INTRACEREBRAL HEMORRHAGE
Cerebral microbleeds
Created 15/04/2021, last revision 21/01/2023
Definition
- cerebral microbleeds (CMBs) – hemosiderin deposits inflicted by small hemorrhages, may serve as a radiologic biomarker of small vessel diseases (SVD)
- black, round, or oval lesions on blood-sensitive MRI sequences – (T2*/GRE or SWI)
- 2-5 mm in diameter (up to 10 mm is acceptable)
- black, round, or oval lesions on blood-sensitive MRI sequences – (T2*/GRE or SWI)
- often found incidentally on MRI scans; incidence increases with age
- incidence in the general population is around 11-15% (Sveinbjornsdottir, 2008)
- 6.5% in persons aged 45-50 years
- up to 40% in the population > 80 years [Poels, 2009]
- incidence in AD 20-43%, in vascular dementia in up to 85%! [Seo, 2007]
- microhemorrhages are associated with:
- older age
- hypertension
- smoking
- white matter disease and lacunar stroke
- previous ischemic stroke or ICH
- COVID-19 leukoencephalopathy (mostly in critically ill patients) (Agarwal, 2020)
- a high microbleed count is associated with an increased risk of:
- cognitive impairment, which may progress to dementia (Werring, 2004) [Akoudad, 2006]
- intracerebral hemorrhage (especially with antithrombotic or fibrinolytic therapy)
- higher risk of progression:
- in severe SVD (Subcortical Vascular Disease or Small Vessel Disease)
- in CAA with APOE ε2 and ε4 [McCarron, 2000]
Classification
- subcortical (mainly caused by arteriolopathy) → Binswanger´s disease
- cortical (mostly caused by CAA – posing a higher risk of lobar hemorrhage)
- combined (combination of CAA and arteriolosclerosis or rather arteriolosclerosis only) [Jung, 2020]
Differential diagnosis
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Management
- no specific therapy
- strict treatment of hypertension
- careful indication and monitoring of anticoagulant (preferably DOAC) and antiplatelet therapy (avoid DAPT if possible)
CMBs and the risk of a hemorrhage
- the risk of ICH increases with the number of CMBs
- ≥ 5 CMBs – OR for ICH is 2.8
- ≥ 10 CMBs – OR for ICH is 5.5!
- according to the CROMIS-2 trial, the risk of bleeding in patients with CMBs is 9.8/1000 vs. 2.6/1000 patient-years (adjusted hazard ratio 3·67, 95% CI 1·27–10·60) [Wilson, 2018]
- the incidence of ICH is up to 5%/year in multiple lobar CMBs [Van Etten, 2014]