Pathophysiology of the Esophagus Flashcards
Describe the anatomy of the oropharynx
The oropharynx consists of 3 sets of constrictor muscles (superior, middle, inferior). The inferior constrictor and cricopharyngeus comprise much of the upper esophageal sphincter. All are striated muscle.
What portion of the swallowing process is the oropharynx responsible for?
Deglutination: the involuntary pharyngeal phase of swallowing.
Which cranial nerves are involved in the involuntary pharyngeal phase of swallowing?
CN V (Trigeminal), X (Vagus), XI (Accessory), XII (Hypoglossal)
What is oropharyngeal dysphagia and what signs/symptoms may result?
OD is difficulty with swallowing. Patients may cough during or after meals, food bolus may pass into trachea or lungs. Can result in pneumonitis or pneumonia risk.
What are the three broad causes of dysphagia?
Neurologic disorders (Stroke, ALS, MS, Parkinson’s);
Skeletal muscle disorders (Myasthenia gravis, muscular dystrophy);
Structural diseases (Benign - Zener’s diverticulum, thyromegaly, Malignant - Squamous Cell Carcinomas, Lymphoma)
What is Zenker’s diverticulum?
An outpouching of the lower oropharynx leading to a defect in the muscular wall. the hypo pharyngeal mucosa projects out through it and produces a pouch. May result in dysphagia, halitosis (with bacterial colonization), and regurgitation of food or water.
Describe the anatomy of the upper third of the esophagus
The upper third is composed of striated muscle and contains the upper esophageal sphincter (Inferior constrictor and criccopharyngeal muscles). Innervation is by the motor efferents of the Vagal nerve from Nuc Ambiguous and uses ACh.
Describe the anatomy of the lower third of the esophagus
The lower third of the esophagus is composed of smooth muscle and contains the lower esophageal sphincter. The Muscularis Propria consists of an inner layer of circular muscle and an outer layer of longitudinal muscle. Innervation is the parasympathetic Vagal nerve (dorsal motor nuc.) and uses ACh.
What is the pathology, clinical presentation, and tests for Esophageal Motility diseases?
Pathology: Dysfunction of the nerve or musculature.
Clinical presentation: Esophageal dysphagia, odynophagia, chest pain, or esophageal reflux symptoms.
Testing: Manometry, 24hr pH testing, or Esophagram (barium X-ray)
What is the pathology, clinical presentation, and tests for Esophageal Structure Diseases?
Pathology: Mechanical or physical defects in the esophageal wall.
Clinical presentation: Esophageal dysphagia, odynophagia (sensation of food or water getting stuck in neck)
Testing: Upper endoscopy, biopsy, therapeutic dilation of strictures
Name three diseases of Esophageal Motility
Achalasia, Systemic neuromuscular diseases (myasthenia graves, muscular dystrophy), GERD
Name three diseases of Esophageal Structure
Esophagitis, Barrett’s metaplasia, Malignant strictures
What is the pathophysiology of GERD?
Gastric juices containing Hal acid, pepsin, and bile acids damage the squamous epithelial cells of the esophagus which lack a protective mucosal layer. May result from transient and inappropriate LES relaxation, Esophageal peristalsis, delayed gastric emptying, or hiatal hernia.
What are the symptoms of GERD?
Heartburn, sour taste, regurgitation of gastric juices without vomiting. Occasionally cough or laryngitis. Symptoms occur after a meal, after exercise, or when lying down.
What are the tests for GERD?
Manometry, 24hr pH study, barium x-ray, EGD (Upper endoscopy)
