Convulsions and transient cortical blindness after cisplatin

Ocular adverse events associated with platins: a disproportionality analysis of pharmacovigilance data and extensive systematic review of case reports

BACKGROUND

Anti-cancer drugs, particularly platinum-based chemotherapy drugs, have been showing ocular adverse events (OAEs) in patients undergoing chemotherapy, which is concerning due to the potential impact on patient's quality of life and the ability to continue effective cancer treatment.

RESEARCH DESIGN AND METHODS

A retrospective case/non-case study was conducted using spontaneous reports on OAEs by platins from the FDA Adverse Event Reporting System (FAERS) database. A disproportionality analysis was performed by calculating the Proportional Reporting Ratio (PRR), Reporting Odds Ratio (ROR), and the Information Component (IC) to identify OAE signals for platinum-based chemotherapy drugs. In parallel, a review of case reports for OAEs from platins was conducted by a systematic literature search in PubMed and Google Scholar.

RESULTS

Using disproportionality analysis, 69 signals were identified for platinum-based chemotherapy drugs and OAEs (carboplatin: 42, oxaliplatin: 16, cisplatin: 11). Choroidal infarction [PRR = 215.1; χ2 = 4527.1; lower bound (LB) ROR = 140.7; IC025 = 5.1] and orbital hemorrhage [PRR = 120.0; χ2 = 300.5; LB ROR = 35.1; IC025 = 1.3] were the strong signals identified for carboplatin. Optic disc hyperemia [PRR = 208.2; χ2 = 742.5; LB ROR = 74.1; IC025 = 2.2] and blindness cortical [PRR = 23.7; χ2 = 382.5; LB ROR = 14.8; IC025 = 3.1] were the signals identified for oxaliplatin and cisplatin, respectively. A total of 32 case reports of OAEs from platinum-based chemotherapy drugs were identified through a systematic search in PubMed and Google Scholar, strengthening the association.

CONCLUSION

The study revealed a potential risk of OAEs when using platinum-based chemotherapy drugs as an anticancer medication.

Drug-Induced Seizures: Considerations for Underlying Molecular Mechanisms

A broad spectrum of chemical entities have been associated with drug-induced seizure (DIS), emphasizing the importance of this potential liability across various drug classes (e.g., antidepressants, antipsychotics, antibiotics, and analgesics among others). Despite its importance within drug safety testing, an understanding of the molecular mechanisms associated with DIS is often lacking. The etiology of DIS is understood to be a result of either a deficit in inhibitory (e.g., gamma aminobutyric acid) or an elevated excitatory (e.g., glutamate) signaling, leading to synchronous neuronal depolarization affecting various brain regions and impairing normal neurological functions. How this altered neuronal signaling occurs and how these changes interact with other non-brain receptor driven DIS-associated changes such as metabolic disturbances, electrolyte imbalances, altered drug metabolism, and withdrawal effects are poorly understood. Herein, we discuss important molecular mechanisms identified in DIS for several drugs and/or drug classes. With a better understanding of the molecular mechanisms associated with DIS, in vivo or in vitro models may be applied to characterize and mitigate DIS risk during drug development. Susceptibility stratification for DIS presents species differences in the following order beagle dogs > rodents and cynomolgus monkeys > Göttingen minipigs with a more than 2-fold difference between canines and minipigs, which is important to consider during non-clinical species selection. While clinical signs such as myoclonus, severe muscle jerks, or convulsions are often associated with abnormal epileptiform EEG activity, tremors are most of the time physiological and rarely observed with concurrent epileptiform EEG activity which need to be considered during DIS risk evaluation.

Chemotherapy-Related Encephalopathy With Super-Refractory Status Epilepticus in a Child With Osteosarcoma: A Case Report With a Review of Literature

Osteosarcoma is the most frequent primary cancer of the bones, and a combination of primary chemotherapy, surgery, and adjuvant chemotherapy is its current treatment. In adults, some authors have reported problems with memory and concentration following chemotherapy, but in children, severe neurologic dysfunction has been rarely reported. This report describes a 13-year-old patient with primary high-grade nonmetastatic osteosarcoma of the tibia who developed encephalopathy with super-refractory status epilepticus related to chemotherapy. He received methotrexate (MTX) and cisplatin (CDDP)-containing polychemotherapy, and after the first course of drug administration, he developed fever, confusion, a state of psychomotor agitation, and super-refractory status epilepticus with normal laboratory and imaging findings. The causal relationship between the administration of the first polychemotherapy course and his neurological manifestations may be supported by the evaluation and exclusion of other causes. The administration of antiepileptic drugs and off-label atypical antipsychotics was necessary to treat his neurological complications and behavioral changes. This patient represents the first known example of super-refractory status epilepticus in a child treated with MTX and CDDP-containing chemotherapy. Physicians should be aware that encephalopathy and seizures are possible consequences of CDDP therapy when administered alone or in combination with other chemotherapeutic agents. Further studies are needed to better define this relationship in children.

Status epilepticus associated with platinum chemotherapy in a patient with cervical cancer: a case report

Background

While peripheral neuropathy is a common side effect of platinum-based chemotherapy, central nervous system (CNS) toxicity, such as encephalopathy or seizures, appears to be rare. This manuscript describes the only reported case of nonconvulsive status epilepticus associated with cisplatin in a cervical cancer patient who does not have other underlying medical conditions.

Case presentation

The patient is a 54-year-old Chinese female with recurrent stage IIIB moderately differentiated squamous cell carcinoma of the cervix who was being treated with cisplatin and topotecan. During the sixth cycle of this regimen, the patient presented with mental status changes. While imaging and laboratory values were within normal limits, the patient’s EEG revealed nonconvulsive status epilepticus. After appropriate intervention, she made a complete recovery with no further seizures. The patient currently remains on antiepileptic therapy, but is no longer receiving cisplatin.

Conclusion

Patients who present with new onset seizures should primarily be evaluated for underlying medical conditions. Among patients who are suspected to have CNS side effects associated with platinum use, we recommend avoidance of platinum agents in future chemotherapeutic regimens. Although rare, providers should be aware of the potential for CNS toxicity associated with this drug class.

Cisplatin overdose: toxicities and management

Cisplatin is one of the most widely used antineoplastic agents in the treatment of solid tumour and haematological malignancies, including cancers of the testes, ovary, bladder, head and neck, oesophagus, stomach and lung, as well as lymphoma and osteosarcoma. Its non-specific targeting commonly results in adverse effects and toxicities affecting the gastrointestinal, renal, neurological and haematological systems even when administered at standard doses. Since cisplatin-related toxicities are dose-dependent, these may be more pronounced in the setting of a cisplatin overdose, resulting in significant morbidity and/or mortality. The incidence of cisplatin overdoses is unknown; however, early-phase clinical trials utilizing high-dose cisplatin, and case reports in the overdose setting have characterized the clinical features associated with cisplatin overdoses, highlighting some therapeutic strategies for consideration. To date, no published guidelines exist for managing a cisplatin overdose. The major toxicities of a cisplatin overdose include nausea and vomiting, renal insufficiency, electrolyte abnormalities, myelosuppression, ototoxicity, peripheral neuropathy, hepatotoxicity and retinopathy. Diarrhoea, pancreatitis, seizures and respiratory failure have also been reported. No specific antidote for cisplatin exists. Key management principles and strategies to lessen toxicities include renoprotection and enhancing drug elimination with aggressive intravenous hydration with or without the use of an osmotic diuretic, and avoidance of nephrotoxic medications. Sodium thiosulfate and plasmapheresis, with or without haemodialysis support, should be strongly considered. Close monitoring of clinical and laboratory parameters, and institution of supportive therapies, including antiemetics and haematopoietic colony stimulating factor support, are warranted. Based on the current literature, experimental therapies such as amifostine, ditiocarb sodium (diethyldithiocarbamate), acetylcysteine, fosfomycin and colestipol are of limited clinical effectiveness and remain investigational. This review serves to highlight the clinical spectrum of toxicities resulting from a cisplatin overdose, to critically appraise the available literature and to present a suggested algorithmic approach for the initial management of a cisplatin overdose.

Cisplatin-induced encephalopathy and seizures

Cisplatin induces mainly a peripheral sensory neuropathy, but occasionally may also induce an encephalopathy with or without seizures. We describe the clinical signs and symptoms of cisplatin encephalopathy. The clinical events in three patients that developed seizures and encephalopathy with focal signs are described. Two patients completely recovered, one patient developed a focal status epilepticus, refractory to antiepileptic treatment, and died due to ongoing seizures. Post-mortem examination of the central nervous system in this patient showed an ischemic lesion in the left temporal area and mild gliosis of the white matter. One patient was rechallenged with cisplatin after which he developed a second episode of encephalopathy. We conclude that physicians using cisplatin chemotherapy should be aware of this rare complication.

Subacute encephalopathic toxicity of cisplatin

Acute blindness or seizures are usually the first signs of central neurotoxicity from cisplatin. We report a case of subacute neurotoxicity caused by cisplatin. Progressive encephalopathy and partial loss of vision were the main observed signs. This condition was completely reversible upon cisplatin discontinuation, as is usually the case with acute central neurotoxicity.