General Stool Examination

1. General Stool Examination Advanced laboratory techniques Third stage Lecture (5) ( Theortical) Asisstant lecturer RajaaSaihood Abbas

2. stool analysis • A stool analysis is a series of tests done on a stool (feces) sample to help diagnose certain conditions affecting the digestive tract . • These conditions can include infection (such as from parasites, viruses, or bacteria), poor nutrient absorption, or cancer. • For a stool analysis, a stool sample is collected in a clean container and then sent to the laboratory analysis. Laboratory analysis includes microscopic examination, chemical tests, and microbiologic tests. The stool will be checked for color, consistency , weight (volume), shape, odor, and the presence of mucus. The stool may be examined for hidden (occult) blood, fat, meat fibers, bile, white blood cells, and sugars called reducing substances. The pH of the stool also may be measured. A stool culture is done to find out if bacteria may be causing an infection.

3. Why Stool analysis is done ? • Stool analysis is done to: 1- Help to identify diseases of the digestive tract, liver, and pancreas. Certain enzymes(such as trypsin or elastase) may be evaluated in the stool to help determine how well the pancreas is functioning. 2- Help find the cause of symptoms affecting the digestive tract, including prolonged diarrhea, bloody diarrhea, an increased amount of gas, nausea, vomiting, loss of appetite, bloating, abdominal pain , and fever. 3- Screen for colon cancer by checking for hidden (occult) blood. 4- Look for parasites, such as pinworms or Giardia lamblia. 5- Look for the cause of an infection, such as bacteria, a fungus, or a virus. 6- Check for poor absorption of nutrients by the digestive tract (mal absorption syndrome). For this test, all stool is collected over a 72-hour period and then checked for the fat and meat fibers. This test is called a 72-hour stool collection or quantitative fecal fat test.

4. Abnormal values • High levels of fat in the stool may be caused by diseases such as pancreatitis, sprue (celiac disease), cystic fibrosis, or other disorders that affect the absorption of fats. •The presence of undigested meat fibers in the stool may be caused by pancreatitis. •A low pH may be caused by poor absorption of carbohydrate or fat. Stool with a high pH may mean inflammation in the intestine (colitis), cancer, or antibiotic use. •Blood in the stool may be caused by bleeding in the digestive tract. •White blood cells in the stool may be caused by inflammation of the intestines, such as ulcerative colitis, or a bacterial infection. Rotaviruses are a common cause of diarrhea in young children. If diarrhea is present, testing may be done to look for rotaviruses in the stool. •High levels of reducing factors in the stool may mean a problem digesting some sugars. •Low levels of reducing factors may be caused by sprue (celiac disease), cystic fibrosis, or malnutrition.

5. Diseases and disorders of the Intestine •Gastroenteritis: is an inflammation of the intestines. •Ileitis: inflammation of the ileum. •Colitis : is an inflammation of the large intestine •Crohn'sdisease : is a type of inflammatory bowel disease that may affect any part of the gastrointestinal tract. •Irritable bowel syndrome. •Constipation . •Diarrhea .

6. Diarrhea • Diarrhea : is the condition of having three or more loose or liquid bowel movements per a day or as having more stools than is normal for that person . • Diarrhea occurs when the food and fluids you ingest pass too quickly or in too large an amount — or both — through your colon. Normally, your colon absorbs liquids from the food you eat, leaving a semisolid stool. But if the liquids from the foods you eat aren't absorbed, the result is a watery bowel movement. • Diarrhea is the most common cause of gastroenteritis.It is a common cause of death in developing countries and the second most common cause of infant deaths worldwide.

7. Types of diarrhea • The loss of fluids through diarrhea can cause dehydration and electrolyte disturbances such as potassium deficiency or other salt imbalances. • Oral rehydration solutions (ORS) with modest amounts of salts and zinc tablets are the treatment of choice and have been estimated to have saved 50 million children in the past 25 years.

8. Types of diarrhea 1- Secretory diarrhea means that there is an increase in the active secretion, or there is an inhibition of absorption. The most common cause of this type of diarrhea is a cholera toxin that stimulates the secretion of anions, especially chloride ions. Therefore, to maintain a charge balance in the lumen, sodium is carried with it, along with water.

9. Osmotic diarrhea 2- Osmotic diarrhea occurs when too much water is drawn into the bowels. In healthy individuals, too much magnesium or vitamin C or undigested lactose can produce osmotic diarrhea and distention of the bowel. A person who has lactose intolerance can have difficulty absorbing lactose after an extraordinarily high intake of dairy products. In persons who have fructose malabsorption, excess fructose intake can also cause diarrhea.

10. Inflammatory diarrhea 3- Inflammatory diarrhea occurs when there is damage to the mucosal lining, which leads to a passive loss of protein-rich fluids and a decreased ability to absorb these lost fluids. Features of all three of the other types of diarrhea can be found in this type of diarrhea. It can be caused by bacterial infections, viral infections, parasitic infections, or autoimmune problems such as inflammatory bowel diseases. It can also be caused by tuberculosis, colon cancer, and enteritis.

11. Dysentery Dysentery If there is blood visible in the stools, it is not diarrhea, but dysentery. The blood is trace of an invasion of bowel tissue. Dysentery is a symptom of, among others, Shigella, Salmonella, and Entamoebahistolytica.

12. Infections diarrhea • There are many causes of infectious diarrhea, which include viruses bacteria and parasites. Norovirus is the most common cause of viral diarrhea in adults, but rotavirus is the most common cause in children under five years old. Adenovirus types 40 and 41, and astroviruses cause a significant number of infections.

13. Infections diarrhea • The bacterium Campylobacter is a common cause of bacterial diarrhea, but infections by Salmonellae, Shigellaeand some strains of Escherichia coli(E.coli) are frequent. • Parasites do not often cause diarrhea except for the protozoan Giardia, which can cause chronic infections if these are not diagnosed and treated with drugs such as metronidazole.

14. Gastroenteritis or infectious diarrhea Gastroenteritis Is a medical condition characterized by inflammation of the gastrointestinal tract that involves both the stomach ("gastro"-) and the small intestine ("entero"-), resulting in some combination of diarrhea, vomiting, and abdominal pain and cramping. Gastroenteritis has also been referred to as stomach virus. Although unrelated to influenza, it has also been called stomach flu and gastric flu. Signs and symptoms usually begin 12–72 hours after contracting the infectious agent. If due to a viral agent, the condition usually resolves within one week. Some viral causes may also be associated with fever, fatigue, headache, and muscle pain. If the stool is bloody, the cause is less likely to be viral and more likely to be bacterial. Some bacterial infections may be associated with severe abdominal pain and may persist for several weeks.

15. Gastroenteritis or infectious diarrhea • Children infected with rotavirus usually make a full recovery within three to eight days. However, in poor countries treatment for severe infections is often out of reach and persistent diarrhea is common. Dehydration is a common complication of diarrhea, and a child with a significant degree of dehydration may have a prolonged capillary refill, poor skin turgor, and abnormal breathing.

16. Viral causes Viral causes of gastroenteritis :- • Rotavirus, norovirus, adenovirus, and astrovirus are known to cause viral gastroenteritis. Rotavirus is the most common cause of gastroenteritis in children. • Viruses cause about 70% of episodes of infectious diarrhea in the pediatric age group. Rotavirus is a less common cause in adults due to acquired immunity. • Norovirus is the leading cause of gastroenteritis among adults in America, causing greater than 90% of outbreaks. Norovirus is the cause of about 10% of cases in children.

17. Bacterial causes • In the developed world Campylobacter jejuniis the primary cause of bacterial gastroenteritis. • In children, bacteria are the cause in about 15% of cases, with the most common types being Escherichia coli, Salmonella, Shigella, and Campylobacter species. If food becomes contaminated with bacteria and remains at room temperature for a period of several hours, the bacteria multiply and increase the risk of infection in those who consume the food. • Toxigenic Clostridium difficileis an important cause of diarrhea that occurs more often in the elderly. Infants can carry these bacteria without developing symptoms. It is a common cause of diarrhea in those who are hospitalized and is frequently associated with antibiotic use. Staphylococcus aureusinfectious diarrhea may also occur in those who have used antibiotics. "Traveler's diarrhea" is usually a type of bacterial gastroenteritis.

18. Parasitic causes • A number of protozoans can cause gastroenteritis – most commonly Giardia lamblia – but Entamoebahistolytica and Cryptosporidium species have also been implicated. As a group, these agents comprise about 10% of cases in children. Giardia occurs more commonly in the developing world, but this etiologic agent causes this type of illness to some degree nearly everywhere.