Hyperammonemic encephalopathy after tyrosine kinase inhibitors: A literature review and a case example.

OBJECTIVE: To review the evidence of uncommon but fatal adverse event of hyperammonemic encephalopathy by tyrosine kinase inhibitors (TKI) and the possible mechanisms underlying this condition and to describe the case of a patient that developed drug-induced hyperammonemic encephalopathy related to TKI. DATA SOURCES: Literature search of different databases was performed for studies published from 1 January 1992 to 7 May 2023. The search terms utilized were hyperammonemic encephalopathy, TKI, apatinib, pazopanib, sunitinib, imatinib, sorafenib, regorafenib, trametinib, urea cycle regulation, sorafenib, carbamoyl-phosphate synthetase 1, ornithine transcarbamylase, argininosuccinate synthetase, argininosuccinate lyase, arginase 1, Mitogen activated protein kinases (MAPK) pathway and mTOR pathway, were used individually search or combined. DATA SUMMARY: Thirty-seven articles were included. The articles primarily focused in hyperammonemic encephalopathy case reports, management of hyperammonemic encephalopathy, urea cycle regulation, autophagy, mTOR and MAPK pathways, and TKI. CONCLUSION: Eighteen cases of hyperammonemic encephalopathy were reported in the literature from various multitargeted TKI. The mechanism of this event is not well-understood but some authors have hypothesized vascular causes since some of TKI are antiangiogenic, however our literature review shows a possible relationship between the urea cycle and the molecular inhibition exerted by TKI. More preclinical evidence is required to unveil the biochemical mechanisms responsible involved in this process and clinical studies are necessary to shed light on the prevalence, risk factors, management and prevention of this adverse event. It is important to monitor neurological symptoms and to measure ammonia levels when manifestations are detected.

Management of heparin-induced thrombocytopenia during extracorporeal membrane oxygenation support: a case of neutropenia caused by argatroban anticoagulation.

We present the case of a man in his 70s admitted to the intensive care unit (ICU) after mitral valve replacement and coronary artery bypass graft surgery requiring extracorporeal membrane oxygenation support due to haemodynamic instability. He received anticoagulation therapy with heparin sodium and, after 5 days, the patient presented with thrombocytopenia and deep venous thrombosis. Heparin-induced thrombocytopenia was suspected based on a positive 4T score and confirmed by antiplatelet factor 4/heparin antibodies, so argatroban was initiated as an alternative anticoagulation therapy. In the following days the patient developed severe neutropenia requiring discontinuation of argatroban and the administration of granulocyte colony-stimulating factor. According to the Naranjo Adverse Drug Reaction Probability Scale, this event would be classified as a 'probable' argatroban-related adverse event. Argatroban should be conisdered as a possible cause of neutropenia and appropriate interventions need to be implemented due to the gravity of this adverse event in the ICU.