Early-Onset Dropped Head Syndrome and Person-in-the-Barrel Syndrome After Radiation Therapy: Clinical, Electromyographic, and MRI Findings.

Dropped head syndrome (DHS) involves severe weakness of the neck extensor muscles causing the mandible to drop to the chest wall. Isolated neck extensor weakness is a rare complication of radiotherapy. This condition may result within a few weeks or months following radiotherapy (early-onset) or several years after radiotherapy (late-onset), with the latter more commonly encountered. Person-in-the-barrel syndrome is marked by bilateral brachial diplegia, intact cranial nerves, and preserved lower extremity strength. We describe the unique clinical profile of a patient with a six-week history of significant neck and bilateral upper extremity weakness who was diagnosed three months prior to the onset of these symptoms with moderately differentiated squamous cell carcinoma within the base of the tongue (Stage III T2N1M0) and metastasis to the cervical lymph nodes. She underwent concurrent chemotherapy with three cycles of cisplatin (197 mg {100 mg/m2} x 197 m2) and hyperfractionated external beam radiation therapy (total dose cGy 7000 cGy in 35 fractions {200 cGy per fraction}). She reported the rapid onset of neck and bilateral upper extremity weakness six weeks following cisplatin termination and four weeks after radiation termination. A cervical MRI suggested myositis of the cervical paraspinal muscles, and electrodiagnostic studies indicated an inflammatory myopathic process involving the cervical paraspinal and shoulder girdle muscles. The patient attained a complete resolution of her symptoms eight months after onset. This case illustrates the rare phenomenon of early-onset DHS and person-in-the-barrel syndrome caused by radiation-induced myositis. Prompt recognition of the symptoms associated with DHS and timely treatment offer the best prognosis for recovery.