Bloating

Bloating is a sensation of ‘fullness’ and tightness within the abdomen. It may be accompanied by swelling of the abdomen (distension). Bloating due to the build up of gas within the gastrointestinal tract will often be relieved by belching or flatulence.

Bloating should be differentiated from angina pectoris and myocardial infarction which are two cardiac conditions that may not always result in pain but can be fatal.

Obesity and Pregnancy

Persistent bloating should be investigated as the cause may not be related to gas or the digestive processes. Obesity often results in lax abdominal muscles with a superficial layer of fat tissue that contributes to abdominal distension. Pregnancy causes an increased abdominal diameter as the growing fetus expands within the abdominoperineal cavity. The expanding uterus may compress the organs of digestion thereby contributing to the sensation of bloating. This form of distension is considered a medical norm and is not indicative of any underlying pathology.

Ascites

Swelling is often incorrectly thought to be abdominal distension due to fluid while bloating is ascribed to gas build up. Any abdominal distension is a swelling of the abdomen. Bloating is the sensation of ‘fullness’ and tightness of the abdomen with or without abdominal distension.

Ascites is the medical term for abdominal swelling due to fluid accumulation within the abdominal and pelvic cavities. Swelling may be caused by peritoneal fluid or blood and should be investigated immediately. Ascites can often be diagnosed by physical examination where a succussion splash (sound of moving fluid) indicates fluid accumulation compared to the hollow sound of gas or dull sound of a solid mass. Further investigation is required and an ultrasound, X-ray or MRI scan could provide more definitive evidence of ascites.


Mechanism of Gas and Flatulence

Flatulence is a voluntary or involuntary expulsion of gas through the anus commonly referred to as passing gas or ‘farting’. Gas produced by the breakdown of food within the gastrointestinal tract may cause bloating and discomfort which is relieved upon passing flatus (‘fart’).

Digestion is a physical and chemical process that produces byproducts, including gas that is passed out as flatus. These processes are facilitated by the body’ physical and chemical factors as well as commensal bacteria in the gastrointestinal tract. All the causative factors of belching may also contribute to flatulence and bloating if the trapped gas is not expelled through the mouth.

Flatus is primarily composed of odorless gases. The process of food decomposition and gas produced by intestinal bacteria contribute to the odor of flatus.

Splenic-Flexure Syndrome

Gas trapped within the left side of transverse colon (near the spleen) can cause splenic-flexure syndrome:

  • upper abdominal bloating, often described as an “under ribs” or gastrointestinal chest pain
  • cramping and strong left upper abdominal pain that can be confused with heart related or pancreatic pain

Sulfur Gas

Flatulence with a sulfur-like odor is mainly due to hydrogen-sulfide, a gas responsible for the ‘rotten egg’ odor. Hydrogen-sulfide is produced by the intestinal bacteria. Foreign invading bacteria, yeasts and other parasites (gut fermentation) may contribute significantly to hydrogen-sulfide production within the bowels.

Causes :

  • Foods high in sulfur including eggs, meat, cabbage and beer.
  • Gastroparesis
  • Irritable bowel syndrome
  • Gut fermentation
  • Food intolerance
  • Bowel obstruction

Putrid Gas

Flatus in certain cases may have an offensive putrid odor. This may be described as a ‘dead animal’, ‘rotting garbage’ or ‘fishy’ odor.

Causes :

  • Necrosis of sections of the intestinal lining, like in Ulcerative colitis or Crohn disease
  • Food poisoning
  • Pseudomembranous colitis
  • Any prolonged infection of the gut

Causes of Bloating and Gas

EATING AND BREATHING

1. Aerophagia

Aerophagia is the voluntary or involuntary swallowing of air.

Causes :

  • Eating or drinking
  • Chewing gum
  • Smoking
  • Nasal breathing (blockage of nasal passages)
  • Anxiety (hyperventilation)
  • Poorly fitted dentures

Air is usually trapped within the esophagus and passed out with a belch. If the gas passes lower down the gastrointestinal tract, it will remain trapped until passed out as flatus. Air swallowing is not a common cause of flatulence and bloating but in cases of severe aerophagia, it can contribute to flatulence.

2. Foods That Contribute to Bloating and Gas

Certain foods have a tendency to produce more gas due to the action of intestinal bacteria. These foods are usually carbohydrates and indigestible fiber which may not be digested or absorbed by the body.Carbonated beverages may also contribute to flatulence if gas is not passed out with a belch.

Causes :

  • Carbonated drinks and beverages like beer.
  • High fiber foods like beans, brussel sprouts, celery, cabbage and other fibrous vegetables.
  • Alcohol in excess
  • Sugary foods like sweets
  • Starchy foods: wheat (white bread, pasta), oats, potatoes, corn, and rice
  • Medications: chemotherapy, antibiotics, laxatives, or medicines for diarrhea or pain (naproxen, ibuprofen) can cause gas.

Symptoms may vary but gas and bloating is often noticed a few minutes to hours after consuming the causative foods and beverages.


STOMACH

3. Helicobacter Pylori Infection

Helicobacter pylori is species of bacteria that can infect the stomach cavity. Chronic H.pylori infection (1) may contribute to gastroesophageal reflux disease (GERD), gastritis and peptic ulcers. The pathophysiology of these disease may contribute to flatulence and bloating. H.pylori survives in the stomach acid by producing ammonia which is broken down to form carbon dioxide gas.

Chronic H.pylori infection may be asymptomatic. Typical symptoms are:

  • Uper abdominal bloating
  • Nausea
  • Heartburn
  • Belching
  • Gas (rarely)

4. Dumping Syndrome

Dumping syndrome is the rapid emptying of gastric contents into the intestine.

Causes :

  • Gastric bypass surgery for weight loss
  • Damage of pylorus due to operation or disease (adhesions, cancer)
  • Zollinger-Ellison syndrome (2)
  • Diabetic neuropathy
  • Metoclopramide

Acute symptoms that appear 10-60 minutes after the meal:

  • Nausea
  • Vomiting
  • Abdominal pain and cramps
  • Diarrhea
  • Dizziness
  • Belching
  • Bloating
  • Fatigue
  • Heart palpitations

The following delayed signs and symptoms may develop 1.5-4 hours after eating :

  • Sweating
  • Weakness, fatigue
  • Dizziness
  • Shakiness
  • Feelings of anxiety, nervousness
  • Heart palpitations, rapid heart rate
  • Fainting
  • Mental confusion
  • Diarrhea

With time, many patients start to lose weight because of fear of eating.

5. Slow Gut Motility

Slow gut motility increases the time span that food stays within the gut.

Causes :

  • Gastroparesis
  • Anorexia nervosa
  • Disorders of the nerve supply to the gastrointestinal tract (diabetic neuropathy, atherosclerosis of intestinal artheries)
  • Disorders of the smooth muscle on the gastrointestinal tract
  • Certain drugs may affect normal gut motility (peristalsis): anx
  • Bowel obstruction due to swelling, polyps, tumors

Symptoms :

  • Nausea
  • Vomiting
  • Belching
  • Bloating
  • Flatulence
  • Constipation

PANCREAS

6. Pancreatic Insufficiency

In pancreatic insufficiency, digestive enzymes secreted by the pancreas are reduced or stopped altogether from entering the small intestine.

Causes :

  • Pancreatitis (acute or chronic)
  • Gallstones
  • Hyperlipidemia or hypercalcemia
  • Certain drugs including corticosteroids, NSAID’s, blood pressure lowering agents, antibiotics and immune-suppressants.
  • Surgery
  • Anatomical abnormalities of the pancreas
  • Abdominal trauma
  • Cystic fibrosis
  • Genetic conditions
  • Pancreatic cancer
  • Viral and bacterial infections of the pancreas

Symptoms :

  • Abdominal pain in upper central or left abdomen aggravated after eating and drinking
  • Whitish diarrhea, floating, sticky, and foul smelling stools
  • Bloating
  • Flatulence

LIVER, GALLBLADDER

7. Biliary Stasis

Biliary stasis is the reduction or absence of bile production or secretion into the gut.

Causes :

  • Gallstones
  • Cholecystitis (inflammation of the gallbladder)
  • Cholecystectomy (surgical removal of the gallbladder)
  • Gallbladder cancer
  • Hepatitis
  • Cirrhosis
  • Other liver disease

Symptoms :

  • Pain of the upper right quadrant of the abdomen.
  • Nausea
  • Vomiting (bile may be regurgitated in biliary reflux)
  • Belching
  • Bloating
  • Flatulence
  • Weight loss
  • Anorexia
  • Whitish lose floating sticky stools (if a common hepatic dusct is ocluded with astone)

SMALL INTESTINE

8. Food Poisoning

Food poisoning is a disorder of the gut usually caused by food contaminated with bacteria, viruses or parasites or their byproducts. Food poisoning can also result from chemicals within certain foods. Food poisoning is a common cause of traveler’s diarrhea. (4)

Causes :

  • Microorganisms including viruses, bacteria, parasites
  • Intestinal worms
  • Foods, including certain types of mushrooms, plants or meat. (5)

Symptoms :

  • Nausea
  • Vomiting
  • Watery diarrhea
  • Abdominal pain
  • Stomach cramps
  • Bloating
  • Flatulence
  • Loss of appetite
  • Fatigue
  • Fever

9. Small Intestinal Bacterial Overgrowth (SIBO)

Small intestine bacterial overgrowth is the increased bacterial population within the small intestine. This refers to an overgrowth of the naturally occurring bacterial population within the small intestine.

Causes :

  • Diabetes (Type I or II)
  • Anorexia nervosa
  • Damage to nerve or muscle due to surgery or other trauma
  • Thyroid disorders
  • Pancreatitis
  • Scleroderma
  • Postviral syndromes
  • Intestinal Obstruction
  • Diverticuli
  • Slow gut motility

Symptoms :

  • Belching
  • Bloating
  • Abdominal pain
  • Flatulence
  • Diarrhea
  • Nutritional deficiencies

10. Fructose and Sorbitol Malabsorption

Fructose and sorbitol malabsorption is the body’s inability to digest and absorb these carbohydrates.

Triggers :

  • Genetic factors
  • Sweeteners as sorbitol, xylitol, erythritol, found in “sugar free” gum or soda, and many “low-calorie” foods
  • Most fruits, especially pears, apples, prunes, sweet cherries, dried fruits, fruit juices
  • Vegetables, like brocolli, artichokes
  • Honey

Symptoms :

  • Belching
  • Nausea
  • Bloating
  • Flatulence
  • Abdominal cramps
  • Diarrhea

Hereditary fructose intolerance (HFI), that usually become obvious when a baby gets its first solid food, may cause more severe symptoms if dietary changes are not implemented. An excessive intake of fructose and/or sorbitol can cause the following symptoms :

  • Vomiting
  • Jaundice
  • Fatigue
  • Enlarged liver
  • Seizures

11. Lactose Intolerance

Lactose Intolerance is the body’s inability to digest lactose due to a deficiency of the enzyme lactase. Symptoms usually appear a few minutes to hours after consuming milk and dairy products.

Causes :

  • Decrease of lactase activity with age
  • Genetic factors (rarely)
  • Radiotherapy, chemotherapy, food poisoning or other intestinal diseases can cause temporary lactose intolerance

Symptoms:

  • Belching
  • Nausea
  • Bloating
  • Flatulence
  • Abdominal cramps
  • Diarrhea

12. Celiac Disease

Celiac disease is a digestive disorder commonly referred to as gluten intolerance. The inability to absorb the protein gluten within certain starchy foods, grains and legumes like wheat, barley, rye and oats.

Causes :

  • Unknown factors
  • Genetic factors (if not triggered at birth, may be triggered after pregnancy or stress)
  • Surgery
  • Physical injury
  • Infection

Symptoms :

  • Diarrhea
  • Weight loss
  • Abdominal cramps or pain
  • Flatulence and bloating
  • Steatorrhea (foul smelling, light colored and smelly stools that may have fatty or oily residue)

Further complications and other symptoms may include :

  • Malnutrition which may cause stunted growth in children and vitamin/mineral
  • Swelling (edema)
  • Skin rash (dermatitis herpetiformis)
  • Osteoporosis due to calcium deficiency
  • Neuropathy due to vitamin B12 deficiency
  • Weakness and/or fatigue due to iron deficiency anemia

13. Intestinal Obstruction

Intestinal Obstruction is a total blockage or significant partial obstruction of the small or large intestine.

Causes :

  • Intestinal adhesions
  • Hernia
  • Tumors
  • Congenital abnormalities (like Hirschsprung’s disease)
  • Intestinal telescoping (intussusception)
  • Intestinal twisting (volvulus)
  • Hard mass of intestinal contents (meconium) which is more common in newborns and infants
  • Diverticulitis
  • Foreign bodies
  • Scar tissue or inflammation due to Crohn’s disease
  • Ischemia of intestinal tissue

Symptoms :

  • Intermittent abdominal pain and cramps
  • Fever
  • Bloating
  • Difficulty passing gas
  • Vomiting
  • Nausea
  • Anorexia
  • Abdominal distension
  • Peritonitis

14. Short Bowel Syndrome

Short bowel syndrome is a malabsorption disorder due to a functional disorder or surgical removal of a portion of the small intestine.

Causes :

  • Surgical resection
  • Crohn’s disease
  • Mesenteric ischemia
  • Recurrent intestinal obstruction
  • Trauma
  • Radiation enteritis
  • Cancer
  • Volvulus
  • Necrotizing enterocolitis (in premature newborns)
  • Congenital short bowel

Symptoms :

  • Nutritional malabsorption
  • Diarrhea
  • Steatorrhea (oily/fatty residue in stool)
  • Dehydration
  • Intestinal cramping
  • Bloating
  • Abdominal pain
  • Fatigue
  • Weight loss

15. Gut Fermentation

Gut fermentation (dysbiosis) is the increased decomposition and fermentation of food and bowel contents by naturally occurring and/or foreign micro-organisms.

Causes :

  • Chronic use of antibiotics, antiviral and antifungal oral medication
  • Chemotherapy
  • Bacterial, yeast or parasitic overgrowth within the bowels.

Symptoms :

  • Bloating
  • Flatulence with an offensive odor
  • Intestinal cramping
  • Watery diarrhea

COLON

16. Irritable Bowel Syndrome (IBS)

Irritable bowel syndrome (IBS) is a functional disorder of unknown origin usually affecting bowel movements. Food either passes too fast or too slow through the gut and this affected transient time can cause a host of symptoms.

Causes :

  • Causes of irritable bowel syndrome (IBS) are unknown.
  • Nerves and muscles of the bowels affected by a range of factors.

Aggravating factors :

  • Emotional stress
  • Diet
  • Drugs
  • Stimulants like caffeine and nicotine
  • Alcohol
  • Allergenic foods like dairy, wheat and nuts.

Symptoms :

  • Flatulence
  • Bloating
  • Constipation or diarrhea or both alternating
  • Abdominal pain or discomfort
  • Abdominal cramps
  • Sensation of incomplete emptying after defecation

17. Constipation

Constipation is the difficulty in passing stool or infrequent stools associated with straining and hard stools.

Causes :

  • Low fiber intake
  • Low fluid intake
  • Poor bowel habits
  • Irritable bowel syndrome
  • Malabsorption syndromes
  • Lack of activity/exercise
  • Bowel obstruction
  • Drugs

Constipation can occur as a condition itself or as a symptom of other conditions. (3)

Symptoms :

  • Infrequent stools less than 3 times a week.
  • Hard stool
  • Straining upon passing stool
  • Abdominal pain and discomfort
  • Flatulence
  • Bloating

18. Pseudomembranous Colitis

Pseudomembranous colitis (antibiotic-associated colitis) is the inflammation of the colon mainly due to an overgrowth of Clostridium difficile.

Causes :

  • Antibiotics
  • Oral antiviral and antifungal agents
  • Chemotherapy
  • Immuno-suppressants
  • Recent surgery

Symptoms usually appear within 10 days of starting antibiotic therapy, or only after weeks:

  • Nausea
  • Abdominal cramps
  • Bloating
  • Flatulence, barnyard smell of the gas
  • Diarrhea (usually of a watery nature)
  • Blood, mucus or pus in the stool, green stools
  • Low grade fever
  • Dehydration

19. Diverticulosis and Diverticulitis

Diverticuli are small outpouchings of the gastrointestinal tract. Diverticulosis is common in people over the age of 50 years and can affect any part of the gut. If these pouches become infected or inflamed (diverticulitis), it can cause a range of symptoms.

Causes :

  • Spastic colon or any condition causing spasms of the muscles of the intestinal wall
  • Prolonged increase in intestinal pressure
  • Weakening of the intestinal wall
  • Perforations of the intestinal wall
  • Bacterial infection of pouches
  • Inflammation of pouches

Symptoms :

  • Pain in the left low abdominal quadrant
  • Vomiting
  • Bloating
  • Flatulence
  • Abdominal tenderness
  • Abdominal cramps which are often painful
  • Rectal Bleeding
  • Changes in bowel movement

Diagnosis

A case history is essential to diagnose the causative factor. The following information needs to be taken into account.

Concomitant symptoms will provide a better indication for a differential diagnosis. Changes in bowel movement. Pain after eating or drinking.

Medical and family history will assist with identifying any predisposing factors. Lactose intolerance. H.pylori infection. Aggravated by certain foods.

This information should be carefully noted and provided to the consulting physician to assist with a diagnosis.

Tests :

  • An endoscopy and/or colonoscopy are the most definitive diagnostic tools.
  • Stool samples will often indicate the presence of microbial byproducts and residue of foods.
  • Stool cultures will assist with identifying causative micro-organisms.
  • X-rays and ultrasound scans will assist with identifying anatomical features / abnormalities.
  • Barium contrast X-rays are useful in identifying anatomical abnormalities within the gut.
  • Hematological studies will indicate nutritional deficiencies, infection and therapeutic drug use.
  • Paracentesis is the withdrawal of fluid from the abdominal cavity and this is a useful investigative technique to identify the cause of ascites.

Treatment

Treatment should be directed at the causative factor(s).

  • Discontinue the foods or lifestyle factors that contribute to the condition.
  • Activated charcoal may be used in cases of chemical and or food poisoning.
  • Studies have indicated that activated charcoal may assist directly with flatulence and reduction of malodor. (6)
  • Fiber may assist with irritable bowel syndrome and constipation but may exacerbate flatulence.
  • Probiotic supplements containing intestinal bacterial spores may assist with restoring intestinal bacterial populations.
  • Antibiotics and other antimicrobial agents are required for infections within the gut.
  • Antidiarhheals (loperamide) and laxatives are useful for restoring bowel movements.
  • Antispasmodics (scopolamine butylbromide) are useful for intestinal cramping.
  • Surgical intervention may be necessary in cases of intestinal obstruction.
  • Bloating accompanied by dizziness, sweating and fainting should be treated as an emergency and immediate medical attention should be sought.

Related Articles:

References:

  1. Helicobacter Pylori (emedicine.com)
  2. Zollinger-Ellison Syndrome (merck.com)
  3. Constipation (healthhype.com)
  4. Traveler’s Diarrhea (cdc.gov)
  5. Food poisoning (merck.com)
  6. Treatment of Bloating and Gas (ncbi.nlm.nih.gov)

Article reviewed by Dr. Greg. Last updated on November 8, 2011