Cerebral microhemorrhage
Updates to Article Attributes
Cerebral microhaemorrhages, or cerebral microbleeds,are small focal intracerebral haemorrhages, often only visible on susceptibility-sensitive MRI sequences.
Pathology
Common aetiologies
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especially Zabramski classification type IV malformations
causes include multiple (familial) cavernous malformation syndrome and post-cerebral radiotherapy
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cerebral amyloid angiopathy 1,8
typically involves the grey-white matter junction; usually spares the basal ganglia
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chronic hypertensive encephalopathy 1,8
typically involve the basal ganglia, thalami, brainstem, cerebellum and corona radiata
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diffuse axonal injury (DAI) and other trauma 1,8
typically involves the grey-white matter junction, splenium of the corpus callosum, and dorsolateral brainstem
Less common aetiologies
cathepsin A-related arteriopathy with strokes and leukoencephalopathy (CARASAL) 29,30
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cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) 1,8
microhaemorrhages have been reported to occur in 25–70% of cases without a characteristic distribution
cardiac bypass for surgery 15,31
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cerebral vasculitis (primary or secondary) 1,8
microhaemorrhages usually located at the corticomedullary junction
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COL4A1 brain small-vessel disease 5,8
microhaemorrhages have been reported in up to 53% of cases, characteristically in the centrum semiovale, deep gray matter, or brainstem 5,8
Fabry disease35,36
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haemorrhagic micrometastases 1,8
especially melanoma or renal cell carcinoma
hypoxia and/or being critically ill (e.g. acute respiratory distress syndrome, high-altitude exposure, COVID-19) 8-10
immune effector cell-associated neurotoxicity syndrome (ICANS) 32
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intracranial embolism
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usually from fractures 4,8,14
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gas embolism 6,7
many causes including: intravenous catheter placement, decompression sickness, extracorporeal membrane oxygenation, hydrogen peroxide ingestion, etc.
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septic embolism
usually from infective endocarditis 3,8
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intracranial infection (e.g. cerebral malaria, mycotic aneurysm) 8
moyamoya disease and moyamoya syndrome 22,23
neurosarcoidosis 12,13
pontine autosomal dominant microangiopathy with leukoencephalopathy (PADMAL) 27,28
retinal vasculopathy with cerebral leukoencephalopathy and systemic manifestations (RVCL-S) 33,34
Sneddon syndrome 18,19
thrombotic microangiopathies (e.g. haemolytic uraemic syndrome (HUS) and thrombotic thrombocytopenic purpura (TTP)) 8
Radiographic features
MRI
Cerebral microhaemorrhages are only seen on MRI and are only seen on susceptibility weighted T2* sequences such as gradient-recalled echo (GRE) and susceptibility weighted imaging (SWI) 24.
They appear as conspicuous 2-10 mm punctate regions of signal drop out with blooming artifact 24. This blooming grossly overestimates the size of the lesions, thus they are usually inapparent on other MRI sequences and CT 24.
Differential diagnosis
artificial heart valve metallic emboli (very rare) 8
punctate regions of signal loss in chronic lymphocytic inflammation with pontine perivascular enhancement responsive to steroids (CLIPPERS) 26
pneumocephalus (very rare without preceding surgery) 2
- +<li><p><a href="/articles/fabry-disease" title="Fabry disease">Fabry disease</a> <sup>35,36</sup></p></li>
References changed:
- 35. Kono Y, Wakabayashi T, Kobayashi M et al. Characteristics of Cerebral Microbleeds in Patients with Fabry Disease. J Stroke Cerebrovasc Dis. 2016;25(6):1320-5. <a href="https://doi.org/10.1016/j.jstrokecerebrovasdis.2016.02.019">doi:10.1016/j.jstrokecerebrovasdis.2016.02.019</a> - <a href="https://www.ncbi.nlm.nih.gov/pubmed/26987491">Pubmed</a>
- 36. Cocozza S, Russo C, Pontillo G, Pisani A, Brunetti A. Neuroimaging in Fabry Disease: Current Knowledge and Future Directions. Insights Imaging. 2018;9(6):1077-88. <a href="https://doi.org/10.1007/s13244-018-0664-8">doi:10.1007/s13244-018-0664-8</a> - <a href="https://www.ncbi.nlm.nih.gov/pubmed/30390274">Pubmed</a>
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