Intracerebral Hemorrhage in a Young Urban Population: Etiologies and Outcomes in Patients 50 and Younger

Altered fibrin clot phenotype in young adults with intracerebral hemorrhage of unknown cause: A case-control study

BACKGROUND

Intracerebral hemorrhage (ICH) of undetermined etiology occurs infrequently in young and middle-aged adults. We hypothesized that slight decreases in coagulation factors and formation of less compact fibrin clots prone to faster lysis predispose to this type of ICH.

METHODS

We recruited 44 consecutive patients aged <50 years following ICH of unknown cause at least 3 months since the event. Subjects free of ICH (n = 47) matched for age, sex, BMI, and hypertension served as the control group. We assessed plasma fibrin clot permeability, turbidity and fibrinolytic capacity, along with thrombin generation, coagulation factors (F) II, FV, FVII, FVIII, FIX, FX, FXI, antithrombin, and fibrinolysis proteins.

RESULTS

ICH patients (median age 41 years, 45.5 % women) had 8.4 % lower FII (p = 0.0001) and 10.1 % lower FVII activity (p = 0.0003), 9.4 % higher antithrombin activity (p = 0.0004) and 13.5 % lower platelet count (p = 0.02). Other factors and thrombin generation did not differ between the two groups. The ICH survivors were characterized by impaired fibrin polymerization reflected by 10.1 % longer lag phase of the turbidimetry curve (p = 0.0002), decreased fiber density indicated by 11.8 % lower maximum absorbance (p = 0.004), as well as 11.1 % shorter clot lysis time (p = 0.014) and 10.0 % faster increase of maximal D-Dimer levels (p = 0.000001).

CONCLUSIONS

We demonstrated a prohemorrhagic fibrin clot phenotype, along with lower FII, FVII and higher antithrombin activity in adults below 50 years of age who suffered from ICH of unknown cause, which might indicate novel mechanisms contributing to ICH in younger individuals.

Prevalence, Characteristics, and Outcomes of Undetermined Intracerebral Hemorrhage: A Systematic Review and Meta-Analysis

BACKGROUND AND PURPOSE

There are scarce data regarding the prevalence, characteristics and outcomes of intracerebral hemorrhage (ICH) of undetermined (unknown or cryptogenic) etiology. We sought to determine the prevalence, radiological characteristics, and clinical outcomes of undetermined ICH.

METHODS

Systematic review and meta-analysis of studies involving patients with spontaneous ICH was conducted to primarily assess the prevalence and clinical-radiological characteristics of undetermined ICH. Additionally, we assessed the rates for ICH secondary to hypertensive arteriopathy and cerebral amyloid angiopathy. Subgroup analyses were performed based on the use of (1) etiology-oriented ICH classification, (2) detailed neuroimaging, and (3) Boston criteria among patients with cerebral amyloid angiopathy related ICH. We pooled the prevalence rates using random-effects models, and assessed the heterogeneity using Cochran Q and I² statistics.

RESULTS

We identified 24 studies comprising 15 828 spontaneous ICH patients (mean age, 64.8 years; men, 60.8%). The pooled prevalences of hypertensive arteriopathy ICH, undetermined ICH, and cerebral amyloid angiopathy ICH were 50% (95% CI, 43%-58%), 18% (95% CI, 13%-23%), and 12% (95% CI, 7%-17% [P<0.001 between subgroups]). The volume of ICH was the largest in cerebral amyloid angiopathy ICH (24.7 [95% CI, 19.7-29.8] mL), followed by hypertensive arteriopathy ICH (16.2 [95% CI, 10.9-21.5] mL) and undetermined ICH (15.4 [95% CI, 6.2-24.5] mL). Among patients with undetermined ICH, the rates of short-term mortality (within 3 months) and concomitant intraventricular hemorrhage were 33% (95% CI, 25%-42%) and 38% (95% CI, 28%-48%), respectively. Subgroup analysis demonstrated a higher rate of undetermined ICH among studies that did not use an etiology-oriented classification (22% [95% CI, 15%-29%]). No difference was observed between studies based on the completion of detailed neuroimaging to assess the rates of undetermined ICH (P=0.62).

CONCLUSIONS

The etiology of spontaneous ICH remains unknown or cryptogenic among 1 in 7 patients in studies using etiology-oriented classification and among 1 in 4 patients in studies that avoid using etiology-oriented classification. The short-term mortality in undetermined ICH is high despite the relatively small ICH volume.