Risk Factors of Chronic Subdural Hematoma Progression after Conservative Management of Cases with Initially Acute Subdural Hematoma

OBJECTIVE: Acute subdural hematoma (ASDH) patients are treated conservatively or surgically according to the guidelines for surgical treatment. Many patients with thin ASDH and mild neurologic deficit are managed conservatively, but sometimes aggravation of thin ASDH to chronic subdural hematoma (CSDH) results in exacerbated clinical symtoms and consequently requires surgery. The aim of this study is to evaluate risk factors that indicate progression of initially non-operated ASDH to CSDH. METHODS: We divided 177 patients, presenting with ASDH (managed conservatively initially) between January 2008 to December 2013, into two groups; 'CSDH progression group' (n=16) and 'non-CSDH progression group' (n=161). Patient's data including age, sex, past medical history, medication were collected and brain computed tomography was used for radiologic analysis. RESULTS: Our data demonstrated that no significant intergroup difference with respect to age, sex ratio, co-morbid conditions, medication history, ischemic heart disease, liver disease and end-stage renal disease was found. However, Hounsfield unit (hematoma density) and mixed density was higher in the 'ASDH progression group' (67.50±7.63) than in the 'non-CSDH progression group' (61.53±10.69) (p=0.031). Midline shifting and hematoma depth in the 'CSDH progression group' were significantly greater than the 'non-CSDH progression group' (p=0.067, p=0.005). CONCLUSION: Based on the results of this study, the risk factors that are related to progression of initially non-operated ASDH to CSDH are higher Hounsfield unit and hematoma depth. Therefore, we suggest that ASDH patients, who have bigger hematoma depth and higher Hounsfield unit, should be monitored and managed carefully during the follow-up period.