Department of Internal Medicine D, "G.B. Rossi" University Hospital, Verona, Italy.
J Endocrinol Invest. 2013 Oct;36(9):753-8. doi: 10.3275/8942. Epub 2013 Apr 18.
New aspects have emerged in the clinical and diagnostic scenarios of insulinoma: current guidelines have lowered the diagnostic insulin threshold to 3 μU/ml in the presence of hypoglycemia (<55 mg/dl); post-prandial hypoglycemia has been reported as the only presenting symptom; preexisting diabetes mellitus (DM) was recognized in some patients.
To evaluate clinical features, diagnostic criteria and glucose metabolic profile in a monocentric series of patients affected by insulinomas including two subgroups: sporadic and multiple endocrine neoplasia type-1 syndrome (MEN-1).
Clinical, pathological and biochemical data regarding 33 patients were analyzed.
following the current guidelines the 72-h fasting test was initially positive in all cases but one. In this case the test, initially negative, became positive after a 2-yr follow-up. Nadir insulin level was ≥ 3 μU/ml but <6 μU/ml in 3 patients and ≥ 6 μU/ml in the remaining 30 cases. At presentation, 27 patients (82%) reported only fasting symptoms, 3 (9%) only post-prandial and 3 (9%) both. Seven cases (21%) had previously been affected by type 2 DM or impaired glucose metabolism.
In our series the new cut-off of insulin increased the sensitivity of the 72-h fasting test from 87% to 97%. The absence of hypoglycemia during the test cannot definitively rule out the diagnosis and the test should be repeated in every highly suspicious case. Post-prandial hypoglycemia can be the only presenting symptom. DM may be associated with the occurrence of insulinoma. So that a possible diagnosis of insulinoma must not be ignored if previous impaired glucose handling is evident.
胰岛素瘤的临床和诊断情况出现了新的方面：目前的指南将低血糖（<55mg/dl）时的诊断胰岛素阈值降低到 3μU/ml；已报道餐后低血糖是唯一的表现症状；一些患者被诊断为原有糖尿病（DM）。
评估单中心一系列胰岛素瘤患者的临床特征、诊断标准和糖代谢特征，包括两个亚组：散发性和多发性内分泌肿瘤 1 型综合征（MEN-1）。
分析了 33 名患者的临床、病理和生化数据。
根据目前的指南，72 小时禁食试验在所有病例中均为阳性，但有 1 例为阴性。在这种情况下，该试验最初为阴性，但在 2 年的随访后变为阳性。胰岛素水平最低值≥3μU/ml但<6μU/ml 的有 3 例，其余 30 例≥6μU/ml。在就诊时，27 例（82%）患者仅报告空腹症状，3 例（9%）仅报告餐后症状，3 例（9%）同时报告空腹和餐后症状。7 例（21%）患者曾患有 2 型糖尿病或糖代谢受损。
在我们的系列中，胰岛素的新切点将 72 小时禁食试验的敏感性从 87%提高到 97%。试验期间无低血糖并不能明确排除诊断，应在每个高度怀疑的病例中重复进行该试验。餐后低血糖可能是唯一的表现症状。DM 可能与胰岛素瘤的发生有关。因此，如果之前存在糖代谢受损，即使有明显的胰岛素瘤可能，也不应忽视可能的胰岛素瘤诊断。
