ベーチェット病における黄斑部の細動脈の分布と視力および血小板機能検査との関連

The relationship between the distribution in the macula and the platelet function or visual acuity in Behçet disease

　ベーチェット病群，原田病群，対照群の3群に分けて，視神経乳頭径を校正とした関心領域を黄斑部に設定し，その黄斑部領域に対する細動脈の面積の割合を画像解析し，比較検討した．さらに，ベーチェット病群では，視力，血液生化学的検査結果および血小板機能検査との関係を検討した．

（1）3群の群間比較では，面積比はベーチェット病群が平均値で最も低く，対照群に比べ有意に低値であった（P＜0.01）．

（2）ベーチェット病群では，面積比の低下している例に視力低下傾向を認めた．

（3）ベーチェット病群での白血球数CRP,IgG，IgM，フィブリノーゲン，血小板数は，面積比との関連はみられなかった．血小板機能検査結果で，面積比の低下している例ほど血小板粘着能および凝集能の亢進傾向がみられた．

　ベーチェット病の細動脈病変は，血小板機能亢進による可能性が高いと推測された．

To investigate the obstructive arteriolitis of ocu-lar vessels in Behçet's disease, we divided the patients into the three groups : Group I (Behçet'sdisease : n=11), group II (Harada's disease of the uveitis without any vasculitis ; n=9) and Group III ('Control' patients without any vasculitis nor uveitis ; n=11).

Using a computer-assisted image analysis of fluorescein angiography, the region of interest (ROI) was positioned over the macular region after the size of ROI was calibrated by the diameter of optic disc. We measured a number of the terminal branches of arterioles in ROI by the visual inspec-tion. After the border edge of arterioles was enhan-ced by the differential function, we calculated a ratio per mil of the area of arterioles in ROI to the area of ROI itself. We correlated this ratio of area with visual acuity and platelet function in 8 patientsof Group I . The results were as follows : 1) A number of the terminal branches in Group I (4.5±2.5 : meant±SD) was decreased more than those in both Group II (6.3±1.9) and Group III (6. 0±2.0), but not significant. 2) The area ratio in Group I (16.1±9.3%) was reduced more than those in Group II (23.7±8.3%, NS) and Group III (30.5± 11.4%, p<0.01). 3) The visual acuity was de-creased in proportion to the reduction of area ratio in Group I. 4 ) The platelet function (retention and aggregation by adenosine diphosphate of 1.0, 3. 0 pM) was increased in patients with the reducedratio of area in Group I.

These results suggested that the thrombotic obstruction and/or stenosis of ocular arteriolitis in Behcet's disease may be probably due to the ab-nomalities of platelet function, and may cause the decrease in visual acuity.

Rinsho Ganka (Jpn J Clin Ophthalmol) 41(8) : 927-931, 1987