Esophageal Pathophysiology Flashcards
Three muscles in the upper esophageal sphincter?
Inferior pharyngeal constrictor
Cricopharyngeus
Cervical esophagus
(all striated muscle)
Two types of muscle in the esophagus?
Striated (skeletal) muscle at the top, smooth muscle for most of it.
How is breathing related to lower esophageal sphincter (LES) function? In what condition will this not well?
In inhaling, contraction of diaphragm will squeeze the LES at the esophageal hiatus.
This won’t work well when patient has a hiatal hernia.
Does the esophagus have a serosal layer? Why is that significant?
No. Not having a serosal layer means… cancer spreads more easily to lymphatics.
2 nuclei in brain from which motor signals for swallowing originate?
Skeletal muscle: Nucleus ambiguus.
Smooth muscle: Dorsal motor nucleus (of CN X)
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?
Caudal DMN first sends inhibitory signals to smooth muscle.
Raustral DMN then sends activating signals to smooth muscle.
This happens in waves -> peristalsis.
What kinds of synapses (i.e. which neurotransmitter) are used for inhibitory and excitatory signaling to esophagus smooth muscle?
Excitatory: Cholinergic
Inhibitor: Non-cholinergic (the picture says NO)
What’s the LES doing most of the time? What happens when you swallow?
Having basal tone.
When there’s swallowing, relaxation is induced by NANC inhibitory neurons (using NO).
What happens when you burp, or otherwise when the stomach is distended and stuff needs to get out?
Transient LES Relaxation (TLESR).
What’s dysphagia?
Sensation of swallowing being abnormal.
What’s odynophagia?
Pain when swallowing.
What’s globus?
Sensation of something being stuck in throat.
What is regurgitation?
Effortless return of material into the esophagus (not to be confused with vomiting, which is forceful)
When a patient says “I have heartburn,” you should ask…
“What do you mean by heartburn?”
What is achalasia?
Impaired esophageal motility.
What parts (UES, esophagus, LES) don’t work in achalasia?
UES relaxes, but the peristalsis of the esophagus doesn’t happen.
What’s the pathophysiology of achalasia?
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)
Achalasia histology?
Inflammation in the myenteric plexus of the esophagus followed by scarring.
What’s pseudoachalasia? Causes?
Mimicking of achalasia due to various cancers, surgery, benign tumors, etc.
Treatments for achalasia?
Meds - not very effective
Botox injection - effect is very transient.
Pneumatic dilation
Heller myotomy (cut the LES)
What’s the Montreal definition of GERD?
> 2 episodes of heartburn a week.
Adversely affecting patient’s well-being.
Why is decreased salivation related to GERD?
Saliva has antacid in it.
3 things that can cause GERD? (there are probably more)
Hiatal hernia - very common.
Reduced LES tone.
Delayed gastric emptying.
In patients WITHOUT hiatal hernia, main cause of GERD is…
TLESR
In patients WITH hiatal hernia, main cause of GERD…
is still TLESR, but other causes like strain and low LES pressure are almost as common
What is one discreet GERD-related phenomenon that obesity increases?
TLESR
due to increased intra-abdominal pressure
What does esophagus look like normally? Can it look normal in GERD?
“Pearly white”
Yes, patients with GERD can a normal looking esophagus.
2 types of anti-secretory meds?
Proton-pump inhibitors (PPIs)
H2 antagonists
Important lifestyle changes to help GERD?
Weight loss.
Avoid nighttime meals.
Odynophagia with a irregular looking esophagus on barium swallow x-ray is bad.
Yeah, it might be cancer, which has a tendency to quickly metastasize.
What is Barrett’s esophagus? What is required for diagnosis?
Squamous -> columnar metaplasia of the esophagus.
Diagnosis requires that you see this both in endoscopy and histology.
Why do we care about Barrett’s esophagus?
It’s a precursor lesion to adenocarcinoma of the esophagus.
Really fine detail?: 2 morphogenetic factors that might be involved in the squamous -> columnar metaplasia of Barrett’s esophagus?
CD-X and BMP-4
it’s tiny on the slide, but he did read it…
3 candidate cells of origin in Barrett’s esophagus?
Squamous epithelium via transdifferentiation.
Stem cells (Basal layer, submucosal, hematopoetic?)
Residual embryonic tissue at GE junction
Treatments for cancerous lesions of the esophagus?
Endoscopic resection (just cut it out. Curative if local.) Radiofrequency ablation (burn away all the stuff, cut out remaining lesions later)
What does eosinophilic esophagitis classically look like on endoscopy?
“trachea-like” fibrous rings
eosinophilic exudate (but it looks like pus, grossly)
food stuck in esophagus
Common presenting symptoms of eosinophilic esophagitis?
Dysphagia Food impaction Heartburn Chest pain (abdominal pain and odynophagia)
Pathophysiology of eosinophilic esophagitis?
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
What’s the chemokine that attracts eosinophils to the esophagus?
Eotaxin-3 (induced by IL-13 made by Th2 cells)
Treatment for esinophilic esophagitis? (4 things)
Avoid common food allergens.
Dilation
PPIs
Topical steroids
What are 2 diseases that can cause fibrosis of the esophagus?
Eosinophilic esophagitis
Scleroderma
