Insulinoma: Cost-effective Care in Patients with a Rare Disease

An insulinoma is the quintessential example of the elusive but curable endocrine disorder. It is a rare condition, estimated to occur four times per million person-years [1], and has nonspecific neurologic and adrenergic manifestations. It frequently eludes diagnosis for years. The neurologic manifestations, especially those that affect behavior and consciousness, are often frightening and embarrassing to those who have this condition and to those around them. An insulinoma is potentially lethal. Once identified, it is curable by surgery [1]. When an isolated benign insulinoma is removed (and most are benign), the patient has a normal life expectancy [1]. A patient with an insulinoma presents a series of challenges. The physician must recognize that the patient's symptoms are attributable to hypoglycemia, exclude other exogenous and endogenous causes of hypoglycemia, obtain appropriate hormonal studies to establish the diagnosis beyond any doubt, and guide the patient toward appropriate surgical treatment.

Our ability to diagnose and treat patients with insulinomas has improved markedly since the disorder was initially described in 1927 [2] and since Allen O. Whipple proposed the criteria now known as the Whipple triad: 1) the occurrence of “attacks” attributable to hypoglycemia, especially but not exclusively in the fasting state or after exertion; 2) measurement of a low circulating glucose level when the patient has symptoms [spontaneously or after a fast]; and 3) alleviation of the patient's symptoms and signs by the administration of glucose [3, 4]. The availability of methods to measure accurately circulating levels of insulin, C-peptide, and proinsulin has dramatically improved the ability of the physician to diagnose an insulinoma preoperatively with a high …