Fusiform dilatation of vessels of circle of Willis to form large aneurysms, termed "Cerebral Aneurysmal Childhood Arteriopathy", is an exceedingly rare complication of pediatric HIV(1). We report one such case in a 12-year-old-child with WHO clinical-stage-4 HIV disease, who was admitted with complaints of headache and right hemiparesis.

He was diagnosed with vertically acquired HIV infection at age of 2-years. There was no previous history of neurologic symptoms or neurocognitive dysfunction. He was on antiretroviral treatment (ART) since last 4 months and his recent CD4-cell-counts were 217 cells/µL. A magnetic resonance imaging (MRI) of the brain revealed an aneurysm of the supraclinoid portion of left internal carotid artery (ICA). A cranial magnetic resonance angiographic scan was consistent with intracranial arteritis and revealed a large fusiform aneurysm of the left ICA beyond the common siphon (Fig. 1). Because of the surgical risk, no intervention was attempted. He is on ART and continues to be monitored closely for improvement.

Fig. 1 T2W Coronal Section of Magnetic Resonance Angiography (MRA) Brain showing a flow void in the left internal carotid artery (arrow). The left internal carotid artery appears dilated and ectatic suggestive of fusiform aneurysm of left internal carotid artery.

There is an increased incidence of cerebrovascular disease in HIV infected children who are severely immunosuppressed (CD4-counts < 200 cells/µL) and who acquire the infection vertically or in the neonatal period(2). The formation of fusiform aneurysm has been described previously(3), and it may be a feature specific to AIDS(4). The proximal segments of middle and anterior cerebral arteries and the supraclinoid segment of ICA (as in our patient) are the most common sites for aneurysms(2). Vascular immaturity is suggested as a possible contributory factor(2).

Most of these patients are asymptomatic during the early stages of the disease(2). With severe immunosuppression and usually after infancy, they present with an acute intracerebral event(5). Hence, screening of high risk children, preferably by MRI, is advisable for the early detection of cerebrovascular abnormalities(2). The fusiform nature and location of these aneurysms makes any form of surgical intervention or embolization impossible(1). Early detection and intervention with ART could prevent entirely or diminish the incidence and severity of cerebral vasculopathy(2).

Dr Mamta V Manglani, Professor and Head, Department of Pediatrics for her guidance.