The 5-year-old child is brought to the emergency department (ED) after a fall at school that has resulted in a broken wrist. The nurse notes the child is thin, with curved femurs and kyphosis. Metaphyseal fraying and cupping is noted on x-ray of the wrist. There is evidence of old fractures that healed poorly, as if they hadn’t been set properly. Upon review of the patient’s medical history, it does not appear that the patient has received ongoing well-child care. After laboratory evaluation, the child is diagnosed with rickets. The nurse prepares information on which medication for the family?

The 4-hour-old neonate in the nursery begins making rhythmic movements with the hands and smacking of the lips. An electroencephalogram is performed, and seizures are observed. The nurse prepares to administer which medication?

The patient is being treated with intravenous quinidine for malaria that was contracted while in Africa. Several hours after administration of the medication, the patient develops palpitations and dizziness. Electrocardiogram shows tachycardia and twisting of the QRS complexes around an isoelectric line. Which best describes the most likely etiology of this patient’s arrhythmia?