How do you monitor spleen involvement in a patient with infectious mononucleosis (mono)?

Monitoring Spleen Involvement in Infectious Mononucleosis

For patients with infectious mononucleosis, clinical monitoring with serial physical examinations and patient education about warning signs is the primary approach, as routine imaging is not indicated unless complications are suspected.

Clinical Monitoring Approach

Initial Assessment

• Perform baseline physical examination focusing on left upper quadrant tenderness and splenomegaly, though clinical splenomegaly is only present in 30% of cases 1
• Educate patients immediately about warning signs: left upper quadrant or shoulder pain (Kehr's sign), right shoulder/scapular pain from diaphragmatic irritation, and any signs of peritoneal irritation 2, 3
• Counsel patients not to remain alone or in isolated places during the high-risk period 4

Surveillance Period and Activity Restriction

• Restrict all physical activity for at least 3-4 weeks from symptom onset, as 73.8% of splenic injuries occur within 21 days but 90.5% occur within 31 days 5
• Consider extending restriction to 6 weeks for athletes or those engaged in contact sports 3
• Maintain bed rest for 48-72 hours during the acute phase if moderate symptoms are present 4, 6

Indications for Imaging

Urgent Imaging Required

• Obtain immediate abdominal ultrasound or CT scan if any of the following develop 2, 7:
  • Left hypochondrial pain (rare in uncomplicated mononucleosis)
  • Pain referred to left or right shoulder
  • Signs of peritoneal irritation
  • Hemodynamic instability (hypotension, tachycardia, altered mental status)
  • Progressive anemia or decreasing hematocrit

Imaging Modality Selection

• CT scan with intravenous contrast is the gold standard for diagnosis of splenic complications, with 90-95% sensitivity and specificity 1
• Doppler ultrasound can be used as an initial screening tool and for follow-up evaluation of splenic vascularization 6, 1

Serial Monitoring Protocol

Laboratory Monitoring

• Serial hematocrit measurements every 6 hours are necessary during the first 24-72 hours if hospitalized for suspected complications 4
• Monitor for signs of ongoing bleeding: decreasing hematocrit, persistent tachycardia, or transfusion requirements 4

Follow-up Imaging

• Routine follow-up imaging is NOT recommended in asymptomatic patients with uncomplicated mononucleosis 4
• Consider repeat CT scanning only if 4, 1:
  • Decreasing hematocrit develops
  • New or worsening abdominal pain occurs
  • Fever persists or recurs (suggesting abscess formation)
  • Patient remains hospitalized for complications

Critical Warning Signs

High-Risk Features Requiring Emergency Evaluation

• Splenic rupture occurs in 0.1-0.5% of mononucleosis cases with 30% mortality if not promptly recognized 2, 5
• Most ruptures occur within 31 days of symptom onset, with mean time of 15.4 days 5
• 19% of delayed ruptures occur within first 48 hours, but most commonly between 4-10 days after symptom onset 4

Physical Examination Red Flags

• Kehr's sign (left shoulder pain from diaphragmatic irritation) 2, 3
• Right shoulder or scapular pain from free intraperitoneal blood 3
• Peritoneal signs (guarding, rebound tenderness) 2
• Hemodynamic instability (systolic BP <90 mmHg, tachycardia, altered consciousness) 6

Common Pitfalls to Avoid

• Do not rely on palpable splenomegaly as it is only present in 30% of cases and is not a reliable indicator of complications 1
• Do not discharge patients prematurely during the first 3 weeks, as this is the highest risk period for delayed rupture 8
• Do not perform routine imaging in asymptomatic patients, as this is not cost-effective and management strategies using patient education are superior 4
• Do not allow return to contact sports or vigorous activity before 31 days from symptom onset, as current 3-week guidelines may be insufficient 5

Management of Complications

If Splenic Rupture Suspected

• Emergency splenectomy is typically required for hemodynamically unstable patients with confirmed rupture 2, 7
• Immediate laparotomy is indicated for unresponsive hemodynamic instability or peritonitis 8
• Survival rate is 100% for true spontaneous ruptures when promptly recognized and treated 3

Splenic Infarction Management

• Most splenic infarcts are managed conservatively with supportive care and close monitoring 1, 9
• Monitor closely for progression to abscess (persistent fever, ongoing pain, bacteremia) 1
• Splenectomy is reserved for life-threatening complications such as rupture, abscess formation, or persistent hemorrhage 1