Diagnosis Insulinoma

1 diagnosis

1.1 blood tests
1.2 suppression tests
1.3 diagnostic imaging

diagnosis

the diagnosis of insulinoma suspected in patient symptomatic fasting hypoglycemia. conditions of whipple’s triad need met diagnosis of true hypoglycemia made:

blood tests

these blood tests needed diagnose insulinoma:

glucose
insulin
c-peptide

if available, proinsulin level might useful, well. other blood tests may rule out other conditions can cause hypoglycemia.

suppression tests

normally, endogenous insulin production suppressed in setting of hypoglycemia. 72-hour fast, supervised in hospital setting, can done see if insulin levels fail suppress, strong indicator of presence of insulin-secreting tumor.

during test, patient may have calorie-free , caffeine-free liquids. capillary blood glucose measured every 4 hours using reflectance meter, until values < 60 mg/dl (3.3 mmol/l) obtained. then, frequency of blood glucose measurement increased every hour until values < 49 mg/dl (2.7 mmol/l). @ point, or when patient has symptoms of hypoglycemia, blood test drawn serum glucose, insulin, proinsulin, , c-peptide levels. fast stopped @ point, , hypoglycemia treated intravenous dextrose or carbohydrate-containing food or drink.

diagnostic imaging

the insulinoma might localized noninvasive means, using ultrasound, ct scan, or mri techniques. indium-111 pentetreotide scan more sensitive ultrasound, ct, or mri detection of somatostatin receptor positive tumors, not diagnostic tool insulinomas. endoscopic ultrasound has sensitivity of 40-93% (depending on location of tumor) detecting insulinomas.

sometimes, angiography percutaneous transhepatic pancreatic vein catheterization sample blood insulin levels required. calcium can injected selected arteries stimulate insulin release various parts of pancreas, can measured sampling blood respective veins. use of calcium stimulation improves specificity of test.

during surgery remove insulinoma, intraoperative ultrasound can localize tumor, helps guide surgeon in operation , has higher sensitivity noninvasive imaging tests.