Causes and development (etiology and pathogenesis) | Gastrointestinal bleeding

Causes and development (etiology and pathogenesis)

The triggers of gastrointestinal bleeding (gastrointestinal bleeding) are very diverse: can be responsible for bleeding of the stomach or intestine. Burns caused by stomach acid and malignant tumors of the stomach (stomach cancer) are also possible causes. As a rule, gastric bleeding is a consequence of various underlying diseases and manifests itself either as an acute, life-threatening or chronic complication.

In about 50% of the patients who suffer from gastric bleeding, so-called gastric ulcers (ulcus ventriculi) are present. This is a defect in the stomach wall that extends beyond the stomach mucosa and can be caused by stress, reduced mucosal blood flow, chronic intake of anti-inflammatory and painkilling drugs (NSAIDs such as ibuprofen, diclofenac) or a stomach mucosal infection with the bacterium Helicobacter pylori. If peptic ulcers persist untreated over a long period of time, they can deepen and spread further, so that under certain circumstances they can lead to destruction of stomach vessels or even to perforation of the stomach wall.

In 15% of cases, however, damage to only the stomach lining (erosion) is responsible for the bleeding that occurs. This usually occurs at the bottom of an inflammatory stomach disease (erosive gastritis), which can also be caused by medication (NSAIDs, glucocorticoids), bacteria (Helicobacter pylori) or viruses (e.g. noroviruses), stress, but also by alcohol or nicotine abuse as well as autoimmune reactions and bile acid reflux from the small intestine. However, excessive and long-term alcohol consumption can lead to gastritis as well as to the so-called Mallory-Weiss syndrome, in which tears in the stomach lining can be caused by violent vomiting and choking.

These tears can also cause 5-10% of gastric bleeding. Dilated stomach vessels (gastric varices; fundus varices), which can occur in various diseases of the spleen and liver, are also potential sources of bleeding. Among the rarer causes are benign or malignant gastric tumors (approx.

1%), which can destroy stomach vessels as they grow.On the other hand, vascular malformations in the stomach wall (angioplasia) can also lead to bleeding if they open up by themselves or are accidentally injured by sharp-edged food components.

  • Drugs, so-called NSAIDs (non-steroidal anti-inflammatory drugs)
  • Portal vein hypertension (medical: portal hypertension) and the often associated formation of dilated veins of the esophagus with a tendency to bleed (medical: esophageal varices),

Both short-term, severe stress (e.g. major surgery, burns, blood poisoning, shock, polytrauma, psychological stress) and chronic stress over a longer period of time are major risk factors for the development of gastritis and peptic ulcers, which may lead to gastric bleeding. The cause of this is the increased production and release of stress hormones (adrenaline, noradrenaline) from the adrenal glands (adrenal medulla), which takes place in acute stress situations and leads, among other things, to vasoconstriction of the stomach lining and increased production of gastric acid aggressive to the lining.

The resulting reduced blood flow and the beginning of self-digestion of the mucous membrane layer of the stomach can result in inflammatory changes and destruction of the stomach wall. The body usually reacts to chronic stress with a reduced resistance, permanently high blood pressure, delayed wound healing, increased tiredness and lack of concentration, reduced physical performance, loss of libido and stomach and intestinal problems. The latter are not caused by increased stress hormone production, as is the case with acute stress, but rather by increased cortisone release from the adrenal glands (adrenal cortex), which leads to reduced mucus formation in the gastrointestinal tract.

This mucus, which is normally responsible for neutralizing gastric acid, is only produced in a reduced amount or is absent completely, so that the protective barrier of the stomach mucosa is lost. The result is also here an increasing destruction of the mucous membrane, which can turn into inflammation, ulcers and bleeding. In addition, gastrointestinal problems under constant stress are also caused by the fact that the gastrointestinal tract is less supplied with blood in order to be able to supply all blood and energy reserves to the organs (heart, lungs, muscles, brain) that are under increased stress.

The result is reduced gastrointestinal activity, which can lead to a wide variety of symptoms such as nausea, vomiting, constipation or even diarrhea. In addition to the damage to the liver and its secondary diseases, which are known to occur in many cases, increased alcohol consumption over a longer period of time can also damage the stomach. Along with nicotine and some drugs, alcohol is one of the toxic substances that can irritate and damage the stomach lining.

In the course of time, it can lead to the development of acute or chronic gastritis or even to the formation of stomach ulcers. Both diseases can lead to the opening of blood vessels through progressive destruction of the stomach lining or stomach wall, resulting in bleeding in the stomach. In addition, bleeding in the stomach can also be caused by the so-called Mallory-Weiss syndrome, which occurs more frequently in patients with a history of long-term alcohol consumption and a previously damaged stomach lining.

If strong vomiting and/or choking occurs in the course of alcohol excesses, the associated increase in pressure in the stomach can lead to tearing of the mucous membrane in the transition area of the stomach to the esophagus. If injuries or ruptures of the stomach vessels also occur, this can cause light to heavy bleeding. Taking some drugs or combining certain drugs over a longer period of time is associated with an increased risk of gastrointestinal or gastrointestinal bleeding.

Bleeding in the gastrointestinal tract is increasingly associated with so-called NSAIDs (non-steroidal antiphlogistics). In addition to a pain-relieving effect, they also have an anti-inflammatory effect. Typical representatives of the NSAID group are Ibuprofen®, Diclofenac® and Naproxen® as well as Aspirin® (acetylsalicylic acid).

In addition to regular intake, the dosage level also plays an important role in the occurrence of side effects. Inflammatory changes in the mucous membranes and ulcers are among the complications, but more serious ones such as the bleeding mentioned above or perforations and obstructions of the stomach and intestinal wall are also among them. In general, taking this medicine increases the risk of side effects, but the more serious complications are still rare.In the case of diclofenac, such side effects have been observed in about 3 patients out of a total of 1000 with a daily intake of 150 mg.

The above-mentioned NSAIDs (non-steroidal anti-inflammatory drugs), which are anti-inflammatory painkillers, include both Aspirin® (active ingredient: acetylsalicylsäre/ASS) and Voltaren® (active ingredient: diclofenac). Their mode of action is identical; both inhibit an enzyme that is mainly responsible for the formation of tissue hormones (prostaglandins). These tissue hormones play a major role in the development of pain and inflammation, among other things.

A major side effect of the permanent intake of aspirin/voltars with regard to the gastrointestinal tract is that the tissue hormone E2 (prostaglandin E2) produced by the gastrointestinal mucosa is also inhibited in its formation. This leads to the fact that the stomach mucosa in particular can produce less neutralizing mucus, which protects against the aggressive stomach acid. The result is a significantly increased risk of gastritis and the formation of gastric ulcers (Ulcus ventriculi), both of which can lead to gastric bleeding due to the destruction of stomach wall vessels.

However, the risk of bleeding depends on the dose and duration of drug therapy. For example, 75mg ASA increase the risk by a factor of 2, 150mg already by a factor of 3. Ibuprofen belongs to the group of non-steroidal anti-inflammatory drugs and has an analgesic, anti-inflammatory and antipyretic effect.

In addition, it also reduces the production of mucus in the stomach and thus increases the risk of mucosal damage. According to a study, the risk of suffering a serious complication such as gastrointestinal bleeding within one year is around 1% if 2400mg of ibuprofen is taken daily. In general, such side effects are more frequently observed in patients of advanced age.

Aspirin with the active ingredient acetylsalicylic acid also belongs to the group of non-steroidal anti-inflammatory drugs and reduces the risk of cardiovascular diseases such as heart attacks. It reduces the probability of platelets clumping together in the blood vessels. According to one study, a daily intake of 1200mg of ASA has a risk of less than one percent of gastrointestinal bleeding.

With long-term use of aspirin, especially in combination with other antithrombotic drugs, a gastric protection (proton pump inhibitor) should always be prescribed. A further cause is the Mallory Weiss lesion, which accounts for 10% of all bleeding in the upper gastrointestinal tract and is a rather rare condition in which increased pressure in the stomach, e.g. in severe vomiting, leads to a bleeding tear in the lower esophagus. 20% of bleeding occurs in the varices (varicose veins) of the esophagus, which occur when the blood flow through the liver is disrupted by excessive alcohol consumption due to the connective tissue remodelling (cirrhosis of the liver): Instead of taking the direct route to the lower vena cava leading to the heart, the blood flows via the by-passages – the veins of the esophagus – which are now under greater strain (medically: collateral circulation is formed).

The pathologically dilated veins are called varices and can lead to potentially fatal bleeding. Medications associated with an increased risk of bleeding include aspirin (because it inhibits the formation of blood-clotting substances in the blood platelets) and other related pain and fever-reducing drugs, i.e. those also classified as NSAIDs (= non-steroidal anti-rheumatic drugs). Also the anticoagulants (medical term for blood coagulation inhibitors) administered specifically to inhibit blood coagulation, which include e.g.

phenprocoumon (trade name: Marcumar), Coumadin (trade name: Warfarin) and heparins (e.g. Liquemin, Fragmin), can cause gastrointestinal bleeding, especially in the case of overdoses. The above-mentioned causes usually lead to localized bleeding in the upper gastrointestinal tract, which by definition includes not only the esophagus and stomach, but also the first section of the small intestine. The most common causes of bleeding localized in the lower GI tract (gastrointestinal bleeding) are age-related.

If younger patients up to 30 years of age suffer from bleeding in the intestine, a congenital malformation known as Meckel’s diverticulum is most likely to be responsible. This is an approximately five centimeter large protrusion of the small intestine, which is located 60-90 centimeters in front of the valve separating the small and large intestine. (The valve is called the ileocecal valve after the sections of the intestine that separate it; the cecum is the old spelling: Coecum- means nothing else than the gastrointestinal bleeding better known to the population.

The function of the ileocecal valve, also known as Bauhin’s valve, is to prevent backflow of intestinal contents from the colon, which is heavily colonized with bacteria, into the small intestine). The Meckel’s diverticula, which are usually located in the upper small intestine, often do not cause any complaints; however, half of the affected persons have a diverticulum containing (during embryonic development) disrupted stomach lining or other tissue, which in addition to bleeding can lead to long-lasting pain, a feeling of fullness, digestive problems and inflammation, up to potentially life-threatening closure of the intestine (medically: mechanical ileus). The bleeding is caused by the production of aggressive hydrochloric acid through the stomach lining.

The acid then corrodes surrounding tissue and vessels, causing bloody erosions (superficial tissue defects) and ulcers (deep tissue defects that often extend into the muscles). In patients up to 60 years of age, however, bleeding diverticula of the colon mucosa, i.e. protrusions of the intestinal mucosa through the outer connective tissue layer covering the entire intestine (medically: serosa), are the most common cause of gastrointestinal bleeding (gastrointestinal bleeding). The exact mechanism of the development of colon diverticula, which, if they occur multiple times, cause the “diverticular disease” (medically: diverticulosis), which is referred to as the entire clinical picture, is unknown. Presumably a low-fiber diet and lack of exercise promote the formation of diverticula. Malformations of the vessels (angiodysplasias) are the most common source of bleeding in people over 60 years of age.