Updated: 11/5/2019

Thoracic Outlet Syndrome (TOS)

0%
Topic
Review Topic
0
0
N/A
N/A
Questions
1 1
0
0
https://upload.medbullets.com/topic/112011/images/04052018.1vldstep1mskthoracicoutletanatomy.jpg
Snapshot
  • A 25-year-old woman with no history of trauma presents with right arm pain. She reports that her right arm is easily fatigable, especially after she cooks. She is a chef and denies any history of smoking, hyperlipidemia, or peripheral artery disease. On physical exam, her right upper extremity is pale and cool to the touch. Her distal right radial pulse is diminished compared to her left. Radiography reveals a cervical rib.
Introduction
  • Clinical definition
    • syndrome resulting from compression/obstruction of the lower trunk of the brachial plexus and subclavian vessels as it passes through the thoracic outlet 
      • the thoracic outlet is above the first rib and behind the clavicle
      • classified into three types
        • neurogenic (compression of brachial plexus)
        • arterial (obstruction in arteries)
        • venous (obstruction in veins)
  • Epidemiology
    • demographics
      • adults
  • Etiology
    • bony
      • cervical rib 
        • an extra rib arising from 7th cervical vertebra
      • rudimentary first rib
    • soft tissue
      • fibrous band from the first rib to the tip of C7 transverse process
      • hypertrophy of nearby muscles (e.g., sternocleidomastoid or scalene muscle)
        • more commonly in weightlifters or athletes
      • Pancoast tumor causing compression
      • cysts
    • trauma
  • Pathogenesis
    • compression of brachial plexus can cause neuropathies
    • compression of subclavian vein or artery can cause pain and edema
Presentation
  • Symptoms
    • neurogenic
      • difficulty grasping or gripping
      • numbness and tingling in ulnar distribution
      • pain or weakness with elevation or repetitive use of the affected arm
    • arterial
      • claudication
      • diffuse arm and hand pain
      • fatigue and ache, especially after exertion of muscle
    • venous
      • upper extremity swelling
      • diffuse arm or hand pain
  • Physical exam
    • careful neurovascular exam should be performed
    • neurogenic
      • atrophy of intrinsic hand muscles
      • decreased sensation in ulnar nerve distribution
      • reproducible pain with elevation of arms
    • arterial
      • pallor and cool upper extremities
      • weak or absent radial or ulnar pulse
      • may have decreased blood pressure in the affected arm
    • venous
      • edema
      • cyanosis of upper extremity
      • distended veins
Imaging
  • Radiographs
    • indication
      • may reveal bony abnormalities
    • findings
      • cervical or rudimentary first rib
      • Pancoast tumor
  • Magnetic resonance imaging (MRI)
    • indication
      • may reveal soft tissue abnormalities
  • Ultrasound
    • indication
      • if vascular TOS is suspected
    • finding
      • vascular compression
  • Angiography
    • indication
      • if vascular TOS is suspected but ultrasound is unrevealing or further clarification is needed
    • finding
      • compression
Studies
  • Making the diagnosis
    • most cases are clinically diagnosed
Differential
  • Other causes of vascular compromise, such as emboli
    • distinguishing factor
      • pain worsened with exertion of the affected muscle and relieved with rest
Treatment
  • Conservative
    • physical therapy
      • indication
        • for all patients
  • Medical
    • nonsteroidal anti-inflammatory drugs (NSAIDs)
      • indication
        • pain management
    • anticoagulation       
      • indication
        • patients with suspected thrombosis causing compression
  • Operative
    • surgical decompression
      • indications
        • patients with fibrous band
        • patients with cervical rib
        • pain refractory to conservative management
Complications
  • Aneurysm formation (post-stenotic)
  • Thromboembolism
 

Please rate topic.

Average 5.0 of 4 Ratings

Questions (1)
Lab Values
Blood, Plasma, Serum Reference Range
ALT 8-20 U/L
Amylase, serum 25-125 U/L
AST 8-20 U/L
Bilirubin, serum (adult) Total // Direct 0.1-1.0 mg/dL // 0.0-0.3 mg/dL
Calcium, serum (Ca2+) 8.4-10.2 mg/dL
Cholesterol, serum Rec: < 200 mg/dL
Cortisol, serum 0800 h: 5-23 μg/dL //1600 h:
3-15 μg/dL
2000 h: ≤ 50% of 0800 h
Creatine kinase, serum Male: 25-90 U/L
Female: 10-70 U/L
Creatinine, serum 0.6-1.2 mg/dL
Electrolytes, serum  
Sodium (Na+) 136-145 mEq/L
Chloride (Cl-) 95-105 mEq/L
Potassium (K+) 3.5-5.0 mEq/L
Bicarbonate (HCO3-) 22-28 mEq/L
Magnesium (Mg2+) 1.5-2.0 mEq/L
Estriol, total, serum (in pregnancy)  
24-28 wks // 32-36 wks 30-170 ng/mL // 60-280 ng/mL
28-32 wk // 36-40 wks 40-220 ng/mL // 80-350 ng/mL
Ferritin, serum Male: 15-200 ng/mL
Female: 12-150 ng/mL
Follicle-stimulating hormone, serum/plasma Male: 4-25 mIU/mL
Female: premenopause: 4-30 mIU/mL
midcycle peak: 10-90 mIU/mL
postmenopause: 40-250
pH 7.35-7.45
PCO2 33-45 mmHg
PO2 75-105 mmHg
Glucose, serum Fasting: 70-110 mg/dL
2-h postprandial:<120 mg/dL
Growth hormone - arginine stimulation Fasting: <5 ng/mL
Provocative stimuli: > 7ng/mL
Immunoglobulins, serum  
IgA 76-390 mg/dL
IgE 0-380 IU/mL
IgG 650-1500 mg/dL
IgM 40-345 mg/dL
Iron 50-170 μg/dL
Lactate dehydrogenase, serum 45-90 U/L
Luteinizing hormone, serum/plasma Male: 6-23 mIU/mL
Female: follicular phase: 5-30 mIU/mL
midcycle: 75-150 mIU/mL
postmenopause 30-200 mIU/mL
Osmolality, serum 275-295 mOsmol/kd H2O
Parathyroid hormone, serume, N-terminal 230-630 pg/mL
Phosphatase (alkaline), serum (p-NPP at 30° C) 20-70 U/L
Phosphorus (inorganic), serum 3.0-4.5 mg/dL
Prolactin, serum (hPRL) < 20 ng/mL
Proteins, serum  
Total (recumbent) 6.0-7.8 g/dL
Albumin 3.5-5.5 g/dL
Globulin 2.3-3.5 g/dL
Thyroid-stimulating hormone, serum or plasma .5-5.0 μU/mL
Thyroidal iodine (123I) uptake 8%-30% of administered dose/24h
Thyroxine (T4), serum 5-12 μg/dL
Triglycerides, serum 35-160 mg/dL
Triiodothyronine (T3), serum (RIA) 115-190 ng/dL
Triiodothyronine (T3) resin uptake 25%-35%
Urea nitrogen, serum 7-18 mg/dL
Uric acid, serum 3.0-8.2 mg/dL
Hematologic Reference Range
Bleeding time 2-7 minutes
Erythrocyte count Male: 4.3-5.9 million/mm3
Female: 3.5-5.5 million mm3
Erythrocyte sedimentation rate (Westergren) Male: 0-15 mm/h
Female: 0-20 mm/h
Hematocrit Male: 41%-53%
Female: 36%-46%
Hemoglobin A1c ≤ 6 %
Hemoglobin, blood Male: 13.5-17.5 g/dL
Female: 12.0-16.0 g/dL
Hemoglobin, plasma 1-4 mg/dL
Leukocyte count and differential  
Leukocyte count 4,500-11,000/mm3
Segmented neutrophils 54%-62%
Bands 3%-5%
Eosinophils 1%-3%
Basophils 0%-0.75%
Lymphocytes 25%-33%
Monocytes 3%-7%
Mean corpuscular hemoglobin 25.4-34.6 pg/cell
Mean corpuscular hemoglobin concentration 31%-36% Hb/cell
Mean corpuscular volume 80-100 μm3
Partial thromboplastin time (activated) 25-40 seconds
Platelet count 150,000-400,000/mm3
Prothrombin time 11-15 seconds
Reticulocyte count 0.5%-1.5% of red cells
Thrombin time < 2 seconds deviation from control
Volume  
Plasma Male: 25-43 mL/kg
Female: 28-45 mL/kg
Red cell Male: 20-36 mL/kg
Female: 19-31 mL/kg
Cerebrospinal Fluid Reference Range
Cell count 0-5/mm3
Chloride 118-132 mEq/L
Gamma globulin 3%-12% total proteins
Glucose 40-70 mg/dL
Pressure 70-180 mm H2O
Proteins, total < 40 mg/dL
Sweat Reference Range
Chloride 0-35 mmol/L
Urine  
Calcium 100-300 mg/24 h
Chloride Varies with intake
Creatinine clearance Male: 97-137 mL/min
Female: 88-128 mL/min
Estriol, total (in pregnancy)  
30 wks 6-18 mg/24 h
35 wks 9-28 mg/24 h
40 wks 13-42 mg/24 h
17-Hydroxycorticosteroids Male: 3.0-10.0 mg/24 h
Female: 2.0-8.0 mg/24 h
17-Ketosteroids, total Male: 8-20 mg/24 h
Female: 6-15 mg/24 h
Osmolality 50-1400 mOsmol/kg H2O
Oxalate 8-40 μg/mL
Potassium Varies with diet
Proteins, total < 150 mg/24 h
Sodium Varies with diet
Uric acid Varies with diet
Body Mass Index (BMI) Adult: 19-25 kg/m2
Calculator

Question locked
Sorry, this question is for
PEAK Premium Subscribers only
Upgrade to PEAK
Topic COMMENTS (2)
Private Note