Deep versus Superficial Spontaneous Cerebellar Hemorrhages: Separated Vascular Etiologies with Different Clinical Consequences

Background: Spontaneous cerebellar hemorrhage (CH) is a critical neurosurgical event. It is usually categorized as a homogenous group under the general term of deep/nonlobar intracerebral hemorrhage. However, increasing evidence suggests it is composed of 2 subgroups, separated from each other by their anatomic location (deep vs. superficial), as well as by their vascular etiology (small vessel disease vs. cerebral amyloid angiopathy). Objective: To identify any clinically significant differences between anatomically separated subgroups of CHs: deep versus superficial. Methods: This is a retrospective study on patients who were diagnosed with spontaneous CHs at a single tertiary center. On the basis of the radiologic location of the hematoma, patients were divided into 2 groups: deep (group 1) and superficial (group 2). Computerized medical records were extracted for multiple variables. Results: A total of 69 patients fulfilled the inclusion criteria. Fifty-three (77%) were in group 1, and 16 (23%) were in group 2. Having any vascular risk factor was associated with the highest odds ratio for having a deep CH. Morbid obesity (body mass index ≥30) and the use of antiplatelets were also associated with increased odds ratios. Group 1 is also associated with high prevalence of intraventricular hemorrhage, acute hydrocephalus, and less favorable outcome. Conclusions: This study supports the notion that CH is most likely a heterogenous condition, composed of 2 subgroups, separated from each other in terms of anatomic location, vascular etiologies, and clinical consequences. Further studies on large cohort of patients are needed in order to accurately define the subgroups of this life-threatening event.