Intracerebral hemorrhage (ICH) is uncommon in young adults (age < 50 years) but is more likely to be associated with specific underlying vascular abnormalities than in older patients. Given this, diagnostic evaluation is often more involved and complex.
Acute medical management is broadly similar to that in older patients. Careful monitoring is critical due to the high risk of clinical deterioration. Aggressive blood pressure lowering may limit hemorrhage expansion. While there is very limited data for specific blood pressure targets in younger patients, considering premorbid blood pressure when determining the target is likely sensible, with more aggressive lowering in previously normotensive patients.
Given the higher prevalence of structural vascular abnormalities in younger patients, immediate vessel imaging is appropriate for almost all patients. Computed tomography angiography (CTA) can be obtained rapidly and is probably more sensitive than magnetic resonance angiography for identifying small vascular malformations. If the clinical scenario or hemorrhage pattern is concerning for cerebral venous sinus thrombosis, venous imaging should be obtained acutely. Lobar hemorrhage with associated edema or venous infarction should raise the suspicion for sagittal sinus or cortical vein thrombosis; bilateral thalamic hemorrhage should raise suspicion for straight sinus thrombosis. Testing for coagulopathy and a toxicology screen should be sent. While stimulants (e.g., cocaine, amphetamine) are associated with ICH in the young, a positive toxicology result should not prevent further diagnostic testing as vascular malformations often coexist in these patients.
Specific features of the medical history and clinical presentation may suggest an underlying mechanism for the ICH and help target diagnostic testing.
If vascular imaging does not reveal a clear etiology, perform brain magnetic resonance imaging (MRI) brain with contrast, being sure to include susceptibility-weighted or gradient-echo sequences to detect areas of chronic hemorrhage. Cerebral cavernous malformations are angiographically occult and thus best seen on MRI. While hypertension is a much less frequent cause of ICH in the young than in older patients, it still accounts for many cases. Severe microvascular disease with multiple microhemorrhages on MRI supports this as a cause. Evidence of contrast enhancement may suggest hemorrhage into tumor.
Noninvasive imaging studies such as CTA are less sensitive than catheter angiography for identifying some important causes of ICH in the young, including reversible cerebral vasoconstriction syndrome (RCVS), dural arteriovenous fistulas, and small arteriovenous malformations. If ICH is unexplained after noninvasive imaging, catheter angiography should be pursued.
Up to 25% of patients with RCVS will have a normal catheter angiogram early in their clinical course, with abnormalities becoming apparent on repeat angiogram several days to a week later. Therefore, if there is strong clinical suspicion for RCVS (i.e., recurrent thunderclap headaches, associated convexity subarachnoid hemorrhage), early repeat angiography should be done. Note also that concurrent arterial dissections can be seen with RCVS and may be an important clue to this diagnosis.
If initial evaluation is unrevealing, MRI brain with contrast should be repeated 4–8 weeks later. This time allows for resolution of the hematoma and associated edema, which may mask underlying pathology. If this study is unrevealing, consider repeat catheter angiography. Small arteriovenous malformations may initially be compressed by the acute hematoma and may only become apparent on follow-up angiography.