Insulinoma is a tumor in the pancreas derived from the beta cells and is characterized by insulin excess and uncontrolled.
The pancreas is an organ made up of different types of cells, each of these cells produces a class of substances known as hormones and blood poured to cover different functions in the body. One of these is the cell beta cells that make insulin.
In normal pancreatic beta cells produce insulin when blood sugar levels rise, for example when we eat, and are inhibited (not manufacture insulin) when the numbers are normal or low, fasting or exercise. But for unknown reasons, the pancreatic beta cells may begin to make insulin in excess and without the control exercised by the level of blood sugar have.
The beta tumor cells provides a beta cell mass formed. If you look under the microscope all tumors of the pancreas that produce insulin we find a wide range of injuries: 70% are benign tumors (adenomas) solitary adenomas 10% are multiple, 10% are malignant tumors (carcinomas), and a 10% are benign lesions characterized by a greater number of beta cells without control but which are not a mass but are distributed diffusely throughout the pancreas and we call diffuse hyperplasia of beta cells.
Insulinomas are usually small (smaller than 2 cm) and single (90% of cases), although there are so small that even tumors are difficult to see on the operating table and make it very difficult to reach a diagnosis.
The average age at which are the insulinomas (adenomas and carcinomas) are 40-50 years old. Instead, diffuse hyperplasia of beta cells is seen mostly in infants of diabetic mothers, these children are exposed during pregnancy to high sugar figures of mother and beta cells respond by increasing in size and number.
The vast majority of insulinomas are located in the pancreas, although there was pancreatic tumors also produce insulin are called extrapancreatic tumor.
Moreover, some of these insulinomas are associated with the presence of other tumors in other organs such as parathyroid, pituitary or thyroid gland, forming this association called multiple endocrine neoplasia type I.
Insulin secretion increased and uncontrolled way is what causes the symptoms and make us suspect the presence of this tumor. Only at a later stage of evolution, the tumor produces symptoms also by himself, such as abdominal pain.
Typical symptoms are manifestations as clumsiness, confusion, headache, visual difficulties, inconsistent and unusual behavior, unexplained irritation and disorientation, and can lead to seizures and coma. These symptoms are due to the hypoglycemic effect on the brain and are known under the name of the symptoms. Typically, these symptoms are observed especially in situations of fasting (upon rising in the morning, or just before lunch or dinner) or when practicing physical activity (not necessarily strong), because at that time the amount of sugar (or glucose) in the blood is markedly lower.These crises are alleviated quickly after administration of any food or beverage that sugar content. Also during hypoglycaemia some patients may have symptoms secondary to excessive release of adrenaline and noradrenaline, which include sweating, tremor and palpitations.
Although it may seem very easy to get to the diagnosis of an insulinoma, this is not so. Initially the individual will have the symptoms reported before and it will correspond to the presence of a very small tumor or not detectable with imaging techniques usually used as ultrasound or computed tomography (CT) abdominal. It can take a long time between the onset of these symptoms and diagnosis, even years.
The diagnosis of insulinoma begins by demonstration of high levels of insulin in blood at the time of hypoglycemia. As discussed above, in normal pancreas stops making insulin if there is a decrease in blood sugar numbers. In case of an insulinoma, the pancreas continues to manufacture insulin, although the numbers are low sugar or low. This has allowed us to develop a test to diagnose insulinoma and that is to produce a fast of 72 hours with the guy in the hospital, and go making determinations in blood glucose, insulin and C-peptide (or proinsulin) every so often. If at any time the patient has symptoms or blood glucose levels are consistently below 40 mg / dL (= 2’2 mmol / L), the test will end.
C-peptide measurements done to rule out hypoglycemia those caused by the individual, either with the use, inadvertent or not, of insulin or oral hypoglycemic agents. Insulin is a protein that is produced as a large protein (proinsulin) having two chains connected by a very small chain (C-peptide). Insulinomas In addition to plasma levels of insulin, are elevated plasma levels of C-peptide and proinsulin, which does not occur in the exogenous administration of insulin or oral antidiabetic drugs.
When this test is performed fasting is good and positive, is usually sufficient for diagnosis. But then you have to locate the tumor using imaging techniques: ultrasound, computed tomography (CT) and magnetic resonance imaging of the abdomen. Sometimes you can use endoscopic ultrasound to locate very small tumors. Where these techniques do not detect the tumor image or when the suspected tumor is out of the pancreas, ie it has metastasized, the scan can be used with somatostatin analogues (or pentreótido octreotide), although it is important know that this technique detects only less than half of insulinomas.
The treatment requires two different strategies. On one hand, the treatment of symptoms caused by hormone excess (hypoglycemia). And, secondly, treating the tumor itself.
Treatment of insulinoma is surgical and involves removal of the tumor. The surgeon will decide which type of surgery is appropriate in each case. Up to 75 to 95% of patients are cured by surgery. If surgery is effective is shown by the immediate recovery of blood glucose to normal values and the disappearance of symptoms neuroglucémicos. In addition, removal of the tumor allows us to study and know whether it is benign or malignant.
In cases where the tumor can not be operated (because there are metastases), or reappears after tumor surgery, nonsurgical measures will arise. These measures include control hypoglycemia by frequent small meals, and the use of drugs such as diazoxide, verapamil, phenytoin and octreotide. These measures are also used nonsurgical before carrying out the surgery to avoid hypoglycemia during surgery. In inoperable tumors or metastatic chemotherapy can be used, being the most useful drugs doxorubicin and streptozocin.
There are no preventive treatments to prevent this tumor appears. The best prevention is to have a high index of suspicion in the individual. Insulinoma is suspected in any patient with repeated hypoglycemia, especially in times of fasting or exercise, and in people with a family history of multiple endocrine neoplasia type 1.
Insulinoma is a rare tumor and usually difficult to diagnose and difficult to locate. The most effective treatment is surgery and removal can cure the disease.
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