Clinical Reasoning: Stepwise paralysis in a patient with adenocarcinoma of lung.

SECTION 1 A 54-year-old man presented with pain in the left chest for 3 days. His medical history was remarkable for hyperlipidemia managed with diet and statin. He denied tobacco smoking and consumption of alcohol. Physical examination was unrevealing. The patient was diagnosed with an adenocarcinoma of the lung harboring an epidermal growth factor receptor (EGFR) mutation that metastasized to T2-T4 levels. He was treated with radiotherapy and dexamethasone followed by Gefitinib. In the subsequent weeks, the patient developed flaccid paraparesis with Medical Research Council (MRC) graded strength of 3/5 in most muscles of the lower limbs and normal power (MRC of 5/5) in the upper limbs. Deep tendon reflexes were symmetrical and grade 11 in the lower limbs and 21 in the upper limbs. Plantar responses were flexor. Sensory examination revealed impaired pinprick caudal to the T4 level. Cranial nerve examination was unremarkable. The patient was diagnosed with a T2-T4 pathologic fracture causing spinal cord compression. He underwent urgent T2-T4 laminectomy, T3-T4 vertebrectomy, and resection of epidural tumor with partial recovery (MRC of 4/5 at most in muscles of the lower limbs and MRC of 5/5 in the upper limbs) after rehabilitation. Approximately 2 weeks after his surgery, the patient developed rapidly progressive, severe weakness affecting lower and upper limbs with increasing respiratory discomfort over a 3-day period. The patient was intubated and transferred to the intensive care unit due to respiratory distress. He was alert without obvious cranial nerve dysfunction. Neurologic examination was remarkable for a severe, flaccid tetraparesis (MRC of 1/5 at most in all tested muscles in the lower limbs and MRC of 2/5 at most in all tested muscles in the upper limbs) in addition to diffuse areflexia and neutral plantar responses.