Our patient was a 71 year old woman diagnosed with a high-grade right triceps pleomorphic sarcoma in 2017, which was resected with a wide local excision and treated with adjuvant radiation. A surveillance computed tomography (CT) scan of the thorax showed metastases to the lung and mediastinum in September 2018 and she was treated with 6 cycles of doxorubicin. Progression of disease identified in January 2019 necessitated a change of treatment to ifosfamide and mesna, and she was admitted for each cycle. Re-staging CT scan after 2 cycles demonstrated an interval decrease in the size and number of the multiple pulmonary nodules with one nodule reducing in size from 18 mm down to 6 mm, complete resolution of a 15 mm right para-oesophageal node and no new disease identified.\nPast medical history included hypertension, hysterectomy for menorrhagia and appendectomy. Her medications on admission were lercanidipine, losartan, hydrochlorothiazide, potassium supplement, enoxaparin (thrombosis prophylaxis), senna, domperidone, aprepitant, Fortisip Compact Fibre, Procal Shot, multivitamin and evening primrose oil (not administered due to unknown possible drug interactions). She was known to develop a rash with penicillin but had no other allergies.\nExamination on admission for cycle 3 was remarkable for oral candidiasis. Routine blood investigations identified potassium 2.7 mmol/l which was replaced with IV and oral potassium and albumin of 32 g/l. She developed nausea after day 2 and had one episode of vomiting.\nOn day 3, she was noted to be resting during the morning, however was easily rousable and able to stay awake. Chemotherapy was commenced at midday. Within 4 h, it was noted that she was difficult to rouse. Vital signs were within normal ranges. A blood gas confirmed a potassium of 2.7 mmol/l, but no other abnormality was identified and the pH was uncompensated and in the normal range. An ECG was unremarkable. It was hypothesized that she had developed ifosfamide encephalopathy and an EEG was obtained.
A 25-year-old male patient diagnosed as a case of Philadelphia chromosome-negative B-cell acute lymphoblastic lymphoma (ALL) and who had relapsed after receiving the Berlin-Frankfurt-Münster 90 acute lymphoblastic leukemia protocol (BFM ALL protocol) was started on MINE protocol (injection ifosfamide 4 g/m2 was divided over 3 days [day 1–3] and administered IV over a 1 h period, injection mitoxantrone 8 mg/m2 [day 1] administered as a short IV infusion, injection etoposide 65 mg/m2/day [day 1–3] was infused over 1 h, and injection mesna 1330 mg/m2 [days 1–3]) after the patient had progressed on DHAP regimen (injection cisplatin 100 mg/m2 [day 1], high-dose cytarabine 2 g/m2 twice a day [day 2], and tablet prednisolone 40 mg/day [day 2–4]). After 24 h of the 1st day of chemotherapy, the patient started developing headache, vomiting which was followed in couple of hours by disoriented behavior, and one episode of seizure. In view of above complaints, patient chemotherapy was withheld as the patient developed headache and vomiting. For the above complaints, patient's all routine investigations such as complete blood count, renal function, and liver function test were performed along with albumin and electrolytes. All the investigations were within normal limits. Electrocardiogram was done which was within normal limits. Magnetic resonance imaging of brain was obtained which did not show any abnormality. Considering the above case scenario and ruling out the possible causes of acute delirious state such as electrolyte abnormalities and intracranial bleed, we entertained the possibility of IIE. The patient was started on hydration therapy with IV fluids and dextrose normal saline infusion at the rate of 100 ml/m2 followed by which injection methylene blue was procured and started at the dose of 50 mg (1% aqueous solution) IV over 5 min, six times daily, and antiemetics such as ondansetron 4 mg by needle were administered twice a day for initial 3 days and then whenever needed. Within a period of 24 h, the patient started improving in the form of decrease in vomiting and response to oral commands. Later complete recovery occurred within 48–72 h. Till then injection methylene blue and hydration were continued. Furthermore, the patient was given IV 5% albumin.\nHence, the patient who had presented with above-mentioned complaints with normal imaging and blood investigations and who had responded to methylene blue confirmed our diagnosis of the IIE. Furthermore, retrospectively, we looked over the factors that precipitated the IIE. Albumin, renal and liver function, and electrolytes were well within normal limits at the start of infusion of ifosfamide. However, the patient had received injection fosaprepitant before the start of injection ifosfamide.\nWe then reviewed the literature, and it confirmed that the precipitating factor for IIE was none other than aprepitant.