Carpal Tunnel Syndrome: This condition is a common cause of wrist and arm weakness, especially in middle-aged individuals. It occurs due to compression of the median nerve at the wrist, leading to symptoms such as numbness, tingling, and weakness in the hand and arm.

Radial Neuropathy: This condition affects the radial nerve, causing weakness or paralysis of the muscles it supplies, which can lead to wrist drop and weakness in the arm.
Cervical Spondylosis: This is a common condition in middle-aged individuals, characterized by wear and tear of the cervical spine, which can compress nerves and cause arm weakness.
Thoracic Outlet Syndrome: This condition involves compression of the nerves and/or blood vessels that pass into the arm, leading to pain, numbness, and weakness in the arm and hand.

Multiple Sclerosis: Although less common, multiple sclerosis is an autoimmune disease that can cause a wide range of neurological symptoms, including arm weakness. Missing this diagnosis could lead to delayed treatment and significant morbidity.
Spinal Cord Compression: This is a medical emergency that requires prompt attention. Compression of the spinal cord can cause arm weakness, among other symptoms, and delayed treatment can result in permanent neurological damage.
Brachial Plexus Injury: Trauma to the brachial plexus can cause severe and potentially permanent arm weakness. Early diagnosis and treatment are crucial to prevent long-term disability.

Amyotrophic Lateral Sclerosis (ALS): A progressive neurological disease that affects nerve cells in the brain and spinal cord, causing loss of muscle control. ALS is a rare condition but should be considered in the differential diagnosis of persistent arm weakness.
Plexiform Neuroma: A rare type of nerve tumor that can cause arm weakness and other neurological symptoms.
Neurosyphilis: A rare condition caused by the spread of syphilis to the nervous system, which can cause a wide range of neurological symptoms, including arm weakness.