The authors' intention in reporting this case was twofold: first, to note a rare, unusual initial presentation of this disease that began with inaugural, disabling headaches. Second, we aimed to contribute to the African data, particularly in sub-Saharan Africa, regarding this disease.
Moyamoya disease is rare, and its main clinical manifestation is stroke. Headache is one of the more unusual initial presentations. They may therefore delay diagnosis, especially when they are incipient and disabling without obvious objective neurological signs at onset, as observed in our case. As initially presented in our patient, it was difficult to associate the symptoms with stroke, especially in the absence of localizing signs.
In addition, the cranioencephalic CT scan was normal. The secondary development of motor deficits two weeks after the onset of headache in the absence of imaging suggested the diagnosis of an intracranial expansive process or encephalitis. A cranioencephalic MRI unexpectedly revealed a bilateral infarct in several different arterial territories. The cardiac etiologic work-up failed to reveal an obvious cause, as did the other conventional etiologic work-ups. Finally, cerebral angiography revealed radiologic evidence consistent with moyamoya. These angiographic images in a 9-year-old child, the bilateral nature of the infarcts, and the absence of other associated pathologies after investigation led to the conclusion of moyamoya disease. In fact, there are two main age groups for the onset of Moyamoya disease: 5 to 10 years and 25 to 49 years [5].
In addition, individuals with moyamoya disease usually present with bilateral pathognomonic arteriographic findings in the absence of associated risk factors. In contrast, people with characteristic Moyamoya vasculopathy who also have certain associated conditions, such as sickle cell disease, neurofibromatosis, Down syndrome, autoimmune diseases, congenital heart disease, and posterior fossa malformations, are classified as having Moyamoya syndrome. People with unilateral arteriographic findings also have Moyamoya syndrome, even if they have no other associated risk factors [8]. In addition, in our patient, there was also stenosis of the left posterior cerebral artery, which is not usually affected by moyamoya disease. However, according to authors such as Ohkura et al., the posterior cerebral artery is the most important independent predictor of cerebral infarction in moyamoya patients. Thus, the prediction and inhibition of steno-occlusive changes in the posterior cerebral artery may help prevent cerebral infarction [9].
Headache associated with moyamoya disease in children accounts for 20–30% of cases and is most often chronic [10]. In addition, unlike in adults, cases of headache that are diagnosed as moyamoya disease are rare [11, 12, 13, 14]. Therefore, the case presented here expands the presentation of the disease. Headaches in moyamoya disease are not specific but are dominated by migraine-type headaches [15, 16]. In our patient, the headaches were frontal and then diffuse.
Moyamoya disease is found throughout the world, but mainly in East Asia. Its incidence in European and North American populations is low [4]. This disease is rare in Africa, especially in sub-Saharan Africa, and its incidence and prevalence are not known. A 1992 study of the distribution of the disease worldwide revealed 52 cases in Africa, including 44 in North Africa, 5 in Central Africa, 3 in South Africa, and none in sub-Saharan Africa [17].
In a tertiary hospital in sub-Saharan Africa, Nigeria, a study conducted between 2003 and 2021 to identify rare cranial neurosurgical pathologies, published in 2022, recorded no cases of Moyamoya disease [18]. More recently, in 2022, a case of moyamoya disease was reported in Burkina-Faso, but stroke was the first sign and was associated with hyperhomocysteinemia [19].
In terms of treatment, cerebral surgical revascularization is not a panacea, as it may either relieve or worsen headache [6]. Moreover, some patients improve spontaneously without this treatment, as in our patient who received conservative treatment.
The case we report here illustrates the diversity of the presentation of this vasculopathy. Therefore, the importance of considering moyamoya disease as one of the probable etiologies in the setting of a child's first disabling headache and performing cerebral MRI in conjunction with cerebral angio-MRI without delay is emphasized. Early diagnosis and appropriate treatment improve patient prognosis.