Doctors believe the underlying caus

Doctors believe the underlying cause of migraines is related to changes in the blood flow in certain areas of the brain, with subsequent alterations in the blood vessels in that region. Chemical reactions may lead to swelling and irritation of the blood vessels (thought to contribute to the characteristic “throbbing” quality of a migraine headache).The specific cause of tension-type headache is unknown. Doctors believed at one time that chronic muscle tension was the underlying factor, but there now appears to be a more complicated combination of factors that are involved.

Results (Chinese) 1:

医生们认为偏头痛的根本原因与在大脑的某些部位的血流的变化，随着血管在该地区进一步修改。化学反应可以导致肿胀和血管的刺激（认为有助于特性“跳动”偏头痛的质量）。

紧张型的具体原因头痛是未知的。医生一次认为慢性肌肉张力是潜在因素，但是现在似乎是所涉及的因素的更复杂的组合。

Results (Chinese) 2:

医生认为，偏头痛的根本原因与大脑某些区域的血流变化有关，随后该地区血管发生了改变。化学反应可能导致血管肿胀和刺激（被认为会导致偏头痛的"跳动"特征）。

紧张型头痛的具体原因不明。医生们一度认为，慢性肌肉紧张是根本因素，但现在看来，所涉及的因素组合更为复杂。

Results (Chinese) 3:

医生认为偏头痛的根本原因与大脑某些区域的血流变化有关，随后该区域的血管也发生了变化。化学反应可能导致血管肿胀和刺激（被认为有助于偏头痛特有的“悸动”性质）。
紧张型头痛的具体原因尚不清楚。医生一度认为，慢性肌肉紧张是根本因素，但现在似乎有一个更复杂的因素组合涉及。