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Neat Little Guide — 29 minutes

Digestive Disorders

How the digestive system works

a spicy soup

Digestion is a biological process that breaks down and transforms the food you eat into nutrients that pass through your intestinal wall and enter your bloodstream. It starts in your mouth, where you chew food and mix it with saliva, and then it continues in your stomach, which secretes digestive juices to help break down the food and contracts to crush it.

The predigested food (or chyme) then enters your intestine, which continues to break it down with more digestive juices from your pancreas and gallbladder. The nutrients cross the wall of your intestine and circulate in your blood, where your body uses it to produce energy, among other things. All non-absorbed food is combined with dead cells from your intestinal wall and transformed into fecal matter in your colon.

Causes, symptoms and risk factors

Digestive system disorders include problems and diseases that affect multiple parts of your digestive system at once, as well as those that affect only one part. They are numerous and varied and can sometimes be caused by food allergies or intolerances.

Functional digestive disorders, or dyspepsia

Functional digestive disorders are caused by improper functioning of the digestive system. Most of them develop in your stomach (e.g. loss of appetite, nausea, burning, hiccups and bloating) or as intestinal disorders (e.g. bloating and intestinal gas).

If you suffer from dyspepsia you have difficulty digesting, which can entail bloating, nausea and the feeling that your stomach is constantly full.

The causes of functional digestive disorders may include a copious meal that is difficult to digest (e.g., fats, spices and acidic foods), eating food without chewing properly, drinking carbonated beverages or abusing alcohol, as well as stress or anxiety.

Aerophagy occurs when a large amount of air in the stomach causes swelling, intestinal pain and burping (for example if you swallow too much air while eating or during the day, or if you chew gum or smoke). Pregnant women are more at risk of suffering from aerophagy.

Irritable bowel syndrome (or functional colopathy) is partly caused by the same factors as dyspepsia and leads to intestinal pain, bloating, flatulence and diarrhea or constipation. Certain foods, digested too quickly or too slowly, can trigger the symptoms (e.g. legumes, cabbage, garlic, onion, radish, leeks, artichokes, French fries, fatty meats, sauces and fermented cheeses).

Please note

Although functional digestive disorders are generally benign, they should be monitored by a health care professional in the following cases:

  • If you experience symptoms suddenly with no apparent cause
  • If you experience intense abdominal pain
  • If symptoms persist for a long time
  • If symptoms occur after you return from a trip abroad
  • If symptoms occur after you take a new medication
  • If you have difficulty swallowing
  • If you experience sudden weight loss
  • If you notice blood in your vomit or stool
  • If you have a fever
  • If you have symptoms of dehydration (e.g. cramps, sunken eyes, infrequent need to urinate)

Risk Factors

We can all suffer from the occasional digestive disorder, but some people are more at risk:

  • Pregnant women (the uterus may touch the intestine and stomach during pregnancy, and hormonal changes often cause constipation, dyspepsia or heartburn)
  • People who practice endurance sports (dehydration, poor diet, vascular disorders)
  • People suffering from anxiety or depression
  • People who have other chronic illnesses such as type 2 diabetes, migraines and hypothyroidism

Diseases of the digestive system

Several factors can lead to diseases of the digestive system. Below you will find information on the most common diseases.

Gastroesophageal reflux pathology (GERD)

The esophagus connects your mouth with your stomach. Gastroesophageal reflux occurs when the gastric juices (acid) produced by your stomach travel up your esophagus. Reflux causes inflammation of the esophagus and results in burning and irritation. If left untreated, it can cause damage to the esophagus.


Gastroesophageal reflux is caused by a malfunction of the esophageal sphincter. During normal digestion, the sphincter (located where the esophagus and stomach meet) opens to let swallowed food pass through and closes to prevent it from moving back up into the stomach. If the sphincter fails to close, contents of the stomach move up into the esophagus, causing reflux.

Gastroesophageal reflux can also be caused by a hiatal hernia, which occurs when a part of the stomach “rises” with the esophagus toward the rib cage via the orifice of the diaphragm (the hiatal orifice).


  • Burning sensation behind the sternum, which radiates into the throat
  • Regurgitations
  • Acidic or bitter taste in the mouth
  • Hoarse voice, especially in the morning
  • Chronic sore throat
  • Asthma
  • Frequent coughing and hiccups
  • Bad breath
  • Loss of tooth enamel


  • Inflammation (esophagitis) causing lesions (ulcers) in the esophagus which may bleed (upper digestive hemorrhage)
  • Narrowing of the diameter of the esophagus (peptic stricture), which causes difficulty swallowing and pain
  • Barrett’s esophagus, i.e. a change in the cells of the esophageal wall (replaced by cells that normally develop in the intestine). This disease can cause cancer of the esophagus.
  • Chronic cough, hoarse voice
  • Cancer of the esophagus or larynx

Treatment for gastroesophageal reflux disease (GERD)

Treatment of GERD depends on the frequency and severity of symptoms. For benign cases, many physicians begin by prescribing simple changes to the patient’s diet, as well as recommending over-the-counter antacids (sodium bicarbonate, sodium alginate, etc.). If symptoms persist, H2 histamine receptor antagonists (cimetidine, famotidine, ranitidine, etc.) are also available over the counter. For more severe cases, the next step consists of prescribing more powerful drugs called proton pump inhibitors (PPIs), such as omeprazole, esomeprazole, pantoprazole, etc. Other physicians, especially in more symptomatic cases, prefer to start directly with a PPI, although doses should then be gradually reduced and switched to non-prescription drugs. In the most refractory cases, anti-reflux surgery by laparoscopy helps strengthen the valve between the esophagus and the stomach.

Gastroduodenal ulcer

Called a gastric if it is located in the stomach, and duodenal if it forms in the duodenum, this ulcer forms in the wall of the digestive track. It is quite painful because it comes into direct contact with the acid in the digestive tract.


Helicobacter pylori (H. pylori), a bacterium that survives acidity, is responsible for most ulcers, causing 60-80% of stomach ulcers and 80-85% of duodenal ulcers. It attacks the layer of mucus that normally protects the stomach and small intestine from acidity.

Aspirin and non-steroid anti-inflammatory drugs, or NSAIDs (e.g. ibuprofen, Naproxen, Celebrex, etc.), are the second most common cause of ulcers in the digestive tract. When taken in combination with an H. Pylori bacterial infection, they increase the risk of ulcers by a factor of 60.

Smoking, alcohol abuse, stress or a hereditary predisposition can also cause excessive acid production in the stomach.


  • Burning sensation in the upper abdomen
  • Pain caused by a stomach ulcer is aggravated by eating or drinking.
  • In the case of duodenal ulcers, the pain lessens when eating, but increases one to three hours after eating and when the stomach is empty.
  • The feeling of having eaten too much
  • Burping and bloating


  • The ulcer may cause hemorrhage inside the digestive tract (vomiting of blood or blood in the stool)
  • It can pierce the wall of the digestive tract and cause peritonitis, a medical emergency.

Gastroduodenal ulcer treatment

Treatment with antibiotics is prescribed for a bacterial infection with Helicobacter pylori, the most common cause of gastroduodenal ulcers. Those ulcers not caused by H. pylori are treated the same way as cases of gastroesophageal reflux disease (GERD). Changes to diet, stopping the use of nonsteroidal anti-inflammatory agents and taking antacids available over the counter are usually sufficient. If needed, histamine h2 antagonists (cimetidine, famotidine, etc.), or proton pump inhibitors (PPIs), such as omeprazole, esomeprazole and pantoprazole, can be prescribed. In rare cases, surgery is indicated for treating certain medication-resistant ulcers, or if gastric cancer is suspected.

Hiatal hernia

Hiatal hernia occurs when the stomach partly rises through a small opening called the esophageal hiatus (located in the diaphragm, the respiratory muscle between the chest cavity and the abdomen). There are two main types of hiatal hernia:

  • Sliding hiatal hernia or type I, which accounts for about 85 to 90% of cases. When the junction between the esophagus and the stomach (cardia) rises into the rib cage, this can cause a burning sensation related to gastroesophageal reflux.
  • Paraesophageal (or rolling hernia or type II) occurs when the cardia remains in place below the diaphragm, but most of the stomach surrounds it and passes through the esophageal hiatus, forming a pocket. This hernia usually causes no symptoms, but can sometimes lead to severe complications.


The exact cause of hiatal hernia is poorly understood. In some cases, it is present at birth and caused by a hiatus that is too wide, or the entire diaphragm is poorly closed. However, the elderly are more likely to suffer from a hernia because the elasticity and stiffness of the diaphragm tend to decrease with age and the hiatus tends to widen. In addition, structures that attach the cardia to the diaphragm and keep the stomach in place change with age.

Obesity or pregnancy may also be associated with hiatal hernia.


Sliding hiatal hernia

As this type of hernia can sometimes cause or worsen gastroesophageal reflux, so its symptoms are similar to reflux:

  • Burning sensations along the esophagus (acid reflux)
  • Bad taste in the mouth
  • Chronic cough
  • Sore throat or hoarseness

Paraesophageal hiatal hernia

This type of hernia does not cause heartburn or any other symptom. It may cause occasional discomfort.

The most common symptoms are:

  • Chest or gastric pain, such as stomach cramps
  • Feeling of heaviness and bloating after a meal, giving the impression of having overeaten
  • Respiratory discomfort, i.e. shortness of breath caused by the stomach compressing the lungs
  • Anemia caused by minimal and continuous bleeding

Treatment for hiatal hernia

The treatment for sliding type hiatal hernia is the same as for gastroesophageal reflux disease (GERD). Diet modifications and over-the-counter antacids (sodium bicarbonate, sodium alginate, etc.) are often sufficient. If symptoms persist, H2 histamine receptor antagonists (cimetidine, famotidine, ranitidine, etc.) can be used. The next step involves more powerful drugs called “proton pump inhibitors” (PPIs), such as omeprazole, esomeprazole and pantoprazole. The rarely occurring and less symptomatic paraoesophageal type of hiatal hernia may require surgery that consists of moving the stomach back into the abdominal cavity and closing the hiatus to prevent the stomach from re-herniating.

Vesicular lithiasis and biliary colic

Vesicual lithiasis is the formation of stones in the gallbladder, the organ that stores bile secreted by the liver. Theses stones look like little pebbles and are composed of cholesterol, bile pigments and calcium.

The stones may be numerous if they are small (like a grain of salt), and they can be as large as a golf ball.

Biliary lithiasis, or gallbladder stones, is quite widespread and affects two to three times more women than men. Starting at age 70, ten to fifteen percent of men are affected, as well as 25 to 30% of women. The risk of gallbladder stones may increase with age, reaching 60% after age 80. Only 20% of people affected will experience complications.

A hepatic colic or biliary colic attack is caused by a gallstone passing into the gallbladder, temporarily blocking it and preventing the bile from draining. Such an attack can last 30 minutes to four hours, and pain begins to subside when the gallstone is dislodged. An attack can occur at any time with no triggering event.


Cholesterol gallstones are formed when:

  • There is too much cholesterol in the bile
  • There is not enough bile salt in the bile
  • The gallbladder does not contract regularly

It is not clear what triggers the formation of the gallstones, but the most common risk factor is obesity.

Symptoms In most cases, biliary lithiasis does not cause symptoms. Gallstones are therefore diagnosed during a bladder ultrasound.

When gallbladder stones cause symptoms, you may feel:

  • Sudden, intense and constant pain, such as a tightening in the upper right part of the abdomen. Pain may radiate toward the right shoulder and shoulder blade.
  • Nausea and vomiting

Treatment for vesicular lithiasis and biliary colic

Most cases of asymptomatic vesicular lithiasis (gallstones) do not need treatment. Occasional (hepatic colic) or constant and severe pain (cholecystitis) can be treated with analgesics, or sometimes with antibiotics (cholecystitis), anti-spasmodics and anti-emetics to relieve nausea and reduce vomiting. Surgery is eventually needed to remove the gallbladder and gallstones (cholecystectomy). This procedure can be performed through small incisions in the abdomen (laparoscopy), or can take the form of open surgery (laparotomy). For non-urgent cases, an oral treatment is available with a drug (ursodiol) that dissolves certain stones within six months to two years.

Diverticulosis and diverticulitis

Diverticula can form in the large intestine of people ages 40 and over. These are small “pockets” a few millimetres in size and located in various locations in the large intestine. While diverticulosis mainly affects the colon or large intestine, diverticula can also be found throughout the entire digestive tract, including the stomach and small intestine.

Diverticulitis is an inflammation of the diverticula caused by an infection. Diverticulosis of the colon is widespread, affecting about 50% of people in Western countries over the age of 60. It can cause severe pain.


Diverticula form when weak areas in the colon wall stretch under pressure. If the pressure causes a small lesion on the wall of the diverticula, an infection may occur. Causes include a sedentary lifestyle and a diet with not enough fibre.



Diverticulosis does not cause symptoms. However, when the diverticula become swollen or infected, diverticulitis is the result.


Intense and sudden pain at the bottom of the abdomen on the left hand side. Sometimes the pain is moderate, variable and gradually increases over several days.

  • Intense and sudden pain in the lower abdomen on the left side
  • Sometimes the pain is moderate and variable, gradually increasing over several days.
  • Abdominal tenderness
  • Fever
  • Nausea
  • Constipation or diarrhea

Treatment for diverticulosis and diverticulitis

Asymptomatic diverticulosis does not require treatment. However, increasing the amount of fibre in the patient’s diet is recommended. One quarter of patients develop diverticulitis, which is treated with painkillers and oral antibiotics (at home) or intravenous antibiotics (in hospital). Also in 25% of cases, surgery is required to remove the diseased part of the colon. This surgery often requires creating a bowel connection through an opening in the abdomen (stoma) which allows an ostomy bag to be attached. In most cases, the bag can be removed within three to six months after surgery. Bleeding from the diverticula is usually reabsorbed, but if it persists, a colonoscopy and other interventions may be necessary.


Appendicitis is a sudden inflammation of the appendix, a small worm-shaped protrusion located at the beginning of the large intestine, on the lower right side of the abdomen. It most often occurs between the ages of 10 and 30, affecting one in 15 people, and slightly more often in men than in women.

Appendicitis must be treated promptly or the appendix could burst and cause peritonitis, an infection of the peritoneum, the thin wall that surrounds the abdominal cavity and contains the intestines. In some cases, peritonitis requires emergency medical treatment and can be fatal.


Appendicitis is often the result of a fecal or mucous obstruction. The appendix then becomes swollen with bacteria and deteriorates over the long term.


  • Pain usually begins near the navel and gradually progresses to the lower right side of the abdomen
  • Over a period of 6 to 12 hours, pain gradually increases, localized halfway between the navel and pubic bone, on the right side of the abdomen.
  • Coughing, walking or even breathing can worsen the pain. Pressing on the abdomen and suddenly releasing can also aggravate the pain.

Pain is often accompanied by the following symptoms:

  • Nausea or vomiting
  • Loss of appetite
  • Low fever
  • Constipation, diarrhea or gas
  • Bloating or rigidity of the abdomen

Treatment for acute appendicitis

Acute appendicitis can lead to serious complications, such as a ruptured appendix and a peritoneal infection (peritonitis). Surgical removal of the appendix (appendectomy) is the most effective way to treat acute appendicitis. An appendectomy can be performed through a large abdominal incision (laparotomy) or through smaller incisions (laparoscopy) that allow the insertion of a small video camera and surgical instruments. Antibiotics are often administered before and after surgery. Recovery after an appendectomy usually takes only a few days. Certain medical centres (mainly in Europe) tend to treat simple appendicitis cases with antibiotics alone. This treatment avoids the need for immediate surgery, but when the appendix is left in place, there is a risk of reinfection.

Chronic inflammatory bowel diseases (IBDs)

Chronic inflammatory bowel disease, or IBDs, include Crohn’s disease and ulcerative colitis.

Crohn’s disease, a chronic inflammation of the digestive system, develops in a cycle of attacks and phases of remission. It causes abdominal pain and diarrhea, which can last for several weeks or months and lead to fatigue, weight loss and even malnutrition. It can also cause non-digestive symptoms that affect the skin, joints or eyes.

Crohn’s disease can affect any part of the digestive tract, from the mouth to the anus. However, it is most often found at the junction of the small intestine and the colon (large intestine).


The causes of inflammation are poorly understood, but research has shown that it may be linked to genetic, autoimmune and environmental factors.

Genetic factors

Although Crohn’s disease is not entirely genetic, some genes may increase the risk of developing it. As with many other diseases, it appears that a genetic predisposition, combined with environmental or lifestyle factors triggers the disease.

Autoimmune factors

Researchers now believe that inflammation of the digestive tract may be linked to the body’s excessive immune response against viruses or bacteria in the intestine.

Environmental factors

The incidence of Crohn’s disease is higher in industrialized countries and has increased considerably since 1950. This suggests that it is linked to the Western lifestyle. However, no specific factors have yet been identified and research continues.


  • Frequent abdominal pain and cramps, which worsen after meals
  • Chronic diarrhea (lasting more than two weeks)
  • Fatigue and general discomfort
  • Low appetite and weight loss
  • Blood in the stool, sometimes in large quantities (hemorrhaging)
  • Thick mucus in the stool, having the consistency of an egg white
  • Nausea and vomiting.
  • Mild fever (38ºC to 40ºC)
  • Joint pain

Treatment for Crohn’s disease

The treatment of Crohn’s disease depends on many factors, including age, disease severity and personal resistance to a drug’s side effects. Various oral anti-inflammatory drugs such as glucocorticoids (budesonide, prednisone) and sulfasalazine are administered first. More severe cases require the use of stronger immunomodulating agents (azathioprine, 6-mercaptopurine), including biologicals such as infliximab. Fifty percent of patients with Crohn’s disease need surgery during their lifetime, either to unblock segments of the intestine or to remove a diseased section of the colon.

Ulcerative colitis

Llike Crohn’s disease, ulcerative colitis is a chronic inflammatory bowel disease (IBD) that affects the lining of the rectum and moves up into the colon. It is diagnosed mostly in people between the ages of 30 and 40, but can occur at any age in both men and women.


Scientists believe that the inflammation of the colorectal mucosa is caused by an excessive immune response against viruses or bacteria in the gut, and that this reaction is directed against the “good” bacteria normally living in the digestive tract (intestinal flora).

Ulcerative colitis may also be linked to environmental factors, while stress and food intolerances can trigger symptoms in some people. However, these factors do not cause the disease.


The following symptoms appear during an attack:

  • Painful abdominal cramps, especially in the lower belly
  • Blood in the stool
  • Diarrhea
  • Frequent bowel movements
  • An urgent need to defecate, even if there are no stools to evacuate (rectal tenesmus)
  • Weight loss due to reduced appetite and poor absorption of nutrients into the intestine
  • Fatigue
  • Fever

Possible Complications

  • Obstruction (partial or total) of the digestive tract, caused by chronic inflammation that thickens the wall of the digestive tract
  • Ulcers in the wall of the digestive tract
  • Colon dilation and puncture
  • Wounds, fistulas or abscesses around the anus
  • Bleeding in the digestive track
  • Increased risk of developing colon cancer
  • Delayed growth and puberty in children and adolescents
  • Iron-deficiency anemia
  • Non-digestive health problems such as arthritis, skin conditions, inflammation of the eyes, oral ulcers and kidney stones

Treatment for ulcerative colitis

The treatment for ulcerative colitis is similar to the treatment for Crohn’s disease. Contrary to Crohn’s disease, which can affect the entire digestive tract, ulcerative colitis affects mainly the lower colon and rectum. Various anti-inflammatory agents such as mesalamine and glucocorticoids (prednisone) can be administered, in the form of suppositories or rectal suspension (enema). More severe cases will require the use of strong immunosuppressants (azathioprine, 6-mercaptopurine, infliximab, etc.). Severe cases may require surgery to remove the colon, rectum and sometimes even the anus. In the latter case, a permanent stoma is required.

Celiac disease

Celiac disease is a chronic bowel disease triggered by consuming gluten, a mixture of proteins found in wheat, barley and rye. People who suffer from this disease have an abnormal immune response when they consume foods containing gluten. This reaction causes inflammation and damages the intestinal wall. If the inflammation persists, the damaged intestine can no longer absorb certain nutrients, vitamins and minerals, which can result in malnutrition despite a healthy diet.

Celiac disease is not an intolerance to gluten, which is a term often used to describe it. It is an abnormal immune system response.


Health care professionals have not yet determined the cause of celiac disease, but the following factors may play a role in its onset: a disruption of the immune system linked to a genetic predisposition, as well as the intestine’s reaction to gluten (known as the primary trigger).

Recent research has revealed that almost all individuals with celiac disease have the HLA-type genes DQ2 or DQ8, but other genes may also be responsible.


If people living with celiac disease do not adopt a gluten-free diet, they run a higher risk of suffering serious complications related to poor absorption of nutrients in the intestine, such as:

  • Malnutrition
  • Lactose intolerance
  • Anemia (caused by poor iron absorption)
  • Osteoporosis (caused by poor absorption of calcium and vitamin D)
  • Kidney stones (caused by abnormal absorption of oxalate)

Treatment for celiac disease

Because celiac disease involves an immune reaction to gluten, treatment is based entirely on adopting a gluten-free diet (i.e. no rye, wheat or barley, and sometimes no oats, due to frequent cross-contamination with grains containing gluten). They should also avoid exposure to flour dust in the air. The advice of a dietician is essential to help identify products that obviously contain gluten, as well as those that are less obvious (e.g. prepared foods, drugs, dietary supplements). There are also numerous websites on the topic. A dietician can help the patient find a balanced diet to correct any nutritional deficiencies caused by the disease. As celiac disease is largely hereditary, it is important to screen all members of the immediate family.


Gastroenterology is the medical specialization concerned with studying and managing the digestive tract. In research, there have been major advances in recent years in the diagnosis, treatment and exploration of digestive diseases.

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