Pyloric obstruction

Introduction to pyloric obstruction The pylorus is the narrowest part of the digestive tract, and the normal diameter is about 1.5 cm, so it is prone to obstruction. As the pylorus passes through the obstacle, the contents of the stomach cannot enter the intestine smoothly, but a large amount of retention in the stomach leads to hypertrophy of the muscular layer of the stomach wall, enlargement of the gastric cavity and inflammation of the gastric mucosa, edema and erosion. Clinically, due to long-term failure of patients to eat normally, and a large number of vomiting, leading to severe malnutrition, hypoproteinemia and anemia, and severe water dehydration, low potassium and alkali poisoning and other water and electrolyte disorders. The general patient has a history of longer ulcers. As the lesion progresses, the stomach pain gradually worsens, and there are symptoms such as hernia and nausea. Patients often get anorexia due to bloating, and antacids are becoming ineffective. The stomach gradually expands, the upper abdomen is full, and there is a moving mass. Signs: weight loss, burnout, dry skin and loss of elasticity, can appear signs of vitamin deficiency, dry lips, dry tongue, moss, eyeball retraction. The upper abdomen swells significantly, and the stomach type and the gastric peristaltic wave moving from left to right can be seen. Percussion of the upper abdomen drum sound, vibration water sound is obvious. basic knowledge The proportion of illness: 0.06% Susceptible people: no special people Mode of infection: non-infectious Complications: constipation

Cause of pyloric obstruction

Ulcer (10%):

Ulcers located near the pylorus or pylorus may be due to mucosal edema, or reflex pyloric ring muscle contraction due to ulcers. The more common cause is submucosal fibrosis caused by chronic ulcers, scarring stenosis, pyloric obstruction caused by ulcer disease About 10%.

Scar contracture (20%):

The pyloric stenosis caused by scar contracture, scar pyloric obstruction, can not be alleviated. And constantly increasing. The pyloric fistula is purely functional, and the rest are all organic lesions. Pyloric edema is associated with inflammation of the stomach. Although it is an organic disease, it can heal itself. Only scarring stenosis can not be solved by surgery.

Pyloric muscle hypertrophy (30%):

In addition, adults can also develop pyloric muscle hypertrophy and produce pyloric obstruction. The onset or exacerbation of pyloric fistula is often paroxysmal, and the obstruction can be relieved by itself. Mucosal edema can be resolved with the reduction of inflammation. The occurrence of pyloric obstruction is often not a single factor, but a combination of multiple factors. See Obstruction due to tumors can be found in gastric cancer.

Pathogenesis

1. Pathological classification: gastric pyloric obstruction is divided into 3 types:

1 pyloric sphincter reflex sputum, obstruction is intermittent.

2 pyloric obstruction is edematous, also manifested as intermittent.

3 scar, persistent, is an indication of absolute surgery. In the early stage of obstruction, the stomach wall promotes emptying by strengthening peristalsis and compensatory stomach wall thickening.

2. Pathophysiology: Once the obstruction occurs, the food and gastric juice are detained, can not enter the small intestine through the pylorus, and even vomiting, not only affects the digestion and absorption of normal food, but also can cause a large loss of water and electrolytes, resulting in systemic A series of pathophysiological changes.

(1) Systemic pathophysiological changes:

1 Nutritional disorders: due to ingestion of food can not be fully digested and absorbed, coupled with vomiting, will inevitably lead to nutritional disorders, including anemia and hypoproteinemia.

2 water and electrolyte disorders: normal adults secrete 1500ml of saliva per day, 2500ml of gastric juice, a total of 4000ml, the average gastric juice per liter of chlorine contains 140mmol, sodium 60mmol, potassium 12mmol, when the pyloric obstruction, the secreted liquid can not be absorbed back, On the contrary, due to vomiting, the electrolyte is largely lost. The loss of water first affects the extracellular fluid. As a result, the osmotic pressure of the extracellular fluid is increased, and the intracellular water is removed, causing dehydration in the cells. If vomiting continues, and no supplement is obtained, Circulatory failure can occur, and since the vomit still contains a large amount of electrolyte, the following can occur:

A. Potassium deficiency: Because the potassium content in gastric juice is higher than serum potassium, when the gastric juice is lost a lot, the potassium ions can be lost a lot, and the patient can't eat, can't get from food, and the kidney continues to drain potassium. Potassium is more deficient. In the state of starvation, catabolism occurs in the body. As a result, potassium is moved from the inside to the outside of the cell. At this time, although there is a serious potassium deficiency, the serum potassium can be only slightly lower than normal and easily misdiagnosed.

B. Sodium deficiency: Although the content of sodium in gastric juice is lower than that of plasma, such as a large amount of vomiting, and can not be taken orally, it can also cause sodium deficiency, pyloric obstruction, due to a large amount of vomiting, extracellular fluid is reduced, blood is concentrated, Therefore, plasma sodium is only slightly reduced, and it is easy to be misdiagnosed.

C. Acid-base balance disorder: Wall cells of normal stomach can produce water with CO2, which dissociates into H+ and HCO3-, H+ enters the gland lumen and Cl- combines with hydrochloric acid (HCl), and HCO3- returns Circulation, intestinal mucosal epithelium can also produce carbonic acid (H2C03) in alkaline environment, dissociated into HCO2- and H+, the former enters intestinal fluid, the latter returns to blood circulation, neutralizes HC03- in blood circulation; HCl in gastric juice In the intestine and HC03-neutralization, so as to achieve acid-base balance, pyloric obstruction, due to a large amount of vomiting, the loss of HCl in the stomach, the above balance was destroyed, blood HCO3- gradually increased, destroyed (HCO3- ) / (H2CO3) ratio, the total amount of buffered alkali in the blood increased, pH increased, causing metabolic alkalosis, such alkali poisoning, mostly low chlorine and low potassium, said low chloride and low potassium alkalosis, for the pylorus The metabolic disorder characteristic of obstruction, due to the lack of potassium in the blood, the potassium ion in the distal renal tubular cells is also reduced, so only the hydrogen ion (H+) exchanges with the sodium ion, and the amount of urinary excretion H+ increases, making the urine acidic. This patient with metabolic alkalosis has a paradox of acidic urine and is also a pyloric obstruction. Phenomenon peculiar low chlorine alkalosis instructions in addition, there exists in patients with hypokalemia.

(2) Local pathophysiological changes: pyloric obstruction is often gradually formed, that is, partial obstruction gradually increases to complete obstruction. In the early stage of obstruction, in order to enable chyme to be discharged into the duodenum, gastric peristalsis is enhanced, and the gastric wall muscle layer is replaced. Compensatory hypertrophy, but the stomach does not significantly expand, as the obstruction continues to increase, although the stomach has strong peristalsis, it is difficult to overcome the resistance of the pylorus, the stomach is gradually expanding, the peristalsis is weakened, the stomach wall is slack, the stomach is retained, and the bag is dilated.

Due to the retention of gastric contents, the pyloric sinus mucosa is stimulated to produce gastrin, which promotes the secretion of gastric parietal cells, inflammation of the gastric mucosa, and even ulceration.

Pyloric obstruction prevention

Active and effective treatment of ulcer disease, to prevent obstruction caused by spasm, edema and scarring pyloric stenosis. Improve eating habits, mainly digestible foods, avoid irritating substances, eat seven full, maintain regular, normal eating habits. Although the ulcer is easy to treat, it is easy to relapse. In addition to diet, pay attention to tobacco, alcohol, to maintain adequate sleep, moderate exercise and eliminate excessive tension, is a basically effective method.

Pyloric obstruction complications Complications constipation

The course of the disease is longer, the patient gradually develops general malaise, is getting thinner, loses weight, has less urine, constipation, and sometimes has mental symptoms and hand, foot and ankle.

Pyloric obstruction symptoms Common symptoms Anti- gastric hernia bloating constipation shock water sound gastrointestinal motility food in the stomach through the stomach dilatation of the duodenum with a notch or narrow edema

symptom

The specific symptom of pyloric obstruction is vomiting overnight food, whether it is accompanied by pain and the severity of vomiting is related to ulcer site and obstruction.

1. Vomiting:

Vomiting is a prominent symptom of pyloric obstruction. It is characterized by: vomiting occurs mostly in the afternoon or evening, and the amount of vomiting is large. It can reach more than one liter at a time. The vomit is smoldering food, accompanied by acid odor, without bile, after vomiting. Feeling comfortable in the abdomen, so patients often induce vomiting to relieve symptoms.

2. Gastric peristaltic wave:

The stomach type in which the upper abdomen can be bulged, sometimes sees the gastric peristaltic wave, and the peristalsis starts from the left rib arch, goes to the right abdomen, and even creeps in the opposite direction.

3. Earthquake sound:

The stomach expands and contains a lot of contents. When you hit your upper abdomen by hand, you can hear the sound of water shock.

4. Other:

Less urinary, constipation, dehydration, weight loss, and severe dyscrasia in severe cases.

5. Pain

Patients with pyloric obstruction do not necessarily have pain. For example, after ulceration, the pyloric obstruction caused by scar, although abdominal distension and vomiting are serious, but generally there is no abdominal pain. In the attack period of ulcer disease, local edema, inflammation Or pyloric obstruction caused by pyloric fistula, often accompanied by obvious upper abdominal pain, pyloric tube ulcer, pyloric or duodenal ulcer close to the pyloric can produce pain, such abdominal pain is mostly persistent, abdominal pain after eating Increased, can be alleviated after vomiting, most patients have a temporary effect on non-surgical treatment.

Signs:

The patient is thin, burnout, dry skin, loss of elasticity, and signs of vitamin deficiency, dry lips, dry tongue, and eyeballs. The upper abdomen swells significantly, and the stomach type and the gastric peristaltic wave moving from left to right can be seen. Percussion of the upper abdomen drum sound, the water sound is obvious. I can hear the sound of gas, but it is rare. Chvostek and Trousseau were positive.

classification

There are four types of ulcer disease complicated with pyloric obstruction:

1. Spastic obstruction: ulcer near the pylorus, stimulating the pyloric sphincter reflex sputum.

2. Inflammatory edema obstruction: Inflammation and edema of the pyloric area ulcer itself.

3. Scarring obstruction: ulcers and induration, scars and contractures after ulceration.

4. Adhesive obstruction: inflammation or perforation causes adhesion or traction.

Pyloric obstruction

Due to dehydration, there is obvious blood concentration. When the disease course is long, there may be mild anemia, hypoproteinemia, serum potassium, sodium, and chlorine. When low-chlorine and low-potassic alkalosis has occurred, the carbon dioxide binding capacity is increased, and blood gas analysis is performed. pH>7.45, BE>+3, PCO2 can be reduced. Severe patients may have elevated blood urea nitrogen or non-protein nitrogen due to less urine. If the patient has potassium deficiency, the urine may be acidic.

Stomach volume suction

It is a simple and reliable method to determine whether there is gastric retention. For example, if you have more than 300ml of gastric juice, you can still take out more than 200ml of gastric juice in the morning after fasting, which indicates that the stomach is retained. If the stomach juice is mixed with food, it will support Diagnosis of pyloric obstruction.

2. Salt water load test

After draining the gastric juice, inject 750 ml of isotonic saline, and then extract all the contents of the stomach after 30 minutes. If it reaches 400 ml or more, it may be considered that there is a pyloric obstruction.

3. X-ray inspection

Abdominal X-ray film can be seen in the swelling of the stomach, such as the upper digestive tract barium meal examination, can be clearly diagnosed, and can understand the nature of obstruction, but for patients with severe obstruction, due to the presence of a large amount of food in the stomach, affecting Filling of the agent, it is often impossible to determine the nature of the obstruction. For such patients, gastrointestinal decompression can be performed first. After the stomach is exhausted, the barium meal examination is performed, which is often helpful for diagnosis.

4. Fiber endoscopy

Fiberoptic endoscopy can not only determine the presence or absence of obstruction, but also determine the nature of obstruction, and can be used for scrubbing cell examination or biopsy to confirm the diagnosis, such as the effect of gastric retention, can be checked after direct vision.

Diagnosis of pyloric obstruction

diagnosis

According to the history of ulcers and typical symptoms and signs, the diagnosis is not difficult, but the exact cause of obstruction, as well as some rare upper gastrointestinal obstructive diseases, including external compression, require some special examination to confirm the diagnosis.

Physical examination: patients with malnutrition, weight loss and obvious dehydration signs, the longer the obstruction time, the more obvious the symptoms, such as untreated, the clinical manifestations of alkalosis.

Abdominal examination can be seen in the upper abdomen bulging and the gastric peristaltic wave moving from the upper left to the lower right. A few patients can also see the reverse peristalsis. The left upper abdomen can be slightly stimulated to have a peristaltic wave. For example, in the upper abdomen, there is a vibration sound in the upper abdomen. , it has diagnostic significance.

Differential diagnosis

Patients with a history of long-term ulcers and typical symptoms of gastric retention and vomiting, if necessary, X-ray or gastroscopy, diagnosis is not difficult, need to be identified with the following diseases.

1. pyloric spasm and edema caused by ulcer during active period

There are ulcer pain symptoms, obstruction is intermittent, although vomiting is very intense, but the stomach does not expand, vomit does not contain food, medical treatment of obstruction and pain symptoms can be alleviated or alleviated.

2. Pyloric obstruction caused by gastric cancer

The course of disease is shorter, the degree of gastric dilatation is lighter, gastric peristaltic waves are rare, and the upper abdomen can touch the mass. X-ray barium meal examination shows filling defects of gastric antrum, and biopsy can be confirmed by gastroscopy.

3. Obstructive lesions below the duodenal bulb

Such as duodenal tumor, annular pancreas, duodenal stasis can cause duodenal obstruction, accompanied by vomiting, gastric dilatation and retention, but its vomit contains more bile, X-ray barium meal or endoscopic examination can be determined Hard resistance properties and parts.

4. Gastric pyloric hard cancer

The disease period is shorter than ulcerative obstruction. X-ray barium meal examination has pyloric filling defect, and gastroscopy plus biopsy can confirm the diagnosis.

5. Adult pyloric hypertrophy

X-ray barium meal found the pyloric tube small and smooth, with a concave shadow on the bottom of the duodenal bulb.

6. Obstruction below the duodenal bulb

Such as duodenal tumor, superior mesenteric artery compression syndrome, annular pancreas, pancreatic head cancer.

7. Gastric mucosal prolapse intermittent upper abdominal pain

The antacid can not be relieved, and the position may be relieved when the position is changed to the left lateral position. The X-ray barium meal is a "parachute" defect of the duodenal bulb.

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