LAUSR

Dear Sir, Neuralgic amyotrophy (NA), also referred to as PersonageTurner Syndrome or idiopathic brachial plexopathy, is a rare disorder with sudden onset of shoulder pain, usually unilateral, replaced over a course from a few days to weeks, with progressive motor weakness, numbness, and dysesthesia [1]. Although NA etiology remains unknown, different risk factors and antecedent events have been identified in about 28–83% of affected patients, such as autoimmune or rheumatic diseases, infections, surgery, anesthesia, trauma, vaccines, radiation therapy, and inherited factors [2]. Early diagnosis and therapy are recommended for a good prognosis; usually, about 89% of patients fully recover in 1–2 years [2]. We report a case of progressive, painless NA, with a late diagnosis and positive response to intravenous immunoglobulin (IVIg) treatment. A 39-year-old Italian man was admitted to our department for the insidious appearance, in the last 2 years, of progressive weakness of the left upper limb, most pronounced in the shoulder and during the elbow flexion movements. Family and personal medical histories were unremarkable. Neurological examination showed the absence of reflexes of the left upper limb, atrophic changes, and sporadic myokymia in deltoid and biceps brachii, associated with hypoesthesia in the region of the shoulder and of the left arm. According to the Medical Research Council scale (MRCs), strength reduction in the flexion and supination of the left forearmwas confirmed (MRC: 3/5). A slighter weakness in external arm rotation movements has also been observed (4/5). Electrodiagnostic (EDX) study allowed to localize the damage, showing decreased compound muscle action potential amplitude (CMAP) in the left deltoid and the left biceps brachii, respectively following axillary and musculocutaneous nerves stimulation at the Erb’s point (recorded with surface electrodes), in comparison to the left ones (Table 1). Sensory nerve action potential (SNAP) tests showed a significant asymmetry (greater than 50%) in the left lateral antebrachial cutaneous (LAC) and in the left median (stimulated at thumb) nerves if compared to the right side. The remaining EDX findings (medial antebrachial cutaneous, median, ulnar, and radial nerves) resulted normal. Standard needle electromyography (EMG) of left deltoid and biceps brachii showed a neurogenic pattern (polyphasic motor unit action potentials of increased duration and high amplitude, with reduced recruitment at full effort). Infraspinatus, triceps, extensor digitorum, intrinsic hand muscles, C5-C6 paraspinal muscles, and somatosensory evoked potentials (SEPs) of the left median and ulnar nerves, resulted normal. To exclude infiltrative or compressive processes involving cervical cord and brachial plexus, we performed a magnetic resonance imaging (MRI) that revealed thickening and increased T2 signal with mild gadolinium enhancement in the upper trunk and left roots C5–C6, diffuse spondylosis in absence of neoplastic lesions, signal changes or intervertebral narrowing (Fig. 1). Cerebrospinal fluid analysis (CSF) showed increased protein and albumin values (50.1 mg dl and 43 mg/dl respectively) and normal cell count (< 5 μl). Extensive laboratory screening including metabolic (vitamin B12 and E and folate values in particular), rheumatic and virologic text (herpes, rubella, measles, parotitis, and adenovirus), toxoplasmosis, borreliosis, and paraneoplastic assay and anti-GM1, antiGM2, and anti-GQ1b antibodies screening resulted negative. Assuming an inflammatory process, the patient underwent IVIg 0.4 g/kg/day with a loading dose of 2 g/kg in 5 days followed by a maintenance dose of 2 g/kg every 3 weeks. After 6 months, neurological examination revealed the absence of sensory symptoms, improvement of the muscle strength of the biceps brachii (4/5), and full recovery in the * Claudia Vinciguerra [email protected]