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neuropathic pain when they directly invade local nerves or when they cause local edema that affects the nerves in the vicinity Tumor infiltrating an organ may cause ill-defined pain as the organ capsule becomes stretched Bone pain may signify a pathologic fracture from a tumor weakening the bone, as can occur with Ewing sarcoma or osteosarcoma The bones may also hurt due to tumor invading the bone marrow space Pain in the head and neck may result from increased ICP or tumor involvement of the meninges/cerebrospinal fluid (most common in hematologic malignancies) On the other hand, pain may be related to cancer treatment In these cases, the patient or family may report that this particular pain has been historically linked to a specific therapy A particularly challenging problem is the phantom pain that can occur after limb amputation In addition, oncology patients may experience pain of the mouth, GI tract, or even urethra as part of mucositis Pain could also represent a focal infection, complicating the patient’s compromised immune system Bone pain may reflect recent therapy with hematopoietic growth factors to stimulate neutrophil recovery after chemotherapy Radiation therapy can induce local tissue injury, which may be very painful Abdominal pain is a common complaint in cancer patients and can arise from several sources The differential diagnosis may be very wide including pancreatitis, hepatitis, cholecystitis, constipation, mucosal injury, intra-abdominal infection, and bowel obstruction (see “Hepatic and Gastrointestinal Complications of Cancer Treatment” section) Clinical Considerations Clinical Assessment An important first step in management is to explicitly address pain when taking the patient’s history Even patients who come to the ED for other reasons may have pain complicating their presentation Upon determining that a patient is in pain, according to the patient’s report as opposed to the clinician’s assessment, the emergency clinician must initiate immediate pain treatment The remainder of the history and physical examination should be used to identify the cause of the pain and to explore specific treatment for that cause Management Acetaminophen is a useful analgesic with minimal side effects for most patients, remembering to avoid the rectal route if the patient is neutropenic NSAIDs and aspirin may be effective as pain relievers but are generally avoided in this patient population due to their antiplatelet effect in the setting of frequent thrombocytopenia Opioids represent the mainstay of pain treatment for the pediatric oncology patient General principles of dosing include the following: A dose that is commonly used as a standard starting dose may be insufficient to provide adequate pain relief if the patient is not opioid naïve Far more important than the actual dose is the dose to effect Patients may need repeated doses in order to get control of their pain and repeated doses should not be limited when analgesia has not yet been attained A patient-controlled analgesia (PCA) pump is frequently needed for several types of pain, particularly mucositis where oral intake can be limited In some institutions, such pumps may be initiated in the ED using morphine, fentanyl, or hydromorphone Small children and infants may benefit from nursing-controlled analgesia (NCA) Parents should not control analgesic pumps except in the setting of end-of-life care, per institutional policy Long-acting opioids, such as MS Contin, Oxycontin, and methadone, may be appropriate in the setting of chronic pain These medications should not be used in the setting of acute pain and are rarely initiated in the ED unless in consultation with a pain expert Careful consideration must be given to decisions about whether patients in pain may be discharged to home If oral medications seem to be relieving the pain, then it is generally acceptable to discharge the patient after ensuring an adequate supply of the analgesics for use at home If the pain is inadequately controlled on oral medications and parenteral administration is required, then the patient will need to be admitted NEUROLOGIC COMPLICATIONS OF CANCER TREATMENT Neurologic complications in children with cancer are extremely common and may relate to disease, cancer treatment, or supportive care medications Drug-related side effects are extremely frequent Many of the common problems are reversible but a few can lead to permanent neurologic injury The cancer-specific history is critical to identify the likely causes of neurologic problems The diagnosis and management of neurologic problems in children is covered in Chapter 97 Neurologic Emergencies This section focuses on the unique considerations in the pediatric cancer patient Both motor and sensory peripheral neuropathies are common in children with cancer Vincristine and vinblastine, two chemotherapy agents used to treat many kinds of childhood cancer, cause reversible neuropathy affecting motor, sensory, and autonomic nerves Thalidomide can also cause peripheral neuropathy, which may or may not be fully reversible Initial management tends to focus on establishing the diagnosis by the cancerdirected history and physical examination Pain secondary to chemotherapy 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 An oncology-directed history, with particular attention to a detailed medication history, is critical to narrowing the differential diagnosis Physical examination should look for other findings such as papilledema or focal neurologic findings that may also narrow the differential diagnosis Laboratory evaluation should be carried out as recommended in Chapter 97 Neurologic Emergencies If a drug-related cause is suspected, specific drug levels when available may be helpful If a lumbar puncture is planned to look for malignant cells or an infectious etiology, the risk of herniation should be assessed Imaging studies may be appropriate if an intracranial lesion is suspected or when the diagnosis is unclear A CT scan without contrast can be useful to identify midline shift, increased ventricular size, or a hemorrhagic stroke A CT scan with contrast can identify likely carcinomatous meningitis or a supratentorial mass lesion MRI can identify mass lesions anywhere in the CNS including below the tentorium, ischemic stroke, hypertensive encephalopathy, or encephalitis Management of drug-related altered mental status usually involves withholding the offending agent and supporting the patient until return to baseline If narcoticrelated, avoid rapid and complete reversal with standard doses of naloxone, which could cause excruciating pain that will be unresponsive to further narcotics for to hours Supportive care such as stimulation should be tried prior to reversal If reversal is required, the appropriate dose of naloxone (0.1 mg/kg) should be diluted in 10 mL of normal saline and then administered in 1-mL aliquots while titrating to effect Alternatively, dosing can be initiated at µg/kg for mild respiratory depression and 10 µg/kg for reversal of moderate to severe respiratory depression as needed Laboratory evaluation of hepatic and renal function may identify contributing factors to increased drug effect If ifosfamide neurotoxicity is suspected, many recommend methylene blue treatment using dosages that have been extrapolated from other settings The usual dose for adolescents and adults is 50 mg administered orally or by slow IV push There is no clear dosage for younger children but there are case reports using to mg/kg as in the treatment for methemoglobinemia For management of hypertensive encephalopathy, see Chapter 37 Hypertension ...thrombocytopenia Opioids represent the mainstay of pain treatment for the pediatric oncology patient General principles of dosing include the following: A dose that is commonly... in Chapter 97 Neurologic Emergencies This section focuses on the unique considerations in the pediatric cancer patient Both motor and sensory peripheral neuropathies are common in children with... 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