Patient Education - Endocrine Encyclopedia
Endocrine Surgery Encyclopedia
Definition:
An insulinoma is a tumor in the pancreas that produces too much insulin.
Alternative Names: Insuloma; Islet cells adenoma
Causes, incidence, and risk factors:
The pancreas is an organ in the abdomen that makes the hormone insulin. Insulin is
required to regulate blood sugar levels. Tumors of the pancreas that produce too
much insulin (hyperinsulinemia) are called insulinomas.
High insulin levels cause low blood glucose (sugar), also called hypoglycemia.
The hypoglycemia may be mild, leading to symptoms such as anxiety and hunger, or
severe, leading to seizures, coma, and even death.
Insulinomas are rare tumors. They usually occur as single, small tumors in adults.
They are very rare in children. Most children with hyperinsulinism have multiple
pockets of overactive insulin-secreting cells in the pancreas, rather than a single
discrete tumor.
Most insulinomas are not cancer. However, about five to ten percent are cancer.
People with the genetic syndrome called multiple endocrine neoplasia Type I (MENI)
are at risk for developing insulinomas.
Symptoms:
- sweating
- tremor
- rapid heart rate
- anxiety
- hunger
- dizziness
- headache
- clouding vision
- confusion
- behavioral changes
- convulsions
- loss of consciousness
Signs and tests:
- The person's blood may be tested while fasting (not eating). The person may
have:
- low blood glucose
- high serum insulin level
- high C-peptide level
Other tests may include:
- CT scan or MRI of the abdomen to look for a pancreatic tumor
- Endoscopic ultrasound to look for a pancreatic tumor (when CT or MRI scan is
normal)
- Octreotide scan to look for a pancreatic tumor (when CT or MRI scan is normal)
- Pancreatic arteriography (when CT or MRI scan is normal)
- Pancreatic venous sampling for insulin (when CT or MRI scan is normal)
Treatment:
Surgery is the preferred treatment for insulinoma. The location of the tumor is determined
using diagnostic testing or surgical exploration. Single tumors are removed, but
patients with multiple tumors usually require partial removal of the pancreas (partial
pancreatectomy). At least 15% of the pancreas is left to prevent nutrient malabsorption
from lack of pancreatic enzymes.
If no tumor is found during surgery or a patient is not a candidate for surgery,
the drug diazoxide may be given to lower insulin secretion and avoid hypoglycemia.
A diuretic (water pill) is given with this medication to keep the person's body from
retaining fluid.
Octreotide has been used to suppress insulin secretion in some patients. Medication
is also used to stabilize the person prior to surgery.
Support Groups:
Expectations (prognosis):
In a majority of cases, the tumor is benign and surgery is effective. However, a
severe hypoglycemic reaction or the spread of cancerous tumors to other organs can
be fatal.
Complications:
-
severe hypoglycemic reaction
- cancerous tumor spreading (metastasis)
Calling your health care provider:
Call your health care provider if symptoms of insulinoma develop. Convulsions and
decreased consciousness are emergency symptoms.
Prevention:
Review Date: 12/14/2004
Reviewed By: Stephanie Fish, M.D., Division of Endocrinology, Division of Endocrinology,
University of Pennsylvania Medical Center, Philadelphia, PA. Review provided by VeriMed
Healthcare Network.
A.D.A.M.,
Inc. is accredited by URAC, also known as the American Accreditation HealthCare Commission
(www.urac.org). URAC's accreditation program is an independent audit to verify that A.D.A.M.
follows rigorous standards of quality and accountability. A.D.A.M. is among the first to
achieve this important distinction for online health information and services. Learn more
about A.D.A.M.'s editorial policy, editorial process and privacy policy. A.D.A.M. is also
a founding member of Hi-Ethics and subscribes to the principles of the Health on the Net
Foundation (www.hon.ch).
The information provided herein should not be used during any medical emergency or for
the diagnosis or treatment of any medical condition. A licensed medical professional should
be consulted for diagnosis and treatment of any and all medical conditions. Call 911 for
all medical emergencies. Links to other sites are provided for information only -- they do
not constitute endorsements of those other sites. © 1997- 2007 A.D.A.M., Inc. Any duplication
or distribution of the information contained herein is strictly prohibited.
|
