Chronic enteritis - Diagnosis

Laboratory and instrumental data

• _{General blood test: iron deficiency hypochromic, B12} deficiency hyperchromic or polyfactorial anemia are quite often detected.
• General urine analysis: without significant changes. With the development of hypothalamic-pituitary insufficiency and diabetes insipidus syndrome, urine density decreases. In severe cases of chronic enteritis, slight proteinuria and microhematuria are possible; with putrefactive intestinal dyspepsia, indican excretion is increased.
• Biochemical blood test: decreased blood levels of total protein, albumin, calcium, sodium, iron; often hypoglycemia; with the development of reactive hepatitis, increased levels of bilirubin, alanine aminotransferase, cholesterol.
• Hormonal levels in the blood: in hypothyroidism - decreased levels of thyroxine, triiodothyronine; in hypocorticism - decreased levels of cortisol; in hypothalamic-pituitary insufficiency - decreased levels of somatotropin, gonadotropins, thyrotropin, corticotropin; in hypofunction of the sex glands - decreased levels of sex hormones in the blood.
• Coprological analysis: the following changes in feces (coprocytograms) are characteristic of chronic enteritis:
  • polyfecalia (the amount of feces increases to 300 g or more per day);
  • the color of the stool is straw-yellow or greenish-yellow;
  • there are pieces of undigested food;
  • mucus (in small quantities);
  • steatorrhea (fatty acids and soaps are detected in large quantities - intestinal type of steatorrhea);
  • creatorrhea (undigested muscle fibers are detected in the feces);
  • amylorrhea (undigested starch);
  • gas bubbles, foamy stools in fermentative dyspepsia;
  • acidic stool reaction (pH below 5.5) indicates a violation of carbohydrate digestion;
  • increased excretion of enterokinase and alkaline phosphatase in feces.
  • Bacteriological examination of feces reveals dysbacteriosis.
• Study of the functional capacity of the intestine:
  • Study of the intestinal absorption function.

The intestinal absorptive capacity is assessed by the rate and quantity of various substances taken orally or introduced into the duodenum through a tube appearing in the blood, saliva, urine and feces. The most commonly used test is D-xylose. D-xylose is taken orally in the amount of 5 g, then its excretion with urine is determined over 5 hours. In chronic enteritis, the excretion of D-xylose with urine is reduced (normally, 30% of all D-xylose taken orally is excreted).

To exclude the influence of the kidneys on the test results, it is advisable to determine the level of D-xylose in the blood 60 and 120 minutes after taking 25 g of D-xylose orally. Normally, the content of D-xylose in the blood after 60 minutes is 0.15±0.03 g/l, after 120 minutes - 0.11+0.02 g/l.

In chronic enteritis, these indicators are reduced.

The D-xylose test allows one to evaluate the functional capacity of the predominantly proximal part of the small intestine.

The lactose test is used to diagnose lactose breakdown and absorption disorders. Normally, after oral administration of 50 g of lactose, the blood glucose level increases by at least 20% compared to its initial value. Glucose is formed after lactose is broken down by lactase. In chronic enteritis, lactose breakdown and absorption are disrupted, and the glucose level increases by less than 20% compared to the initial level.

The potassium iodide test is a simple indicative test for assessing the state of the intestinal absorption function, in particular, the absorption of salts.

The patient takes 0.25 g of potassium iodide orally, then the time of iodine appearance in saliva is determined by the reaction with a 10% starch solution (when iodine appears, saliva turns blue when starch is added). Normally, iodine appears in saliva no later than 6-12 minutes, with chronic enteritis and impaired absorption function of the small intestine, this time increases.

Calcium chloride test. The patient takes 20 ml of a 5% calcium chloride solution orally, then after 2 hours the calcium content in the blood is determined. With normal absorption function, the calcium level in the blood increases, with chronic enteritis it practically does not change.

A test with a load of albumin labeled with¹¹ I. The test allows one to evaluate the absorption of proteins in the small intestine. In case of a violation of absorption in the small intestine, a flat curve of blood radioactivity, a decrease in the excretion of ¹¹ I with urine and an increase in excretion with feces are observed.

The Van de Kamer test is used to study fat absorption. The patient is prescribed a diet containing 50-100 g of fat, then the fat content in the daily feces is determined. In healthy people, the loss of fat with feces per day does not exceed 5-7 g. In case of impaired fat absorption, the amount of fat excreted with feces per day can be 10 g or more.

¹¹ I-labeled lipid loading test. The patient takes sunflower oil or trioleateglycerol labeled with ¹¹ I orally; then the radioactivity of the blood, urine, and feces is determined. When lipid absorption in the intestine is impaired, the radioactivity of the blood and urine decreases, but the radioactivity of the feces increases.

Hydrogen test. The essence of the test is to determine hydrogen in exhaled air. Hydrogen is normally formed in the large intestine as a result of flora activity, absorbed into the blood and released by the lungs. If the breakdown and absorption of disaccharides (lactose, lactulose) in the small intestine are impaired, they enter the large intestine, are broken down by bacteria, a large amount of hydrogen is formed and, consequently, its amount in the exhaled air increases sharply.

• Study of the excretory function of the small intestine.

Studying the excretory function of the intestine is very important, especially in exudative hypoproteinemic enteropathy. The simplest test for determining protein excretion is the Triboulet test. It consists of adding the same amount of saturated mercuric chloride solution to 6 ml of 10% fecal emulsion. With increased protein excretion, the solution becomes clearer above the sediment after shaking the solution and settling it at room temperature.

More accurate methods for determining the excretory function of the intestine are a fecal electropherogram to determine soluble protein, as well as a radionuclide method (intravenous administration of human serum albumin labeled with ¹¹ I, followed by determination of the radioactivity of blood plasma, intestinal juice and feces).

• Study of intestinal motility.

To study the motor function of the intestine, the radio telemetry method is used (using radionuclides and an endoradiosonde); the introduction into the intestine of radioactive substances that are not absorbed in the intestine - rose bengal, labeled with ³¹ I, etc., with subsequent study of their movement through the intestine.

An accessible method for assessing intestinal motor activity is to determine the passage of the radiopaque substance barium sulfate. Normally, barium fills the jejunum in 25-30 minutes, the ileum in 3-4 hours, fills the entire colon in 34 hours, and complete emptying of the colon occurs in 48-72 hours.

In chronic enteritis, the motor function of the small intestine is usually increased.

• Study of the digestive function of the small intestine.

To study the digestive function of the small intestine, the activity of enterokinase and alkaline phosphatase in intestinal juice, feces and the mucous membrane of the small intestine is determined. Normally, the content of enterokinase in the duodenal contents is 48-225 U/ml, alkaline phosphatase - 10-45 U/ml. In chronic enteritis, these values are significantly reduced.

Parietal digestion is assessed based on the determination of intestinal digestive enzymes in washings from a biopsy of the small intestinal mucosa after removal of intestinal juice from the surface and sequential desorption of the biopsy.

Parietal digestion is impaired in chronic enteritis.

• X-ray examination: X-ray examination of the small intestine reveals signs characteristic of chronic enteritis:
  • the relief of the mucous membrane is unevenly thickened, deformed, the folds are smoothed out;
  • accumulation of fluid and gas due to impaired absorption function (in severe forms of enteritis);
  • increased motility of the small intestine (in severe cases of enteritis, decreased motility of the small intestine is possible).
• Endoscopic examination of the small intestine mucosa: the duodenum can be examined using a fibrogastroduodenoscope, and the remaining sections of the small intestine can be examined using an intestinal fibroscope. A flexible intestinal endoscope allows for examination of both the proximal and distal sections of the small intestine. However, the examination is technically quite complex and somewhat burdensome for the patient.

In chronic enteritis (especially during the exacerbation period), the mucous membrane of the small intestine is focally or diffusely hyperemic, edematous, the vessels are injected, the folds are wide, thickened, sometimes deformed. In long-term chronic enteritis, the mucous membrane is pale, atrophic, its folds are thinned, smoothed.

In doubtful cases, a biopsy of the mucous membrane is performed to confirm the diagnosis of chronic enteritis and exclude other diseases of the small intestine. Chronic enteritis is characterized by inflammatory-dystrophic changes in the mucous membrane of the small intestine, atrophy of varying degrees of severity.

Differential diagnosis

Differentiation of forms of chronic enteritis depending on the localization of the small intestine lesion

It is of great clinical interest to determine the localization of the predominant lesion of the jejunum or ileum in chronic enteritis.

Differential diagnostics of chronic enteritis and intestinal tuberculosis

Intestinal tuberculosis can be diagnosed based on the following signs:

• presence in the anamnesis of indications of a previous tuberculosis process;
• predominant damage to the ileocecal region (ileotyphlitis);
• characteristic palliative changes in the terminal section of the ileum and cecum - pain, compaction, nodularity and poor mobility of these parts of the intestine;
• prolonged increase in body temperature, accompanied by sweating, especially at night;
• palpation pain in the projection of the mesenteric root and enlargement of the mesenteric lymph nodes, determined to the left above the navel and in the right iliac region;
• positive tuberculin tests;
• positive reaction to occult blood in feces and determination of mycobacteria in feces;
• detection of calcified mesenteric lymph nodes during radiological examination;
• detection of tuberculous ulcers in the anal area that do not tend to heal;
• detection during X-ray examination of intestinal ulcerations of the mucous membrane, cicatricial stenosis, sometimes filling defects of the cecum, a narrow ulcerated terminal ileum, pathological shortening in the region of the cecum and ascending colon;
• detection of oval or round ulcers, pseudopolyps during colonoscopy;
• detection of Mycobacterium tuberculosis and epithelioid granulomas with Pirogov-Langhans giant cells in intestinal mucosa biopsies;
• detection of enlarged mesenteric lymph nodes during ultrasound, as well as a symptom of an affected hollow organ - an ultrasound image of an oval or round shape with an anechoic periphery and an echogenic center; the peripheral part reflects the pathologically altered intestinal wall, the echogenic center - the contents and folds of the mucous membrane.

Differential diagnosis of chronic enteritis and intestinal amyloidosis

The following symptoms are characteristic of intestinal amyloidosis:

• the presence of symptoms of the underlying disease causing the development of amyloidosis (tuberculosis, bronchiectasis, rheumatoid arthritis, periodic disease, etc.).
• persistent, often profuse diarrhea that does not respond to active treatment with diet, antibacterial, astringent, adsorbent agents;
• involvement of other organs in the pathological process - liver, spleen, kidneys, pancreas, heart;
• _{increased levels of a 2} - and y-globulins in the blood;
• significant increase in ESR;
• positive Bengol's test (absorption of more than 60% of the Congo red dye injected into the vein);
• detection of amyloid in biopsies of the gums, jejunum, duodenum and rectum.

Differential diagnosis of chronic enteritis and ileitis in Crohn's disease

The following symptoms are characteristic of ileitis in Crohn's disease:

• systemic manifestations (erythema nodosum, eye damage in the form of episcleritis, uveitis, keratitis, iritis; polyarthritis with damage to large joints; kidney damage);
• aphthous ulcers of the oral mucosa and tongue;
• colicky pain in the right half of the abdomen, localized palpation pain and palpation of a tumor-like formation in the right iliac region;
• mushy, loose, or watery stools;
• absence of polyfecal matter and steatorrhea (in contrast to chronic enteritis);
• during an X-ray examination of the small intestine (it is advisable to administer barium through a tube behind the Treitz ligament), strictures, fistulas, pseudodiverticula, ulcers of the mucous membrane of various sizes, narrowing (the “cord” symptom), and shortening of the altered sections of the intestine are revealed;
• During laparoscopy, the terminal section of the ileum appears hyperemic and loosened, the mesentery and lymph nodes are compacted and have a reddish tint.

Differential diagnostics of chronic enteritis and enzymatic enteropathies

Most often, it is necessary to differentiate chronic enteritis from gluten and disaccharide enteropathy.

In differential diagnostics with celiac disease, the main importance is given to the improvement of the condition and the disappearance of diarrhea after the use of a gluten-free diet, the detection of circulating antibodies to gluten in the blood, a positive gliadin load test (a rapid increase in the blood level of glutamine after oral administration of 350 mg of gliadin per 1 kg of body weight); a long history of the disease, beginning in childhood.

In the diagnosis of disaccharidase enteropathy, the main importance is given to indications of intolerance to milk, sucrose and a decrease or disappearance of enteral symptoms (diarrhea, flatulence) after eliminating milk and products containing milk and sucrose from the diet.

The diagnosis of chronic enteritis is established based on the anamnesis (the presence of an etiologic factor), clinical picture, examination data, as well as laboratory and instrumental studies. In the clinical picture, the combination of intestinal symptoms with malabsorption syndrome is of particular importance.

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