esophagus

what are the two main jobs of the esophagus

• convey solids and liquids from the hypopharynx to the stomach and keep it there

• prevent gastric contents from refluxing and regurgitating

what is refluxing

gastric contents going into the esophagus

what is regurgitating

gastric contents going to the mouth or airway

what is the role of the lower esophageal sphincter (LES)

• prevent reflux

• allow contents to pass into stomach

what is the role of the upper esophageal sphincter (UES)

• prevents regurgitation

• will relax to allow passage into esophagus

what is the role of the enteric nervous system

enteric neurons will relay neurons between the vagus and the smooth muscle cells in the GI tract

the enteric nervous system can/will act _____________ (independently/dependently), the role of the Vagus is to modulate the _________________

will act independently; vagus will modulate the enteric nervous system

what type of muscle is the UES

• cricopharyngeal muscle

• striated

what type of muscle is the LES

• smooth muscle

• augmented by diaphragmatic hiatus and phreno-esophageal ligaments

which sphincter can you learn to control voluntarily

UES

what is the role of nitrous oxide in esophageal motility

will inhibit/help the sphincter to relax

what is the role of acetylcholine in esophageal motility

excitatory/ close sphincter

what is Auerbach’s plexus

part of the enteric nervous system; will control peristalsis

what is peristalsis

wavelike muscular contractions in tubular structures that are characterized by coordination alternating contractions

what modulates peristalsis

• vagus

• esophagus and bowel movements can still funx w/o the vagus

what is primary peristalsis

initiated by swallowing

what is secondary peristalsis

initiated by stretch of the esophageal wall or the presence of refluxed material

what are the 2 protective mechanisms that breakdown in GERD

• keep acid in the stomach

• neutralizes/clear acid from the esophagus

what role does salivary secretions play in the esophagus

will neutralize any acid in the esophagus w bicarb (salivary dysfunc→ GERD)

what are tLESRs and what role do they play in GERD

transient lower esophageal sphincter relaxation; help release gastric pressure— particularly the air you swallow while you eat, is the root of most GERD

what effect does sleep have on salivary secretion and esophageal peristalsis

• saliva production dec

• no esophageal peristalsis

what is a hiatal hernia

part of the stomach is projected up above the diaphragm into the chest

why are pts w hiatal hernias more predisposed to reflux

they have lost the diaphragmatic component to help keep things in stomach → tLESR can result in gastric acid leaving the little pouch and will go to esophagus (does NOT mean pt has reflux)

how do esophageal motor disorders present in terms of symptoms

• problem of smooth muscle OR the nervous system wiring to the muscle

• typically presents w dysphagia

what are the two types of esophageal motor disorders

• scleroderma

• achalasia

what is scleroderma and how does this affect the esophagus

• autoimmune destruction of smooth muscle that gets replaced w fibrous tissue

• no proper peristalsis

what are the two types of scleroderma and their prognosis

• generalized→ poor prognosis

• localized/CREST → better prognosis

what is CREST

• Calcinosis

• Raynaund’s

• Esophageal dysmotility

• Skin thickening

• Telangiectasia

describe the process of how scleroderma can lead to adenocarcinoma

smooth muscle atrophy, dysmotility, loss of longitudinal folds → lower LES pressure → more reflux → GERD → Barrett → adenocarcinoma

what is achalasia and how does this affect the esophagus

result of the destruction of the enteric nervous system in the esophagus → poor-to-no peristalsis and failure of LES to relax bc no nitrous

manometry of achalasia

poor peristalsis w HIGH sphincter resting pressure “snapped shut”

in achalasia, compared to cancer, is there progressive dysphagia w liquids then solid or solids then liquids

• achalasia: liquids then solids

• cancer: solids then liquids

what are the primary causes of achalasia

rare: neural degenerative conditions

what are the secondary causes of achalasia (3)

• autoimmune associations

• infiltrative disorders

• infections

prognosis of achalasia

inc risk of esophageal SCC

what do you see histologically in achalasia

progressive loss of ganglion cells in myenteric auerbach plexus

what are the common symptoms of esophageal disease

• odynophagia

• heartburn

• dysphagia

what is odynophagia

acute pain during swallowing of solids or liquids

what can cause odynophagia

ulcerations of the esophageal mucosa → herpes, candida

what is dysphagia

sensations of ingested bolus arrested or slowed in transit down esophagus

what can cause dysphagia

dysmotility or obstructing lesion→ problems w smooth muscle or problems w innervations to the smooth muscle

what are the main layers of the GI tract from deepest to superficial

1. mucosa

2. submucosa

3. muscularis propria/externa

4. adventitia vs serosa (depending on where you are in the GI tract)

what resides in the mucosa layer of the GI tract

• epithelium

• lamina propria- contains loose CT w lymphocytes, plasma cells, eosinophils, macrophages, mast cells, and neutrophils

• muscularis mucosa

what resides in the submucosa layer of the GI tract

• glands

• nerve plexi- meissner

• blood vessels and lymphatics

• loose CT/stroma

what resides in the muscularis propria/externa in the GI tract

• inner and outer muscle layers

• nerve plexi- auerbach

what components reside in the adventitia vs serosa in the GI tract

• both contain: nerves, blood vessels, lymphatics, and loose CT

• adventitia LACKS mesothelial lining cells

the esophagus _____________ (does/does not) have serosa, what effect does this have on esophageal cancers

does not have serosa; esophageal cancers are less contained

what type of mucosa is in the esophagus

stratified squamous epithelium: non keratinized, appears pale, white, flat and grossly

what layer is Aurbach’s plexus in

muscularis propria

what does auerbach’s plexus control

peristalsis

what is schatzki’s ring and where is it found

muscular or mucosal ring in the distal esophagus

what is schatzki’s ring associated w

hiatal hernia

how can schatzki’s ring symptoms present

may be asymptomatic or symptomatic- dysphagia

what is zenker’s diverticulum and where is it

pseudodiverticulum- only in the mucosa and submucosa proximal to the UES

clinical characteristics of zencker’s diverticulum

• herniates at weak points→ pharynx-esophageal junction

• dysmotility, inadequate sphincter relaxation → high intraluminal pressure

• halitosis→ from food getting stuck in pouch

what is mallory weiss tear and where does it occur

tears in esophageal mucosa due to rapid inc in intraluminal pressure along lesser curvature and GEJ

what can cause a mallory weiss tear

excessive vomiting and retching

clinical presentation of mallory weiss tear

• vomiting bright red blood

• can rupture → mediastinitis

what is boerhaave syndrome and where does it occur

full thickness esophageal rupture due to inc in intraluminal pressure by the GEJ

why is boerhaave syndrome a medical emergency

• rupture → mediastinitis → sepsis

• 60% mortality despite intervention

• 100% mortality rate w/o timely tx

what are esophageal varices

dilated submucosal veins due to portosystemic collaterals due to portal hypertension (most commoly due to cirrhosis)

clinical presentation of a pt w esophageal varices

will be asymptomatic until it ruptures, vomit bright red blood

what is the most common cause of death in pts w cirrhosis

esophageal varices

what is esophagitis

inflammation of the esophagus

what are the major causes of esophagitis (4)

• GERD

• chemicals

• infections

• immune-mediated

where do pills often get stuck in the esophagus

at level w the aorta

what underlying conditions can allow for candida, herpes, and CMV esophagitis

• immunosuppression

• HIV/AIDS

• malignancy

• radiation

• steroid use

• antibiotic use

what is GERD

reflux of stomach acid

causes of GERD (4)

• medication

• alcohol and tobacco use

• obesity

• diabetic neuropathy

what is barrett’s esophagus

ongoing reflux of acid going into the esophagus

what is barrett’s esophagus associated w

GERD

how is dx of barrett’s esophagus made

gastric columnar epithelium WITH GOBLET CELLS- these are normally only seen in the intestinal epithelium

why is barrett’s esophagus dangerous

can lead to adenocarcinoma

what is the most common esophageal carcinoma in the west

esophageal adenocarcinoma

clinical presentation of esophageal adenocarcinoma

presents w solid then liquid dysphagia, weight loss, or hematemesis (vomit blood)

risk factors for esophageal adenocarcinoma (4)

• Barrett’s esophagus- MAIN RISK FACTOR

• obesity

• smoking

• radiation exposure

prognosis of esophageal adenocarcinoma

poor, but if limited to mucosa/submucosa, 5 yr survival rate inc drastically

what is the number 1 cancer type in the world

SCC

clinical presentation of esophageal SCC compared to esophageal adenocarcinoma

presents the same as adenocarcinoma

causes of SCC (5)

• alcohol and smoking- MOST COMMON

• diet high in nitrates, hot liquids

• esophgeal webs, diverticuli, achalasia, etx

• plummer-vinson syndrome

• HPV

prognosis of SCC

poor

where does SCC of the esophagus typically arise

upper and middle sections of the esophagus

where does adenocarcinoma of the esophagus typically arise

lower section of the esophagus