200 Section - Bilateral Upper Limb Motor Neuron Syndrome: Distinguishing Brachial Amyotrophic Diplegia from Mimickers

A 48-year-old male referred from the Orthopedics and Traumatology Clinic (with diagnosis of cervical myelopathy) for electrodiagnosis evaluation and rehabilitation management. The patient was presented with progressive (since 2 years ago) bilateral upper limb weakness without any sensory changes. The weakness was initially affecting the right hand before involving both arms and shoulders. Initial clinical evaluation and cervical MRI were conducted by the to rule out structural spinal pathology. He also had cardiomegaly and hypertensive heart disease. The patient is still working as food seller with assistance from his wife. He hoped that he could still be able to continue working to support his family. 


Discussions:

The patient exhibited severe motor impairment without sensory deficits, bulbar involvement, nor lower limb weakness. The Nerve Conduction Studies (NCS) showed bilateral low motor amplitudes with normal sensory nerve conduction. The needle electromyography (EMG) revealed widespread denervation, fibrillation potentials (Fibs), large amplitude, polyphasic motor responses in the upper extremities, but not in the tongue. The tounge showed complex polyphasic motor unit with normal amplitude and duration, no fibs or PSWs. These findings were consistent with BAD. Cervical MRI showed degenerative changes but no significant compression explaining the symptoms. The electrophysiological findings were essential in differentiating BAD from conditions such as cervical myelopathy and multifocal motor neuropathy.


Conclusions:

This case underscores the importance of an early electrodiagnostic assessment in diagnosing BAD and distinguishing it from other upper motor neuron disorders and cervical myelopathy. Awareness of this rare entity is crucial for timely intervention, rehabilitation planning, and long-term disease management. The rehabilitation management should focus on maintaining and improving functional independence to improve quality of life.