The nurse would include in a teaching plan about mouth care for a child receiving chemotherapy to:

A white glow of the pupil, often referred to as "cat's eye reflex" or "leukocoria," is a significant and characteristic sign of retinoblastoma. It occurs when the tumor within the eye reflects light, resulting in a white or yellowish glow in the pupil when light is shined into it. This can be seen in flash photographs or in certain lighting conditions. It's a crucial sign that may indicate the presence of retinoblastoma, a rare eye cancer that primarily affects young children.

The other options, B (ptosis of the eye), C (fixed and dilated pupil), and D (purulent eye discharge), are not typically associated with retinoblastoma. Ptosis is the drooping of the upper eyelid, a fixed and dilated pupil is usually a sign of neurological issues, and purulent eye discharge is often associated with eye infections rather than retinoblastoma.

A. Obtaining a throat culture and B. visualizing the epiglottis with a tongue depressor are not safe actions for the nurse to perform without appropriate medical equipment and expertise. These actions can trigger a sudden airway obstruction in a child with epiglottitis. The priority is to ensure airway patency and seek immediate medical assistance.

C. Place the child in an upright position.

Suspected epiglottitis is a medical emergency that can result in rapid airway obstruction. Placing the child in an upright position helps improve airflow by allowing the throat to open and reduces the risk of complete airway obstruction. It's important not to perform invasive procedures (such as throat culture or visualization of the epiglottis) without proper medical equipment and expertise, as these actions can lead to worsening airway obstruction.

D. Transporting the child to radiology for a throat x-ray is not appropriate in this situation, as it may delay necessary interventions to secure the airway.