Can Arteriovenous Malformations (AVMs) in the brain develop later in age?

Brain Arteriovenous Malformations (AVMs) Development in Later Age

While brain arteriovenous malformations (AVMs) are generally considered congenital lesions, they can become symptomatic or be detected later in life, though they likely formed during embryonic development rather than developing de novo in adulthood. 1

Epidemiology and Natural History

• An estimated 20% of cerebral AVMs are diagnosed during infancy and childhood, with the remainder being detected in adulthood 1
• The annual AVM detection rate across all ages is approximately 1.34 per 100,000 person-years 1
• First-time AVM-related hemorrhage incidence is 0.51 per 100,000 person-years 1
• The annual risk of hemorrhage for previously unruptured AVMs is approximately 2-3% per year 1

Age-Related Presentation Patterns

• AVMs can remain clinically silent for decades before becoming symptomatic 1
• The most common initial presentation of AVMs across all age groups is hemorrhage (50-60% of cases) 1
• Presentation patterns differ by age group:
  • Children often present with hemorrhage (>75% of symptomatic pediatric cases) 1, 2
  • Adults commonly present with seizures (20-25% of cases) or headaches (15% of cases) 1
  • Elderly patients show less frequent epileptic presentation and more frequent infratentorial lesions 3

Why AVMs Appear to "Develop" Later in Life

• AVMs are generally believed to be congenital lesions that form during embryonic development 4
• Several factors contribute to their apparent "development" or detection later in life:
  • Growth and structural changes of existing AVMs over time 5
  • Hormonal changes (particularly during puberty or pregnancy) may influence AVM growth or rupture risk 6, 2
  • Improved imaging technology leading to incidental discovery during workups for unrelated conditions 5
  • Progressive hemodynamic changes that eventually lead to symptoms 1

Risk Factors for Hemorrhage

• Prior hemorrhage is a strong predictor of future hemorrhage 1
• Small AVM size may paradoxically be associated with higher hemorrhage risk 1, 6
• The presence of intranidal aneurysms increases hemorrhage risk 6
• Deep venous drainage patterns may increase risk 6, 5
• The lifetime risk of hemorrhage can be approximated by: Lifetime risk (%) = 105 - (patient's age in years) 1

Clinical Implications

• The risk of recurrent hemorrhage is elevated in the first year after initial hemorrhage (6-32.9% depending on the study) 1
• Mortality from first hemorrhage ranges between 10-30%, with 10-20% of survivors experiencing long-term disability 1
• Comprehensive evaluation requires both MRI and cerebral angiography to properly delineate AVM anatomy 6
• Treatment decisions should weigh the natural history risk against intervention-related morbidity and mortality 1, 6

Management Considerations

• Treatment options include surgical excision, endovascular embolization, or stereotactic radiosurgery 6, 2
• The Spetzler-Martin grading system helps estimate surgical risks based on size, location, and venous drainage patterns 6
• In elderly patients, surgery may be acceptable for grade I and II AVMs, while benefits for grade III AVMs are less clear 3
• Regular monitoring is essential for stable AVMs to detect any changes in size or characteristics 6

Key Takeaway

While AVMs are believed to be congenital in origin, they can remain clinically silent for decades before manifesting symptoms or being incidentally discovered. Their apparent "development" later in life typically represents growth or changes in existing malformations rather than de novo formation in adulthood.