軽微な受傷後眼球後面膿瘍を形成した竹小片穿通症の１例

抄録

Penetrating intraorbital injuries of foreign bodies cause various symptoms and complications, and it might be difficult to diagnose especially small foreign body depending on its characteristics. We report a case of intraorbital abscess due to an inserted bamboo fragment via a small wound. An 82–year–old man felt a sharp right supraorbital pain during handling with bamboo. As the pain was transient, he did not consult to any medical doctors. Ten days after the injury, he visited our hospital complaining with progressing redness of the right conjunctiva. Plain computed tomography (CT) showed a hyperdense lesion in the right retroocular space and some air–like spots. However, we could not identify this lesion. We per­form magnetic resonance imaging (MRI) examinations. T1–weighted imaging (T1WI) showed the low intensity tissue surround­ing the linear foreign body showing lower intensity. The foreign body was a well delineated stick–shape object. Considering the image findings and his medical history, we made a diagnosis as intraorbital abscess due to an inserted bamboo fragment. After performing pterional craniotomy, orbital rim was removed. We opened periorbita and approached retroocular space. We found abscess, in which we re­moved a small fragment of bamboo. His postoperative course was uneventful. Postoperative CT scan and MRI showed the abscess dis­appeared and the impairment of the right eye movement gradually alleviated. According to this case experience, we examined MRI findings of wet and dry bamboo pieces, which found that wet bamboo showed high intensity but dry one showed very low intensity. When a small foreign body penetrates the orbit without passing through conjunctiva, patients are sometimes asymptomatic and unable to notice it at the acute phase. In this case, we could make a diagnosis based on the detailed medical history, the presence of abscess and characteristic imaging findings. We must notice of difficulty of imag­ing diagnosis of penetrated bamboo pieces.