Headache Outpatient Clinic, Azienda Sanitaria Locale Roma 1, Rome, Italy.
Cephalalgia. 2021 Jun;41(7):871-874. doi: 10.1177/0333102420985444. Epub 2021 Jan 12.
Persistent migraine with aura and neuroimaging examinations revealing ischaemia in the contralateral cortex may be associated with migrainous infarction. Despite being a neurological symptom that is distinct from migraine with aura, the visual snow phenomenon may also be associated with cerebral ischaemia. Here we describe a patient who reported short-lasting daily symptoms of visual snow that affected his entire visual field before becoming continuous and left-sided following acute occipital brain ischaemia.
In February 2017, a 74-year-old retired male was referred to our headache outpatient clinic with a diagnosis of recent right occipital cerebral ischaemia and migraine with aura. The patient reported visual snow symptoms that had changed from being bilateral and temporary to left-sided and permanent one day upon awakening; after being admitted to hospital a few hours later, he discovered he had had a stroke. He said he had never had any symptoms of migraine with aura. The visual snow phenomenon disappeared completely after about 1 year.
In our patient, a temporary daily visual snow phenomenon reversed to a persistent one. This phenomenon occurred in the part of his visual field that had been affected by the ischaemic occipital stroke, as typically happens in migrainous infarction. We hypothesise that the occipital lesion disrupted the inhibitory circuits, leading to a quadrantopic persistent visual snow. Since the mechanism may be the same as that observed in migrainous infarction, though with a different pathophysiology, it is possible to speculate that the aura in this case is the result, as opposed to the cause, of stroke in most patients.
伴有先兆的持续性偏头痛和影像学检查显示对侧皮质缺血可能与偏头痛性梗死有关。尽管视觉雪现象是一种与先兆性偏头痛不同的神经系统症状，但也可能与脑缺血有关。在这里，我们描述了一位患者，他报告说短暂的每天视觉雪症状，影响他的整个视野，然后变得连续，并在急性枕叶脑缺血后变成左侧。
2017 年 2 月，一位 74 岁的退休男性因近期右侧枕叶脑缺血和先兆性偏头痛被转介到我们的头痛门诊。患者报告说，他的视觉雪症状已经从双侧和短暂变为左侧和永久性的，在一天醒来时；几个小时后住院后，他发现自己中风了。他说他从未有过先兆性偏头痛的症状。大约 1 年后，视觉雪现象完全消失。
在我们的患者中，短暂的每日视觉雪现象转变为持续的现象。这种现象发生在他的视野受缺血性枕叶中风影响的部分，这在偏头痛性梗死中很常见。我们假设枕叶病变破坏了抑制性回路，导致象限性持续性视觉雪。由于机制可能与偏头痛性梗死相同，尽管病理生理学不同，因此可以推测，在大多数患者中，这种情况下的先兆是中风的结果，而不是原因。
