Conceptually, brain microbleeds can be thought as very tiny amounts of blood (less than a drop) getting out of brain small vessels. The small vessel diseases that result in microbleeds also cause larger brain bleeds. In that sense, even if the microbleeds are silent, they are markers of higher bleeding risk in both asymptomatic individuals and cerebral hemorrhage survivors. There is no specific treatment for microbleeds, the aim is to prevent the progression of the underlying small vessel disease (hypertension or cerebral amyloid angiopathy) and most importantly to adjust medical treatment to prevent potentially fatal hemorrhagic strokes.
Large scale studies show that about one fifth of otherwise healthy population over 45 years of age have at least one brain microbleed. They are commonly seen on MRIs obtained for unrelated complaints. Brain microbleeds are particularly important when found in patients who need strong blood thinner medications (anticoagulants) for common conditions such as atrial fibrillation as anticoagulants increase the risk of potentially fatal brain bleeds. In such a situation, it is a good approach to consider risks/benefits of anticoagulants for the individual patient and alternatives to life-long anticoagulation if possible (see Atrial Fibrillation part of this website as an example).
Overall, it is important to obtain and carefully review the MRI sequences that show chronic blood products (called GRE or SWI) in every patient who undergo MRI study. If microbleeds or superficial siderosis is found, referral to an expert can improve management by decreasing bleeding risks.