compression carcinomatous meningitis spinal cord seizure brain metastases disorder active compression cord leptomeningeal spinal metastases brain disease cns carcinomatosis uncontrolled muscular myopathies dystrophy neuromuscular amyotrophic atrophy lateral ck sclerosis spinal spinal cord compression untreated brain metastases leptomeningeal symptomatic metastasis stable brain carcinomatous compression meningitis spinal cord leptomeningeal new evidence metastases spinal cord compression tumor evidence cauda imminent brainstem impending radiation compression cord spinal brain metastases stable unless asymptomatic steroids treatment