Parsonage-Turner Syndrome

Authors:
Tyler Drewry, MD, and Hillary Mount, MD
The Christ Hospital/University of Cincinnati Family Medicine Residency Program, Cincinnati, Ohio

Citation:
Drewry T, Mount H. Parsonage-Turner syndrome. Consultant. 2018;58(3):126.

A 29-year-old man presented to the emergency department after having awakened that morning with complete paralysis of his right arm. He was HIV-positive and had a history of attention-deficit/hyperactivity disorder, depression, substance use, and anal carcinoma now in remission. He reported having gone to sleep the previous night with no weakness in his right arm, although he did state that he had slept in an unusual position. Upon awakening, he was unable to move his right arm from the shoulder to the fingertips, and he noticed a painful tingling sensation throughout the arm.

History. The patient stated that he had a normal CD4 lymphocyte count and that his only medications were sertraline and a fixed-dose combination of abacavir, dolutegravir, and lamivudine. He denied any history of recent trauma, recent substance use, stroke, neurologic disorders, chest pain, dyspnea, fever, chills, nausea, vomiting, visual disturbances, syncopal episodes, or loss of bowel or bladder function.

Physical examination. The patient had mild tachycardia to 111 beats/min. He demonstrated flaccid paralysis of the right biceps, triceps, deltoid, and wrist extensors and flexors, retaining only trapezius and levator scapulae function. He had normal radial pulses and normal sensation throughout his right upper extremity, but with decreased biceps and brachioradialis reflexes. He also had crepitus over the right side of his neck and slight tenderness with palpation of the right chest wall.

NEXT: Diagnostic tests

Diagnostic tests. Laboratory test results on admission showed a leukocytosis of 21,400 white blood cells/µL and a slight elevation of the aspartate aminotransferase level to 77 U/L.

A computed tomography (CT) scan of the head and neck demonstrated no acute intracranial processes, but abnormal air was noted within the deep spaces of the neck, primarily in the retropharyngeal space, the right carotid space, and the right posterior cervical space, extending into the mediastinum (Figure 1). A CT scan of the chest, abdomen, and pelvis demonstrated a pneumomediastinum primarily in the posterior mediastinum, which extended to the level of the gastroesophageal junction. These findings, according to the radiology report, were most likely related to tracheal or esophageal injury.

A consulting gastroenterologist recommended a barium esophagram, the findings of which were normal. An otorhinolaryngologist performed a fiberoptic laryngoscopy, the findings of which also were normal. An infectious disease specialist started the patient on a regimen of empiric piperacillin-tazobactam, along with fluconazole to cover for infection with the concern for a perforated viscus.

Further tests yielded a normal erythrocyte sedimentation rate but an elevated C-reactive protein level of 29.8 mg/L. Blood cultures were negative, and levels of thyrotropin, lactate, total creatine kinase, and aldolase were all normal. The leukocytosis and transaminitis normalized during the course of hospitalization.

A consulting neurologist believed that the patient’s symptoms likely were secondary to a brachial plexopathy from compression of the brachial plexus due to air and recommended magnetic resonance imaging (MRI) of the head and right upper extremity. The head MRI findings were normal, but the right upper extremity scan demonstrated torn distal fibers of the right levator scapulae muscle with some associated edema, possibly the result of trauma or strenuous exercise (Figure 2). There also were edematous changes within some of the small muscles of the neck, which had resulted in mass effect on the trunks of the brachial plexus. The most likely etiology was a pulmonary bleb rupture or occult esophageal rupture.

Based on the patient’s presentation, laboratory test results, and imaging findings, the pneumomediastinum was felt to be a pulmonary bleb rupture or occult esophageal rupture that had sealed quickly. Trauma was suspected as the etiology but never was endorsed by the patient. He received a diagnosis of Parsonage-Turner syndrome.

NEXT: Discussion

Discussion. When encountering patients with unilateral weakness, consider a broad differential diagnosis that includes cerebrovascular accident (CVA), transient ischemic attack, seizure, drug use, metabolic disturbances, and intracranial mass. In a young patient without risk factors for CVA, the differential diagnosis also should include unusual causes such as infectious myositis, unusual trauma, vasculitis, conversion disorder, or Parsonage-Turner syndrome.

Parsonage-Turner syndrome, which is also known as brachial plexopathy, neuralgic amyotrophy, or brachial neuritis, is a rare inflammatory condition of the brachial plexus. The etiology is unknown, but the condition may be the result of an immune-​mediated or infectious process, trauma, exercise, surgery, or vaccination.¹ The primary lesion is axonal loss, which eventually leads to demyelination and conduction block.² Most cases are idiopathic or hereditary.³ The sequence of events leading to a plexopathy and weakness is unclear, but some investigators suggest that an inflammation-related constriction precedes nerve torsion, which is worsened by limb rotation.⁴ The estimated annual incidence ranges from 2 to 100 per 100,000 people, with a male to female ratio of 2 to 1.^5,6 The highest prevalence is among young to middle-aged adults.⁷

The presentation of Parsonage-Turner syndrome is characterized by a sudden onset of unilateral shoulder pain and flaccid paralysis of the shoulder and parascapular muscles within a few days. Up to two-thirds of cases begin during the nighttime.³ The presentation is extremely variable, with some individuals exhibiting mild paralysis, while others demonstrate extensive nerve involvement. Motor nerves seem to be affected more than sensory nerves, which fits with the characteristic clinical presentation.^5,8 Winging of the scapula may be seen, as well as supraspinatus, infraspinatus, and deltoid involvement. Considerable atrophy and wasting may occur.

Treatment is conservative. Pain management consists of nonsteroidal anti-inflammatory drugs or opioids in severe cases. There is considerable variability in prognosis; some studies report good recovery and a return to normal strength, while others report that some residual paralysis may be present as long as 3 years after the injury.^5,8,9 Full recovery may take months to years depending on the severity and number of muscles affected.⁸ Corticosteroids and physical therapy have not been shown to accelerate resolution of symptoms.¹⁰

Recurrence is a concern with Parsonage-Turner syndrome. One study⁵ reported a 26% recurrence rate, with the median time to recurrence just over 2 years, which is higher than in previous reports.⁸

NEXT: Outcome of the case

Outcome of the case. The patient was discharged on a 2-week regimen of corticosteroids and intravenous antibiotics. He had a referral visit with a brachial plexus specialist, at which he was given a sling and instructions for physical therapy to avoid adhesive capsulitis. He had only minimal improvement at a follow-up visit and then was lost to follow-up. 

References:

1. Feinberg J H, Radecki J. Parsonage-Turner syndrome. HSS J. 2010;6(2):​199-205.
2. Ferrante MA, Wilbourn AJ. The utility of various sensory nerve conduction responses in assessing brachial plexopathies. Muscle Nerve. 1995;18(8):​879-889.
3. Ashworth NL. Brachial neuritis. Medscape. https://emedicine.medscape.com/article/315811-overview. Updated January 18, 2017. Accessed February 28, 2018.
4. Arányi Z, Csillik A, Dévay K, et al. Ultrasonographic identification of nerve pathology in neuralgic amyotrophy: enlargement, constriction, fascicular entwinement, and torsion. Muscle Nerve. 2015;52(4):503-511.
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6. van Alfen N, van Eijk JJJ, Ennik T, et al. Incidence of neuralgic amyotrophy (Parsonage Turner syndrome) in a primary care setting—a prospective cohort study. PLoS One. 2015;10(5):e0128361.
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9. Cup EH, Ijspeert J, Janssen RJ, et al. Residual complaints after neuralgic amyotrophy. Arch Phys Med Rehabil. 2013;94(1):67-73.
10. Van Eijk JJJ, Groothuis JT, Van Alfen N. Neuralgic amyotrophy: an update on diagnosis, pathophysiology, and treatment. Muscle Nerve. 2016;53(3):​337-350.