What could be the cause of sudden right elbow pain, numbness, tingling, and pain radiating to the hand, especially in a hairdresser, after hearing a pop while reaching?

Acute Distal Biceps Tendon Rupture

This presentation is most consistent with an acute distal biceps tendon rupture, given the sudden "pop" during a reaching motion, immediate onset of pain with edema, and neurological symptoms radiating to the hand.

Clinical Reasoning

The key diagnostic features pointing to distal biceps tendon rupture include:

• Acute traumatic mechanism: The audible "pop" during an eccentric loading motion (reaching backward) is pathognomonic for tendon rupture 1
• Immediate symptom onset: Pain, swelling, and functional impairment occurring simultaneously with the injury event 1
• Neurological symptoms: Numbness and tingling radiating to the hand suggests associated nerve involvement, likely median or radial nerve irritation from acute hematoma or anatomical disruption 2
• Occupational risk: Hairdressers perform repetitive forearm pronation/supination and gripping motions, creating chronic stress on the distal biceps insertion that predisposes to acute rupture 3

Differential Considerations

While the presentation strongly suggests distal biceps rupture, nerve entrapment must be considered given the prominent neurological symptoms:

• Cubital tunnel syndrome (ulnar nerve): Can present with acute onset when associated with trauma or medial elbow pathology, though typically causes numbness in the 4th and 5th digits specifically 2, 4
• Acute median nerve compression: Less common at the elbow but possible with significant soft tissue swelling or hematoma 2
• Combined injury: Distal biceps rupture with secondary nerve compression from hematoma formation is possible and would explain the complete symptom complex 5

Immediate Diagnostic Approach

Initial imaging must begin with radiography of the elbow to exclude fracture, avulsion injury, or other bony pathology 1. The ACR Appropriateness Criteria designate radiography as "usually appropriate" for initial evaluation of acute elbow pain 1.

If Radiographs Are Normal or Indeterminate:

Ultrasound or MRI without IV contrast are equivalent first-line options for evaluating suspected tendon, ligament, or muscle injury 1. The choice depends on local availability and expertise:

• Ultrasound advantages: Immediate availability, dynamic assessment capability, high sensitivity (81%) and specificity (91%) for complete tendon tears 1
• MRI advantages: Superior for detecting partial tears, associated soft tissue injuries, and nerve pathology; T2-weighted sequences are the reference standard for nerve entrapment evaluation 1

Critical Pitfalls to Avoid

• Do not dismiss neurological symptoms as secondary: Acute nerve compression from hematoma or anatomical disruption requires urgent evaluation, as delayed diagnosis can lead to permanent dysfunction 2, 4
• Examine for associated injuries: The mechanism that causes distal biceps rupture can also injure the brachialis muscle, anterior capsule, or collateral ligaments 1
• Assess vascular status: Significant swelling in the antecubital fossa can compromise brachial artery flow; check distal pulses and capillary refill 2

Immediate Management Pending Imaging

Following American Heart Association recommendations for acute soft tissue injury 6:

• Cold therapy: Apply ice and water surrounded by damp cloth for 20-30 minutes, 3-4 times daily to reduce pain and swelling 6
• Avoid direct ice contact to prevent cold injury 6
• Immobilization: Position elbow at 90 degrees flexion with forearm in neutral rotation to minimize tension on injured structures 6
• Avoid provocative activities: No lifting, pulling, or resisted supination until definitive diagnosis 6
• NSAIDs: May be used for pain management 6

Urgent Surgical Consultation

If distal biceps rupture is confirmed, urgent orthopedic referral is indicated as optimal surgical outcomes require repair within 2-3 weeks of injury. Delayed repair beyond 4 weeks significantly compromises functional outcomes and may necessitate more complex reconstruction procedures.