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The case report concluded with the diagnosis as moyamoya disease. It is possible. However, from the short case summary, CT scan, and anterior-posterior images from cerebral angiography, this could very well be an alternate diagnosis of ruptured anterior communicating aneurysm with severe vasospasm.
The authors remind us that the pattern of moyamoya phenomenon, common to moyamoya disease and moyamoya vasculopathy, is occlusive or occluded supraclinoid internal carotid arteries and anterior and middle cerebral trunks, with a non-specific pattern ganglionic and capsular collaterals. These are merely appropriate natural collaterals anatomically for the affected vessel locations, not specific to any cause. The reported case shows occlusive/occlusion vessels plus absence of contrast filling in the proximal pericallosal arteries, the main continuations of anterior cerebral arteries. The most prominent collaterals seen on these images, including on the videos of the angiographic filling, are leptomeningeal collaterals from distal posterior cerebral vessels to both anterior and middle cerebral arteries, invoked for surface arterial insufficiency as pial vessels in the situation.
The CT slice showing symmetrical substantial intraventricular hematoma plus hydrocephalus always demands immediate consideration of a common diagnosis of anterior communicating aneurysm rupture into the ventricles. To fit that diagnosis with the angiographic findings of bilateral severe occlusive arteries at the basal cisterns puts the time of considered aneurysm rupture as about 5-7 days earlier to allow vasospasm to evolve. The main alternative diagnosis to moyamoya then is anterior communicating aneurysm, not diagnosed immediately after rupture, with subsequent development of very severe vasospasm, severe enough that it induced thrombosis of the aneurysm. This is a known diagnosis and documented in the literature. This writer was an active investigator of the topic (1).
The authors have not considered aneurysm with vasospasm as an alternative, they just recite a list of other things of moyamoya vasculopathy that they know. Anterior communicating aneurysm is a common diagnosis, especially with rupture. Intraventricular hemorrhage and hydrocephalus are commonly associated. What is not common is lack of severe headache and feeling ill at the time of rupture leading to diagnosis of ruptured aneurysm. Yet cases have been seen of intoxication at the time of rupture or another reason that the rupture was not sensed as the worst pain of one’s life, therefore not diagnosed. What is clear is that medicine sees unusual clinical combinations of common diseases as quite possibly the best diagnosis before invoking a more unusual disease. Ruptured anterior communicating artery aneurysm is one such common disease.
In my career caring for thousands of ruptured aneurysms, I've seen the diagnosis of missed anterior communicating aneurysm rupture with delayed presentation with very severe vasospasm enough times to say that this case can be declared typical. The diagnosis of moyamoya disease for this case would be more unusual. If MRI was done, the focus of hemorrhage could be identified at the anterior communicating region. As well it is possible that the occluded aneurysm would be seen as different clot signal than the initial rupture. It would take arterial wall histology or autopsy to prove moyamoya disease for this case.
The authors need to be thanked for bringing this case forward. There is no question that the best diagnosis is anterior communicating aneurysm as described which the authors did not mention. If the authors are able to produce histological proof of moyamoya disease that would be excellent to know as it would elevate their diagnosis from whim. Meanwhile, their list of possible alternatives doesn’t include the most obvious aneurysm rupture with vasospasm.
1) Gacs G, Fox AJ, Barnett HJM. Occurrence and Mechanisms of Occlusion of the Anterior Cerebral Artery. Stroke 1983, 14:952-959