Diagnosis of chronic pancreatitis

Early diagnosis of pancreatitis is based on the complex use of laboratory and instrumental research methods both during a pain crisis and during further observation in order to clarify the etiology, stage of the disease, morphological features of the organ, the state of the duct system, the degree of disturbance of the external and internal secretory function, diagnosis of complications, assessment of the state of adjacent digestive organs and the choice of effective treatment tactics.

Anamnesis

The anamnesis includes an analysis of the child’s developmental characteristics at different periods of life, nutritional status, heredity, and the timing of the onset of early symptoms of the disease.

Physical examination

It is necessary to assess the patient's trophic status, clinical symptoms of the disease, and the nature of the stool.

Laboratory research

• Blood biochemistry:
  • activity of amylase, lipase, trypsin in blood serum;
  • content of creatinine, urea, glucose and calcium;
  • activity of transaminases, alkaline phosphatase, y-glutamyl transpeptidase, concentration of acute phase proteins;
  • content of insulin, C-peptide, glucagon.
• Clinical blood test.
• Clinical urine analysis (amylase, lipase, glucose activity).

Increased concentration of amylase, lipase, trypsin and its inhibitors in blood serum, as well as amylase, lipase in urine reflects the activity of the inflammatory process in the pancreas and indicates pancreatitis. Amylase is included in the group of indicator enzymes. The level of amylasemia in healthy children is a constant value. The amylase activity indicator is maintained by renal and extrarenal elimination of the enzyme, it practically does not depend on the functional state of other enzyme-producing organs. Determination of amylase activity in urine is an informative and convenient screening test for pancreatic diseases. A long-term recorded increase in amylase activity in urine, even against the background of normal enzyme concentration in the blood, may indicate a complicated course of chronic pancreatitis or the formation of a false cyst. In acute pancreatitis, the amylase content in the blood and urine increases by 10 times or more. The frequency of hyperfermentemia detection depends on the phase of the disease and the time of the patient's admission to the hospital. The study of amylase isoenzymes is informative, especially with normal total amylase activity.

Normal or slightly increased enzyme activity in the blood and urine of patients does not exclude a chronic process in the pancreas. In this case, provocative tests are used to diagnose chronic pancreatitis: the activity of serum enzymes is examined on an empty stomach and after stimulation. Hyperfermentemia ("evasion phenomenon") after the introduction of irritants may indicate a pathological process in the gland or an obstruction to the outflow of pancreatic juice. The high diagnostic information content of the study of elastase activity in the blood has been proven, increasing earlier and persisting longer than changes in the activity of other pancreatic enzymes.

Exocrine pancreatic insufficiency is characterized by an increase in neutral fat (steatorrhea) and undigested muscle fibers (creatorrhea) in microscopic examination of a fecal smear. In mild cases of pancreatic damage, the coprogram may not change.

Currently, the determination of fecal elastase-1 is widely used, included in the group of standard methods for examining the pancreas. Elastase-1 is not destroyed during passage through the intestine, this indicator is not affected by taking pancreatic enzymes. The enzyme immunoassay method for diagnosing elastase-1 is more informative, highly specific (93%) and allows assessing the degree of exocrine function impairment. The content of elastase-1 is normally 200-550 μg/g of feces, with moderate exocrine insufficiency 100-200 μg/g. With a severe degree - less than 100 μg/g.

Functional methods of examination of the pancreas

The leading role in studying the state of the gland belongs to functional methods, most often using direct tests to assess external secretion. Direct methods for studying pancreatic secretion - determining the concentration of pancreatic enzymes, bicarbonates in duodenal secretion or pancreatic juice under basal conditions (on an empty stomach) and after the introduction of various stimulants, which allows you to assess the reserve capacity of the organ.

The most complete picture of the exocrine activity of the pancreas is given by a study with intestinal hormones (secretion stimulants) secretin (1 U/kg) and pancreozymin (1 U/kg). The secretin-pancreozymin test is the "gold standard" for diagnosing pancreatic pathology, necessary for verifying the diagnosis of chronic pancreatitis.

Disorders of secretory function can be characterized by 3 pathological types of pancreatic secretion:

• hypersecretory type - an increase in the concentration of pancreatic enzymes with a normal or increased secretion volume and bicarbonate content. Occurs during exacerbation of pancreatitis, reflects the initial shallow inflammatory changes in the pancreas associated with hyperfunction of acinar cells;
• hyposecretory type - decreased enzyme activity against the background of normal or decreased volume of juice and bicarbonates, indicating qualitative insufficiency of pancreatic secretion. Often occurs in chronic pancreatitis, occurring with fibrous changes in the organ;
• obstructive type - a decrease in the amount of pancreatic juice with any content of enzymes and bicarbonates. This type of secretion occurs with obstruction of the pancreatic ducts (stenotic papillitis, duodenitis, spasm of the sphincter of Oddi, choledocholithiasis, obstruction of the ampulla of Vater, duct anomalies, etc.).

The first two types can be considered as transitional, reflecting different stages of progression of inflammatory changes in the gland. In children, there is more often a violation of the enzyme-synthesizing function of the pancreas, a decrease in the content of bicarbonates and secretion can be observed only in severe pancreatic insufficiency.

All of the listed pathological types of secretion reflect varying degrees of functional and morphological changes in the pancreas, which ensures a differentiated approach to treatment.

An indirect method for studying pancreatic secretion, including determination of the activity of pancreatic enzymes in duodenal juice after food stimulation (Lund test) and with the introduction of pancreatic irritants orally, has not become widespread in pediatric practice due to the low sensitivity of the technique and the complexity of assessing the final hydrolysis products.

Instrumental research

Instrumental methods of examining the pancreas include transabdominal ultrasound, endoscopic ultrasonography, CT, MRI, endoscopic retrograde cholangiopancreatography. Plain radiography of the abdominal cavity (diagnosis of calcifications in the projection of the pancreas) and radiocontrast examination of the upper gastrointestinal tract - one of the stages of assessing the anatomical and topographic relationships of the organs of the gastroduodenocholedochopancreatic complex - have not lost their importance.

Ultrasound of the pancreas is the leading method of diagnosing morphological changes in the gland, allowing to establish changes in size, echo density, the presence of hypo- and hyperechoic formations, the state of the duct system. In the case of recurrent chronic pancreatitis, the contour of the gland is often uneven, the parenchyma is compacted, contains hyperechoic areas (fibrosis or microcalcinosis). Cysts are often diagnosed. Repeated ultrasounds allow to evaluate the effectiveness of treatment, detect complications and determine the prognosis. Ultrasound semiotics of pancreatitis depends on the degree and stage of the pathological process.

A new method for qualitative assessment of the morphological structure of the pancreas using physiological load has been developed (patent No. 2163464, 2001). For this purpose, the ratio of the sum of the gland sizes after a food load to the sum of these indicators on an empty stomach is calculated. An increase in the sum of the linear sizes of the pancreas after a standard breakfast of less than 5% indicates a high probability of chronic pancreatitis. With an increase in size by 6-15%, reactive pancreatitis is diagnosed. A ratio of over 16% is an indicator of a normal postprandial reaction of the pancreas.

Endoscopic retrograde cholangiopancreatography studies the pancreatic duct system and bile ducts in detail. On cholangiopancreatograms, one can see various abnormalities in the development of the gland's ducts, uneven contours in the form of stenosis and dilation, delayed contrast or accelerated emptying of the ducts, calcium deposition inside the ducts, and calcification of the pancreatic parenchyma. Changes in the bile ducts are diagnosed at the same time.

Endoscopic ultrasonography allows for examination of the duodenum to detect erosions, ulcers or diverticula, the area of the ampulla of Vater to diagnose papillitis, and to assess the condition of the biliary and pancreatic ducts.

The main indications for CT and magnetic resonance cholangiopancreatography are complicated chronic pancreatitis and suspected volumetric process in the pancreas and adjacent digestive organs.

Differential diagnostics

A necessary and complex stage of diagnostics of chronic pancreatitis in children is the exclusion of a number of diseases with similar symptoms: cystic fibrosis, erosive and ulcerative lesions of the stomach and duodenum, diseases of the biliary tract (cholelithiasis, cholangitis, developmental anomalies). Difficulties arise in differential diagnostics with diseases of the small intestine, with severe malabsorption syndrome (celiac disease, disaccharidase deficiency, chronic enteritis, etc.). It is possible to establish a final diagnosis with the consistent implementation of the diagnostic protocol, confirming the pathology of the pancreas. Chronic pancreatitis is characterized by pain syndrome, exocrine insufficiency, inflammatory-dystrophic process (positive amylase, elastase and other tests) and changes in the structure of the pancreas (ultrasound, CT, endoscopic retrograde cholangiopancreatography, etc.).

Differential diagnosis of dispancreatitis, reactive and chronic pancreatitis

Sign	Dyspancreatism	Reactive pancreatitis	Chronic pancreatitis
Definition	Reversible dysfunction without morphological changes	Interstitial OP against the background of gastroduodenal or biliary diseases	Inflammatory-degenerative process with the development of fibrosis and exocrine insufficiency
Pain	Unstable, spilled	Intense, above the navel and to the left, radiating to the left and to the back	Recurrence of pain or mild persistent pain
Painfulness	Epigastrium, hypochondrium, Mayo-Robson point	Zones: Shoffara, Guber-gritsa; Points: Kacha, Mayo-Robson	Zones: Chauffard, Gubergrits; points of Kach, Mayo-Robson
Dyspeptic disorders	Nausea, flatulence, belching	Nausea, vomiting, flatulence, sometimes short-term diarrhea	Polyfecalia, mushy, shiny stool, sometimes alternating diarrhea and constipation
Coprogram	Norm	Normal or intermittent steatorrhea	Steatorrhea with neutral fat, less often with creatorrhea
Blood and urine amylase	Inconstantly elevated	Increased	May be elevated or normal
Ultrasound	Enlargement of parts of the pancreas (may be normal)	Enlarged pancreas, fuzzy contours, decreased echogenicity	Hyperechogenicity of the pancreas, changes in shape, size, contours, expansion of the Wirsung duct
EGDS	Signs of duodenitis, papillitis	Signs of duodenitis, papillitis	There are possible options

Indications for consultation with other specialists

In case of severe condition of the patient with chronic pancreatitis, persistent abdominal pain syndrome, development of complications, consultation with a pediatric surgeon, endocrinologist is indicated. The presence of a volumetric process in the gland requires consultation with a pediatric oncologist. To confirm the hereditary nature of pancreatitis, consultation with a geneticist is recommended.

In case of concomitant diseases of other organs and systems, consultation with doctors of the relevant specialties (pulmonologist, endocrinologist, nephrologist, neurologist, etc.) is necessary.

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