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Diagnosing Upper Extremity Pain Syndromes
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Posted on: 10/26/2015
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Upper extremity pain can neurologic, musculoskeletal, vascular or related to other causes such as tumors or infection. The two most common causes of pain in based on these four categories are neurologic and musculoskeletal. Neurologic pain of the upper extremity can result from pathology of the cervical spine, peripheral nerve compression or neuropathy. Musculoskeletal pain results from pathology affecting the bones and muscles of the shoulder, elbow, wrist and hand.
Cervical spine pathology can be due to degenerative changes, which may include bone spurs, disc herniation, and ligament changes, that lead to impingement of the nerves within the spine. The symptoms that result include referred pain, radiculopathy, and cervical myelopathy. Referred pain results from irritation of the nerve innervating a disc at the spinal segment that causes pain, which is then referred to the head and neck, but rarely extends beyond the shoulder. Cervical radiculopathy is compression of a nerve root at the spinal level that results in pain, paresthesia, sensory changes, weakness or loss of reflexes along the upper extremity following the path of the affected nerve root. Radiculopathy can affect just one or both sides and can involve more than one level. A common description of cervical radiculopathy includes radiating severe arm pain that is relieved when placing the hand on top of the head. Clinically the individual will present with a positive Spurling test, decreased pain with cervical distraction, decreased range of motion to the same side as pain, and pain with an upper limb tension test. Cervical myelopathy results from compression of the cervical spinal cord. Clinical presentation includes progressive neurologic functional loss, such as loss of coordination, that can be with or without pain. Patients will describe difficulty with use of their hands due to spasticity or weakness and can present with atrophy of hand muscles.
Peripheral nerve conditions affecting the upper extremity involve one or more of the three major nerves, the median, ulnar and radial nerve, that are vulnerable to compression at multiple points along their course. Carpal tunnel syndrome, which involves compression of the median nerve at the wrist under the carpal ligament, is the most common peripheral neuropathy. Symptoms include report of parathesia and diminished sensation at the radial three and a half fingers and waking with pain at night. The median nerve can also be compressed under other upper extremity structures such as pronator muscles, but this compression does not reproduce the night pain common with carpal tunnel. There are some clinical tests, such as Tinnels and Phalens to assist in diagnosis, but EMG testing is the gold standard and cortisone injection is often used to confirm.
Other peripheral nerve conditions include anterior interosseous nerve syndrome, Parsonage-Turner syndrome, cubital tunnel syndrome, ulnar tunnel syndrome, radial neuropathy, and thoracic outlet syndrome. Anterior interosseous nerve syndrome results in no sensory loss but does present with weakness of the thumb and index finger flexors. Parsonal Turner syndrome is similar to anterior interosseous nerve syndrome but is often preceded by a viral illness. Patients report a sudden and severe shoulder pain that radiates and may last for weeks. As the pain dissipates, flaccid paralysis, fatigue, muscle atrophy and weakness is common. Cubital tunnel syndrome is caused by ulnar nerve compression at the elbow. It results in parathesia and diminished sensation in the ulnar one and a half fingers and report of medial elbow pain. In severe cases intrinsic hand muscle weakness and clawing of the ring and pinky finger may result. Nerve conduction velocity testing will show delayed conduction across the elbow joint and loss of innervation to some of the muscles within the hand. Ulnar tunnel syndrome results often due to trauma that causes compression of the ulnar nerve as it passes through the wrist. Symptoms present in the palm and ulnar one and a half fingers, and nerve conduction velocity is slowed across the wrist joint.
Radial neuropathy can occur at any of three sites, above the elbow, at the elbow and at the end of the forearm. It can be associated with trauma and lead to varying finger, thumb and wrist dysfunction, depending on where the nerve is affected. If the nerve is compressed above the elbow, the patient will lose finger, wrist and thumb extension. When compressed at the elbow, the injury is termed PIN syndrome as the nerve compression takes place at the posterior interosseous nerve, PIN. Typically symptoms are weakness with thumb extension, wrist extension that occurs with radial deviation, and weakness of finger extension at the interphalangeal joint. This can be differentiated from radial tunnel syndrome as there is typically pain with radial tunnel syndrome but not with PIN syndrome. When the nerve is compressed in the distal forearm it affects the superficial radial nerve, SRN, and is called Wartenburg Syndrome. It causes pain and paresthesia on the back of the forearm, thumb, index and middle fingers.
Thoracic Outlet Syndrome, TOS, is compression of the bundle of nerves, the brachial plexus, that passes through the scalene muscles, collar bone and first rib. It can be either vascular or neurogenic. Vascular TOS is confirmed with clinical testing, and signs such as swelling, cyanosis and claudication. Neurogenic TOS causes weakness, muscle atrophy and sensory deficits. As there is no gold standard criteria for diagnosing TOS, it is typically diagnosed based on clinical findings.
Aside from compressive peripheral nerve injuries, there are also noncompressive injuries to peripheral nerves in the upper extremity that may include metabolic, infectious or genetic disorders. Neuropathy can affect a single or multiple nerves and can result in pain, paresthesias, loss of sensation, and weakness in the upper extremity. Upon physical examination a stocking and glove distribution of the neurologic symptoms is common.
Musculoskeletal injuries of the upper extremity involve both the shoulder and the elbow. Injury can be due to trauma such as direct falls, inflammatory or arthritic conditions, of movements that irritate the joint. The shoulder joints that may be affected include the acromioclavicular and sternoclavicular joints at either end of the clavicle, the glenohumeral joint which is the ball and socket shoulder joint, or the scapulothoracic joint where the shoulder blade articulates with the thoracic spine. Symptoms may include tenderness to touch, pain with movement, swelling and feeling of weakness or instability. There are many pathologies that can affect these joints including tendinitis, joint dislocation, tendon or ligament tears, arthritis, bone fracture, and instability. Clinical tests to diagnose will include testing range of motion, strength and provocative orthopedic tests designed to assess a specific structure. Particularly in the case of the scapulothoracic joint, assessment of movement is also important as scapular dyskinesia is fairly common and can often overlap with cervical referred pain syndromes. In general musculoskeletal pain syndromes of the shoulder joint are reproduced with movement whereas neurologic pain is not. Diagnostic cortisone injections, X-rays and MRI tests are common to further diagnose upper extremity musculoskeletal conditions.
At the elbow joint, the three main causes of musculoskeletal pain are lateral and medial epicondylitis and elbow osteoarthritis. Lateral epicondylitis involves small tears where the extensor carpi radialis muscle meets the outer aspect of the elbow. Medial epicondylitis results from small tears where the flexor carpi ulnaris and pronator meet the inner aspect of the elbow. Both are results of repetitive overuse that causes inflammation and sometimes degenerative changes. Symptoms typically include pain with movement and to palpate. Elbow osteoarthritis is a loss of cartilage within the elbow joint and can result in pain and loss of motion at the end ranges of elbow flexion and extension. In some cases, patients complain of catching and locking.
It is important to acknowledge the differential diagnosis of upper extremity pain as symptoms often overlap. Clinical findings, diagnostic tests and a thorough understanding of musculoskeletal, neurologic and vascular conditions is important.
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References:
Ponnappan RK et al. Clinical Differentiation of Upper Extremity Pain Etiologies. In the Journal of the American Academy of Orthopaedic Surgeons. Vol 23. No 8. Pp 492-500.
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*Disclaimer:*The information contained herein is compiled from a variety of sources. It may not be complete or timely. It does not cover all diseases, physical conditions, ailments or treatments. The information should NOT be used in place of visit with your healthcare provider, nor should you disregard the advice of your health care provider because of any information you read in this topic. |
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