Macroamylasemia

Answer 1

Definition

Macroamylasemia is the presence of an abnormal substance called macroamylase in the blood.

Causes, incidence, and risk factors

Macroamylase is a substance that consists of an enzyme, called amylase, attached to a protein. Because it is large, macroamylase is filtered very slowly from the blood by the kidneys.

Most people with macroamylasemia have no serious underlying disorder, but the condition has been associated with:

• Celiac disease
• Lymphoma
• HIV infection
• Monoclonal gammopathy
• Rheumatoid arthritis
• Ulcerative colitis

Symptoms

Macroamylasemia does not cause symptoms.

Signs and tests

A blood test will show high levels of amylase. However, macroamylasemia can be confused with acute pancreatitis, which also causes high levels of amylase in the blood.

Macroamylasemia can be diagnosed by measuring amylase levels in the urine. Urine levels of amylase are low. (Urine amylase levels are high in patients with acute pancreatitis.)

References

Owyang C. Pancreatitis. In: Goldman L, Ausiello D, eds. Cecil Medicine. 23rd ed. Philadelphia, Pa: Saunders Elsevier; 2007:chap 147.

Answer 2

Definition

Macroamylasemia is the presence of an abnormal substance called macroamylase in the blood.

Causes, incidence, and risk factors

Macroamylase is a substance that consists of an enzyme, called amylase, attached to a protein. Because it is large, macroamylase is filtered very slowly from the blood by the kidneys.

Most people with macroamylasemia have no serious underlying disorder, but the condition has been associated with:

• Celiac disease
• Lymphoma
• HIV infection
• Monoclonal gammopathy
• Rheumatoid arthritis
• Ulcerative colitis

Symptoms

Macroamylasemia does not cause symptoms.

Signs and tests

A blood test will show high levels of amylase. However, macroamylasemia can be confused with acute pancreatitis, which also causes high levels of amylase in the blood.

Macroamylasemia can be diagnosed by measuring amylase levels in the urine. Urine levels of amylase are low. (Urine amylase levels are high in patients with acute pancreatitis.)

References

Owyang C. Pancreatitis. In: Goldman L, Ausiello D, eds. Cecil Medicine. 23rd ed. Philadelphia, Pa: Saunders Elsevier; 2007:chap 147.

Reviewed By

Review Date: 01/20/2010

David C. Dugdale, III, MD, Professor of Medicine, Division of General Medicine, Department of Medicine, University of Washington School of Medicine; and George F. Longstreth, MD, Department of Gastroenterology, Kaiser Permanente Medical Care Program, San Diego, California. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.