Antiepileptic drug for chronic subdural hematoma
Larger postoperative depressed brain volume was the only factor independently associated with suspected postoperative seizure, and it could help identify a subgroup of patients with higher susceptibility to epileptic events. Based on our data, no formal recommendation can be made regarding the prophylactic use of anti-epileptic drugs. Nevertheless, the relative safety of new generation antiepileptic drugs and the detrimental effect of postoperative seizure on outcome may justify its use in a selected patient population. 1).
The incidence of postoperative seizures in patients with CSDH evacuated via burr holes was low. Prophylactic AEDs should not be routinely administered if no other risk factor for seizure exists. Demographic and clinical factors did not appear to influence post-operative seizures 2).
Chen et al. tried to correlate the pre-operative computed tomographic (CT) appearance of the CSDH with the need for post-operative seizure prophylaxis. From April 1998 to November 2001, 128 cases of CSDH surgically treated at our hospital were studied. All patients underwent burr-hole craniotomy with closed system drainage. All CSDHs were classified as low-density, isodense, and mixed-density lesions according to CT findings. The incidence of early post-operative seizures (within 3 weeks of surgery) among all patients was 5.4% (7/128). In the subgroups by lesion density, the incidences were 6.2% (1/16) in the low-density group, 2.4% (2/83) in the isodense group, and 13.7% (4/29) in the mixed-density group (all p < 0.05). The mean age among the seven patients (five males and two females) who had seizures was 71 years. The locations of the CSDHs among the 128 patients were the left side of the brain in 53 (41.4%) patients, the right side in 45 (35.2%), and bilateral in 30 (23.4%) patients. Among the seven patients who suffered from post-operative seizures, five (71.4%) had left-side CSDHs, one (14.2%) had right-side CSDH, and one (14.2%) had bilateral CSDHs. They concluded that the post-operative seizure rate appeared high in the group with mixed-density type lesions on CT and in those with left unilateral CSDH. They suggest the use of prophylactic anticonvulsants for patients with mixed-density lesions on pre-operative CT 3)
A total of 129 patients treated for chronic subdural haematoma were studied retrospectively to evaluate the incidence of seizures. None of 73 patients who were given prophylactic antiepileptic drug treatment developed seizures. Only two of 56 patients not given prophylaxis, developed early postoperative seizures. In these two, surgical technique was thought to be responsible. One patient developed complex partial seizures preoperatively. The incidence of seizures was therefore low, and similar to that previously reported for minor head injury. This study suggests that routine use of antiepileptic prophylaxis is not justified in patients with chronic subdural haematoma caused by minor head injuries, or other causes when there are no additional lesions present on CT scans 4).
Case reports
A case of fatal status epilepticus with progressive respiratory complication following early discontinuation of prophylactic antiepileptic drug in an 84-year-old man who had undergone bilateral BHT and closed-system drainage for bilateral CSDH. Although the efficacy of the prophylactic anticonvulsants in BHT for CSDH has been controversial, the development of status epilepticus postoperatively seems to be strongly associated with an increased mortality rate in aged patients. Therefore, prophylactic anticonvulsants should be administrated in aged patients who undergo surgery for CSDH, until a definitive clinical treatment guideline is suggested 5).