A 74-year-old woman developed sudden severe left shoulder, arm, and forearm pain that suddenly developed. This pain lasted approximately 2 months. Approximately 1-2 months after the resolution of the first pain she developed a different type of pain which she described as a tingling, burning, pins and needle sensation that radiated from her shoulder past her elbow into the dorsal and palmar aspect of her hand in the thumb, index, and long fingers. Additionally, she developed numbness in her hand along the palmar thumb, index, and long fingers. Two months following the onset of the initial type of pain, she developed left hand weakness that progressively worsened.
PHYSICAL EXAMINATION• Decreased light touch over the posterior forearm, lateral forearm, absent light touch and pin over the dorsal radial aspect of the thumb, index and long fingers as well as the palmar aspect of thumb, index and longer fingers.• Absent pronator teres and triceps reflexes.• Manual muscle testing was 5/5 in strength except as follows in the left upper limb:-shoulder external rotators, elbow flexors and flexor digitorum profundus 4/5 in the index and long fingers. -elbow extensors 3/5 -extensor carpi radialis, extensory digitorum communis, flexor carpi radialis, flexor pollicus longus, flexor digitorum superficialis, and abductor pollicus brevis 0/5.
DIAGNOSIS AND TREATMENTPrevious work-up included:• Inconclusive EMG/NCS performed by a physical therapist,• MRI of cervical spine which revealed non-focal degenerative changes• MRI of her left shoulder which revealed moderated tendinosis of the rotator cuff with focal tearing of the distal infraspinatus, mild subacromial bursitis and mild glenohumeral joint osteoarthritis.• MRI of her left brachial plexus did not show evidence of nerve injury. Patient was referred again for a repeat EMG/NCS.
RESULTSEDX study, 4 months from onset of symptoms, revealed absent median and radial motor-sensory nerve conduction. EMG revealed complete denervation of FDP in the index and long fingers, as well as the pronator teres, partial reinnervation of the triceps, and no abnormal cervical paraspinal spontaneous activity. See Detailed results in Figure 1.
DISCUSSIONThis case fits the clinical description of neuralgic amyotrophy of Parsonage and Turner 1,2 . Typically, patients will have sudden severe neuropathic pain that resolves preceding the onset of weakness. 3 Most patients will develop atrophy within the first 5 weeks of onset of symptoms. 3 Alternative diagnosis in this case are less likely for the following reason. It is unlikely to be a concomitant radial neuropathy at the spiral groove and proximal median neuropathy with simultaneous onset. There is no evidence of myelinopathy (ie, demyelinating disease) as there is no conduction block to explain her weakness. Finally, exam and imaging were not consistent with more common neuromusculoskeletal pathologies.The etiology of neuralgic amyotrophy of Parsonage and Turner remains unclear, but it has been associated with infection, trauma, surgery, strenuous e...