Introduction: Benign enlargement of the subarachnoid spaces (BESS) in infancy occurs due to a transient accumulation of cerebrospinal fluid (CSF). Buildup of CSF can be caused by insufficient reabsorption, including impaired venous outflow from the head. Despite the commonality of BESS during infancy, its etiologies remain to be determined. BESS has generally been described as a variation of normal neurodevelopment and clinically presents as macrocephaly, with normal intracranial pressure. However, it carries an increased risk of subdural hemorrhage, arachnoid cyst formation, and hydrocephaly. We hypothesized that chronic upper respiratory infections (URIs) and increased right atrial pressure (RAP), which hinder venous drainage, could be possible causes for BESS in pediatric patients under the age of 2.
Methods: We conducted a retrospective review of patients diagnosed with macrocephaly or BESS before the age of 2, within a 125-mile radius of Lubbock, Texas, from 2010 to 2015. We determined the prior incidences of chronic URIs and increased RAP in the specified population and conducted a chi-square goodness of fit test to analyze the statistically significant difference from those of the general population.
Results: During the study period, 29 patients with macrocephaly or BESS were identified without any confounding diagnoses and syndromes. In these patients, the prior incidences of chronic URIs and elevated RAP were 37.9% and 10.3%, respectively—compared to 19.6% and 0.001% in the general population. The incidences of chronic URIs and elevated RAP were significantly higher in the BESS population.
Conclusions: While the etiologies of BESS are unknown, our study presents potential factors leading to the development of BESS. While it is generally considered a transient condition during normal neurodevelopment, it could also be a result of pathological processes in some children. Pediatricians should, therefore, advise the parents of such patients about the increased risk of BESS and subsequent subdural hemorrhage, among other indicated complications.
Patient Care: Chronic upper respiratory infections and transient right atrial pressure elevation could possibly lead to benign enlargement of subarachnoid space in pediatric patients. Therefore, the parents of infants with such conditions should be advised of their increased risk of BESS and subsequent subdural hemorrhage, due to a lowered force threshold.
Learning Objectives: By the conclusion of this session, participants should be able to: 1) Describe BESS and the pathophysiology behind impaired venous outflow from the head, 2) Discuss, in small groups, the implications and potential outcomes of BESS, and 3) Identify potential preventions and interventions.
References: 1. Aguilar-Perez M, Henkes H. Treatment of Idiopathic Intracranial Hypertension by Endovascular Improvement of Venous Drainage in the Brain. Opthalmologe. 2015;112(10):821-827. doi:10.1007/s00347-015-0136-1.
2. Aoki N. Extracerebral fluid collections in infancy: role of magnetic resonance imaging in differentiation between subdural effusion and subarachnoid space enlargement. Journal of Neurosurgery. 1994;81(1):20-23. doi:10.3171/jns.1994.81.1.0020.
3. Greitz D. Radiological assessment of hydrocephalus: new theories and implications for therapy. Neurosurgical Review [serial online]. July 2004;27(3):145-165. Available from: MEDLINE Complete, Ipswich, MA. Accessed February 26, 2016.
4. Hatt A, Cheng S, Tan K, Sinkus R, Bilston LE. MR Elastography Can Be Used to Measure Brain Stiffness Changes as a Result of Altered Cranial Venous Drainage During Jugular Compression. American Journal of Neuroradiology. 2015;36(10):1971-1977. doi:10.3174/ajnr.a4361
5. Hellbusch LC. Benign extracerebral fluid collections in infancy: clinical presentation and long-term follow-up. Journal of Neurosurgery: Pediatrics. 2007;107(2):119-125. doi:10.3171/ped-07/08/119.
6. Kuruvilla L. Benign enlargement of sub-arachnoid spaces in infancy. Journal Of Pediatric Neurosciences [serial online]. May 2014;9(2):129-131 3p. Available from: CINAHL Complete, Ipswich, MA. Accessed February 26, 2016.
7. Lorch S, D'Agostino J, Zimmerman R, Bernbaum J. 'Benign' extra-axial fluid in survivors of neonatal intensive care. Archives Of Pediatrics & Adolescent Medicine [serial online]. February 2004;158(2):178-182 5p. Available from: CINAHL Complete, Ipswich, MA. Accessed February 26, 2016.
8. Maytal J, Alvarez L, Elkin C, Shinnar S. External hydrocephalus: radiologic spectrum and differentiation from cerebral atrophy. AJR. American Journal Of Roentgenology [serial online]. June 1987;148(6):1223-1230. Available from: MEDLINE, Ipswich, MA. Accessed February 26, 2016.