Immune effector cell-associated neurotoxicity synd, grade 4

This code signifies the most severe form of neurological toxicity resulting from immune effector cell therapy, such as CAR T-cell therapy. It indicates life-threatening or disabling symptoms requiring urgent intervention, often including mechanical ventilation or deep coma. This condition is a serious adverse event associated with these advanced cancer treatments.

Use this code when documentation explicitly states "immune effector cell-associated neurotoxicity syndrome, grade 4" or describes severe, life-threatening neurotoxicity directly attributed to immune effector cell therapy. This typically involves symptoms like refractory seizures, deep coma, cerebral edema, or other critical neurological events requiring intensive care. Documentation should clearly link the neurotoxicity to the immune effector cell therapy and specify the grade.

• Ensure the documentation clearly specifies "grade 4" neurotoxicity; do not assign this code for lower grades of ICANS.
• Always sequence this code after the underlying malignancy for which the immune effector cell therapy was administered.
• Look for specific terms like "ICANS grade 4," "life-threatening neurotoxicity," or "disabling neurotoxicity requiring critical care" in the physician's notes.