Rosen & Barkin's 5-Minute Emergency Medicine Consult (708 page)

• The symptoms of thoracic outlet syndrome (TOS) are produced by compression of the brachial plexus, subclavian vein, or subclavian artery during their passage from the cervical area toward the axilla and proximal arm.
  
• Subdivided into 3 categories depending on the predominant symptoms:
  
  • Neurogenic thoracic outlet syndrome (NTOS):
    
    • Comprises 90–98% of adult patients
      
    • Female > male
      
    • True (1–3%): Those with objective findings
      
    • Disputed (90%): Those with no or limited objective findings
      
  • Venous thoracic outlet syndrome (VTOS):
    
    • 2–4% of patients
      
  • Arterial thoracic outlet syndrome (ATOS):
    
    • Least common, <1%
      
    • Male = female
      
• Vascular manifestations are more common in adolescents, seen in >50% of teens with TOS.
  
• Right extremity is more commonly affected.
  

• Anatomic anomalies:
  
  • Bony anomalies include cervical rib, 1st thoracic rib, or clavicular abnormalities:
    
    • Cervical ribs occur in <1% of the population, ∼70% in women, and most are asymptomatic.
      
    • Less commonly, fracture of the clavicle and trauma to the sternoclavicular and costoclavicular joints
      
  • Congenital bands or anomalous muscles
    
  • May play a role in neurologic and venous types but is almost always implicated in arterial type
    
• Neurogenic:
  
  • Often have a history of neck trauma, such as whiplash (hyperextension injuries) or with repetitive motion patterns
    
• Venous:
  
  • May be preceded by excessive activity, especially in adolescent athletes
    
  • Caused by acute thrombosis of the subclavian vein (also called Paget–Schrötter disease) or by venous impingement
    
• Arterial:
  
  • Often develop spontaneously
    
  • Unrelated to trauma or work
    
  • May experience true claudication with overhead exercises
    
  • Almost always have a complete cervical rib or an anomalous 1st rib
    
  • Caused by subclavian artery aneurysm or subclavian/axillary artery impingement:
    
    • Arterial emboli that arise from either mural thrombus in the subclavian artery aneurysm or from thrombus forming distal to subclavian artery stenosis
      
• Descent of the shoulder girdle and sagging musculature can also predispose to TOS:
  
  • Aging
    
  • Obesity
    
  • Heavy breasts
    

DIAGNOSIS

• Neurogenic:
  
  • Classically, pain, paresthesia, and weakness of the hand, arm, and shoulder
    
  • May see wasting of the thenar eminence, also known as Gilliatt–Sumner hand
    
  • Analogous but not as severe as Erb–Duchenne syndrome
    
  • May also see Raynaud phenomenon, hand coldness, color change:
    
    • Not caused by ischemia, rather due to overactive sympathetic fibers that run on the circumference of the lower trunks of the brachial plexus
      
    • Similar symptoms can be seen in arterial TOS, so the 2 must be differentiated by evaluating for other signs and symptoms.
      
• Venous:
  
  • Swelling of the arm and cyanosis:
    
    • NTOS and ATOS do not exhibit arm swelling.
      
  • May see pain, aching of the arm
    
  • Hand paresthesia:
    
    • May be due to swelling as opposed to nerve compression
      
• Arterial:
  
  • Digital ischemia, claudication, pallor, coldness, paresthesia, and pain of the hand
    
  • Usually spares the shoulder and neck
    
  • Pallor and coldness are due to ischemia and not Raynaud
    
  • Aneurysmal:
    
    • Painless pulsating mass
      

• May be positional or exacerbated by repetitive use (i.e., working overhead)
  
• Usually insidious in onset and progressive
  
• Can occur or worsen suddenly after trauma or with acute clot
  

Provocative maneuvers can reveal NTOS (VTOS and ATOS often diagnosed with history and symptoms only):

• Roos, aka elevated arm stress test (EAST):
  
  • Arms abducted 90° from the thorax and elbows flexed at 90°
    
  • Shoulders braced slightly back of the frontal plane
    
  • Fists are open and closed for 3 min.
    
  • Early heaviness and fatigue of the arm
    
  • Gradual onset of hand numbness
    
  • Progressive aching through the arm and top of shoulder
    
  • Negative test is having only fatigue in forearms
    
• Adson test:
  
  • Arm down, patient rotates head toward extremity, looks up, and inhales.
    
  • Positive result is the alteration or obliteration of the radial pulse or change in the BP.
    
  • Not a reliable test, as many patients with NTOS have a negative test and many control patients have a positive test.
    
• Wright test:
  
  • Progressive hyperabduction and external rotation of affected arm while palpating pulse on ipsilateral side
    
  • Positive result if parasthesias or diminishing pulses
    
• None of the above is very sensitive nor specific.
  
• Difference of >20 mm Hg in BP is suggestive of compromise of subclavian artery in right clinical context
  

• Careful history and physical exam
  
• EKG to rule out cardiac ischemia
  

Consider a coagulation workup for either venous or arterial TOS.

• Perform as outpatient except in case of limb-threatening ischemia and/or suspicion of venous thrombus
  
• CXR:
  
  • Assess for anatomic abnormalities: 1st rib, cervical rib, clavicle deformity:
    
    • Without an abnormality, ATOS is very unlikely.
      
  • Pulmonary disease
    
• Cervical spine series:
  
  • Fracture
    
  • Scoliosis
    
• US can diagnose venous thrombosis
  
• Duplex scanning is the best way to screen for subclavian artery aneurysm or stenosis, which, if present, can lead to arteriography
  
• Arteriogram:
  
  • Usually used to help a surgeon plan reconstruction
    
  • Indications include:
    
    • Decreased radial pulse
      
    • BP is 20 mm Hg less than the opposite limb.
      
    • Suspected subclavian stenosis
      
    • Bruit or abnormal supraclavicular pulsations or pulsating mass
      
    • Peripheral emboli in the upper extremity
      
• Venography:
  
  • Indicated if edema, peripheral unilateral cyanosis, or distended thoracic and extremity veins
    
• NTOS:
  
  • No gold standard test: Diagnosis remains mostly clinical.
    
  • Electromyography and nerve conduction velocity tests are often normal.
    
• MRI may be required to assess for spinal cord disease, herniated cervical disk, or assessing for pancoast tumor.
  

• Cardiac ischemia
  
• Cervical spondylosis or disk disease
  
• Carpal tunnel syndrome or nerve entrapments
  
• Pancoast tumor; other neck/mediastinum malignancies
  
• Neuritis
  
• Myositis
  
• Raynaud disease
  
• Multiple sclerosis or degenerative spinal cord disease
  
• Shoulder inflammatory diseases: Arthritis, rotator cuff injury, bicipital tendonitis
  
• Atherosclerotic or thromboembolic disease
  

TREATMENT

• Heparinization if signs of arterial or venous thrombosis
  
• Vascular surgery consult for signs of ischemia and for catheter-directed thrombolysis if needed:
  
  • Anticoagulation and thrombolysis followed by surgical decompression is required for thrombosis
    
• Initial management:
  
  • The majority improve with conservative treatment consisting of physical therapy and medications for symptomatic relief.
    
• Surgery reserved for failure of medical therapy:
  
  • Often required for vascular forms
    
  • People with NTOS often undergo more extensive evaluation and medical management prior to surgical intervention
    
  • 70–90% of patients experience some to complete relief postoperatively.
    

• Cyclobenzaprine: 10 mg PO TID
  
• Diazepam: 5 mg PO TID
  
• Ibuprofen: 800 mg PO TID
  
• Methocarbamol: 1,000–1,500 mg PO TID
  
• Soothing liniments or ointments
  

FOLLOW-UP

• Ischemia
  
• Venous thrombosis
  
• Arterial thrombosis
  
• Arterial aneurysm or stenosis
  
• Intractable pain
  

• Nonlimb-threatening neurologic findings
  
• Absence of arterial or venous thrombosis
  

Vascular, neurologic, or orthopedic consultation is indicated according to the pathologic condition.

• 3 types of TOS: Neurogenic, arterial, and venous:
  
  • Neurogenic is most common in adults.
    
  • ATOS and VTOS are the more common types in children and adolescents.
    
• VTOS is the only type that has arm swelling and edema.
  
• Both NTOS and ATOS have hand coldness and pallor, but for different reasons.
  
• May have a history of repetitive use or trauma
  
• Exam or imaging may reveal a congenital abnormality such as a cervical rib.