Insulinoma - Understanding Its Causes, Symptoms & Treatment
An insulinoma is a rare tumour that develops in the pancreas. The pancreas produces insulin, a hormone that helps maintain normal blood sugar levels. Normally, insulin production decreases when blood sugar levels fall. However, an insulinoma can continue releasing insulin even when blood sugar is already low. This can result in repeated episodes of hypoglycaemia, or low blood sugar.
Most insulinomas are non-cancerous. However, some can be cancerous and may spread to other parts of the body. Early diagnosis and appropriate treatment can help manage the condition and prevent complications caused by repeated low blood sugar.
Insulinoma Causes
The exact cause of most insulinomas is not known. In a small number of cases, insulinoma may be associated with inherited conditions such as Multiple Endocrine Neoplasia type 1 (MEN 1).
An insulinoma develops from insulin-producing cells in the pancreas. When these cells form a tumour, they may produce insulin even when the body does not need it. This excess insulin can cause blood sugar levels to fall.
Most people with insulinoma do not have a known risk factor.
What Are the Symptoms of Insulinoma?
The symptoms of insulinoma are mainly related to low blood sugar. They may occur after going without food for several hours and may improve after eating or drinking something that increases blood sugar.
Common symptoms include:
- Sweating
- Weakness or tiredness
- Headache
- Hunger
- Dizziness or light-headedness
- Anxiety or irritability
- Nausea
- Blurred vision
- Confusion
When blood sugar falls severely, a person may experience seizures or lose consciousness. Severe hypoglycaemia requires immediate medical attention.
Some people with insulinoma may also gain weight because they eat frequently to prevent or relieve episodes of low blood sugar.
How Is Insulinoma Diagnosed?
Diagnosing insulinoma usually involves confirming that the symptoms are caused by low blood sugar and determining whether the body is producing too much insulin.
Healthcare professionals may consider the Whipple triad, which includes:
- Symptoms associated with low blood sugar.
- A blood test showing low blood glucose during the symptoms.
- Improvement of symptoms after blood sugar is raised.
Once low blood sugar is confirmed, further tests may be performed to identify the cause.
What Tests Are Used for Insulinoma?
Several tests may be used during an insulinoma diagnosis.
Blood Tests
An insulinoma blood test may measure blood glucose, insulin, C-peptide, and proinsulin levels. These tests can help determine whether the pancreas is producing an unusually high amount of insulin when blood sugar is low. Healthcare professionals may also check for certain medicines that can cause low blood sugar.
72-Hour Fasting Test
A supervised fasting test may be recommended when the diagnosis is unclear. During this test, the person is monitored by healthcare professionals while fasting. Blood sugar and other relevant hormone levels are checked when hypoglycaemia develops.
The test can continue for up to 72 hours, although it may end earlier if the necessary findings are obtained.
Imaging Tests
After blood tests suggest insulinoma, imaging may be performed to locate the tumour in the pancreas. Depending on the situation, Healthcare professionals may recommend:
- CT scan
- MRI scan
- Endoscopic ultrasound
- PET scan
These tests can help determine the size and location of the tumour and whether it has spread.
What Is the Treatment for Insulinoma?
The insulinoma treatment depends on factors such as the location and size of the tumour, whether it is cancerous, and the person's overall health.
Insulinoma Surgery
Surgery is the main treatment for many insulinomas, particularly when the tumour can be safely removed. The type of surgery depends on the tumour's location and its relationship with nearby structures.
In some cases, the surgeon may remove only the tumour. This procedure is called enucleation. If necessary, part of the pancreas may also be removed. More extensive pancreatic surgery may be considered for certain tumours.
Surgery can cure many insulinomas that have not spread beyond the pancreas.
Medical Treatment
If surgery is not possible or while waiting for surgery, medicines may be used to help control low blood sugar. These medicines can reduce insulin release or help maintain blood sugar levels.
Dietary changes, such as having regular meals and avoiding long periods without food, may also be recommended by a healthcare professional.
Treatment for Cancerous Insulinoma
If an insulinoma is cancerous or has spread to other parts of the body, additional treatment may be required. Depending on the individual case, treatment can include surgery, chemotherapy, radiation therapy or other specialised treatments.
What are the Complications of Insulinoma?
Repeated episodes of low blood sugar can affect the brain and other organs. Severe hypoglycaemia may cause confusion, seizures, loss of consciousness or coma.
Therefore, repeated unexplained episodes of low blood sugar should not be ignored. Prompt medical evaluation can help identify the underlying cause and determine appropriate treatment.
When Should You Consult a Doctor/ Healthcare professional?
Consult a healthcare professional if you frequently experience symptoms such as sweating, dizziness, weakness, confusion, or unusual hunger, particularly when they occur after several hours without food.
Seek emergency medical care if severe low blood sugar causes seizures, loss of consciousness, or severe confusion.
Reader Information: This article is for informational purposes only and does not replace professional medical advice, diagnosis, or treatment. If you experience recurrent symptoms of low blood sugar, such as sweating, dizziness, shakiness, confusion, or unexplained weakness, consult a qualified healthcare professional for appropriate evaluation and care. These symptoms may have various causes, including insulinoma.
