Slippery platelet syndromes in subdural hematoma.

BACKGROUND: This study investigates platelet dysfunction in patients with subdural hematomas (SDH) using platelet function analysis (PFA).
METHODS: PFA using the PFA-100 (Dade International Inc., Miami, FL) was performed at admission using the collagen-epinephrine and collagen-ADP assays in 58 SDH patients. Clinical and radiologic information was collected.
RESULTS: Normal PFA results were present in 36 patients (62%; PFA collagen:epinephrine assay (s) 118 ave; PFA collagen:adenosine diphosphate assay (s) ave 75) and abnormal platelet function in 22 patients (38%; PFA collagen:epinephrine assay (s) 231 average; PFA collagen:adenosine diphosphate assay (s) 124 average). Compared to patients with normal PFA results, patients with abnormal PFA results were more likely to have hypertension (22 vs. 55%; P = 0.01), take clopidogrel (3 vs. 32%; P = 0.001), and use anti-platelet medications and non-steroidal anti-inflammatory agents (22 vs. 59%; P = 0.004). Measurements of baseline CT for midline shift, maximum thickness, presence of blood/fluid levels in the hematoma, and presence of additional sites of intracranial bleeding did not reveal significant differences based on PFA testing. Platelet dysfunction improved after platelet transfusions (PFA collagen:epinephrine assay: baseline 270 s, CI 61 s; after transfusion 124 s, CI 50 s, P < 0.001).
CONCLUSION: Platelet dysfunction was found in 38% of SDH patients. This finding adds to our understanding of the pathophysiology of SDH. Since platelet transfusions are indicated for platelet dysfunction accompanied by major bleeding or need for surgery, these results impact peri-operative management.