Diarrhea

Generality

Diarrhea is a defecation disorder characterized by rapid emission of large and poorly formed stools.

In order to speak of diarrhea, both of these conditions must be present simultaneously:

• at least three evacuations a day;
• alterations in the quantity or quality of dejections (presence of poorly formed stools: liquid or semi-liquid)

Diarrhea is not a real disease but a nonspecific symptom, common to many diseases (mostly gastrointestinal) or to non pathological conditions (trivial food intolerances, stress, etc.). Diarrhea is often accompanied by a constant urge to evacuate, even in the absence of faecal material (rectal tenesmus). We speak instead of dysentery when the diarrhea is complicated to cause an important evacuation of liquids with no more fecal characteristics (presence of water, mucus, pus, proteins, electrolytes, fats and blood).

Insights

Feces formation and diarrheaDiarrhea causesCare and treatment of diarrhea Remedies for Combating DiarrheaDiarrhea as a symptomDiarrhea in Children Intestinal influenzaDiarrhea medicationsTypes of diarrheaComplicationsDiet and diarrheaDrive diarrhea and Diarrhea and Antibiotics: cause or therapy?

Diarrhea, considered by many to be a banal disease linked mostly to certain food choices, stress or seasonal ailments, is actually a sneaky enemy that causes over three million deaths every year worldwide. In these cases diarrhea is caused by various infectious diseases that can spread due to poor personal hygiene or through water and contaminated food. However, these are circumscribed events that are frequent in patients who are weak and live in developing countries, but extremely rare in industrialized ones. In Italy, for example, mortality from diarrhea is less than 0.4 per thousand.

Despite this danger, diarrhea must still be interpreted as a sort of defensive response of the organism. In fact, diarrheal discharges favor the elimination of pathogenic microorganisms, toxins or irritants. For this reason it is good to avoid using antidiarrheal drugs, without having first discovered the real cause of diarrhea.

Feces formation and diarrhea

Between ingested liquids, foods and secretions (saliva, gastric juice, bile, pancreatic secretion and enteric juice), about 10 liters of material pass through the digestive tract every day. Of these, approximately 90% is absorbed at the level of the ileum (terminal part of the small intestine); the remaining 10% is instead absorbed at the level of the colon, which has the ability to reabsorb up to 4-5 liters of liquids. Under normal conditions, the water content of the faeces is about 100 ml / day; if it exceeds 200ml / day and is accompanied by frequent discharges (> 3 die) we can speak of diarrhea.

The secretions poured along the digestive tract, besides containing a good percentage of water, are rich in proteins and mineral salts and in particular sodium, chlorine, bicarbonate and potassium. These electrolytes are largely reabsorbed along the large intestine where the digestion process is completed. Thanks to the activity of this terminal tract of the digestive tract the semi-liquid content is gradually depleted of water and minerals until it assumes the consistency and the hydrosaline balance typical of faeces.

A simple alteration, even modest, of these reabsorption mechanisms can cause diarrhea.

However, not all forms of diarrhea are linked to a reduction in the capacity for colic or ileal absorption: the presence of liquid stools can also be due to bacterial or viral infections, food intolerances or alterations in gastric motility.

Types of diarrhea

Based on the frequency of symptoms, diarrhea is classified into:

• recurrent diarrhea (with cyclical pattern and diarrheal episodes close together)
• acute diarrhea (less than three weeks)
• chronic diarrhea (lasting more than three to four weeks)

Specifically, at least four different mechanisms capable of causing diarrhea are discovered:

• DIARREA DA ALTERATO ABSORPTION: caused by a deficiency of the active pumps, special mechanisms that provide for the intestinal reabsorption of the electrolytes (mineral salts). Even a reduction in the intestinal surface can decrease the ability to absorb water, electrolytes and nutrients causing diarrhea (surgical resections or by-passes; diseases that alter the villi and intestinal mucosa: celiac disease, diverticulitis, etc.).
• DIARRHEM OSMOTIC: caused by the intake of non-absorbable and osmotically active substances (they recall water). In these cases, diarrhea can be caused by osmotic laxatives (magnesium salts, etc., dietary foods (presence of polyalcohols or large amounts of fructose), malabsorption, food intolerances (lactose, gluten, soy protein, etc.)
• DIARRHEA SECRETORIA OR INFLAMMATORY: caused by an intestinal hypersecretion of water and electrolytes. Many infections or food poisonings are responsible for this type of diarrhea which can also be caused by hormone-secreting intestinal tumors or some types of laxatives. Because of this phlogosis (inflammation) the faeces contain considerable amounts of water and are often enriched with protein, pus and blood (dysentery).
• DIARREA MOTORIA: caused by an alteration of motility and speed of intestinal transit (hyperperistaltism). Increased peristalsis reduces digestion and absorption of water and various nutrients causing diarrhea. This type of diarrhea is common in patients suffering from irritable or carcinoid colon with hyperproduction of 5-hydroxy-tryptamine.