Pediatric Intracranial Aneurysms

Intracranial pediatric aneurysms arising in children are rare. The treatment of these lesions requires both an understanding of their unique features as well as surgical, interventional, and pediatric critical care expertise offered through a multidisciplinary setting. The patient population, clinical presentation, complications, and trends in treatments are discussed in this article.

Intracranial aneurysms in children are rare; 0.5% to 4.6% of intracranial aneurysms occur in patients aged 18 years or younger. In a cooperative study reported in 1966, only 41 of 6368 (0.6%) ruptured aneurysms were found in patients younger than 19 years. Aneurysms occurring in very young children and infants are exceedingly rare. In adults, aneurysms are believed to form as a result of multiple risk factors (eg, family history, age older than 50 years, smoking, cocaine use, and hypertension) present over the course of an individual’s life span. In childhood, most of these aneurysmal risk factors do not exist, and for this reason, the pathogenesis is believed to be different. Some investigators have proposed that a vasculopathy predisposes regions of the cerebral vasculature to aneurysm formation. In multiple case series, primarily since the 1970s, pediatric aneurysms have been reported to exhibit features that differ from those in adults, such as male predominance, a higher incidence in locations such as the posterior circulation and internal carotid bifurcation, and greater numbers of giant aneurysms.

Discrepancies exist in the clinical description of pediatric aneurysms, likely related to the small numbers reported in most case series. Since the comprehensive review by Huang, other case series (including from the authors’ institution) have been published. Data from these larger series have confirmed some earlier findings and have contradicted others. It is likely that considerable heterogeneity exists with respect to the pathology, diagnosis, and treatment of these lesions.

The past 20 years have witnessed a gradual shift from exclusively surgical approaches toward endovascular treatment and multimodality therapeutic plans. The increasing number of options available for the treatment of complex aneurysms suggest that treatment should be guided by the best available evidence and executed by centers with expertise in each of these therapeutic tools.

Clinical presentation

As in adults, children with intracranial aneurysms can present with subarachnoid hemorrhage (SAH), headache, direct compressive effects, focal neurologic deficits, or seizures. If SAH is present, nearly 60% of patients will have a cerebral aneurysm. Fusiform aneurysms tend to present with nonhemorrhagic deficits. Many patients (30%–85%) with SAH confirmed by radiographic imaging or lumbar puncture typically present good clinical function defined by a Hunt and Hess grade between 1 and 3. Patients with poor clinical function have a Hunt and Hess grade of 4 to 5, occurring 15% to 42% of the time ( Table 1 ). The reason for the better clinical grade at presentation is unclear but may be because of several factors, such as fewer comorbidities, clouding the initial diagnosis, and a greater tendency to refer cerebrovascular cases to tertiary centers. Specific biologic features such as the activity of the nitric oxide synthase pathway and the robustness of leptomeningeal arterial collaterals may also play a role.

Table 1

Summary of published reports describing pediatric intracranial aneurysms

Year	Authors	Cases (n)	Boys (%) ^a	Girls (%) ^a	SAH (%)	Good Grade (%)	Poor Grade (%)	Giant (%)	ICA Terminus (%)	Posterior Circulation (%)	Surgical or Endovascular Treatment (%)	Good Outcome (%)	Death (%)	Years of Follow-Up
1939	McDonald and Korb	61	60	34	87	^a	^a	^a	16	23	^a	^a	^a	^a
1940–64	Case reports	9	78	22	100	22	78	11	22	22	33	33	66	^a
1963	Stehbens	3	33	66	33	0	100	^a	^a	^a	^a	^a	100	^a
1965–1990	Case reports	35	^a	^a	^a	^a	^a	^a	^a	^a	67	25	75	^a
1965	Matson	13	92	8	92	^a	^a	^a	8	15	92	62	23	0–12
1966	Locksley et al	41	73	27	100	^a	^a	^a	15	17	^a	^a	^a	^a
1971	Patel and Richardson	58	55	45	100	69	31	0	34	5	64	52	31	1–22
1973	Sedzimir and Robinson	50	56	44	100	^a	^a	^a	36	4	50	70	28	2–15
1975	Amacher and Drake	16	69	31	88	44	44	44	13	31	69	56	38	^a
1977	Almeida et al	11	55	45	91	82	18	0	55	9	91	64	27	0–15
1978	Batnitzky and Muller	12	67	31	83	^a	^a	25	25	25	^a	^a	25	^a
1980	Gerosa et al	15	67	33	80	87	13	20	33	0	100	67	13	2–22
1981	Heiskanen and Vikki	32	53	47	100	^a	^a	^a	50	6	100	75	6	0.5–11
1981	Amacher et al	26	62	38	65	96	4	^a	^a	^a	96	92	4	^a
1982	Storrs et al	29	45	55	76	38	62	31	31	31	72	45	34	^a
1983	Schauseil-Zipf et al	15	67	33	60	20	^a	^a	^a	7	80	13	33	1–17
1983	Ostergaard and Voldby	43	58	42	77	72	28	5	44	7	81	53	30	0.25–14
1985	Humphreys et al	35	^a	^a	74	11	63	29	26	20	66	40	40	^a
1986	Pasqualin et al	31	^a	^a	94	^a	^a	3	29	3	61	52	3	^a
1988	Roche et al	43	70	30	81	^a	^a	7	26	16	95	79	12	^a
1989	Meyer et al	24	71	25	54	50	4	54	8	46	100	92	4	1–7
1991–2002	Case reports	47	^a	^a	^a	^a	^a	^a	^a	^a	70	63	26	0–19
1991	Herman et al	16	56	44	63	38	6	19	6	19	94	75	6	0.67–6
2001	Proust et al	22	73	27	95	59	36	14	36	9	100	64	23	^a
2004	Huang et al	19	68	32	58	42	16	37	11	42	84	95	5	0.1–9
2005	Lasjaunias et al	59	59	41	50	30	18		4	27	67	52	10	0–6
2005	Agid et al	33	16	17	9	^a	^a	30	22	30	70	64	15	12
2005	Krishna et al	22	64	36	91	68	32	13.6	20	24	77	82	10	0.1–2.5
2006	Sanai et al	32	44	56	22	85	15	40	13	28	90	78	0	6
2008	Vaid et al	36	52	48	92	58	42	21	18	30	75	78	11	0.1–3.5
2009	Hetts et al	77	52	48	32	^a	^a	11	^a	22	77	^a	1	^a
Total		965	60	37	74	51	34	21	24	19	79	62	24