Differential Diagnoses for Chronic Shoulder Pain Radiating to the Arm Without Trauma

Primary Differential Diagnoses

Chronic shoulder pain radiating down the arm without trauma strongly suggests cervical spine pathology with nerve root compression, characterized by numbness, tingling, weakness, or radiation of pain down the arm, which are hallmark symptoms of cervical radiculopathy 1
In patients over 35-40 years, rotator cuff disease and degenerative changes are predominant causes of chronic shoulder pain, with anterior shoulder pain specifically suggesting rotator cuff or biceps tendon pathology 1, 2
Most rotator cuff pathology can initially be managed conservatively without surgical intervention, with a focus on rehabilitation and pain management 2

The American College of Physicians recommends documenting exact pain location and radiation pattern to distinguish shoulder pathology from cervical radiculopathy, and assessing for neurological symptoms such as numbness, tingling, weakness in specific dermatomal distributions 1
The American Academy of Neurology suggests testing for regional sensory changes, allodynia, or hyperpathia suggesting neuropathic pain component, and evaluating shoulder range of motion, strength, and impingement signs 3, 4

If cervical radiculopathy is confirmed, the American Academy of Neurology recommends continuing pregabalin as it may provide therapeutic benefit for neuropathic pain, with a typical adult pregabalin regimen of 300-600 mg daily in divided doses 5, 6
If rotator cuff pathology is confirmed, the American College of Sports Medicine recommends referring to a rehabilitation specialist for comprehensive management, with most rotator cuff pathology being managed conservatively initially 2, 4
If neuropathic pain features are present, the American Pain Society suggests prescribing nerve-stabilizing agents such as pregabalin, gabapentin, or duloxetine for pain management, with consideration of botulinum toxin type A injections into affected muscles for cervical dystonia or muscle spasms 4

The American College of Radiology recommends starting with cervical spine imaging if the clinical examination supports radiculopathy, and considering electrodiagnostic testing if imaging is negative or equivocal, with a sensitivity of over 80% and specificity of 95% for confirming nerve compression and localizing the level 7

Shoulder MRI is recommended only if physical examination suggests concurrent rotator cuff pathology, as stated by the Journal of the American College of Radiology 7

The American College of Radiology suggests that cervical radiculopathy most commonly results from herniated discs or osteophytes causing nerve root compression, leading to neuropathic pain radiating from the neck into the shoulder and arm 8, 9
Documenting the exact radiation pattern of pain is crucial to determine if it follows a specific cervical nerve root distribution (C5, C6, C7, or C8) 8
MRI of the 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 8, 9
Plain radiographs of the cervical spine may be obtained first to assess for gross structural abnormalities, degenerative changes, or alignment issues, though they cannot visualize disc herniations or nerve roots 8, 9

The American College of Radiology recommends that if cervical radiculopathy is suspected, one should not assume it is simply "muscle tension" or "muscle spasm" without ruling out structural cervical spine pathology, and imaging should not be delayed if red flags are present 8, 9