The<unk> <unk> , which is a Japanese mimetic word, gets its characteristic name due to the appearance of smoke on relevant angiographs resultant from the tangle of tiny vessels in response to stenosis. This makes the blood leak out of the arteries, causing pressure to the brain and subsequent headaches. Over the last six decades since the<unk>  was first described, pathogenesis of<unk>  remained elusive, although the gene ring finger protein 213 (RNF213) has been implicated. In September 2021, a south Indian researcher has proposed a pathbreaking theory on<unk>  pathogenesis. Coined the "Mechano-biological theory", the<unk>  has a multifactorial pathogenesis. The authors provide a tangible explanation of the occurrence of<unk>  phenomenon in the idiopathic and syndromic variants of the<unk> . In short, the authors report that<unk>  likely occurs due to a number of factors (e.g., differences in vascular anatomy) that ultimately contribute to broad cerebral blood vessel occlusion and consequent shifts in vessel connections to try to provide blood for the compromised brain. Once it begins, the vascular occlusion tends to continue despite any known medical management. In some people this leads to transient ischemic attacks or repeated strokes with severe functional impairment or even death. In others, the blockage may not cause any symptoms. The<unk>  causes constrictions primarily in the internal carotid artery, and often extends to the middle and anterior cerebral arteries, branches of the internal carotid artery inside the skull. When the internal carotid artery becomes completely blocked, the fine collateral circulation that it supplies is obliterated. Patients often survive on the collateral circulation from the back (posterior) of the circle of Willis, arising from the basilar artery. The arterial constrictions in<unk>  are unlike the constrictions in atherosclerosis. In atherosclerosis, the walls of arteries are damaged, leading to the deposition of fat and immune cells, and ultimately the accumulation of immune cells laden with fat. In<unk> , the inner layer of the carotid artery proliferates within the arterial lumen. The artery also fills with blood clots, which may cause strokes.<unk>  tends to affect adults in the third to fourth decade of life. In children it tends to cause strokes or seizures. In adults it tends to cause strokes or bleeding. The clinical features are strokes, recurrent transient ischemic attacks (TIAs), sensorimotor paralysis (numbness and paralysis of the extremities), convulsions and/or migraine-like headaches. Moreover, following a stroke, secondary bleeding may occur. Such bleeding, called hemorrhagic strokes, may also stem from rupture of the weak neovascular vessel walls.
Moyamoya disease
Vein of Galen aneurysmal malformations
Cerebral amyloid angiopathy
Cerebral arteriovenous malformation
Meningism
Giant cell arteritis
Hypertensive leukoencephalopathy
Chiari malformation