Plexopathy Classification and Diagnosis

Anatomical Classification

Plexopathies are classified primarily by anatomical location, with brachial and lumbosacral plexopathies being the two main types, each with distinct etiological subtypes that determine their clinical presentation and management 1
Brachial plexopathy involves the nerve network formed from C5-T1 ventral rami, affecting the shoulder and arm 1
Lumbosacral plexopathy involves the lumbar plexus (L1-L4) and sacral plexus (L4-S4) connected via the lumbosacral trunk, presenting with pain and weakness in the back, hip, and leg 1

Traumatic plexopathy results from blunt force injuries or penetrating injuries, and can be classified as preganglionic or postganglionic 2
Neoplastic plexopathy can be primary, with benign peripheral nerve sheath tumors, or secondary, with direct invasion or metastasis from adjacent tumors 3, 4
Inflammatory/immune-mediated plexopathy includes brachial neuritis and chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) 4
Radiation-induced plexopathy is a delayed complication of radiation therapy, characterized by progressive, painless weakness and sensory loss 1

Clinical diagnosis is confirmed by electrodiagnostic studies showing abnormalities in multiple nerve distributions, and MRI is the imaging modality of choice 1
Plexopathies must be distinguished from radiculopathies, which typically follow a single dermatome distribution 1