Sandbox: esophageal web
Pathogenesis
Inflammation
Esophageal webs are thought to be due to the chronic damage to the esophageal mucosa.
This is supported by the presence of inflammatory cells in the wall of the web.
In allergic esophagitis, eosinophils were found while in cases of chronic inflammation as GERD, lymphocytes prevailed.
Congenital theory
Esophageal webs are thought to be due to failure of the esophagus to recanalize.
Specimens showed that the esophageal webs contained respiratory epithelium supporting this theory.
The webs mostly remain asymptomatic for long times and that is why it is not correlated with being congenital.
Iron deficiency
The esophageal webs of Plummer-Vinson syndrome have been associated with iron deficiency anemia in many studies.
The exact mechanism by which iron deficiency causes esophageal webs is not known, but it was hypothesized that iron deficiency starts a sequence of events in the esophageal epithelium that ends in its damage and formation of a web.
Moreover, treatment of iron deficiency in Plummer-Vinson syndrome patients leads to resolution of dysphagia even before the laboratory results become normal.
Gross picture
Esophageal webs appear as an eccentric narrowing of the esophageal lumen (while rings cause circumferential narrowing).
Microscopic picture
Esophageal webs are covered by esophageal squamous epithelium.
Historical perspective
In 1944, esophageal webs were first described by Templeton and it was thought to be a congenital disease because most of the patients were children.
In 1953, a series of case reports of patients having dysphagia and radiological signs denoting esophageal narrowing made the diagnosis of esophageal rings not confined to the pediatric population.
In 1968, pathological examination of specimens from the esophageal rings proved that none of them had muscle involvement.
Classification
Type A
Type A esophageal rings describe webs that involve the muscle layer of the esophageal wall and lies in close proximity to the squamocolumnar junction.
It is less common than type esophageal webs.
Type B
Type B esophageal rings describe the webs that involve only the mucosa and submucosa of the esophagus.
It is often named Schatzki ring.
It is located exactly at the squamocolumnar junction.
Type C
Type C esophageal rings refer to wall invaginations due to pressure from the diaphragm.
It is rare with no clinical significance.
Causes
Iron deficiency anemia
Plummer-Vinson syndrome
Celiac sprue
Zenkers diverticulum
Epidermolysis bullosa 
Bullous pemphigoid 
Graft versus host disease
Pemphigus Vulgaris
Risk factors
Zenkers diverticulum.
Epidemiology
Prevalence
Webs are diagnosed in 5-15% of patients doing barium esophagogram for diagnosing the cause of dysphagia.
Congenital esophageal webs are estimated to be 1 in 25,000 to 1 in 50,000 live births.
Race
Esophageal webs affects the whites more than other population
Sex
Esophageal webs tend to be more common in females.
This may be due to the increased prevalence of iron deficiency anemia.
Age
Esophageal has no predilection for an age group, however, it is usually not symptomatic until after the age of 40.
History and symptoms
History
Patients are usually older than 40 years because it can be asymptomatic for a long time.
The patient may give a history of the cause such as iron deficiency anemia, GERD, or autoimmune disease.
The patient may give a history of excessive food chewing to facilitate swallowing.
Symptoms
Most of the esophageal webs are asymptomatic.
The major symptom of esophageal webs is dysphagia.
Dysphagia is usually more for solid food.
Esophageal webs does not usually result in malnutrition nor to weight loss.
Physical examination
Esophageal webs do not have significant physical exam findings, however, it might show the signs of the cause such as:
Koilonychia and glossitis in the cases of Plummer-Vinson syndrome.
It might also show the findings in in the cases of skin disorders such as epidermolysis bullosa, 
bullous pemphigoid, and pemphigus vulgaris.
Lab
A Laboratory workup is not necessary for the diagnosis of esophageal webs because the diagnosis is dependent on the symptoms and radiological tests.
CBC might show microcytic hypochromic anemia in cases of Plummer-Vinson syndrome as it is the primary cause of the esophageal web.
Antibody panel might be done to screen for the primary cause.
Radiology
Barium esophagogram
It is more sensitive in detecting esophageal webs than endoscopy.
Webs appear as a uniform narrowing of the esophageal lumen.
Endoscopy
Endoscopy is less sensitive in detecting webs than barium esophagram.
Esophageal webs appear as a smooth membrane which is usually not present all around the lumen.
It allows obtaining a biopsy from the lesion in addition to excluding other causes of dysphagia.
Esophageal webs can go unnoticed during doing esophagram as it is only a mucus membrane fold with no muscle support.
Medical
Patients should be educated to alter their diet and food habits especially in the cases when esophageal webs are secondary to GERD.
H2 blockers or proton pump inhibitors can be used for managing the symptoms of GERD and the prevention of progression to webs.
Proper management of acid reflux after esophageal dilation is associated with decreased recurrence of symptoms.
Surgical
Esophageal dilation is the cornerstone of treating esophageal webs especially in cases refractory to medical treatment.
In cases of eosinophilic esophagitis, dilation should be gradual as sudden forced dilation is associated with muscle tears.
In cases of non-eosinophilic esophagitis, dilation using a single dilator is more effective than graded dilation.
Esophageal dilation is associated with improved symptoms of dysphagia.
Esophageal dilation is associated with symptom recurrence in about 89% at five years and often requires redoing of the procedure.