Clinical Features of Chronic Pancreatitis - Гастроэнтерология (анг,рус) - Конспект лекций
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Гастроэнтерология (анг,рус)

Clinical Features of Chronic Pancreatitis

Patients with chronic pancreatitis seek medical attention predominantly because of two symptoms: abdominal pain or maldigestion. The abdominal pain may be quite variable in location, severity, and frequency. The pain can be constant or intermittent with frequent pain-free intervals. Eating may exacerbate the pain, leading to a fear of eating with consequent weight loss. The spectrum of abdominal pain ranges from mild to quite severe with narcotic dependence as a frequent consequence. Maldigestion is manifested as chronic diarrhea, steatorrhea, weight loss, and fatigue. Patients with abdominal pain may or may not progress to maldigestion, and ~20% of patients will present with symptoms of maldigestion without a history of abdominal pain. Patients with chronic pancreatitis have significant morbidity and mortality and utilize appreciable amounts of societal resources. Despite the steatorrhea, clinically apparent deficiencies of fat-soluble vitamins are surprisingly uncommon. Physical findings in these patients are usually unimpressive so that there is a disparity between the severity of abdominal pain and the physical signs, which usually consist of some mild tenderness and mild temperature elevation.

It is helpful to differentiate chronic pancreatitis into its different forms. One obvious demarcation is whether the patient has small-duct or large-duct disease. Table 2 describes features that distinguish between these two kinds of pancreatitis. The pathogenesis, diagnostic approach, clinical course, and treatment results vary greatly between these two forms of chronic pancreatitis. In contrast to acute pancreatitis, the serum amylase and lipase levels are usually not elevated in chronic pancreatitis. Elevation of serum bilirubin and alkaline phosphatase may indicate cholestasis secondary to chronic inflammation and/or stricture around the common bile duct. Many patients have impaired glucose tolerance with elevated fasting blood glucose levels. The diagnostic test with the best sensitivity and specificity is the hormone stimulation test utilizing secretin. It becomes abnormal when 60% of the pancreatic exocrine function has been lost. This usually correlates well with the onset of chronic abdominal pain. Approximately 40% of patients with chronic pancreatitis have cobalamin (vitamin B12) malabsorption. This can be corrected by the administration of oral pancreatic enzymes. The serum trypsinogen and D-xylose excretion tests are useful in patients with pancreatic steatorrhea. The trypsinogen level will be abnormal and the D-xylose excretion usually normal in such patients. A decrease of serum trypsinogen level to <20 mg/mL strongly suggests severe pancreatic exocrine insufficiency, as does a fecal elastase of <100 g per gram of stool.

Table 2 Large Duct versus Small Duct Chronic Pancreatitis

 

 

Large Duct

Small Duct

Sex Predominance

Male

Female

Diagnostic Tests

Secretin test

Abnormal

Abnormal

Serum trypsinogen

Often abnormal

Usually normal

Fecal elastase

Often abnormal

Usually normal

Pancreatic calcification on plain film of the abdomen

Frequent

Infrequent

ERCP

Often markedly abnormal

Minimally abnormal to normal

Natural History

Progression to steatorrhea

Frequent

Rare

Therapy of pain

Pancreatic enzymes

Poor response

Good to excellent response

Surgical procedures

Sometimes helpful

Not usually indicated

 

Utilizing radiographic techniques it can be shown that diffuse calcifications noted on plain film of the abdomen usually indicate ~80% damage to the pancreas. While alcohol is by far the most common cause of pancreatic calcification, such calcification may also be noted in severe protein-calorie malnutrition, hereditary pancreatitis, posttraumatic pancreatitis, hypercalcemic pancreatitis, islet cell tumors, and idiopathic chronic pancreatitis. Abdominal ultrasonography, CT scanning, and ERCP greatly aid in the diagnosis of pancreatic disease. In addition to excluding a pseudocyst and pancreatic cancer, sonography and CT may show calcification, dilated ducts, or an atrophic pancreas. ERCP or magnetic resonance cholangiopancreatography (MRCP) provides a direct view of the pancreatic duct and may show a pseudocyst missed by sonography or CT. The role of endoscopic ultrasonography (EUS) in diagnosing early chronic pancreatitis is still being defined. EUS complements pancreatic function tests, and a combination of a hormone-stimulation function test and EUS is the most complete way to evaluate the presence or extent of chronic pancreatitis. Whether EUS can detect early chronic pancreatitis, i.e., small-duct disease, with the same degree of accuracy as the hormone-stimulation test is controversial. Recent data comparing these modalities head-to-head would indicate that EUS is not a sensitive test for detecting early chronic pancreatitis and may lead to false-positive tests in patients who have dyspepsia or even in normal controls.

 

 

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