responds best to agents with efficacy against neuropathic pain such as gabapentin Such drugs rarely have immediate effect and thus narcotics may be needed in the short run There is a wide differential to consider when evaluating a pediatric cancer patient with new-onset cranial nerve palsy Symmetric involvement may reflect vincristineinduced neuropathy, particularly when it involves ptosis Increased ICP from shunt malfunction or tumor progression should also be considered Asymmetric involvement can occur with fatigue or vincristine-induced exacerbation of baseline weakness Vincristine can also cause asymmetric ptosis in some patients, but this should be a diagnosis of exclusion Increased ICP should be suspected in a child with a sixth nerve palsy Carcinomatous meningitis should be considered in patients with a history of tumors likely to involve the cerebrospinal fluid or meninges, such as leukemia, lymphoma, parameningeal sarcomas, and meningeal seeding brain tumors, such as medulloblastoma Patients treated with a scopolamine patch for nausea may develop pupillary asymmetry as scopolamine transferred by fingertip from the patch to the eye can elicit unilateral mydriasis Management in the ED requires an appropriate oncology-directed history and physical examination to establish the potential differential Unless drug effect can be established as the most likely cause, a head CT scan to rule out increased ICP may be required The CT scan findings may also direct the specific ED and post-ED management Admission for observation may be required for some patients where the diagnosis or trajectory is uncertain The most common cause of proximal muscle weakness in pediatric cancer patients is prolonged steroid exposure as part of cancer treatment or management of side effects The diagnosis can usually be established by the appropriate history and physical examination Patients with very severe symptoms whose families cannot manage care at home may require admission for respite care or initiation of rehabilitation Altered mental status in pediatric cancer patients has an extremely broad differential ( Table 98.9 ) Cerebrovascular accident (CVA) as a cause of altered mental status should be considered in patients with risk factors such as thrombocytopenia, DIC, or drug-induced coagulopathy Somnolence can be a side effect of many supportive-care medications such as narcotics, gabapentin, antihistamines, some antiepileptics, and antidepressants Cranial radiation causes somnolence syndrome to 12 weeks after treatment that may last several weeks in duration Typical manifestations are extreme amounts of sleep (up to 20 hours per day) with normal mental status and function when awake Additional drug-specific CNS side effects are listed in Table 98.8