INTRACEREBRAL HEMORRHAGE
Cerebral microbleeds
Created 15/04/2021, last revision 25/05/2023
Definition
- cerebral microbleeds (CMBs) – hemosiderin deposits caused by small hemorrhages, may serve as a radiologic biomarker of small vessel disease (SVD)
- black, round, or oval lesions on blood-sensitive MRI sequences – (T2*/GRE or SWI)
- 2-5 mm in diameter
- 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 approx. 10-15% (Sveinbjornsdottir, 2008)
- 6.5% in the individuals aged 45-50 years
- up to 40% in the population > 80 years [Poels, 2009]
- incidence of CMBs in AD is 20-43%; in vascular dementia 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 number of microbleeds 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 with:
- severe SVD (Subcortical Vascular Disease or Small Vessel Disease)
- CAA with APOE ε2 and ε4 [McCarron, 2000]
Classification
- subcortical (mainly caused by arteriolopathy) → Binswanger´s disease
- cortical (mostly caused by CAA – with a higher risk of lobar hemorrhage)
- combined (combination of CAA and arteriolosclerosis or rather arteriolosclerosis alone) [Jung, 2020]
Differential diagnosis
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Management
- no specific therapy
- strict treatment of hypertension
- careful indication and monitoring of anticoagulant (preferably use DOACs) 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]
- the risk of symptomatic intracranial hemorrhage (sICH) may be increased after thrombolytic therapy in patients with cerebral microbleeds (CMBs)
- CMBs < 10 ⇒ IVT seems safe (ESO 2021) (AHA/ASA 2019 IIa/B-NR)
- CMBs > 10 ⇒ IVT has a higher risk of ICH; the expected benefit of treatment must outweigh the risk – consider IVT in patients with a severe stroke (AHA/ASA 2019 IIb/B-NR)
- the smaller study retrospectively found a slightly increased risk (3%) of bleeding in patients with microbleeds on GRE [Fiehler, 2007]
- increased risk is associated with CAA as a cause of microbleeds
- no MRI screening is recommended to assess CMB burden before making a treatment decision regarding IVT (ESO 2021)
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- single antiplatelet therapy is a safe and beneficial approach, even in the presence of cerebral microbleeds (RESTART trial subanalysis) [Salman, 2019]