Neurotoxicity as a result of chemotherapy occurs when the CNS, peripheral nervous system, cranial nerves or a combination of all three are damaged either directly or indirectly. The damage may be transient, however some patients will experience permanent neurological deficits (Camp‐Sorrell [27]). The severity of toxicities is related to the dose of chemotherapy. Neurotoxicity may manifest in different and unpredictable ways and diagnosis is confirmed by the patient's reporting of the symptoms as well as a physical neurological examination (Camp‐Sorrell [27]). Chemotherapy agents such as platinum, vinca alkaloids and taxanes are known to cause peripheral neuropathy. Chemotherapy‐induced peripheral neuropathy is caused by inflammation, degeneration or injury of the peripheral nerve fibres and requires a dose reduction to alleviate the symptoms (Camp‐Sorrell [27]). Oxaliplatin is known to cause peripheral sensory neuropathy, which is exacerbated by cold air, cold drinks and touching cold surfaces. During or at the end of the infusion of oxaliplatin patients can experience pharyngolaryngeal dysaesthesia, hoarseness, dyspnoea or a tight sensation at the back of the throat. Patients are encouraged to protect themselves from the cold during the winter months with a thick scarf to cover the neck and mouth and gloves to help to prevent the symptoms.

High doses of methotrexate can cause encephalopathy resulting in blurred vision, lethargy and confusion, which normally resolves once the drug is stopped (Camp‐Sorrell [27]). Seizures and cranial nerve and motor dysfunction have been associated with the use of ifosfamide; symptoms resolve within 48–72 hours once the therapy has ceased (Camp‐Sorrell [27]). Methylene blue (MB) can be given for ifosfamide‐induced encephalitis, although there is little conclusive evidence to support its use. It is thought to act as an electron acceptor to prevent the formation of chloroacetaldehyde. Without MB treatment, the reported recovery time from encephalopathy ranges from 2 to 29 days, but published studies show that the time to recovery from encephalopathy with MB varies from 10 minutes to 8 days (LCA [139]).

A neurotoxicity which is becoming recognized is posterior reversible encephalopathy syndrome (PRES) which is associated with the administration of cisplatin, rituximab, bevacizumab and immunosuppressive therapy such as tacrolimus (Camp‐Sorrell [27]). The symptoms are headaches, focal neurological and visual changes, encephalopathy and seizures (Polovich et al. [194]). Diagnosis of PRES is confirmed by MRI of the brain, where symmetrical subcortical white and grey matter lesions can be seen. PRES is reversible and the management of the condition is a reduction or withholding of the causative agent (Camp‐Sorrell [27]).