Differential Diagnosis for Posterior Cord vs Middle Trunk Plexopathy
Single Most Likely Diagnosis
- Posterior cord plexopathy: This is the most likely diagnosis if the patient presents with weakness and atrophy of the muscles innervated by the posterior cord, such as the triceps, extensor carpi radialis brevis, and extensor digitorum communis. The posterior cord is formed by the union of the posterior divisions of the upper, middle, and lower trunks of the brachial plexus.
Other Likely Diagnoses
- Middle trunk plexopathy: This diagnosis is likely if the patient presents with weakness and atrophy of the muscles innervated by the middle trunk, such as the flexor carpi radialis, palmaris longus, and flexor digitorum profundus (lateral half). The middle trunk is one of the three trunks of the brachial plexus.
- Combined posterior cord and middle trunk plexopathy: This diagnosis is possible if the patient presents with a combination of symptoms and signs of both posterior cord and middle trunk plexopathy.
Do Not Miss Diagnoses
- Pancoast tumor: A tumor located at the apex of the lung that can compress the brachial plexus, causing plexopathy. It is essential to rule out this diagnosis as it can be life-threatening if left untreated.
- Traumatic brachial plexus injury: A traumatic injury to the brachial plexus can cause plexopathy, and it is crucial to identify and treat this condition promptly to prevent long-term damage.
- Brachial plexitis (neuralgic amyotrophy): An inflammatory condition that affects the brachial plexus, causing severe pain and weakness. It is essential to recognize this condition to provide appropriate treatment and prevent long-term complications.
Rare Diagnoses
- Hereditary brachial plexus neuropathy: A rare genetic disorder that affects the brachial plexus, causing recurrent episodes of pain and weakness.
- Brachial plexus schwannomatosis: A rare condition characterized by the growth of multiple schwannomas (benign tumors) on the nerves of the brachial plexus, causing plexopathy.
- Radiation-induced brachial plexopathy: A rare condition that occurs after radiation therapy to the chest or neck, causing damage to the brachial plexus and resulting in plexopathy.