Term
| How does the esophagus achieve "Deglutition"? |
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Definition
Form and transport bolus of food.
1) Peristaltic contractions of the muscular walls of the esophagus propel swallowed material into stomach.
**disruption leads to Dysphagia (difficult) or Odynophagia (pain)**
2) Tonically constricted sphincters prevent backflow
**Failure leads to reflux and heartburn or pyrosis** |
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Term
| What is the basic functional anatomy of the swallowing organs? |
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Definition
Pharynx and Esophagus.
1) Pharynx composed of 3 overlying layers of skeletal muscle
- Inferior pharyngeal constrictor thickens to form cricopharyngeaus muscle, which serves as the upper esophageal sphincter.
2) Below pharyngo-esophageal junction, esophagus forms continuous tube to stomach, consisting of and outer longitudinal and an inner circular layers of striated muscle.
- UES has high resting tone (Skel); relaxes with swallowing
- Tubular E has no resting tone; propagates contractions
- LES has high resting tone (Smooth); relaxes with swallowing
- Circular muscle layer thickens at esophagogastric junction to form lower esophageal sphincter |
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Term
| Describe the process of swallowing. |
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Definition
1) Tongue elevates and squeezes bolus into oral pharynx
2) Soft palate elevates to make contact with the posterior pharyngeal wall (sealing oropharynx from nasopharynx) and Larynx is elevated to make contact with epiglottis (closing laryngeal opening)
3) Two types of pharyngeal contraction occur (shortening and peristalsis)
4) UES relaxes its tonic contraction and then contracts powerfully as the peristaltic sequence passes
5) LES relaxes long before the peristaltic wave reaches the sphincter, and it finally contracts when the wave reaches it. |
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Term
| What is the basic neuromuscular control of swallowing? |
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Definition
1) Continuous discharge of efferent nerves from the nuclei of CN IX and X maintain the resting striated muscle tone of the oropharynx and UES.
**Peristaltic contraction occurs as it does, because single motor units are activated in a cranial-to-caudal sequence**
2) Smooth muscle esophagus is innervated by fibers from the DMN of CN X that synapse will neurons in the Myenteric plexus (these post-ganglionic cells actually cause relaxation/contraction)
**Resting contraction of LES is due to myogenic tone of sphincter muscle and NOT to strong tonic discharge. The first swallow-induced event in the UES is relaxation causes by vagal activation of inhibitory myenteric nerves that release NO. Peristaltic contractions in LES follow and occur by intrinsic esophageal neuromuscular mechanisms** |
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Term
| How does the neuromuscular regulation of peristalsis differ in the UES and the LES? |
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Definition
1) In the striated muscle of the UES, peristalsis is initiated by sequential cranio-to-caudal stimulation of motor units by nerve fibers arising from the nuclei of CN IX and X in the brainstem.
2) In the smooth muscle of the LES, the first swallow-induced action is NO-mediated relaxation due to stimulation of inhibitory post-ganglionic neurons in the myenteric plexus by efferents from the DMN of the vagus. This relaxation is following by peristaltic contractions due to "reversal of the inhibition" |
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Term
| What is GERD and how is it defined clinically? |
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Definition
GERD is defined as the experience of heartburn with mucosal inflammation.
Non-erosive RD is heartburn in the absence of mucosal lesions.
- GERD often occurs because LES does not maintain adequate tone at rest or because it relaxes inappropriately
**GERD linked to hiatal hernias (acid creates hernia, which stores more acid). |
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Term
If a patient presents experiencing a "burning" sensation in the mid-epigastric near the xyphoid process. He reports that he feels it every once in a while, especially after eating large, fatty meals. He also reports dysphagia in the context of this pain.
What is the mechanism(s) of this sensation? |
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Definition
Heartburn (dysphagia is common associated symptom due to lesions)
**remember, it should not present as sharp, crampy or squeezy pain**
Multiple ways.
1) Over-eating increases P gradient from stomach to esophagus
2) Fats entering duodenum decrease force of closure of the LES and decrease rate of gastric emptying.
3) Gastric distension increases spontaneous relaxations of LES. |
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Term
| What is the easiest way to tell if heartburn is caused by GERD? How do you confirm Esophagitis? |
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Definition
1) Therapeutic trial with proton-pump inhibitors (inhibit acid production in stomach).
**ONLY in simple cases**
Failure of trial suggests symptoms do not arise from acid reflux and should cause you to make a more extensive evaluation.
2) If worried about mucosal injury (esophagitis), use endoscopy
- Ambulatory intra-esophageal pH monitoring and Barium swallow are second-line option |
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Term
| What is the basic treatment strategy for reflux disease? |
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Definition
1) Lifestyle (over-eating, carbonated beverages, late-evening meals, acid-like foods).
2) Proton pump inhibitors >> Histamine-2 receptor antagonists
3) Surgery is an option |
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Term
| What are the important (3) complications of chronic GERD? |
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Definition
1) Stricture (narrowing) from scar formation
2) Barrett's esophagus
- Metaplasia with cylindrical epithelium and goblet cells
- Cancer risk (Gradual dysplasia to Adenocarcinoma: rapid treatment may not help)
3) Dysphagia (impaired bolus transit along pharyngo-esophageal conduit)
- Can be Oropaharyngeal (commonly neuromuscular) and Esophageal (GERD) |
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Term
| What are the major steps in a workup of a patient with Dysphagia? |
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Definition
1) Characteristics of dysphagia
- Where? How does it feel?
- Suprasternal notch, substernally or in anterior chest wall indicates Esophageal
2) Exacerbating/Relieving factors
- Esophageal is worse with solids than liquids
- Oropharyngeal is worse with liquids than solids
3) Chronology of symptoms
- Esophageal is mild and progressive
4) Associated symptoms
- Oropharyngeal may also have nasopharyngeal reflux, choking and coughing with wallowing |
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Term
| What is the basic diagnostic strategy for Esophageal Dysphagia for Solids? |
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Definition
Sub-sternal or Anterior wall chest pain that is worse with solids than liquids, typically due to structural abnormality.
Get an endoscopy for diagnosis/simple intervention.
Intermittent, esosinophillic process or progressive process indicates heartburn (GERD)
1) Sudden
- Foreign body
2) Intermittent
- Schatzki's mucus ring
- If Eosinopholic, think heartburn and GERD stricture
3) Progressive
- Heartburn (GERD) or Cancer if >50 |
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Term
| What is the basic diagnostic strategy for Esophageal Dysphagia for Solids and Liquids? |
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Definition
More commonly due to functional disturbance, rather than structural (as is case for solids alone)
Infection/Neuromuscular is likely cause
1) Recent
- Think immunosuppression, Ab, HIV (Candida, CMV, HSV)
2) Intermittent
- Chest pain indicates motility disorder
3) Progressive
- Achalasia or Scleroderma |
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Term
| What is Eosinophillic Esophagitis? How do you diagnose/Treat? |
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Definition
1) Asthma equivalent of esophagus (IL-5 mediated), with intermittent dysphagia for solids.
2) Need a biopsy that demonstrates eosinophilic infiltration of epithelium. Give swallowed topical steroids (not inhaled) |
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Term
| What is Esophageal Dysmotility? |
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Definition
Dysphagia, Achalasia and/or Esophageal spasm associated with neuron loss in Myenteric ganglion
- Patients with achalasia have loss of normal peristaltic contractions and incomplete relaxation of LES, which leads to dysphagia and regurgitation.
- Esophageal spasm consists of non-propogating contractions WITH LES relaxation. |
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Term
A patient presents with dysphagia, heartburn and intermittent regurgitation of sour fluid.
What are the major histological features of this condition? |
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Definition
Reflux Esophagitis
**Symptom severity does not correlate with presence of histological esophagitis**
1) Inflammation, with intra-eptithelial lymphocytes, eosinophils and neutrophils
2) Intercellular edema
3) Hyperplasia of basal zone of squamous epithelium
4) Elongation of lamina propria papillae |
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Term
What kind of esophageal disease is described in each of the following histological pictures?
1) Esophageal ulcerations with viral inclusions in the nuclei of squamous epithelial cells, as well as multi-nucleated squamous cells adjacent to the lesions.
2) Ulceration of esophageal mucosa with viral inclusions in the cytoplasm and nuclei of infected stromal, inflammatory and endothelial cells at the base of the ulcer.
3) White plaques in the esophagus with ulceration and oral thrush.
4) Esophageal dysmotility and failure of LES relaxation with absent ganglion cells in the myenteric plexus |
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Definition
All are infectious esophagitis which may present with dysphagia and odynophagia.
1) HSV
2) CMV
3) Candida or other fungal
4) Achalasia from Chagas (T. cruzi) in south/central america
5) Eosinophillic esophagitis (treat with Monelukast, diet and steroids) |
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Term
Patient presents with dysphagia that will not improve with H+ pump inhibitors.
You notice esophageal ulcerations, with proximal stenosis and "corrugation" (trachealized) of the esophagus. You also note a intraepithelial eosinophilic infiltrate.
What is going on and what do you do? |
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Definition
| Eosinophillic esophagitis- treat with Monelukast, diet and steroids |
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Term
| What is the most common type of esophageal neoplasm in the US? |
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Definition
| Adenocarcinoma (It is squamous cell world wide) |
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Term
| What is the most important risk factor for esophageal adenocarcinoma? |
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Definition
Barrett's esophagus, in which acid reflux over type leads to columnar metaplasia of squamous epitheliumin esophagus.
Diagnosed as "columnar epithelium at gastroesophageal junction with goblet cells replacing distal squamous mucosa," also called "Intestinal metaplasia."
In patients with Barrett's esophagus, Smoking is another risk factor |
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Term
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Definition
Important risk factor for invasive cancer in patients with Barrett's esophagus.
Molecular and microscopic changes that are common to invasion (hyper-chromasia, nuclear enlargement, necrosis, variation in shape, mitotic figures) WITHOUT actual invasion beyond BM (as opposed to "Carcinoma")
At molecular level, abnormal chromosome counts (aneuploidy) and mutations in tumor supressor genes. |
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Term
| What is the prognosis of Esophageal adenocarcinoma? How does it compare to Squamous cell? |
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Definition
Remember, adenocarcinoma occurs in distal esophagus in the context of Barrett's esophagus. These patients present with progressive dysphagia for solid food along with weight loss, with or without GERD symptoms (<50%).
- Strongly depends on stage at time of treatment (If there is metastasis 5 year survival is <10%, otherwise it is >80%).
- Squamous cell is also stage-dependent, but tends to be a bit better. |
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Term
| What are the major factors associated with the development of Squamous cell carcinoma of the esophagus? |
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Definition
1) Smoking and Alcohol**
2) Diet
3) Esophageal disorders
4) Genetics |
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Term
| How does the location of esophageal adenocarcinoma and squamous cell carcinomas differ? |
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Definition
1) Adenocarcinoma is in distal esophagus where Barrett's esophagus takes place.
- Looks glandular
2) SCC takes place in middle 1/3 of esophagus (50% of time)
- Look like squamous epithelium with kerratin, desmosomes and intracellular bridges. |
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Term
| How can you tell easily between GERD and eosinophillic esophagitis? |
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Definition
| Eosinophils in GERD will only be in distal esophagus, while they will be up and down in Eosinophillic |
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