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Volume: Barrett's Esophagus
Chapter: Etiology and origins of Barrett's epithelium

The lower esophageal sphincter versus the hiatal hernia in the arena of gastroesophageal reflux disease. A revisited subject.

S.J. Sontag (Hines)

A critical review of the literature regarding the role of hiatal hernia (HH) and lower esophageal sphincter (LES) suggests the following conclusions:
-the HH, by permitting more frequent reflux episodes and greater acid contact time, is the major factor associated with esophagitis;
-that in patients with symptomatic gastroesophageal reflux (GER), the presence of a HH is the single most important predictor of reflux esophagitis;
-that an incompetent LES is not a major etiologic factor in the development of esophagitis.

The long-ranging debate between the role of HH and that of the LES in the development of and contribution to gastroesophageal reflux disease (GERD) has been termed "a tired argument". Although the argument may be tired, the need to know the mechanisms behind GERD should not be underestimated. If the development of a HH is truly the major cause of GERD in Western civilization, then the causes of HH should be sought and, if possible, prevented. We propose three separate etiologies of GERD. We attempt to explain why, after 1.5 million years of standing erect, we have evolved into a species that is destined to live with GERD.

Hypothesis 1: congenital

The antireflux barrier - comprising the smooth-muscled LES, the skeletal-muscled right crural diaphragm, and the phrenoesophageal ligament - does not develop completely due either to a developmental anomaly or an incomplete gestation period of less than 40 weeks.


In 1975, Darling reported that 83 (29%) of a total of 285 infants and children had a HH or GER [1]. In 1976, Astley et al. reported a long-term prospective follow-up of 113 children with vomiting due to a small HH [2]. When reviewed by the same clinical and radiological observers twenty or more years later, more than half still had the HH. Eighteen years later, in 1994, the same group followed-up their report on 118 patients with a HH in childhood [3]. HH continued to persist in more than half the patients, although few complained of significant symptoms. Of interest, two patients who requested endoscopic exams were found to have Barrett's esophagus. In their original population, 27 patients had failure to thrive, 28 had persistent vomiting, 15 had recurrent pneumonia, 16 had esophagitis, 9 had apnea due to laryngeal spasm, and 8 had gastrointestinal bleeding. These cases were considered to be congenital GER and HH. In 1991, Latif Al-Arfaj reported on 10 children with massive HH's in Saudi Arabia [4].

In 1958, Botha demonstrated unequivocally that HH could be congenital and different than the HH in adults. He removed the diaphragm, lower esophagus, upper stomach and surrounding tissues en bloc from 115 children, aged 32 weeks to 8 years, most of whom were less than one month of age [5]. Detailed dissection of these specimens revealed important information: the anatomic difference between the sliding HH of infancy and that of adults was that the former was present at birth as a result of a congenitally short esophagus or a congenitally malformed or underdeveloped diaphragm, whereas the latter is seen in the later decades of life as a result of degenerative changes of normal hiatal structures.


Most of these HH's clearly were congenital, as a majority of the children had symptoms of vomiting and failure to thrive from the time of birth. It is possible that the children were born with normal structures and then developed HH from persistent vomiting within hours after birth. This possibility isn't likely, however, since no cause for the vomiting was reported and most of the children began with vomiting and failure to thrive soon after birth.


These studies clearly demonstrate that a major cause of HH in children is congenital and that the HH persists into adult life in half the children.

Hypothesis 2: acute traumatic etiology

The antireflux barrier in adults suffering acute traumatic injury to the abdomen or chest is permanently disrupted by unexpected forces, such as motor vehicle accidents (with steering wheel crush injury , blows to the abdomen (e.g. activities such as wrestling, boxing, martial arts, heavy lifting) or unphysiologic stress positions (e.g. gymnastic feats).

A 67 years old steroid-dependent asthmatic has severe GER symptoms:
-at the age of 20 years, a grenade blast propelled him out of his foxhole in Iwo Jima, instantly killing his 4 comrades;
-he awoke 2 weeks later in a US hospital with his stomach in his chest;
-several unsuccessful surgeries were attempted to repair the huge rent in the diaphragm and to anchor the stomach back into the abdomen;
-severe symptoms of both GER and asthma developed within weeks of the injury;
-the GER and asthma remained as serious problems until he died at the age of 74 years.

A 25 years old muscular gymnast has continuous heartburn:
-at the age of 24 years, he developed sudden, crushing, retrosternal chest pain during a vertical handstand on the parallel bars;
-myocardial infarction was ruled out at the local hospital;
-within days of the injury, moderate to severe GER symptoms developed and self treatment with antacid tablets began;
-endoscopy revealed a 4 cm HH, esophageal erosions and ulcerations.


According to the histories, neither patient had reflux symptoms before the trauma and both had moderate to severe reflux symptoms beginning soon after the traumatic incident. The patient on Iwo Jima clearly had traumatic injury to the chest and diaphragm from the grenade. The gymnast developed crushing chest pain during strenuous activity and required antacids shortly after the chest pain.

The literature is filled with case reports of patients who required reduction of HH's and closures of diaphragmatic tears due to acute injuries. The exact relationship between acute diaphragm injury and the production of HH is unknown, but may be higher than realized since many patients do not recall the exact injury, especially if it did not require them to seek hospitalization.


We have presented two (of many) patients who clearly developed GER symptoms after an acute injury. Although we cannot say for certain that asymptomatic HH and asymptomatic reflux were not present before their acute event, it is certain that the symptoms began after the acute event. We can only speculate that their HH and reflux began with the acute injury.

Hypothesis 3: chronic traumatic etiology

The antireflux barrier in children and adults is gradually weakened over time as a result of years of straining to defecate and straining in an unphysiologic position, both of which stem from our modern day habits of eating a low fiber diet and living on the high-seated toilet. Insufficient intake of dietary fiber results in small caliber stools that can be expelled only by generating and maintaining very high abdominal pressures. The high-seated toilet promotes a physiologically unsound sitting position which, during straining at defecation, directs the abdominal forces upward through the esophageal hiatus. Thus, the repeated straining results in a weakening of the antireflux barrier, development of a HH, and a useless antireflux mechanism that is incapable of preventing GERD.


In 1975, Burkitt examined all the information known about the effect of diet on the physiology of the gastrointestinal tract, including the influence of fiber on stool volume, water content and transient time. He postulated that abdominal straining during efforts to evacuate hard feces would increase intra-abdominal pressure to a point that would force the gastroesophageal junction upward into the thoracic cavity and produce or exaggerate the herniation through the diaphragmatic hiatus [6]. Burkitt's theory was substantiated by the work of Light and Rutledge who, in 1965, measured the pressures in the sigmoid colon [7]. The values reflected the intra-abdominal pressures, which were highest during the Valsalva manoeuver. In 1979, four years after Burkitt proposed his theory, Fedail et al. measured the intra-abdominal and intrathoracic pressures and the gradient between them during defecation [8]. They also compared pressures in the sitting position with those in the squatting position. The results of their study demonstrated that the intra-abdominal pressures when straining maximally to defecate always exceeded the intrathoracic pressures. The investigators suggested that if this pressure gradient across the diaphragm occurred often and for prolonged periods, the stomach might gradually be pushed up into the chest. Although the difference was not statistically significant, the authors found that squatting during defecation was more protective than sitting on a raised toilet seat, because the pressure gradient across the diaphragm was less during squatting. It is well known that Western populations sit on high toilets and strain to move out hard feces, whereas populations in developing countries eagerly squat and pass out large, soft, bulky stools.


Because continuous straining increases intra-abdominal pressures sufficiently to propel the stomach up into the diaphragmatic hiatus, it is not unreasonable to suggest that constant straining may result in a partial thoracic stomach otherwise known as HH. Indeed, if straining to defecate does weaken the antireflux mechanism over time, then the incidence of HH should increase with age, and it does!


Westernized countries have a low fiber diet that results in hard feces and difficult defecation. Developing countries have a high fiber diet, which results in large soft feces and ease of defecation. Western countries rarely assume the squatting position to defecate, whereas developing countries squat to defecate as a way of life. These factors are extremely important in the development of certain diseases, including HH.


We have presented a rationale for the development of GERD. The overwhelming evidence suggests that the presence of a HH is almost mandatory for severe esophagitis to be present and that half the patients with HH have reflux esophagitis. In the absence of a HH, there is almost never severe esophagitis. We presented three hypotheses that might explain the origins of GERD through the mechanism of HH, which could result from any of three etiologies: 1) congenital, 2) acute trauma, and 3) chronic trauma. We suggested that the congenital etiology is either a developmental anomaly or a result of incomplete gestation; that the acute traumatic etiology is a sudden acute trauma to the abdomen or chest; and that the chronic traumatic etiology a) is the cause of more than 90% of the GERD that stalks the Western world; b) is a direct result of abandoning the popular and worldwide practice of squatting to socialize, eat and defecate; and c) is our just reward for adopting the "civilized" high sitting position on chairs and modern toilets.


1. Darling DB. Hiatal hernia and gastroesophageal reflux in infancy and childhood. Analysis of the radiologic findings. Am J Roentgenol Radium Ther Nucl Med 1975;123:724-736.

2. Astley R, Carre IJ, Langmead-Smith R. A 20-year prospective follow-up of childhood hiatal hernia. Brit J Radiol 1976;50:400-403.

3. Johnston BT, Carre IJ, Thomas PS, Collins BJ. Twenty to 40 year follow-up of infantile hiatal hernia. Gut 1995;36:809812.

4. Latif Al-Arfaj A, Khwaja MS, Upadhyaya P. Massive hiatal hernia in children. Eur J Surg 1991;157:465-468.

5. Botha GSM. Gastroesophageal region in infants: observation on anatomy, with special reference to closing mechanism and partial thoracic stomach. Arch Dis Childhood 1958;33:78-94.

6. Burkitt DP. In: Burkitt DP, Trowell HC, eds. Refined carbohydrate foods and disease: some implications of dietary fibre. London: Academic Press, 1975:161-169.

7. Light HG, Routledge JA. Intra-abdominal pressure. Arch Surg (Chicago) 1965;90:115-117.

8. Fedail SS, Harvey RF, Burns-Cox CJ. Abdominal and thoracic pressures during defaecation. Br Med J 1979;1:91.

Publication date: August 2003 OESO©2015