【用戶】彈跳甲魚湯

【年級】小六下

【評論內容】Chiari-like malformation (CM)為一種遺傳性疾病，由於顱骨頸椎的發育問題造成腦部和頸部脊髓在頭頸部交界處過度擁擠和型態改變 (Rusbridge, 2020)，好發於查理士王小獵犬 (患病比率高達95%)、布魯塞爾犬、吉娃娃等犬隻 (Knowler et al., 2017)。選項A「病因主要是因為小腦發育畸形所引起」應改為「顱骨與頸椎發育畸形所引起」。大多數臨床症狀不具特異性，包含共濟失調或癱瘓的神經症狀、不自主發聲、頭頸和腰部疼痛，選項B的犬隻的隔空搔癢 (phantom scratching)是其中一個典型特徵 (Marino et al., 2020; Rusbridge, 2020)，在貓則可能出現過度理毛或因疼痛造成的進食困難等 (Korff et al., 2020; Minato et al., 2018)。主要確診方式為MRI (Sanchis-Mora et al., 2016)，影像上可以看到枕骨上骨畸形，壓迫小腦導致小腦並可能使之位移到枕骨大孔 (Hechler et al., 2018)。上圖為Chiari-like malformation的MRI影像，箭號為小腦尾側受壓迫而向後位移至枕骨大孔 (Hechler et al., 2018)。內科治療主要是給予NSAIDs來止痛 (carprofen或meloxicam)與抗癲癇藥物 (選項C的gabapentin或pregabalin)緩解臨床症狀，也有人會合併給予減少CSF的藥物 (furosemide或omeprazole)，或是用減少CSF的藥物再合併類固醇 (prenisolone或dexamethasone)治療 (Hechler et al., 2018)。貓隻對omeprazole有較好的反應 (Korff et al., 2020)。其中選項C的gabapentin或pregabalin可調控鈣離子通道，降低興奮性神經傳遞物質麩胺酸 (glutamate) 生成與輸送活性，來抑制選項B隔空搔癢的臨床症狀 (Nalborczyk et al., 2017)。有些個體靠內科治療就能改善症狀，沒改善或臨床症狀較嚴重建議外科手術介入，常見術式為選項D的枕骨大孔減壓術 (foramen magnum decompression, FMD)，術後可能形成疤痕組織 (scar tissue)產生壓迫腦部導致復發率提高 (Dewey et al., 2019)，因此可搭配利用材料填補FMD創口的術式以預防疤痕組織並降低復發率。其一為Cranioplasty，用骨螺絲和鈦金屬的mesh固定創口上，再用聚甲基丙烯酸甲酯 (polymethyl methacrylate, PMMA)填補在上方去模仿頭骨的結構 (Dewey et al, 2007)。其二為Duraplasty，先在FMD的切口將硬腦膜袋狀縫合後縫上豬腸道黏膜下層或牛心包膜等人工材料，用以組織修復來重建硬腦膜 (Ortinau et al., 2015; Park et al., 2017)。Dewey, C.W., Fossum, T.W., 2019. Surgery of the brain, In: Fossum, T.W., Cho, J., Dewey, C.W., Hayashi, K., MacPhail, C.M., Huntingford, J.L., Quandt, J.E. (Eds.), Small Animal Surgery. 5th ed. Elsevier, Inc., Philadelphia, pp. 1344, 1353-1358.Dewey, C.W., Marino, D.J., Bailey, K.S., Loughin, C.A., Barone, G., Bolognese, P., Milhorat, T.H., Poppe, D.J., 2007. Foramen magnum decompression with cranioplasty for treatment of caudal occipital malformation syndrome in dogs. Vet. Surg. 36 (5), 406-415.Hechler, A.C., Moore, S.A., 2018. Understanding and treating Chiari-like malformation and syringomyelia in dogs. Top. Companion Anim. Med. 33 (1), 1-11.Knowler, S.P., Cross, C., Griffiths, S., McFadyen, A.K., Jovanovik, J., Tauro, A., Rusbridge, C., 2017. Use of morphometric mapping to characterise symptomatic Chiari-like malformation, secondary syringomyelia and associated brachycephaly in the Cavalier King Charles Spaniel. PLoS One. 12 (1), e0170315.Korff, C.P., Williamson, B.G., 2020. Clinical presentation of Chiari-like malformation in 2 Persian cats. Top. Companion Anim. Med. 41, 100460.Marino, D.J., Dewey, C.W., 2020. Chiari-like malformation in dogs. In: Tubbs R., Turgut M., Oakes W. (Eds), The Chiari Malformations. Springer, Cham, pp. 529-547.Minato, S., Baroni, M., 2018. Chiari‐like malformation in two cats. J. Small Anim. Pract. 59 (9), 578-582.Nalborczyk, Z. R., McFadyen, A. K., Jovanovik, J., Tauro, A., Driver, C. J., Fitzpatrick, N., Rusbridge, C., 2017. MRI characteristics for “phantom” scratching in canine syringomyelia. BMC veterinary research, 13(1), 1-10.Ortinau, N., Vitale, S., Akin, E.Y., Beasley, M., Shores, A., 2015. Foramen magnum decompression surgery in 23 Chiari-like malformation patients 2007-2010: Outcomes and owner survey results. Can. Vet. 56, 288.Park, W.S., Kang, S.H., Kim, J.S., 2017. Foramen magnum decompression with duraplasty using Lyoplant® for caudal occipital malformation syndrome in a dog. J. Vet. Clin. 34 (6), 449-453.Rusbridge, C., 2020. New considerations about Chiari‐like malformation, syringomyelia and their management. In Pract. 42 (5), 252-267.Sanchis-Mora, S., Chang, Y., Abeyesinghe, S. M., Fisher, A., Upton, N., Volk, H. A., & Pelligand, L. (2019). Pregabalin for the treatment of syringomyelia-associated neuropathic pain in dogs: A randomised, placebo-controlled, double-masked clinical trial. The Veterinary Journal, 250, 55-62.