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Intestinal obstruction (bowel obstruction) involves disruption of the normal movement of fecal matter through the bowel.
Most of the 6-8 litres of fluid that enter the small bowel each day is absorbed through the microvilli in the small intestine. The wall of the small bowel contains layers of smooth muscle and the nerve supply to this smooth muscle is from both the parasympathetic (vagus nerve) and sympathetic divisions of the autonomic nervous system. Parasympathetic stimulation increases movement (motility) through the lumen of the gut wall through pendular contractions and waves of peristalsis. Sympathetic activity has the opposite effect: it brings about a reduction in intestinal motility and peristalsis.
Signs & Symptoms
When intestinal obstruction occurs, peristalsis is either severely reduced or absent. As a result, fluid, gas and intestinal contents accumulate and abdominal distention with nausea and vomiting occurs. This leads to fluid loss, dehydration and electrolyte imbalances involving sodium, potassium and chloride. These disturbances contribute further to the existing intestinal obstuction.
Diagnosis & Tests
Laboratory findings:- Leukocytosis - counts < 15,000/ul suggest simple obstruction; counts > 15,000/ul suggest impaired circulation; counts > 25,000/ul suggest infarction. Leukocytosis may not occur in older, debilitated patients or in those using corticosteroids or other immunosuppressive drugs.
- Leukopenia with left shift suggests infarction with sepsis.
- Increased serum amylase indicates bowel infarction, secondary pancreatitis, and leakage of pancreatic amylase into the peritoneum and bloodstream.
- Decreased pH and C02 content (metabolic acidosis) reflect lactic acidosis occurring with bowel infarction
- Increased pH and C02 content (metabolic alkalosis) secondary to vomiting with loss of fluid, H+, C1 and K
- Increased BUN suggests dehydration, blood in the intestine, or renal damage.
- Increased LDH (all isoenzymes) suggests infarction of the intestine.
- Decreased serum K and C1 seconary to vomiting
- Ascitic fluid - infarction is suggested by bloody fluid, fetid odour, bacteria, elevated amylase
- Gastric contents - presence of blood suggests infarction of the small intestine
- Rectal contents - presence of blood is common due to bleeding from infarcted bowel
Laboratory Findings of Dehydration:- Decreased urine volume occurs early
- Increased haemoglobin and haematocrit
- Increased urine specific gravity
- Increased BUN
Complications
Distention of the bowel wall brings about an increase in capillary permeability, and intestinal fluid and electrolytes leak into the peritoneal cavity, causing peritonitis. Peritonitis is a major cause of paralytic ileus and together with fluid loss and electrolyte disturbances rapidly places the patient -- unless treated correctly -- into a state of hypovolemic shock.
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Signs, symptoms & indicators of Intestinal Obstruction:
Recommendations and treatments for Intestinal Obstruction:
KEY | | Weak or unproven link |  | | Highly recommended |
GLOSSARY
Abdomen (Abdominal)
That part of the body between the chest and the hips that contains the stomach, intestines, liver, bladder, pancreas and other organs.
Acidosis
Specifically, the abnormal buildup of acids in the body, classically caused by diabetes or kidney disease. Broadly, the potential caused by increased protein intake or metabolism, coupled with inadequate intake (or loss) of alkali.
Amylase
A starch-digesting enzyme.
Bacteria (Bacterial, Bacterium)
Microscopic germs. Some bacteria are "harmful" and can cause disease, while other "friendly" bacteria protect the body from harmful invading organisms.
Capillary
Any of the smallest blood vessels connecting arterioles with venules and forming networks throughout the body.
Corticosteroid (Corticosteroids)
Steroid hormone produced by the adrenal cortex.
Distention (Distended)
An excess expansion of a tissue or organ, either from inflammation, injury or gas.
Electrolyte (Electrolytes)
An element or compound that, when melted or dissolved in water or other solvent, breaks up into ions and is able to carry an electric current.
Gastric
Of, relating to, or associated with the stomach.
Ileus
Bowel obstruction.
Kidneys (Kidney, Renal)
Bean-shaped organs, each about the size of a fist. They are located near the middle of the back, just below the rib cage. The kidneys are sophisticated reprocessing machines, each day handling about 50 gallons of blood to sift out about half a gallon of waste products and extra water. The waste and extra water become urine, which flows to the bladder through tubes called ureters. The actual filtering occurs in tiny units inside the kidneys called nephrons. Every kidney has about a million nephrons. In a nephron, a glomerulus -- which is a tiny blood vessel, or capillary -- intertwines with a tiny urine-collecting tube called a tubule. A complicated chemical exchange takes place, as waste materials and water leave your blood and enter your urinary system. The kidneys recycle chemicals such as sodium, phosphorus, and potassium and thus regulate their levels. Renal: Pertaining to the kidneys.
Leukocytosis
Having abnormally high numbers of white blood cells, usually the result of a non-viral infection.
Leukopenia
A condition in which the number of white blood cells circulating in the blood is abnormally low.
Liter (Liters, Litre, Litres)
A metric measure of volume equivalent to 1.057 liquid quarts or 0.2642 gallons.
Lumen
Space in the interior of a tubular structure.
Metabolism (Metabolic, Metabolize, Metabolizes, Metabolizing)
The chemical processes of living cells in which energy is produced in order to replace and repair tissues and maintain a healthy body. Responsible for the production of energy, biosynthesis of important substances, and degradation of various compounds. Also defined as the sum total of changes in an organism in order to achieve a balance (homeostasis): Catabolic burns up, anabolic stores and builds up; the sum of their work is metabolism.
Microliter (uL)
0.000001 or one millionth of a liter.
Motility
Capacity for spontaneous movement, frequently in reference to the intestine.
Nausea
Symptoms resulting from an inclination to vomit.
Nervous System
A system in the body that is comprised of the brain, spinal cord, nerves, ganglia and parts of the receptor organs that receive and interpret stimuli and transmit impulses to effector organs.
Pancreas (Pancreatic)
Opposite the liver and behind the stomach, the pancreas has two main functions - to manufacture various enzymes for digestion, and to release hormones to help control the body's use of carbohydrates. It releases insulin to help each cell absorb glucose to burn as energy. In this way, insulin controls the amount of sugar (glucose) in the blood. Proper pancreatic function is very important: too much, too little, or no insulin production can be life-threatening. Some of the chemicals released by the pancreas are not hormones, but stimulate other glands to make hormones. Once again, balance is necessary. Nutritional requirements for the pancreas are many. Research indicates that chromium vitamins C, E, B-complex, calcium, magnesium and potassium are especially important.
Pancreatitis
Inflammation of the pancreas. Symptoms begin as those of acute pancreatitis: a gradual or sudden severe pain in the center part of the upper abdomen goes through to the back, perhaps becoming worse when eating and building to a persistent pain; nausea and vomiting; fever; jaundice (yellowing of the skin); shock; weight loss; symptoms of diabetes mellitus. Chronic pancreatitis occurs when the symptoms of acute pancreatitis continue to recur.
Parasympathetic
Usually Parasympathetic nervous system: Portion of the autonomic nervous system that is generally associated with increasing digestion and intestinal muscle activity; decreasing blood circulation and respiration.
Peristalsis
Movement characterized by alternate circular contraction and relaxation of the intestine or other tubular structure which propels the contents onward.
Peritoneum
Serous sac lining the abdominal cavity and covering most of the organs inside it.
pH
A measure of an environment's acidity or alkalinity. The more acidic the solution, the lower the pH. For example, a pH of 1 is very acidic; a pH of 7 is neutral; a pH of 14 is very alkaline.
Potassium
A mineral that serves as an electrolyte and is involved in the balance of fluid within the body. Our bodies contain more than twice as much potassium as sodium (typically 9oz versus 4oz). About 98% of total body potassium is inside our cells. Potassium is the principal cation (positive ion) of the fluid within cells and is important in controlling the activity of the heart, muscles, nervous system and just about every cell in the body. Potassium regulates the water balance and acid-base balance in the blood and tissues. Evidence is showing that potassium is also involved in bone calcification. Potassium is a cofactor in many reactions, especially those involving energy production and muscle building.
Sepsis (Blood Poisoning, Septicemia)
Like septicemia, an infection that has moved deeply into the body, involving the subcutaneous or submucosal layers, connective tissue, lymph system, or blood. Septicemia: The presence of pathogenic bacteria or other microbes in the blood stream - a serious business, since most defenses are focused outside the bloodstream and the infection has bypassed them either due to its virulence, the depth and severity of the original focal infection or the weakened state of the body's immunity and life energy. Blood poisoning.
Serum
The cell-free fluid of the bloodstream. It appears in a test tube after the blood clots and is often used in expressions relating to the levels of certain compounds in the blood stream.
Small Intestine (Small Bowel)
The small intestine lies between the stomach and the large intestine. It is about 6 meters (20 feet) long and its primary function is to digest (break down) food and absorb nutrients (vitamins, minerals, proteins, carbohydrates, and fats). The small intestine makes up more than 70% of the length and 90% of the surface area of the gastrointestinal (GI) tract.
Smooth Muscle (Involuntary Muscle)
The human body contains 2 types of muscle - smooth muscle and striated (skeletal) muscle. Smooth muscle is found in our internal organs such as stomach, intestines, blood vessels, or uterus (womb) and causes them to contract. These muscles are involuntary - that is, we don't control their movement.
Sodium
An essential mineral that our bodies regulate and conserve. Excess sodium retention increases the fluid volume (edema) and low sodium leads to less fluid and relative dehydration. The adult body averages a total content of over 100 grams of sodium, of which a surprising one-third is in bone. A small amount of sodium does get into cell interiors, but this represents only about ten percent of the body content. The remaining 57 percent or so of the body sodium content is in the fluid immediately surrounding the cells, where it is the major cation (positive ion). The role of sodium in the extracellular fluid is maintaining osmotic equilibrium (the proper difference in ions dissolved in the fluids inside and outside the cell) and extracellular fluid volume. Sodium is also involved in nerve impulse transmission, muscle tone and nutrient transport. All of these functions are interrelated with potassium.
Vagus Nerve
Also called the pneumogastric nerve, this is the tenth cranial nerve, with many fibers leading to parasympathetic ganglia in internal organs, and can be considered the presynapse starter for the upper parts of the parasympathetic functions.
Villi (Microvilli)
The villi are small but significant structures of the mucosal layer of the small intestine. They are finger-like (or hair-like) projections, 0.5 to 1mm in length, that cover the mucosal surface and increase its absorptive area. Each villus contains a capillary network, a lymphatic vessel, and smooth muscle fibers. The villi are covered with absorptive cells that have cytoplasmic extensions known as microvilli; the microvilli serve to further increase the absorptive surface. The total increase in absorptive surface provided by the villi and microvilli is some 600-fold. The microvilli form what is known as the brush border; the cells that make up the brush border contain many enzymes and carrier substances that facilitate the digestion and absorption of nutrients.
Last updated: Sep 28, 2008
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