Age of meningitis or encephalitis is independently predictive of outcome from anterior temporal lobectomy.

BACKGROUND

The occurrence of meningitis or encephalitis in early childhood, i.e., < or =4 years of age, may be associated with both the development of medial temporal lobe epilepsy (MTLE) and an excellent operative outcome following an anterior temporal lobectomy (ATL). However, whether the predictive value of this risk factor for partial epilepsy is independent of the finding of mesial temporal sclerosis (MTS) on MRI is not known.

METHODS

Consecutive patients (n = 39) with a remote history of meningitis or encephalitis who underwent an ATL were compared with 78 sex- and age-matched control subjects who had not experienced a CNS infection before ATL. All patients in both groups had nonlesional temporal lobe epilepsy and were followed up for at least 12 months postoperatively.

RESULTS

There was a trend for the patients with a history of meningitis or encephalitis to have a lower frequency of class I postoperative outcome (61.5% vs 73.1%, p = 0.21). In the meningitis or encephalitis group, a class I outcome was more frequent in those with a history of meningitis or encephalitis at a young age (<4 years) (19/23 vs 5/16, p = 0.002), those with MTS detected on a preoperative MRI (22/31 vs 2/8, p = 0.04), and those with a history of meningitis (16/21 vs 8/18, p = 0.05). Multivariate logistic regression analysis found that a history of meningitis or encephalitis at a young age (b = 2.0, O.R. = 7.5, p = 0.048) was predictive of a class I outcome independent of the presence of MRI-identified MTS (b = 2.0, O.R. = 7.3, p = 0.07).

CONCLUSION

The age of occurrence of a remote history of meningitis or encephalitis, but not the type of infection, is predictive of outcome after an ATL independent of the finding of MTS on the preoperative MRI.