Clinical and neurophysiological analysis of neuralgic amyotrophy
10.3760/cma.j.cn113694-20240606-00392
- VernacularTitle:神经痛性肌萎缩90例的临床及神经电生理特点分析
- Author:
Mingxia ZHU
1
;
Hongyue MA
;
Xiuli LI
;
Jingyu MOU
;
Hongjing LIU
;
Jing CHEN
;
Guangju QI
;
Xinhong FENG
Author Information
1. 清华大学附属北京清华长庚医院神经内科 清华大学临床医学院，北京102218
- Keywords:
Brachial plexus neuritis;
Neural conduction;
Electromyography;
Neuralgic amyotrophy;
Parsonage-Turner syndrome;
Clinical phenotype
- From:
Chinese Journal of Neurology
2024;57(12):1353-1361
- CountryChina
- Language:Chinese
-
Abstract:
Objective:To analyze the clinical characteristics and neurophysiological features of patients with neuralgic amyotrophy (NA) and explore their neurological function status.Methods:Clinical data and neurophysiological findings of 90 patients diagnosed with NA at Beijing Tsinghua Changgung Hospital from September 2016 to January 2024 were collected and their clinical phenotypes and neurophysiological characteristics were systematically summarized and analyzed.Results:Among the 90 patients, males accounted for 60.0% (54 cases) and females accounted for 40.0% (36 cases). The duration of the disease was 12 (3, 36) months (ranged from 1 week to 5 years). The onset age of the patients was 58 (30, 70) (21-87) years. Unilateral involvement was noted in 94.4% (85/90) of patients, exhibiting a left-to-right ratio of 1∶1.3, while only 5.6% (5/90) had bilateral involvement. The majority of patients demonstrated a monophasic clinical course with a recurrence rate of just 2.2% (2/90). The primary clinical manifestations included upper limb pain in 70.0% (63/90) of patients, which progressed to muscle weakness and atrophy within 1 day to 1 month, whereas 30.0% (27/90) of patients without significant pain symptoms. Lesions predominantly affected the upper trunk of the brachial plexus, which accounted for 64.4% (58/90) of patients. Distal nerve injuries in the upper limb were observed in 14.4% (13/90) of patients, with 6.7% (6/90) demonstrating isolated anterior interosseous nerve involvement and another 6.7% (6/90) exhibiting isolated posterior interosseous nerve involvement; 1 case had concurrent anterior and posterior interosseous nerve damage. Additionally, 1 case presented with bilateral phrenic nerve involvement, and another patient had isolated posterior tibial nerve injury. Electrophysiological evaluations of patients with NA revealed that axonal damage to motor nerve fibers was a hallmark feature of the condition. Among patients undergoing motor nerve conduction studies, 68.8% (55/80) exhibited decreased compound muscle action potential amplitude, and 31.3% (25/80) had prolonged latency. Sensory nerve conduction was normal in 60.0% (48/80) of patients, while abnormalities included prolonged latency in 15.0% (12/80), reduced amplitude in 12.5% (10/80), slowed conduction velocity in 8.8% (7/80), and absent waveforms in 3.8% (3/80) of patients. The rates of abnormal nerve conduction findings in motor nerves were the highest in the suprascapular nerve (70.6%, 36/51), followed by the axillary nerve (58.3%, 35/60), musculocutaneous nerve (50.7%, 35/69), long thoracic nerve (6/17), and both anterior and posterior interosseous nerves (7.5%, 6/80 each). In sensory nerves, abnormalities were predominantly noted in the lateral antebrachial cutaneous nerve (30.0%, 12/40). Needle electromyography demonstrated neurogenic damage, most frequently affecting the infraspinatus muscle (69.2%, 18/26), biceps brachii (68.1%, 49/72), and deltoid muscle (65.3%, 47/72). The positive rate of magnetic resonance neurography (MRN) for NA was 62.1% (41/66), among which 63.4% (26/41) showed localized swelling of the brachial plexus, 51.2% (21/41) exhibited T 2 hyperintensity, and 4.9% (2/41) demonstrated denervated changes in the muscles. The positive rate of ultrasound for NA was 71.1% (59/83), with 91.5% (54/59) showing nerve swelling and 8.5% (5/59) exhibiting hourglass constriction .Conclusions:NA is a peripheral neuropathy characterized by spontaneous pain, limb weakness, and (or) muscle atrophy primarily. Its clinical phenotype predominantly involves damage to the upper trunk of the brachial plexus, which can also manifest as isolated mononeuropathy. Neurophysiological findings most commonly reveal the neurogenic damage to the muscles innervated by the upper trunk of the brachial plexus, mainly characterized by the axonal damage to the motor nerves, and pure motor nerve damage may also be observed. MRN and neuroultrasound can assist in qualitative diagnosis.
