Title: A Puppy with a Mega Problem- Teacher’s guide

Learning Objectives

• Be able to explain megaesophagus and common symptoms.
• Be able to describe peristalsis in normal motility versus megaesophagus motility.
• Be able to describe the difference between primary and acquired megaesophagus.
• Be able to describe common treatments including the Bailey Chair and suggest diagnostics for megaesophagus.

Timeline:

1 hour

Materials Needed:

1. Megaesophagus presentation
2. Copies of case studies for each group of students
3. Computer or phone access for online quizzes, eBook material, and personal research

Lesson Plan:

Set up: Ideally this will be done as an optional activity or to help tie some concepts together for students. Students should understand basic GI physiology. At the beginning of the lesson students will take a two question quiz to check their understanding. Students can be seated in groups of 4 for this activity.

The lesson will include students following along with a pre-recorded PowerPoint. (However the instructor can present the PowerPoint themselves and can add info as they want to). The lesson is that the students are looking to adopt a megaesophagus puppy but do not know much about it so are going on a journey to research into the disorder.

Lesson: Play the PowerPoint for the students, you will stop on slide 2 to allow students to engage in independent research to learn more about megaesophagus. Once they complete this research they will take the short quiz to check their understanding. At this time you can watch responses as they come in and any questions that are consistently wrong can be talked about before students move on to the next part of the lesson.

Questions to ask students:

“Could someone summarize in their own words what megaesophagus is?”

“Did anything jump out at you? Did you find anything surprising?”

“Was there anything you learned that you didn’t know before?”

Next, You will play slides 3 and 4 for students before letting them each pick an envelope and read the blurb to themselves. Have students underline or star information they think is important. Next, students will read their short paragraph to their group and will spend 5 minutes discussing the different owners and whether any of the stories sound similar to the puppy they want to adopt.

Next, assign one of the following conditions to each of the groups to research further. The four conditions that often have megaesophagus as a disorder: Persistent right aortic arch, Myasthenia gravis, congenital idiopathic megaesophagus, and secondary megaesophagus (links to hypothyroidism, addisons, etc).  They need to answer the following questions as a group on their disorder.

When are dogs typically diagnosed?

What are some diagnostics for each of the conditions? What do you expect to see with those diagnostics?

BRIEFLY explain the physiology behind the disorder/disease that leads to the megaesophagus.

What is the treatment?

After 15 minutes have each group share what they find about the conditions. This discussion can then lead into the similarities and differences with Larry (your case study puppy). Which dog is most similar to Larry?

Finish up the PowerPoint.

Have students take a quiz on the differences between each type of disorder.

If you want to go above and beyond you may supply more case studies (below we included one about Charlie) and see if students are able to problem solve and identify what is the most likely diagnosis.

Pre-Learning Check In: Let’s Sit Down and Eat!

Students should answer the following questions to the best of their knowledge. These questions are meant for students to start thinking about the esophagus and its role in the GI tract.

The Esophagus and Motility Control

The GI tract is concerned with the mouth, esophagus, stomach,

small intestine, large intestine, and anus. When animals eat, food enters the mouth and gets chewed by the teeth create what is known as the food bolus (yellow ball in diagram). The bolus gets pushed down into the esophagus where it is squeezed by an involuntary movement called peristalsis until it reaches the stomach.

Peristalsis, or the series of coordinated wave-like muscle contractions allow food to be pushed down the stomach. The primary peristaltic wave occurs when the bolus reaches the esophagus. This wave promotes the relaxation of the lower esophageal sphincter allowing food to reach the stomach. Note: the lower esophageal sphincter closes back up to prevent food from coming back into the esophagus. The secondary peristaltic wave happens when food particles in the esophagus cause distention in the wall. The muscle coordinates contraction above the distention and relaxation below it, pushing the remaining food down into the stomach.

Individual Research: What is Megaesophagus?

Students will take 10-15 minutes to do individual research before sharing what they learned on the following topics:
1. Definition of megaesophagus and motility difference
2. Common symptoms relating to the dysfunction

3. Treatment associated with megaesophagus including the Bailey chair, special diets, and common medications

Supplemental Video: Bailey Chair

Helpful links:

What is Megaesophagus?

Home 1

Megaesophagus

Group Case Studies in envelopes:

Posts about megae

Additional links for the second part of the activity:

PRAA-

https://www.merckvetmanual.com/circulatory-system/congenital-and-inherited-anomalies-of-the-cardiovascular-system/persistent-right-aortic-arch-in-animals

https://www.animalsurgicalcenter.com/persistent-right-aortic-arch

MG:

https://www.vet.cornell.edu/departments-centers-and-institutes/riney-canine-health-center/health-info/myasthenia-gravis#:~:text=MG%20may%20cause%20generalized%20muscle,Regurgitation

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8478050/

http://caninemegaesophagusinfo.com/index.php/myasthenia-gravis/

Congenital Idiopathic Megaesophagus:

https://www.dvm360.com/view/diagnosis-and-management-megaesophagus-dogs-proceedings

https://www.merckvetmanual.com/digestive-system/congenital-and-inherited-anomalies-involving-the-digestive-system/congenital-and-inherited-anomalies-of-the-esophagus-in-animals

Other causes- Secondary Acquired Megaesophagus

https://bdvets.org/JAVAR/V2I2/b69_pp221-224.pdf

https://endocrinevet.blogspot.com/2012/09/megaesophagus-and-hypothyroidism-in-dogs.html

https://veterinarypartner.vin.com/default.aspx?pid=19239&id=4951482

https://www.ivis.org/library/evc/evc-voorjaarsdagen-amsterdam-2013/megaesophagus-associated-addisons-disease-a-dog

Case Study: Charlie and His Megaesophagus

Watch the following video about Charlie and answer the questions below.

1. Dr. Pol suspected megaesophagus prior to performing any diagnostics, what were key signs/symptoms that led the doctor to his suspicions?
2. What is the difference between vomiting and regurgitating? Which one of the two is Charlie exhibiting? Which one of the two is more commonly seen in patients with megaesophagus and why?
3. What treatments did Dr. Pol recommend and how will these help Charlie with his condition?

Test Your Knowledge

Google quiz link here with questions summarizing everything covered in this lesson plan.