Serum amylase is elevated, don't just think of acute pancreatitis

As we all know, serum amylase and lipase are commonly used laboratory indicators for detecting pancreatic function, and the Chinese guidelines for the diagnosis and treatment of acute pancreatitis (AP) also point out that acute pancreatitis can be diagnosed if 2 of the following 3 characteristics are met: (1) abdominal pain consistent with AP (acute, sudden, persistent, severe epigastric pain, often radiating to the back); (2) Serum amylase and (or) lipase activity is at least 3 times higher than the upper limit of normal; (3) Enhanced CT/MRI or abdominal ultrasound showed AP imaging changes

Hyperamylaemia is a common clinical situation, most of which is caused by acute pancreatitis, a small number of hyperamylamyremia is not associated with pancreatitis, often because of misdiagnosis of acute pancreatitis and excessive examination and treatment, not only lead to unnecessary waste of medical resources, but also cause physical and mental damage

Serum amylase is mainly derived from the pancreas and salivary glands, and is mostly metabolized by pathways other than the kidneys, but 25% to 30% are still excreted by the kidneys through the urine

A common cause of elevated serum amylase

1.

Acute pancreatitis is the most common cause of hyperamylase, and serum amylase is an important indicator

2.

Acute abdominal pain with hyperamylasemia can occur in a variety of acute abdomen conditions in addition to pancreatic disease, and differential diagnosis is particularly important

3.

It is an important cause of chronic hyperamylase, which cannot be cleared

4.

Cholecystitis and cholelithiasis can cause a mild increase in serum amylase activity, rarely exceeding 3 times

Hyperamylaemia can also occur in gastroenteritis

5.

Many malignancies can cause elevated serum amylase, the most common being ovarian cancer, lung cancer, and multiple myeloma

6.

Mumps is an acute respiratory infectious disease caused by the invasion of the parotid gland by the mumps virus, non-purulent swelling and pain of the parotid gland is a prominent symptom, and 90% of patients have mild and moderate hypertension of serum amylase

7.
Normal and familial hyperamylaemia

Although the mechanism of familial hyperamylaemia has not yet been elucidated from the gene level, it is suggested that we should consider the possibility of familial hyperamylaemia on the basis of excluding pancreatic diseases in the clinic to avoid too many unnecessary tests
.

Diagnosis of acute pancreatitis, which is better, lipase or amylase?

In recent years, the wide application of blood automatic biochemical analyzer has made the detection of blood amylase and lipase more and more extensive, and the clinical observation of blood amylase and lipase values without abdominal pain symptoms, imaging examination and no evidence of pancreatic disease can often be seen
.
In the case of excluding laboratory testing errors, how to evaluate the elevated values of blood amylase and lipase has become a clear question for clinicians
.

Serum amylase and lipase are still the most commonly used detection indicators in the diagnosis of AP in clinical practice, and urine amylase changes are only for reference
.

Serum amylase usually rises a few hours after onset and returns to normal
after 3 to 5 days.
In addition, renal insufficiency, salivary gland disease, acute appendicitis, cholecystitis, intestinal obstruction, anemia, peptic ulcer, gynecological diseases, etc.
can cause increased blood amylase
.
Persistent increase in serum amylase should pay attention to recurrent disease, complicated by pseudocysts or abscesses, suspected stones or tumors, renal insufficiency, hyperamylasemia and so on
.
The determination of whether the patient is open to diet or the degree of illness cannot rely solely on whether the serum amylase has decreased to normal, and should be judged comprehensively
.

Compared to serum amylase, serum lipase is considered a more valuable diagnostic tool because lipase has a longer half-life than amylase, and its elevation lasts for a longer time, which is an advantage
for patients with delayed onset.
Current studies have shown that 95% to 100% of AP patients have elevated serum lipase, and some patients with acute alcoholic pancreatitis have elevated serum lipase and normal
amylase.
Therefore, the British and Japanese AP guidelines also emphasize serum lipase to have better diagnostic accuracy than amylase
.
However, both serum amylase and lipase are not positively correlated
with the severity of pancreatitis.