The clinical presentation of childhood AIS is quite different from adults’ in many aspects. It depends on the age and the involved artery. Infant and younger children commonly present with nonspecific symptoms such as lethargy, decreased activities, seizures, or mild fever at the onset, while older children and adolescents often present with more specific symptoms such as hemiplegia. Typical features of AIS depending on the involved arterial territory are summarized in Table 8.2. Generally speaking, the presence of hemiparesis, hemisensory deficit, aphasia, or hemianopsia suggests the involvement of one or more of major cerebral arteries, while ataxia and multiple cranial nerve signs suggest the involvement of branch vessels of vertebrobasilar arteries. Small- to medium-sized events tend to present with acute onset focal deficit with preserved consciousness, while larger events tend to have more severe focal deficits and alteration of consciousness. Pure motor or sensory deficits from deep penetrating artery occlusion are rare in children. Furthermore, acute hemiparesis is more likely due to other conditions such as postictal Todd’s paralysis, migraine, and neuro-infectious or inflammatory diseases in children. Seizures have been noted in about one third to half of cases, which means that they can be part of major clinical presentations regardless of ages and independently from the subtype in childhood AIS [40]. Furthermore, the patients who had seizures within first 24 h will be at a higher risk for epilepsy over the next 6 months [41]. Strokes from metabolic causes such as MELAS frequently present with a progressive course of stroke-like episodes.

The diagnosis of childhood AIS is not easy and often delayed due to subtle and nonspecific clinical presentations as well as a complicated differential diagnosis listed in Table 8.3. Considering the complexity, the sudden onset of a focal neurological deficit can be stroke until proven otherwise. Besides hemiparesis, hemisensory, aphasia, and visual or balance impairment also occur. With respect to obtaining clinical history, a variety of risk factors for childhood AIS should be considered and particular attention should be paid to the presence of recent infections, trauma, congenital heart diseases, family history, etc. A complete physical and neurological examination should be performed considering the brain territories potentially involved.

In general, diagnostic investigation in childhood AIS is more complex and extensive than in adult strokes due to a variety of different causes and a complicated differential diagnosis.

Neuroimaging is essential to make a confirmative diagnosis. In the acute setting, laboratory evaluation involves a complete blood counts (CBC), routine chemistry, electrolytes, erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), coagulation studies, lipid profiles, toxicology screen, and β-hCG in adolescents. Further evaluation into specific conditions such as genetic, metabolic, vasculitic, and infectious diseases should be considered under different circumstances (Table 8.4). Electrocardiogram and echocardiogram with venous saline injection are mandatory for any children with suspicion of congenital heart disease or unknown etiology. In some cases, hemoglobin electrophoresis may be indicated to identify SCA or other hemoglobinopathies.

To determine whether the focal neurological deficit is vascular origin or not, it requires a high-grade neuroimaging. Although brain computer tomography (CT) can exclude hemorrhagic stroke and be a first-line tool for the diagnosis of childhood AIS, especially in mature AIS, brain MRI with diffusion-weighted imaging became the gold standard modality for the evaluation of early and small infarcts due to its greater sensitivity and specificity [42]. Diffusion-weighted MRI can demonstrate the lesions within half an hour of onset and up to a week after onset (Figs. 8.1 and 8.2). Magnetic resonance angiography (MRA) or CT angiography (CTA) is considered as the first-line imaging modality unless the case is suggestive of small-vessel occlusion in which case conventional angiography is indicated. MRA may be sufficient to make a diagnosis of moyamoya disease if it shows the typical “puff-of-smoke” pattern of stenosis or occlusion of major cerebral arteries and the abnormal arterial vascular network near the steno-occlusive lesions (Fig. 8.3). However, conventional angiography is warranted because MRA may underestimate or overestimate the degree of condition. By recommendation, the vascular imaging should be done within the first 24 h after onset of symptoms [43]. Single photon emission computed tomography (SPECT) may be helpful to detect areas of hypoperfusion present prior to infarction. Doppler studies including transcranial Doppler imaging can provide valuable dynamic information regarding flow patterns but are still limited in pediatric practice.