What is the workup for suspected bursitis or nerve injury following vaccination?

Workup for Post-Vaccination Bursitis or Nerve Injury

For suspected bursitis or nerve injury following vaccination, immediately obtain shoulder ultrasound or MRI to visualize subdeltoid/subacromial bursa inflammation, and perform a focused neurological examination assessing for paresthesias, motor weakness, and dermatomal sensory deficits in the affected extremity. 1, 2, 3

Immediate Clinical Assessment (Within 48 Hours)

History - Specific Details to Elicit

• Exact timing of symptom onset relative to vaccination - symptoms beginning within 48 hours suggest SIRVA (Shoulder Injury Related to Vaccine Administration), while onset at 5+ days requires evaluation for immune-mediated complications 4, 5, 3
• Injection technique details: needle length used, anatomical landmark identified, needle angle and direction, depth of penetration 3, 6
• Pain characteristics: severe shoulder pain with restricted range of motion indicates bursitis, while radiating pain down the arm suggests nerve injury 4, 3
• Associated symptoms: paresthesias, numbness, weakness, or tingling in specific nerve distributions 4, 7

Physical Examination - Specific Findings to Document

• Range of motion testing: active and passive shoulder abduction, forward flexion, and internal/external rotation - significant limitation suggests bursitis 2, 3, 6
• Neurological examination: test specific nerve distributions (axillary, radial, median, ulnar nerves) for sensory deficits, motor weakness, and reflex changes 4
• Palpation: tenderness over the deltoid insertion, subacromial space, or along nerve pathways 3, 6
• Special tests: Neer's sign, Hawkins-Kennedy test for impingement/bursitis 2

Diagnostic Imaging

First-Line Imaging

• Shoulder ultrasound is the preferred initial imaging modality - identifies subdeltoid/subacromial bursal fluid, inflammation, and can be performed immediately in the emergency or outpatient setting 1, 2
• MRI of the shoulder provides definitive diagnosis of bursitis, showing fluid collection in the subdeltoid/subacromial bursa and inflammatory changes 2, 3, 6

When to Image

• Obtain imaging within 24-48 hours if symptoms persist or worsen beyond typical post-vaccination reactions 1, 3
• Immediate imaging (within 6 hours) allows for early intervention with ultrasound-guided corticosteroid injection, which provides superior outcomes 1

Laboratory Evaluation

For Nerve Injury Suspicion

• Nerve conduction studies and electromyography (EMG) if paresthesias, weakness, or sensory deficits persist beyond 3 days 7
• These studies should be performed 2-3 weeks after symptom onset to allow Wallerian degeneration to occur, improving diagnostic sensitivity 4

For Delayed Symptoms (5+ Days Post-Vaccination)

If symptoms begin 5 or more days after vaccination, particularly with systemic features, obtain:

• Complete blood count (CBC) to assess for thrombocytopenia 5, 7
• D-dimer level - elevated in vaccine-induced thrombotic thrombocytopenia (VITT) 5, 7
• Anti-PF4 antibodies if VITT is suspected (COVID-19 vaccines specifically) 5, 7

Critical Timing Distinctions

Immediate Reactions (0-15 Minutes)

• 89% of vasovagal reactions occur within 15 minutes - characterized by syncope, lightheadedness, transient paresthesias that resolve immediately 4, 5
• These require observation only, not extensive workup 4, 5

Early Reactions (0-3 Days)

• Typical systemic reactions including myalgia, fatigue, and transient paresthesias are self-limited 5, 7
• SIRVA symptoms typically begin within 48 hours and include severe shoulder pain with limited range of motion 3, 6
• Workup is indicated if pain is severe or function is significantly impaired 1, 3

Delayed Reactions (5-30 Days)

• Persistent or new-onset symptoms require urgent evaluation for immune-mediated complications 5, 7
• This is the critical window for VITT and other serious neurological complications 5, 7

Common Pitfalls to Avoid

• Do not dismiss severe shoulder pain as "normal vaccine reaction" - SIRVA causes significant long-term morbidity if untreated, with most patients requiring medical care for severe pain and mobility restriction 3, 6
• Do not delay imaging in patients with persistent symptoms beyond 48 hours - early ultrasound-guided corticosteroid injection (within 6 hours) provides complete and durable symptom resolution 1
• Do not confuse immediate vasovagal paresthesias with nerve injury - vasovagal symptoms resolve within minutes to hours, while nerve injury causes persistent dermatomal deficits 4, 5, 7
• Do not order extensive thrombosis workup for symptoms resolving within 2-3 days - this represents unnecessary testing 5
• Do not miss the 5-30 day window for serious complications - symptoms beginning or persisting in this timeframe require CBC, D-dimer, and consideration of VITT 5, 7

Risk Factors for SIRVA

• Female sex (71.1% of cases) 3
• Mean age 53.6 years (range 22-89) 3
• Improper injection technique: injection site too high on shoulder (should be 2-3 finger breadths below acromion), needle too long (causing deep penetration into bursa), incorrect needle angle (should be perpendicular, not cephalad) 3, 6
• Most commonly associated with influenza and pneumococcal vaccines, though reported with all intramuscular vaccines including COVID-19 vaccines 2, 3, 6