Esophageal Pathophysiology

Question 0

Three muscles in the upper esophageal sphincter?

Answer 0

Inferior pharyngeal constrictor
Cricopharyngeus
Cervical esophagus
(all striated muscle)

Question 1

Two types of muscle in the esophagus?

Answer 1

Striated (skeletal) muscle at the top, smooth muscle for most of it.

Question 2

How is breathing related to lower esophageal sphincter (LES) function? In what condition will this not well?

Answer 2

In inhaling, contraction of diaphragm will squeeze the LES at the esophageal hiatus.
This won’t work well when patient has a hiatal hernia.

Question 3

Does the esophagus have a serosal layer? Why is that significant?

Answer 3

No. Not having a serosal layer means… cancer spreads more easily to lymphatics.

Question 4

2 nuclei in brain from which motor signals for swallowing originate?

Answer 4

Skeletal muscle: Nucleus ambiguus.

Smooth muscle: Dorsal motor nucleus (of CN X)

Question 5

Important: The dorsal motor nucleus (DMN) sends two different types of signals to smooth muscle when swallowing. Where do they come from, what are they, where do they go, and when?

Answer 5

Caudal DMN first sends inhibitory signals to smooth muscle.
Raustral DMN then sends activating signals to smooth muscle.
This happens in waves -> peristalsis.

Question 6

What kinds of synapses (i.e. which neurotransmitter) are used for inhibitory and excitatory signaling to esophagus smooth muscle?

Answer 6

Excitatory: Cholinergic
Inhibitor: Non-cholinergic (the picture says NO)

Question 7

What’s the LES doing most of the time? What happens when you swallow?

Answer 7

Having basal tone.

When there’s swallowing, relaxation is induced by NANC inhibitory neurons (using NO).

Question 8

What happens when you burp, or otherwise when the stomach is distended and stuff needs to get out?

Answer 8

Transient LES Relaxation (TLESR).

Question 9

What’s dysphagia?

Answer 9

Sensation of swallowing being abnormal.

Question 10

What’s odynophagia?

Answer 10

Pain when swallowing.

Question 11

What’s globus?

Answer 11

Sensation of something being stuck in throat.

Question 12

What is regurgitation?

Answer 12

Effortless return of material into the esophagus (not to be confused with vomiting, which is forceful)

Question 13

When a patient says “I have heartburn,” you should ask…

Answer 13

“What do you mean by heartburn?”

Question 14

What is achalasia?

Answer 14

Impaired esophageal motility.

Question 15

What parts (UES, esophagus, LES) don’t work in achalasia?

Answer 15

UES relaxes, but the peristalsis of the esophagus doesn’t happen.

Question 16

What’s the pathophysiology of achalasia?

Answer 16

Loss of myenteric inhibitory, NO-ergic neurons in the esophagus. - demonstrating the importance of the relaxation phase of peristalsis.
May be a autoimmune, viral, or neurodegenerative process.
(why they disappear just in the esophagus, we have no idea)

Question 17

Achalasia histology?

Answer 17

Inflammation in the myenteric plexus of the esophagus followed by scarring.

Question 18

What’s pseudoachalasia? Causes?

Answer 18

Mimicking of achalasia due to various cancers, surgery, benign tumors, etc.

Question 19

Treatments for achalasia?

Answer 19

Meds - not very effective
Botox injection - effect is very transient.
Pneumatic dilation
Heller myotomy (cut the LES)

Question 20

What’s the Montreal definition of GERD?

Answer 20

> 2 episodes of heartburn a week.

Adversely affecting patient’s well-being.

Question 21

Why is decreased salivation related to GERD?

Answer 21

Saliva has antacid in it.

Question 22

3 things that can cause GERD? (there are probably more)

Answer 22

Hiatal hernia - very common.
Reduced LES tone.
Delayed gastric emptying.

Question 23

In patients WITHOUT hiatal hernia, main cause of GERD is…

Answer 23

TLESR

Question 24

In patients WITH hiatal hernia, main cause of GERD...

Answer 24

is still TLESR, but other causes like strain and low LES pressure are almost as common

Question 25

What is one discreet GERD-related phenomenon that obesity increases?

Answer 25

TLESR | due to increased intra-abdominal pressure

Question 26

What does esophagus look like normally? Can it look normal in GERD?

Answer 26

"Pearly white" | Yes, patients with GERD can a normal looking esophagus.

Question 27

2 types of anti-secretory meds?

Answer 27

Proton-pump inhibitors (PPIs) | H2 antagonists

Question 28

Important lifestyle changes to help GERD?

Answer 28

Weight loss. | Avoid nighttime meals.

Question 29

Odynophagia with a irregular looking esophagus on barium swallow x-ray is bad.

Answer 29

Yeah, it might be cancer, which has a tendency to quickly metastasize.

Question 30

What is Barrett's esophagus? What is required for diagnosis?

Answer 30

Squamous -> columnar metaplasia of the esophagus. | Diagnosis requires that you see this both in endoscopy and histology.

Question 31

Why do we care about Barrett's esophagus?

Answer 31

It's a precursor lesion to adenocarcinoma of the esophagus.

Question 32

Really fine detail?: 2 morphogenetic factors that might be involved in the squamous -> columnar metaplasia of Barrett's esophagus?

Answer 32

CD-X and BMP-4 | it's tiny on the slide, but he did read it...

Question 33

3 candidate cells of origin in Barrett's esophagus?

Answer 33

Squamous epithelium via transdifferentiation. Stem cells (Basal layer, submucosal, hematopoetic?) Residual embryonic tissue at GE junction

Question 34

Treatments for cancerous lesions of the esophagus?

Answer 34

``` Endoscopic resection (just cut it out. Curative if local.) Radiofrequency ablation (burn away all the stuff, cut out remaining lesions later) ```

Question 35

What does eosinophilic esophagitis classically look like on endoscopy?

Answer 35

"trachea-like" fibrous rings eosinophilic exudate (but it looks like pus, grossly) food stuck in esophagus

Question 36

Common presenting symptoms of eosinophilic esophagitis?

Answer 36

``` Dysphagia Food impaction Heartburn Chest pain (abdominal pain and odynophagia) ```

Question 37

Pathophysiology of eosinophilic esophagitis?

Answer 37

Seems to be Type 2 Helper T cell (Th2)-mediated and happens in atopic (allergy-prone) patients. Lots of cytokines: IL-13, IL-4, IL-5

Question 38

What's the chemokine that attracts eosinophils to the esophagus?

Answer 38

Eotaxin-3 (induced by IL-13 made by Th2 cells)

Question 39

Treatment for esinophilic esophagitis? (4 things)

Answer 39

Avoid common food allergens. Dilation PPIs Topical steroids

Question 40

What are 2 diseases that can cause fibrosis of the esophagus?

Answer 40

Eosinophilic esophagitis | Scleroderma