A 28-year-old woman comes to the office due to right shoulder pain and weakness. The patient recently returned from a 2-week hike in the Appalachian Mountains and began noticing the symptoms during the trip. She has had no falls or trauma. The patient has no prior medical conditions and takes no medications. Vital signs are within normal limits. Physical examination reveals weakness of right shoulder abduction and external rotation. Passive range of motion is full. Right upper extremity sensation and deep tendon reflexes are normal. The remainder of the physical examination shows no abnormalities. Which of the following is the most likely cause of this patient's current symptoms?

Question

A 28-year-old woman comes to the office due to right shoulder pain and weakness.  The patient recently returned from a 2-week hike in the Appalachian Mountains and began noticing the symptoms during the trip.  She has had no falls or trauma.  The patient has no prior medical conditions and takes no medications.  Vital signs are within normal limits.  Physical examination reveals weakness of right shoulder abduction and external rotation.  Passive range of motion is full.  Right upper extremity sensation and deep tendon reflexes are normal.  The remainder of the physical examination shows no abnormalities.  Which of the following is the most likely cause of this patient's current symptoms?

Quizplus · Accepted Answer

Explanation: 11ec25c8_d231_35ec_bc81_f73aa6609a1a_MD0003_00 This patient most likely has suprascapular nerve entrapment (SNE). The suprascapular nerve provides motor supply to the supraspinatus and infraspinatus muscles. It originates from the brachial plexus and traverses the suprascapular notch below the superior transverse scapular ligament (which effectively transforms the notch into a foramen). Therefore, SNE can develop due to external compression of the nerve at the suprascapular notch, such as from excessive use of a heavy backpack when hiking or commuting; other causes include a direct blow to the nerve (eg, from a fall) or repetitive motion at the shoulder (eg, weight lifting, baseball). Clinical features suggestive of SNE at the suprascapular notch include: shoulder pain weakness of shoulder abduction (supraspinatus muscle) weakness of external rotation (infraspinatus muscle) Passive range of motion is preserved. Examination may show tenderness at the suprascapular notch. Cross-body adduction of the humerus, which abducts the scapula, may reproduce pain along the top of the scapula. In advanced cases, sensory deficits and atrophy of the supraspinatus and infraspinatus muscles may be seen. Initial management includes nonsteroidal anti-inflammatory drugs and activity modification (eg, avoiding the use of backpacks). (Choice A) Acromioclavicular sprain is usually caused acutely by a fall or direct blow to the shoulder. As in SNE, pain may be exacerbated by cross-body adduction of the arm; however, weakness of shoulder abduction is not seen. (Choice B) Biceps tendinopathy presents with anterior shoulder pain radiating to the upper arm. Although the long head of the biceps crosses the glenohumeral joint and rupture may cause partial weakness of shoulder flexion, abduction is not generally affected. Also, this injury is typically associated with a noticeable bulge in the anterior arm. (Choice C) Borrelia burgdorferi infection (ie, Lyme disease) can cause a variety of neuropathic syndromes in the early disseminated phase. However, isolated acute mononeuropathy is a rare presentation, and this patient has no other findings (eg, history of erythema migrans, fever, headache) to suggest Lyme disease. (Choice D) Compression of the C5 and/or C6 nerve roots can present with shoulder pain and weakness of abduction but would typically also cause dermatomal numbness, paresthesia, and diminished biceps and brachioradialis reflexes. Educational objective: Suprascapular nerve entrapment presents with shoulder pain and weakness of shoulder abduction and external rotation. It can be caused by external compression of the nerve at the suprascapular notch (eg, use of a heavy backpack), a direct blow, or repetitive motion at the shoulder. References: Suprascapular nerve injury: a cause to consider in shoulder pain and dysfunction. (http://www.ncbi.nlm.nih.gov/pubmed/27197708)

A 28-Year-Old Woman Comes to the Office Due to Right