Gastroesophageal reflux disease (GERD) affects approximately 40% of adults. Strictures occur in 7 to 23% of patients with GERD who are untreated.

With the exception of a few case reports describing survival without surgery, the mortality of untreated Boerhaave syndrome is nearly 100%. Its treatment includes immediate antibiotic therapy to prevent mediastinitis and sepsis, surgical repair of the perforation, and if there is significant fluid loss it should be replaced with IV fluid therapy since oral rehydration is not possible. Even with early surgical intervention (within 24 hours) the risk of death is 25%.

About 6 to 14 percent of patients who receive a routine barium swallow test of the esophagus are found to have a Schatzki ring.

Esophageal rupture is a rupture of the esophageal wall. Iatrogenic causes account for approximately 56% of esophageal perforations, usually due to medical instrumentation such as an endoscopy or paraesophageal surgery. In contrast, the term Boerhaave syndrome is reserved for the 10% of esophageal perforations which occur due to vomiting.

Spontaneous perforation of the esophagus most commonly results from a full-thickness tear in the esophageal wall due to a sudden increase in intraesophageal pressure combined with relatively negative intrathoracic pressure caused by straining or vomiting (effort rupture of the esophagus or Boerhaave's syndrome). Other causes of spontaneous perforation include caustic ingestion, pill esophagitis, Barrett's esophagus, infectious ulcers in patients with AIDS, and following dilation of esophageal strictures.

In most cases of Boerhaave's syndrome, the tear occurs at the left postero-lateral aspect of the distal esophagus and extends for several centimeters. The condition is associated with high morbidity and mortality and is fatal without treatment. The occasionally nonspecific nature of the symptoms may contribute to a delay in diagnosis and a poor outcome. Spontaneous effort rupture of the cervical esophagus, leading to localized cervical perforation, may be more common than previously recognized and has a generally benign course. Preexisting esophageal disease is not a prerequisite for esophageal perforation but it contributes to increased mortality.

This condition was first documented by the 18th-century physician Herman Boerhaave, after whom it is named. A related condition is Mallory-Weiss syndrome which is only a mucosal tear.

In case of iatrogenic perforation common site is cervical esophagus just above the upper sphincter whereas spontaneous rupture as seen in Boerhaave's syndrome perforation commonly occurs in the lower (1/3)rd of esophagus.

Dilated submucosal veins are the most prominent histologic feature of esophageal varices. The expansion of the submucosa leads to elevation of the mucosa above the surrounding tissue, which is apparent during endoscopy and is a key diagnostic feature. Evidence of recent variceal hemorrhage includes necrosis and ulceration of the mucosa. Evidence of past variceal hemorrhage includes inflammation and venous thrombosis.

Incidence of hiatal hernias increases with age; approximately 60% of individuals aged 50 or older have a hiatal hernia. Of these, 9% are symptomatic, depending on the competence of the lower esophageal sphincter (LES). 95% of these are "sliding" hiatus hernias, in which the LES protrudes above the diaphragm along with the stomach, and only 5% are the "rolling" type (paraesophageal), in which the LES remains stationary, but the stomach protrudes above the diaphragm.

Hiatus hernia are most common in North America and Western Europe and rare in rural African communities. Some have proposed that insufficient dietary fiber and the use of a high sitting position for defecation may increase the risk.

Neonates with TEF or esophageal atresia are unable to feed properly. Once diagnosed, prompt surgery is required to allow the food intake. Some children do experience problems following TEF surgery; they can develop dysphagia and thoracic problems. Children with TEF can also be born with other abnormalities, most commonly those described in VACTERL association - a group of anomalies which often occur together, including heart, kidney and limb deformities. 6% of babies with TEF also have a laryngeal cleft.

Zenker's diverticulum mainly affects older adults. It has an incidence of 2 per 100,000 per year in the UK, but there is significant geographical variation around the world.

Incidence of achalasia has risen to approximately 1.6 per 100,000 in some populations. Disease affects mostly adults between ages 30s and 50s.

A varix (pl. varices) is an abnormally dilated vessel with a tortuous course. Varices usually occur in the venous system, but may also occur in arterial or lymphatic vessels.

Examples of varices include:

- Varicose veins, large tortuous veins usually found on legs

- Sublingual varices

- Esophageal varices, commonly stemming from cirrhosis of the liver, also known as oesophageal varicose

- Gastric varices, commonly stemming from cirrhosis of the liver

- Intestinal varices

- Scrotal varices

- Vulvar varices

- Pelvic varices

- Vesical varices, varicose veins associated with the urinary bladder

- Rectal varices, which can be similar to external haemorrhoids

Esophageal diseases can derive from congenital conditions, or they can be acquired later in life.

Many people experience a burning sensation in their chest occasionally, caused by stomach acids refluxing into the esophagus, normally called heartburn. Extended exposure to heartburn may erode the lining of the esophagus, leading potentially to Barrett's esophagus which is associated with an increased risk of adenocarcinoma most commonly found in the distal one-third of the esophagus.

Some people also experience a sensation known as globus esophagus, where it feels as if a ball is lodged in the lower part of the esophagus.

The following are additional diseases and conditions that affect the esophagus:

- Achalasia

- Acute esophageal necrosis

- Barrett's esophagus

- Boerhaave syndrome

- Caustic injury to the esophagus

- Chagas disease

- Diffuse esophageal spasm

- Esophageal atresia and Tracheoesophageal fistula

- Esophageal cancer

- Esophageal dysphagia

- Esophageal varices

- Esophageal web

- Esophagitis

- GERD

- Hiatus hernia

- Jackhammer esophagus (hypercontractile peristalsis)

- Killian–Jamieson diverticulum

- Mallory-Weiss syndrome

- Neurogenic dysphagia

- Nutcracker esophagus

- Schatzki's ring

- Zenker's Diverticulum

It is not clear exactly what causes esophageal spasms. Sometimes esophageal spasms start when someone eats hot or cold foods or drinks. However, they can also occur with eating or drinking. The increased release of acetylcholine may also be a factor, but the triggering event is not known.

In ideal circumstances, patients with known varices should receive treatment to reduce their risk of bleeding. The non-selective β-blockers (e.g., propranolol, timolol or nadolol) and nitrates (e.g., isosorbide mononitrate (IMN) have been evaluated for secondary prophylaxis. Non-selective β-blockers (but not cardioselective β-blockers like atenolol) are preferred because they decrease both cardiac output by β blockade and splanchnic blood flow by blocking vasodilating β receptors at splanchnic vasculature. The effectiveness of this treatment has been shown by a number of different studies.

However, non-selective β-blockers do not prevent the "formation" of esophageal varices.

When medical contraindications to beta-blockers exist, such as significant reactive airway disease, then treatment with prophylactic endoscopic variceal ligation is often performed.

It can be caused by or associated with gastroesophageal reflux disease, esophagitis, a dysfunctional lower esophageal sphincter, disordered motility, lye ingestion, or a hiatal hernia. Strictures can form after esophageal surgery and other treatments such as laser therapy or photodynamic therapy. While the area heals, a scar forms, causing the tissue to pull and tighten, leading to difficulty in swallowing.

If there is dysphagia to both solids and liquids, then it is most likely a motility problem. If there is dysphagia initially to solids but progresses to also involve liquids, then it is most likely a mechanical obstruction. Once a distinction has been made between a motility problem and a mechanical obstruction, it is important to note whether the dysphagia is intermittent or progressive. An intermittent motility dysphagia likely can be diffuse esophageal spasm (DES) or nonspecific esophageal motility disorder (NEMD). Progressive motility dysphagia disorders include scleroderma or achalasia with chronic heartburn, regurgitation, respiratory problems, or weight loss. Intermittent mechanical dysphagia is likely to be an esophageal ring. Progressive mechanical dysphagia is most likely due to peptic stricture or esophageal cancer.

Esophageal stricture, or narrowing of the esophagus, is usually a complication of acid reflux, most commonly due to gastroesophageal reflux (GERD). These patients are usually older and have had GERD for a long time. Esophageal stricture can also be due to other causes, such as acid reflux from Zollinger-Ellison syndrome, trauma from a nasogastric tube placement, and chronic acid exposure in patients with poor esophageal motility from scleroderma. Other non-acid related causes of peptic strictures include infectious esophagitis, ingestion of chemical irritant, pill irritation, and radiation. Peptic stricture is a progressive mechanical dysphagia, meaning patients will complain of initial intolerance to solids followed by inability to tolerate liquids. When the diameter of the stricture is less than 12 mm the patient will always have dysphagia, while dysphagia is not seen when the diameter of the stricture is above 30 mm. Symptoms relating to the underlying cause of the stricture usually will also be present.

Esophageal cancer also presents with progressive mechanical dysphagia. Patients usually come with

rapidly progressive dysphagia first with solids then with liquids, weight loss (> 10 kg), and anorexia (loss of appetite). Esophageal cancer usually affects the elderly. Esophageal cancers can be either squamous cell carcinoma or adenocarcinoma. Adenocarcinoma is the most prevalent in the US and is associated with patients with chronic GERD who have developed Barrett's esophagus (intestinal metaplasia of esophageal mucosa). Squamous cell carcinoma is more prevalent in Asia and is associated with tobacco smoking and alcohol use.

Esophageal rings and webs, are actual rings and webs of tissue that may occlude the esophageal lumen.

- "Rings" --- Also known as Schatzki rings from the discoverer, these rings are usually mucosal rings rather than muscular rings, and are located near the gastroesophageal junction at the squamo-columnar junction. Presence of multiple rings may suggest eosinophilic esophagitis. Rings cause intermittent mechanical dysphagia, meaning patients will usually present with transient discomfort and regurgitation while swallowing solids and then liquids, depending on the constriction of the ring.

- "Webs" --- Usually squamous mucosal protrusion into the esophageal lumen, especially anterior cervical esophagus behind the cricoid area. Patients are usually asymptomatic or have intermittent dysphagia. An important association of esophageal webs is to the Plummer-Vinson syndrome in iron deficiency, in which case patients will also have anemia, koilonychia, fatigue, and other symptoms of anemia.

Achalasia is an idiopathic motility disorder characterized by failure of lower esophageal sphincter (LES) relaxation as well as loss of peristalsis in the distal esophagus, which is mostly smooth muscle. Both of these features impair the ability of the esophagus to empty contents into the stomach. Patients usually complain of dysphagia to both solids and liquids. Dysphagia to liquids, in particular, is a characteristic of achalasia. Other symptoms of achalasia include regurgitation, night coughing, chest pain, weight loss, and heartburn. The combination of achalasia, adrenal insufficiency, and alacrima (lack of tear production) in children is known as the triple A (Allgrove) syndrome. In most cases the cause is unknown (idiopathic), but in some regions of the world, achalasia can also be caused by Chagas disease due to infection by "Trypanosoma cruzi".

Scleroderma is a disease characterized by atrophy and sclerosis of the gut wall, most commonly of the distal esophagus (~90%). Consequently, the lower esophageal sphincter cannot close and this can lead to severe gastroesophageal reflux disease (GERD). Patients typically present with progressive dysphagia to both solids and liquids secondary to motility problems or peptic stricture from acid reflux.

Spastic motility disorders include diffuse esophageal spasm (DES), nutcracker esophagus, hypertensive lower esophageal sphincter, and nonspecific spastic esophageal motility disorders (NEMD).

- "DES" can be caused by many factors that affect muscular or neural functions, including acid reflux, stress, hot or cold food, or carbonated drinks. Patients present with intermittent dysphagia, chest pain, or heartburn.

Rare causes of esophageal dysphagia not mentioned above

- Diverticulum

- Aberrant subclavian artery, or (dysphagia lusoria)

- Cervical osteophytes

- Enlarged aorta

- Enlarged left atrium

- Mediastinal tumor

A Killian–Jamieson diverticulum is an outpouching of the esophagus just below the upper esophageal sphincter.

The physicians that first discovered the diverticulum were Gustav Killian and James Jamieson. Diverticula are seldom larger than 1.5 cm, and are less frequent than the similar Zenker's diverticula. As opposed to a Zenker's, which is typically a posterior and inferior outpouching from the esophagus, a Killian–Jamieson diverticulum is typically an anterolateral outpouching at the level of the C5-C6 vertebral bodies, due to a congenital weakness in the cervical esophagus just below the cricopharyngeal muscle. It is usually smaller in size than a Zenker's diverticulum, and typically asymptomatic. Although congenital, it is more commonly seen in elderly patients.

In simple words, when there is excessive pressure within the lower pharynx, the weakest portion of the pharyngeal wall balloons out, forming a diverticulum which may reach several centimetres in diameter.

More precisely, while traction and pulsion mechanisms have long been deemed the main factors promoting development of a Zenker's diverticulum, current consensus considers occlusive mechanisms to be most important: uncoordinated swallowing, impaired relaxation and spasm of the cricopharyngeus muscle lead to an increase in pressure within the distal pharynx, so that its wall herniates through the point of least resistance (known as Killian's triangle, located superior to the cricopharyngeus muscle and inferior to the Thyropharyngeus muscle. Thyropharyngeus and Laryngopharyngeus are the superior and inferior parts of inferior constrictor muscle of pharynx respectively). The result is an outpouching of the posterior pharyngeal wall, just above the esophagus.

While it may be asymptomatic, Zenker diverticulum can present with the following symptoms:

- Dysphagia (difficulty swallowing), and sense of a lump in the throat

- Food might get trapped in the outpouching, leading to:

- Regurgitation, reappearance of ingested food in the mouth

- Cough, due to food regurgitated into the airway

- Halitosis, smelly breath, as stagnant food is digested by microorganisms

- Infection

It rarely, if ever, causes any pain.

Cervical webs are seen associated in 50% of patients with this condition.

Rarer forms of cervical esophageal diverticula are the Killian's diverticulum and the Laimer's diverticulum. Killian's diverticulum is formed in the Killian-Jamiseon triangle (located inferior to the cricopharyngeus on both sides of this muscle's insertion into the cricoid cartilage). Laimer's diverticulum is formed in Laimer's triangle (located inferior to the cricopharyngeus in the posterior midline above the confluence of the longitudinal layer of esophageal muscle). Laimer's triangle is covered only by the circular layer of esophageal muscle.

The following are risk factors that can result in a hiatus hernia.

- Increased pressure within the abdomen caused by:

- Heavy lifting or bending over

- Frequent or hard coughing

- Hard sneezing

- Violent vomiting

- Straining

- Stress

In adults, most common causes are hemorrhoids and diverticulosis, both of which are relatively benign; however, it can also be caused by colorectal cancer, which is potentially fatal. In a newborn infant, haematochezia may be the result of swallowed maternal blood at the time of delivery, but can also be an initial symptom of necrotizing enterocolitis, a serious condition affecting premature infants. In babies, haematochezia in conjunction with abdominal pain is associated with intussusception. In adolescents and young adults, inflammatory bowel disease, particularly ulcerative colitis, is a serious cause of haematochezia that must be considered and excluded.

Hematochezia can be due to upper gastrointestinal bleeding. However, as the blood from such a bleed is usually chemically modified by action of acid and enzymes, it presents more commonly as black "tarry" feces known as melena. Haematochezia from an upper gastrointestinal source is an ominous sign, as it suggests a very significant bleed which is more likely to be life-threatening.

Beeturia can cause red colored feces after eating beets because of insufficient metabolism of a red pigment, and is a differential sign that may be mistaken as hematochezia.

Consumption of dragon fruit or pitaya may also cause red discoloration of the stool and sometimes the urine (pseudohematuria). This too, is a differential sign that is sometimes mistaken for hematochezia.

In infants, the Apt test can be used to distinguish fetal hemoglobin from maternal blood.

Other common causes of blood in the stool include:

- Colorectal cancer

- Crohns disease

- Ulcerative colitis

- Other types of inflammatory bowel disease, inflammatory bowel syndrome, or ulceration

- Rectal or anal hemorrhoids or anal fissures, particularly if they rupture or are otherwise irritated

- "Shigella" or shiga toxin producing "E. coli" food poisoning

- Necrotizing enterocolitis

- Diverticulosis

- Salmonellosis

- Upper gastrointestinal bleeding

- Peptic ulcer disease

- Esophageal varices

- Gastric cancer

- Intense exercise, especially a high-impact activity like running in hot weather.

Barrett's esophagus is a premalignant condition. Its malignant sequela, oesophagogastric junctional adenocarcinoma, has a mortality rate of over 85%. The risk of developing esophageal adenocarcinoma in people who have Barrett's esophagus has been estimated to be 6–7 per 1000 person-years, however a cohort study of 11,028 patients from Denmark published in 2011 showed an incidence of only 1.2 per 1000 person-years (5.1 per 1000 person-years in patients with dysplasia, 1.0 per 1000 person-years in patients without dysplasia). The relative risk of esophageal adenocarcinoma is approximately 10 in those with Barret's esophagus, compared to the general population. Most patients with esophageal carcinoma survive less than one year.

They are mainly observed in the Plummer–Vinson syndrome, which is associated with chronic iron deficiency anemia. One in 10 patients with Plummer-Vinson syndrome will eventually develop squamous cell carcinoma of the esophagus, but it is unclear if esophageal webs in and of themselves are a risk factor.

Esophageal webs are associated with bullous diseases (such as epidermolysis bullosa, pemphigus, and bullous pemphigoid), with graft versus host disease involving the esophagus, and with celiac disease.

Esophageal webs are more common in white individuals and in women (with a ratio 2:1). The literature describes relations between these webs and Plummer-Vinson Syndrome, bullous dermatologic disorders, inlet patch, graft-versus-host disease and celiac disease. The postulated mechanisms are sideropenic anemia (mechanism unknown) or some interference of the immune system.

Esophageal webs can be ruptured during upper endoscopy.

Surgical repair can sometimes result in complications, including:

- Stricture, due to gastric acid erosion of the shortened esophagus

- Leak of contents at the point of anastomosis

- Recurrence of fistula

- Gastro-esophageal reflux disease

- Dysphagia

- Asthma-like symptoms, such as persistent coughing/wheezing

- Recurrent chest infections

- Tracheomalacia

Even after successful treatment of achalasia, swallowing may still deteriorate over time. The esophagus should be checked every year or two with a timed barium swallow because some may need pneumatic dilatations, a repeat myotomy, or even esophagectomy after many years. In addition, some physicians recommend pH testing and endoscopy to check for reflux damage, which may lead to a premalignant condition known as Barrett's esophagus or a stricture if untreated.

Esophageal webs and rings can be treated with endoscopic dilation.