Parsonage-Turner syndrome (also called neuralgic amyotrophy or acute brachial neuritis) has a history that spans well over a century, with its modern recognition crystallizing in the mid-20th century.
Early observations
Cases matching this syndrome's description appear sporadically in 19th-century medical literature, though they weren't grouped under a single name. Physicians occasionally described patients who developed sudden, severe shoulder pain followed by weakness and wasting of arm muscles, sometimes following infections, vaccinations, or surgery, but these were treated as isolated curiosities rather than a distinct clinical entity.
The 1948 Lancet paper
The condition gained its eponymous name following a landmark 1948 paper published in The Lancet by Maurice Parsonage and John Turner, two British physicians working in Bristol. They described a series of over 100 patients who presented with a strikingly consistent pattern: abrupt onset of intense shoulder and upper arm pain, followed within days to weeks by weakness and atrophy of specific shoulder girdle muscles, often with the pain subsiding as the weakness emerged. Parsonage and Turner proposed that this represented a coherent syndrome rather than a collection of unrelated nerve injuries, and they used the term "neuralgic amyotrophy" to capture the combination of nerve pain (neuralgia) and muscle wasting (amyotrophy).
https://www.thelancet.com/journals/lancet/article/PIIS0140-6736(48)90611-4/fulltext
Their paper was influential because it brought together a large case series and offered a clear clinical description, allowing physicians elsewhere to recognize the same pattern in their own patients.
Refining the concept
In the decades following, clinicians and researchers worked to better characterize the syndrome's features, including:
Its tendency to affect the upper trunk of the brachial plexus or individual nerves such as the long thoracic, suprascapular, or anterior interosseous nerves, producing recognizable patterns like winged scapula or wrist drop.
Associations with preceding triggers: viral infections, immunizations, surgery, childbirth, and strenuous exercise were all reported as potential precipitants in a subset of cases.
The natural history of slow but often substantial recovery over months to years, distinguishing it from more progressive neurological conditions.
Hereditary forms
A related but genetically distinct entity, hereditary neuralgic amyotrophy, was also described, linked to mutations in the SEPT9 gene. This form tends to recur and run in families, and its identification helped researchers think more carefully about the possible immune-mediated mechanisms underlying the sporadic form as well.
Diagnostic evolution
For much of the syndrome's history, diagnosis relied almost entirely on clinical pattern recognition, since no specific laboratory test existed. Over time, electromyography (EMG) and nerve conduction studies became important tools for localizing the affected nerves and distinguishing the syndrome from cervical radiculopathy, rotator cuff pathology, or other causes of shoulder pain and weakness. More recently, MRI has been used to detect characteristic muscle denervation changes, and high-resolution MRI neurography has allowed visualization of nerve abnormalities such as focal constrictions, sometimes called "hourglass-like" lesions, in certain nerves affected by the syndrome.
Current understanding
Today, Parsonage-Turner syndrome is generally considered an immune-mediated inflammatory process affecting peripheral nerves, though the exact mechanism remains incompletely understood. Diagnosis still relies heavily on clinical history and examination, supported by electrodiagnostic testing and imaging to exclude other causes. The syndrome remains likely underdiagnosed, partly because its initial presentation, severe shoulder pain, can easily be mistaken for a musculoskeletal problem before the characteristic weakness develops.