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thoracic outlet syndrome

Symptoms produced by obstruction of the neurovascular bundle (subclavian artery, subclavian vein, lower trunk of the brachial plexus) as it enters the axilla. Etiology: 1) true neurogenic thoracic outlet syndrome - compression of the lower trunk of the brachial plexus by an anomalous band of connective tissue connecting an elongated transverse process of C7 with the 1st rib 2) arterial thoracic outlet syndrome a) aneurysm of the subclavian artery b) compression of the subclavian artery: - anomalous cervical rib - tumor (especially Pancoast tumor) 3) venous thoracic outlet syndrome - compression of the subclavian vein within the costoclavicular junction as it passes anterior to the anterior scalene muscle - most common in young, active men affecting dominant upper extremity 4) sagging musculature related to aging, obesity, or heavy breasts Clinical manifestations: 1) pain & paresthesias when using the arms, especially when working in certain positions, especially overhead 2) pain in & around in shoulders, in the supraclavicular region or between the shoulders 3) may be palpable abnormality above the clavicle 4) signs referable to the lower part of the brachial plexus a) weakness of the intrinsic muscles of the hand (late manifestation) b) diminished sensation on the palmar aspect of the 4th & 5th digits 5) unilateral Raynaud's phenomenon 6) trophic changes in the fingers 7) sensory loss over the ulnar side of the hand 8) interosseous atrophy may be present 9) sensation of swelling in the arms 10) forearm & hand pain 11) no dizziness 12) arterial arterial thoracic outlet syndrome - Adson's sign - coolness, pallor - arm or hand may be exertional - brachial blood pressure differences between arms - bruit may be heard over affected subclavian artery 13) venous thoracic outlet syndrome - upper extremity edema - upper extremity pain, shoulder pain, chest pain - cyanosis may be present Laboratory: 1) complete blood count 2) erythrocyte sedimentation rate 3) general chemistries - serum Ca+2, serum albumin 4) thyroid function testing 5) antinuclear antibodies 6) rheumatoid factor Special laboratory: 1) electromyography is helpful [2] 2) nerve conduction studies are helpful [2] Radiology: 1) chest X-ray 2) cervical spine films may show cervical rib or elongated transverse process of C7 3) aortic arch arteriogram 4) venogram 5) ultrasound 6) magnetic resonance imaging, magnetic resonance angiography Differential diagnosis: 1) Pancoast tumor 2) subclavian steal 3) impingement of a cervical nerve (cervical radiculopathy) 3) cervical cord tumor 4) brachial plexus paralysis 5) carpal tunnel syndrome 6) hypothyroidism 7) peripheral neuropathy 8) syringomyelia 9) progressive muscle atrophy 10) reflex sympathetic dystrophy 12) thrombophlebitis 13) upper extremity peripheral arterial disease 14) giant cell arteritis - elevated ESR, transient monocular vision loss, fatigue - new-onset arm claudication - symptoms of polymyalgia rheumatica Management: 1) conservative management a) unless pain severe or critical features b) physical therapy - exercises to strengthen muscles around thoracic outlet c) occupational therapy - ergonomics of proper sitting, work, sleeping positions 2) surgery a) < 5% of patients require surgical treatment b) indications: - muscle wasting - persistent sensory loss, - unacceptable pain - progressive arterial or venous insufficiency c) excellent outcomes after surgical intervention [5]

Related

Adson's sign (test) Pancoast tumor (superior pulmonary sulcus tumor) superior vena cava (SVC) syndrome

Specific

cervical rib syndrome scalenus anticus syndrome

General

plexopathy syndrome

References

  1. Medical Knowledge Self Assessment Program (MKSAP) 11, 18, 19. American College of Physicians, Philadelphia 1998, 2018, 2021.
  2. Harrison's Principles of Internal Medicine, 13th ed. Isselbacher et al (eds), McGraw-Hill Inc. NY, 1994, pg 79
  3. Harrison's Principles of Internal Medicine, 14th ed. Fauci et al (eds), McGraw-Hill Inc. NY, 1998, pg 81
  4. UpToDate Online version 15.1 http://www.utdol.com
  5. Orlando MS et al. A decade of excellent outcomes after surgical intervention in 538 patients with thoracic outlet syndrome. J Am Coll Surg 2015 May; 220:934 PMID: 25840533
  6. Kuhn JE, Lebus V GF, Bible JE. Thoracic outlet syndrome J Am Acad Orthop Surg. 2015 Apr;23(4):222-32 PMID: 25808686
  7. NINDS Thoracic Outlet Syndrome Information Page https://www.ninds.nih.gov/disorders/all-disorders/thoracic-outlet-syndrome-information-page