What are the recommended ER diagnostics for a patient with a mouth infection concerning for Ludwig's angina?

Emergency Diagnostics for Ludwig's Angina

For patients with suspected Ludwig's angina, immediate CT imaging of the neck with contrast is the recommended first-line diagnostic study in the emergency setting to evaluate the extent of infection and potential airway compromise.

Clinical Assessment

When evaluating a patient with suspected Ludwig's angina in the emergency department, focus on these critical findings:

• Woody or indurated floor of the mouth
• Bilateral submandibular swelling
• Elevation of the tongue
• Dysphagia and dysphonia
• Pooling of secretions
• Trismus (a late finding)
• Signs of airway compromise (stridor, respiratory distress)

Diagnostic Algorithm

Immediate Airway Assessment

1. Evaluate for signs of impending airway obstruction
2. If severe respiratory distress is present, secure airway before diagnostic imaging
3. Consult anesthesia and otolaryngology emergently if airway compromise is suspected

Imaging Studies

1. CT scan of neck with contrast:

   • First-line imaging modality if patient can safely leave the ED and tolerate lying supine 1
   • Evaluates extent of infection, presence of abscess, and potential spread to mediastinum
   • Can identify fluid collections requiring surgical drainage

2. Point-of-care ultrasound:

   • Alternative when patient cannot tolerate supine positioning 1
   • Can identify abscesses and fluid collections
   • Useful for bedside evaluation when CT is not immediately available

Laboratory Studies

1. Complete blood count with differential
2. C-reactive protein and erythrocyte sedimentation rate
3. Blood cultures (at least 3 sets from separate venipuncture sites)
   • Must be obtained before antibiotic administration

Special Considerations

Airway Management

• Flexible intubating endoscopy with preparation for surgical airway is the first-line approach if definitive airway is required 1
• Elective tracheostomy may be necessary in cases with significant airway compromise 2

Potential Complications to Evaluate

• Spread to deep neck spaces
• Mediastinal extension
• Pleural effusion
• Pericardial involvement
• Sepsis

Pitfalls to Avoid

1. Delayed imaging: Ludwig's angina progresses rapidly; do not delay appropriate imaging when suspected
2. Administering antibiotics before obtaining cultures: This can reduce diagnostic yield
3. Failure to recognize early signs of airway compromise: Subtle signs may precede complete obstruction
4. Underestimating the extent of infection: Ludwig's angina can spread rapidly through fascial planes

Follow-up Diagnostics

After initial management:

• Repeat imaging may be necessary to evaluate response to treatment
• Monitor for development of complications including mediastinitis
• Consider echocardiography if there is concern for endocarditis as a complication

Ludwig's angina represents a true emergency with potential for rapid airway compromise. The diagnostic approach must prioritize airway assessment while simultaneously identifying the extent of infection to guide surgical intervention.