overt splenic rupture 4
• Splenectomy remains the definitive treatment for hemodynamically unstable patients with splenic rupture complicating infectious mononucleosis 6, 7

Hemodynamically Stable Patients

• Non-operative management can be attempted in carefully selected hemodynamically stable patients with subcapsular hematoma without overt capsular rupture 3, 7
• Requires: intensive monitoring with serial clinical examinations, serial hematocrit measurements every 4-6 hours, immediate access to surgery and blood products 1
• Implement strict bed rest for 48-72 hours with continuous monitoring 8, 1
• Transfuse as needed to maintain hemodynamic stability, but continuous transfusion requirements mandate surgical intervention 1

Imaging Findings Guide Management

• Subcapsular hematoma without capsular rupture: attempt non-operative management with intensive monitoring 3, 7
• Free peritoneal fluid or active bleeding: proceed to emergent splenectomy 3, 4
• Large or expanding hematoma on serial imaging: strongly consider splenectomy even if initially stable 1

Critical Pitfalls to Avoid

Diagnostic Errors

• Do not dismiss left upper quadrant pain as "typical" for mononucleosis: abdominal pain is uncommon in uncomplicated infectious mononucleosis, and splenic rupture must be excluded 2, 3
• Do not rely on clinical splenomegaly alone: it is present in only 30% of cases and is not a reliable indicator of rupture risk 1, 5
• Splenic rupture occurs in only 0.1-0.5% of infectious mononucleosis cases, but it is the most feared and potentially fatal complication 2, 7

Management Errors

• Do not delay imaging: the onset of pain may be insidious or abrupt, and rapid deterioration can occur 3, 6
• Do not attempt non-operative management without intensive monitoring capabilities: this requires serial examinations, laboratory monitoring, and immediate surgical availability 1, 7
• Recognize the "double rupture phenomenon": approximately 25% of patients have warning symptoms from an initial small herald bleed followed by major rupture with hemorrhagic shock 8

Post-Diagnosis Activity Restrictions

If Splenic Rupture is Excluded

• Advise strict avoidance of contact sports and strenuous exercise for 8 weeks or while splenomegaly persists 2
• Implement bed rest as tolerated during the acute phase 2
• Counsel patients to avoid remaining alone or in isolated places for the first weeks after diagnosis and warn about alert symptoms 8

If Splenectomy is Performed

• Activity restriction for 3 weeks post-splenectomy, with gradual return to normal activity 8
• Provide post-splenectomy vaccinations (pneumococcal, meningococcal, Haemophilus influenzae type b) to prevent overwhelming post-splenectomy infection 3

Follow-Up Considerations

• Repeat imaging is not routinely necessary if initial imaging excludes rupture and the patient remains clinically stable 8
• Consider repeat CT scan if there is decreasing hematocrit, persistent or worsening pain, or clinical deterioration 8, 1
• Most patients with uncomplicated infectious mononucleosis recover uneventfully with supportive care alone 2