The little boy who visits Joey in the hospital is played by Richard Keith, who portrayed Little Ricky on "I Love Lucy."
The two attending doctors are listed in the credits as Dr. Fisher and Dr. Marks, a hat-tip to Joey's pals Al Fisher and Lou Marks, who had guest starred in the earlier episode "Weekend in the Mountains."
This was the first of six appearances by Joey Forman as Dr. Nolan. (He had also guested as a different character during the first season.)