Diagnosis of acute pancreatitis
Acute pancreatitis should be suspected in the event of severe abdominal pain, especially in people who abuse alcohol, or in patients with diagnosed cholelithiasis. Similar symptoms of acute pancreatitis can be observed with a perforated ulcer of the stomach or duodenum, a mesenteric infarction, strangulation intestinal obstruction, exfoliating aortic aneurysm, biliary colic, appendicitis, diverticulitis, myocardial posterior infarction, abdominal wall abdominal injury and spleen injury.
The diagnosis is established by clinical examination, the determination of serum markers (amylase and lipase) and the absence of other causes that cause symptoms. In addition, a wide range of studies is performed, usually including a general blood test, electrolytes, calcium, magnesium, glucose, blood urea nitrogen, creatinine, amylase and lipase. Other standard studies include ECG and sequential studies of the abdominal cavity (thorax, abdominal cavity in horizontal and vertical position). Determination of trypsinogen-2 in urine has a sensitivity and specificity of more than 90% in acute pancreatitis. Ultrasound and CT, as a rule, do not have high specificity in the diagnosis of pancreatitis, but are often used to assess acute abdominal pain and their performance is indicated in the diagnosis of pancreatitis.
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Laboratory diagnosis of acute pancreatitis
Amylase of serum and concentration of lipase in the blood increase on the first day of acute pancreatitis and return to normal after 3-7 days. Lipase is a more specific indicator for pancreatitis, but the level of both enzymes may increase with renal failure, as well as with other diseases of the abdominal cavity (eg, perforated ulcer, occlusion of mesenteric vessels, intestinal obstruction). Other causes of increased serum amylase include dysfunction of the salivary glands, macromyalasemia and tumors that secrete amylase. Levels of amylase and lipase may remain within normal limits in the event of destruction of the acinar tissue during previous episodes of the disease, which led to a decrease in adequate secretion of enzymes. The serum of patients with hypertriglyceridemia may contain a circulating inhibitor in the blood, which requires dilution to the detected increase in amylase in the serum.
The clearance of amylase / creatinine does not have sufficient sensitivity or specificity in the diagnosis of pancreatitis. This indicator is usually used to diagnose macromyalemia in the absence of pancreatitis. In macroamilasemia, amylase, associated with serum immunoglobulin, gives a false positive result by increasing the level of serum amylase.
Fractionation of total serum amylase by pancreatic type (p-type) and salivary type (s-type) of isoamylase increases the diagnostic value of the serum amylase level. However, the p-type level also increases in renal failure, as well as in other severe diseases of the abdominal organs, in which the clearance of amylase changes.
The number of white blood cells is usually increased to 12 000-20 000 / μL. The discharge of fluid into the abdominal cavity can significantly increase the hematocrit to 50-55%, thereby indicating a severe inflammation. There may be hyperglycemia. The concentration of calcium in the serum decreases on the first day of the disease due to the secondary formation of Ca "soap" as a result of the excess production of free fatty acids, especially under the influence of pancreatic lipase. Serum bilirubin increases in 15-25% of patients due to pancreatic edema and compression of the common bile duct.
Instrumental diagnosis of acute pancreatitis
Conventional radiography of the abdominal cavity can reveal calcification in the area of pancreatic ducts (indicative of previous inflammation and, consequently, phenomena of chronic pancreatitis), calcified gallstones or local intestinal obstruction in the left upper quadrant of the stomach or in mesogastrium ("swollen loop" of the small intestine, widening of the transverse guts or duodenal obstruction). Chest X-ray may reveal atelectasis or pleural effusion (usually left-sided or bilateral, but rarely only in the right pleural cavity).
If the studies are not informative, ultrasound should be performed for the diagnosis of cholelithiasis or dilatation of the common bile duct (which indicates the obturation of the biliary tract). Pancreatic edema can be visualized, but gas in the intestine often obscures the pancreas.
CT with intravenous contrast usually allows to identify necrosis, fluid accumulation or pseudocysts in case of pancreatitis diagnosis. This study is especially recommended in cases of severe pancreatitis or complications (eg, hypotension or progressive leukocytosis and fever). Intravenous contrasting facilitates the recognition of pancreatonecrosis, but this can cause pancreatic necrosis in areas with low perfusion (i.e., ischemia). Therefore, CT with contrast enhancement should be performed only after adequate fluid therapy and dehydration elimination.
If a suspected infection is indicated, a percutaneous puncture of the cyst, a zone of fluid accumulation or necrosis under the control of CT with fluid aspiration, Gram staining, and bacteriological sowing are indicated. The diagnosis of "acute pancreatitis" is confirmed by positive results of blood culture, and especially the presence of pneumatization of the retroperitoneal space with CT of the abdominal cavity. The introduction of MP cholangiopancreatography (MPGHP) into practice makes it possible to make instrumental examination of the pancreas more simple.