A 32 year-old female presents to the emergency room with nausea, vomiting, loss of appetite, extreme weakness, decreased urine output, tingling around her lips, chest pain, palpitations and depressive mood. She was recently diagnosed with Burkitt’s lymphoma and was started on an aggressive rituximab therapy a few days ago. Her past medical history is significant for glucose-6-phosphate dehydrogenase deficiency. She is breast feeding her one-year old baby boy. In physical examination, you notice an anxious individual having some difficulty in breathing, tachycardia and decreased muscle strength. When you tap over the facial nerve in front of the ear you notice ipsilateral contraction of the facial muscles. Laboratory results are given below: Test Result Reference range Potassium (K⁺) 7.7 mEq/L 3.5 – 5.0 mEq/L Calcium 5.6 mg/dL 8.4 – 10.2 mg/dL Uric acid 10.7 mg/dL 3.0 – 8.2 mg/dL Phosphorus 5.2 mg/dL 3.0 – 4.5 mg/dL Creatinine 4.6 mg/dL 0.6 – 1.2 mg/dL Urea nitrogen 27 mg/dL 7 – 18 mg/dL Lactate dehydrogenase 743 U/L 45 – 200 U/L EKG showed QRS prolongation with peaked T waves. Of the following, which is the most likely diagnosis in this patient?
