What is the differential diagnosis (ddx) for periscapular pain?

Differential Diagnosis of Periscapular Pain

Periscapular pain requires systematic evaluation to distinguish between musculoskeletal, neurogenic, referred, and systemic causes, with the most common etiologies being myofascial pain syndromes, scapular dyskinesis, cervical radiculopathy, and rotator cuff pathology.

Musculoskeletal Causes

Primary Scapulothoracic Disorders

• Myofascial pain syndrome involving trapezius, rhomboids, and levator scapulae is extremely common, often related to poor posture and anterior head carriage causing excessive strain of neck and upper back musculature 1
• Scapular dyskinesis (SICK scapula: scapular malposition, inferior-medial border prominence, coracoid pain and malposition, and dyskinesia of scapular movement) results from irregular activity of periscapular muscles 2
• Snapping scapula syndrome presents with painful crepitus during scapular motion 3
• Scapulothoracic bursitis can cause localized pain, though most cases lack correlative imaging findings 4

Nerve Injuries

• Long thoracic nerve palsy causes serratus anterior dysfunction, leading to scapular winging and periscapular pain 2
• Spinal accessory nerve injury results in trapezius weakness, with patients experiencing severe pain over the shoulder ridge and periscapular region, sometimes followed by focal trapezius hypertrophy 5
• Dorsal scapular nerve entrapment causes irritation from poor posture and can be identified through targeted examination 1
• Neuralgic amyotrophy (Parsonage-Turner syndrome) presents with acute severe periscapular pain followed by weakness, often affecting the spinal accessory nerve distribution 5

Rotator Cuff and Shoulder Pathology

• Rotator cuff disease is predominant in patients over 35-40 years, with anterior shoulder pain suggesting rotator cuff or biceps tendon pathology that may radiate to the periscapular region 6, 7
• Acromioclavicular joint arthritis is common in older patients and can cause referred periscapular discomfort 7
• Glenohumeral joint pathology including labral tears and instability may present with periscapular pain, particularly in younger patients under 35 years 7

Referred Pain Sources

Cervical Spine Pathology

• Cervical radiculopathy from herniated discs or osteophytes causes neuropathic pain radiating from the neck into the shoulder and periscapular region, characterized by numbness, tingling, weakness, or radiation following specific cervical nerve root distributions (C5, C6, C7, or C8) 6
• Document exact radiation pattern to determine if pain follows a specific dermatomal distribution 6
• Test for regional sensory changes, allodynia, or hyperpathia suggesting neuropathic pain component 6

Visceral Referred Pain

• Cardiac ischemia can present as left periscapular pain, particularly in patients with risk factors for coronary disease 8
• Pancreatitis may cause referred pain to the periscapular region 8
• Biliary disease occasionally refers pain to the right periscapular area 8

Red Flag Conditions Requiring Urgent Evaluation

Malignancy

• Primary or metastatic cancer can present as progressive periscapular pain, with history of cancer increasing probability from 0.7% to 9% 9
• Unexplained weight loss, failure to improve after 1 month, and age >50 years are additional cancer indicators 9

Vascular Emergencies

• Aortic dissection may present with interscapular pain and should be considered in patients with hypertension or connective tissue disorders 8
• Periscapular collaterals can be palpated in patients with aortic coarctation, accompanied by continuous murmurs around the left scapula 8

Infection

• Septic arthritis of the shoulder or scapulothoracic joint requires immediate evaluation when fever, chills, or constitutional symptoms are present 7
• Vertebral osteomyelitis may present with periscapular pain, particularly in patients with recent infection or intravenous drug use 8

Diagnostic Approach

History Elements

• Timing: onset (acute vs. insidious), duration, and periodicity of pain 8
• Location and radiation: determine if pain follows nerve distribution or remains localized 8
• Quality and severity: sharp, aching, burning, or electric shock-like 8
• Aggravating factors: specific movements (shoulder elevation, scapular protraction), posture, physical activity 8, 1
• Associated symptoms: weakness, numbness, tingling, scapular winging, crepitus 2, 3
• Red flags: fever, weight loss, history of cancer, trauma, progressive neurologic deficits 9, 7

Physical Examination

• Inspection: assess for scapular winging, asymmetry, muscle atrophy or hypertrophy, and postural abnormalities with torso uncovered from front and back 3, 5
• Palpation: identify trigger points in trapezius, rhomboids, levator scapulae; palpate for periscapular collaterals if vascular pathology suspected 8, 1
• Range of motion: evaluate shoulder and scapular motion, noting crepitus or painful arc 3
• Strength testing: assess trapezius (shoulder shrug), serratus anterior (wall push-up test for winging), rhomboids, and rotator cuff strength 2, 3
• Neurologic examination: test sensation in cervical dermatomes, reflexes, and motor strength in specific myotomes 6
• Scapular assistance test: may help predict outcome of treatment for scapular dyskinesis 3

Imaging Strategy

Initial imaging should be guided by clinical suspicion:

• Plain radiographs of the cervical spine and shoulder are appropriate first-line imaging to assess for gross structural abnormalities, degenerative changes, or alignment issues 6
• MRI of cervical spine without contrast is the preferred initial advanced imaging when clinical examination supports radiculopathy, as it directly visualizes disc herniations, osteophytes, and nerve root compression 6
• MRI of chest/periscapular region is needed to capture periscapular muscles when scapular dyskinesis or nerve injury is suspected 3
• Shoulder MRI is recommended only if physical examination suggests concurrent rotator cuff pathology 6
• Ultrasound is useful to assess peripheral nerve injuries (dorsal scapular nerve, spinal accessory nerve) and to guide diagnostic/therapeutic injections into the scapulothoracic interval 4, 3, 1
• Electrodiagnostic testing (EMG/NCS) should be considered if imaging is negative or equivocal, with sensitivity over 80% and specificity of 95% for confirming nerve compression and localizing the level 6, 5
• CT is particularly helpful for skeletal abnormalities but has limited utility for soft tissue evaluation 3

Management Algorithm

Conservative Management (First-Line)

• Physical therapy focusing on postural correction, scapular stabilization exercises, and periscapular muscle strengthening 2, 1
• Ultrasound-guided scapulothoracic interval steroid injections provide safe, easily performed diagnostic and therapeutic intervention for periscapular pain, offering at least short-term symptom relief 4
• Modified 5-in-1 trigger point technique with hydrodissection of dorsal scapular and spinal accessory nerves is safe and effective for medial periscapular pain, providing statistically significant pain relief 1

Neuropathic Pain Management

• Pregabalin 300-600 mg daily in divided doses for confirmed cervical radiculopathy with neuropathic features 6
• Alternative agents: gabapentin or duloxetine for nerve-stabilizing effects 6

Surgical Intervention

• Pectoralis major transfer for symptomatic scapular winging due to long thoracic nerve palsy unresponsive to conservative treatment 2
• Cervical spine surgery for radiculopathy with persistent symptoms at 12 weeks unresponsive to conservative care 9

Common Pitfalls

• Assuming "muscle tension" or "muscle spasm" without ruling out structural cervical spine pathology or nerve injury can delay appropriate diagnosis 6
• Missing cardiac ischemia in patients presenting with left periscapular pain, particularly those with cardiovascular risk factors 8
• Delaying imaging when red flags are present (progressive neurologic deficits, cancer history, unexplained weight loss) worsens outcomes 9
• Overlooking scapular winging during physical examination when patient is fully clothed; examination requires torso exposure from front and back 3
• Failing to consider neuralgic amyotrophy in patients with acute severe periscapular pain following strenuous activity 5