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Insulinomas are malignant neoplasms – fast growing cancerous tissue - of the beta cells in the pancreas. The beta cells primarily make and secrete insulin, which has a variety of effects in the body, the primary one being to regulate glucose throughout the body's cells. Because insulinomas secrete excessive insulin, the blood stream becomes low in glucose (hypoglycemia), which causes weakness and/or neurological problems. This disease does not effect cats as much as it does some other household pets, but it can and does occur.
The most common symptom of an insulinoma is physical collapse or loss of consciousness (syncope). Seizures, extreme weakness, and other neurological abnormalities are also common. Because the insulin is released periodically, symptoms are not consistent and frequency of symptoms is not necessarily predictable.
If your cat should collapse and a blood sample indicates low glucose, your veterinarian will suspect an insulinoma and will follow through with further tests to confirm it. Multiple blood samples may need to be taken over a period of time to determine a persistent low glucose concentration. Fasting from food before these tests are performed is essential for determining true glucose levels - your veterinarian will advise you on the appropriate method for withholding food from your cat before each test. Your veterinarian will also need to determine your cat's insulin concentration at the lowest glucose concentration.
An amended insulin:glucose ratio (AIGR) may be useful when your cat's insulin level is in the lower end of the normal range. Insulinoma is still the expected finding in these types of cases. If the insulin level is inappropriately high for the decreased glucose level, an insulinoma may still be present.
Ultrasound, computed tomography (CT), or magnetic resonance imaging (MRI) can be helpful in determining the extent of the pancreatic tumor and how much it is metastasizing. Typically, insulinomas will not metastasize to the lungs; however, chest x-rays may indicate other types of neoplasias as the cause for persistently decreased glucose. Scintigraphy, a form of imaging that uses radioactive isotopes to identify abnormal tissue, can also be used to identify the location of primary insulinomas and metastasis.
An involuntary action in which the muscles contract; caused by a problem with the brain.
The term for a type of medication that impacts immunity, metabolism, sexual characteristics, and other such elements of a living thing
Fainting; the respiratory and circulatory systems are suspended for a time
A gland that aids in both digestive and insulin functions
The growth of pathogens away from the original site of the disease
A hormone created by the pancreas that helps to regulate the flow of glucose
Something that becomes worse or life threatening as it spreads
Low amounts of glucose in the blood
The occurrence or invasion of pathogens away from the point where they originally occurred