82歳男性。X年健診で糖尿病を指摘され経口血糖降下薬開始となり，X＋15年より強化インスリン療法が導入され血糖コントロールは良好であった。X＋18年頃より血糖コントロールが悪化したためインスリン手技につき問診したところ，穿刺時に出血や疼痛を認めていた。超音波画像上皮下脂肪が薄く，筋肉内に注射している可能性が推察された。マイクロファイン^™プラス32G×4mmペン型注入器用注射器を用いていたが，同針は針基が突起しており皮下脂肪の薄い部位では皮下を貫通する可能性がある。穿刺方法を指導し，ペンニードル^®プラス32G×4mmペン型注入器用注射器へ変更したところ疼痛や出血を認めず良好な血糖コントロールを得た。血糖コントロール不良な症例に対し，超音波検査に基づき穿刺針を変更することが有用となり得る。

   An 82-year-old male patient was diagnosed with diabetes in Year X and put on oral hypoglycemic drugs. At Year X+15, intensive insulin therapy was started, and the patient achieved good glycemic control. However, his glycemic control worsened at around Year X+18, and he was enquired about his insulin administration procedures. It was found that when he inserted his insulin needle, he experienced pain and bleeding. Ultrasound imaging revealed that the patient had very little subcutaneous fat, and we surmised that he may have been injecting his insulin intramuscularly. The patient had been using Micro-Fine™ Plus needles. During the use, the base of this needle protruded somewhat, causing it to potentially pass through the subcutaneous layer in areas where the subcutaneous fat was sparse. Upon providing the patient with injection guidance and urging him to switch Micro-Fine^™Pulus needles to Pen Needle^®Plus-brand needles, his pain and bleeding disappeared, and the patient once again achieved good glycemic control. Thus, the use of ultrasound testing to reconsider needle choice may be helpful in cases with poor glycemic control.