Parsonage-Turner syndrome (PTS) is a rare syndrome of unknown cause, affecting mainly the lower motor neurons of the brachial plexus. The brachial plexus is a group of nerves that conduct signals from the spine to the shoulder, arm, and hand. PTS is usually characterized by the sudden onset of severe one-sided shoulder pain , followed by paralysis of the shoulder and lack of muscle control in the arm, wrist, or hand several days later. The syndrome can vary greatly in presentation and nerve involvement.
PTS, also known as brachial plexus neuritis or neuralgic amyotrophy, is a common condition characterized by inflammation of a network of nerves that control and supply (innervate) the muscles of the chest, shoulders, and arms. Individuals with the condition first experience severe pain across the shoulder and upper arm. Within a few hours or days, weakness, wasting (atrophy), and paralysis may affect the muscles of the shoulder. Although individuals with the condition may experience paralysis of the affected areas for months or, in some cases, years, recovery is usually eventually complete.
Local pain around the shoulder girdle is the prevalent symptom of Parsonage-Turner syndrome. It is usually sudden and often severe, often awakening persons during the night. The pain worsens progressively for up to two days. Described as a constant, severe ache associated with tenderness of the muscles, the pain is not affected by coughing. However, it is accentuated by arm movements and muscular pressure, but almost unaltered by movements of the neck. The pain is commonly distributed across the back of the scapula (shoulder blade) and the tip of the shoulder. Pain often radiates down the outer side of the arm and up along the neck, and seldom spreads down as far as the outer side of the forearm, below the elbow. There is no exact correlation between the localization of the pain and the distribution of the subsequent muscle paralysis.
However, in general, pain radiating below the elbow is associated with involvement of the biceps or triceps, and radiation into the neck involves the sternocleidomastoid and trapezius muscles. Usually the severe pain lasts from a few hours to three weeks and then disappears rather suddenly; at the same time, muscular wasting and weakness are occurring. A less severe pain may persist considerably longer.
As the pain subsides, paralysis of some muscles of the shoulder girdle, and often of the arm, develops. Usually, muscle weakness appears suddenly, but sometimes gradually increases over two or three days, or up to one week in rare cases. The paralysis involves limpness and rapid wasting of the affected muscles. Tendon reflexes might be affected, depending on the severity and extent of muscular paralysis and wasting. Weakened reflexes are frequently encountered, and fasciculations (fine tremors ) occasionally occur.
In the United States, the incidence is approximately 1.64 cases per 100,000 people per year. Internationally, PTS has been described in many countries around the world, although specific rates of incidence have not been reported. There is a male predominance in PTS with a male-to-female ratio ranging from 2:1–4:1. Individuals as young as three months or as old as 74 years can be affected with PTS; however, the prevalence is highest in young to middle-aged adults. When a child develops Parsonage-Turner syndrome, hereditary PTS should be considered.
Causes and symptoms
The exact cause of PTS is unknown, but the condition has been linked to many previous events or illnesses such as:
- viral infection (particularly of the upper respiratory tract)
- bacterial infection (e.g., pneumonia, diphtheria, typhoid)
- parasitic infestation
- trauma (not related to shoulder)
- vaccinations (e.g., influenza, tetanus, diphtheria, tetanus toxoids, pertussis, smallpox, swine flu)
- miscellaneous medical investigative procedures (e.g., lumbar puncture, administration of radiologic dye)
- systemic illness (e.g., polyarteritis nodosa, lymphoma, systemic lupus erythematosus, temporal arteritis , Ehlers-Danlos syndrome)
In addition to these possible causes, a rare hereditary form of PTS has been localized to a defect on chromosome 17, and should be considered a distinct disorder. This form of the disorder occurs in a younger age group, affects males and females equally (autosomal-dominant inheritance), and is characterized by recurrent attacks that often cause pain on both sides of the body.
Acute pain in the shoulder girdle or arm is almost always the first symptom. Shortly thereafter, muscle weakness and wasting in the shoulder girdle and arm occur. The pain, which may be extraordinarily severe for a short time, eventually abates.
PTS is a clinical syndrome, and therefore diagnosis is made by exclusion. Other disorders of the upper extremity or cervical spine have to be excluded, including abnormalities of the rotator cuff, acute calcific tendinitis, adhesive capsulitis, cervical radiculopathy , peripheral nerve compression , acute poliomyelitis , and amyotrophic lateral sclerosis (ALS). PTS may sometimes be confused with peripheral nerve compression or traction injury of the brachial plexus. Affected persons, however, do not experience the acute intense pain associated with PTS, and the loss of strength occurs simultaneously with the sensory changes.
In PTS, x rays of the cervical spine and shoulder show normal findings compatible with the patient's age. Nerve conduction studies and electromyography (EMG) are helpful in localizing the lesion. Three to four weeks after the onset of pain, EMG studies show changes consistent with PTS. Arthrography or ultrasound may be useful to rule out a tear of the rotator cuff. MRI may reveal muscles changes associated with PTS.
A specialist in neuromuscular disease may be consulted to confirm diagnosis and evaluate any potentially underlying causes. An orthopedic surgeon is important when nerve grafting or tendon transfer is necessary. Physical and occupational therapists may be asked to provide a comprehensive rehabilitation program.
No specific treatment has yet been proved efficient in PTS. In the early stages, pain may require treatment. Common analgesic drugs are usually sufficient. Usually, steroidal medications do not relieve the pain or improve muscle function in PTS. Rest is recommended, and immobilization of the affected upper extremity may be helpful in relieving the pain and in preventing stretching of the affected muscles.
As pain subsides, physical therapy is recommended. Passive range of motion exercises of the shoulder and elbow are suggested to maintain full range of motion.
Surgical stabilization of the scapula to the thorax, or tendon transfers have been performed with benefit in persons with PTS who experience continuing pain and muscle weakness.
Recovery and rehabilitation
Physical therapy should focus on the maintenance of full range of motion (ROM) in the shoulder and other affected joints. Passive range of motion (PROM) and active range of motion (AROM) exercises should begin as soon as the pain has been controlled adequately, followed by regional conditioning of the affected areas. Strengthening of the rotator cuff muscles and scapular stabilization may be indicated. Passive modalities (e.g., heat, cold, transcutaneous electrical nerve stimulation) may be useful as adjunct pain relievers.
Another type of rehabilitation therapy in PTS is occupational therapy. Functional conditioning of the upper extremity may be helpful. Assistive devices and orthotics (such as splints or devices for grasping and reaching) may be used, depending on the particular disabilities present.
As of mid-2004, there were no ongoing clinical trials specific for PTS.
The overall prognosis for persons with PTS is good, as recovery of strength and sensation usually begins spontaneously as early as one month after the onset of symptoms. Almost 75% of persons with PTS experience complete recovery within two years. However, the period of time for complete recovery is variable, ranging from six months to five years. It seems that the delay in recovering strength depends on the severity and duration of pain, weakness, or both. Furthermore, patients with involvement of upper trunk lesions have the most rapid recovery. Although not very common, relapse might occur within a few months to several years after full recovery. In general, complete restoration of normal strength and function usually occurs within five years.
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American Autoimmune Related Diseases Association. 22100 Gratiot Avenue, Eastpointe, MI 48021. (586) 776-3900. [email protected] <http://www.aarda.org/>.
NIH/National Arthritis and Musculoskeletal and Skin Diseases Information Clearinghouse. 1 AMS Circle, Bethesda, MD 20892-3675. (301) 495-4484 or (877) 226-4267. [email protected] <http://www.niams.nih.gov>.
Greiciane Gaburro Paneto
Iuri Drumond Louro