Rehabilitation outcomes in encephalitis--a retrospective study 1990-1997

Encephalitis is an uncommon clinical entity compared to traumatic brain injury, and stroke. Many encephalitis survivors have disabling sequelae. There is scant information in the literature addressing outcome following inpatient rehabilitation for encephalitis. Further, it is unclear which of these patients will benefit from acute in-patient rehabilitation.

The purposes of this study are to (1) describe the outcome following in-patient rehabilitation in a cohort of patients with encephalitis, and (2) develop preliminary criteria to guide the selection of patients with encephalitis who may benefit from inpatient rehabilitation.

The demographic, clinical, functional (functional independence measure-FIM) and neuro-psychological data were retrospectively abstracted for eight subjects with a clinical diagnosis of encephalitis aged 5 to 75 years, who were admitted to a brain injury rehabilitation unit between 1990 and 1997.

In the eight subjects, the mean age was 38 years, mean acute hospital stay (ALOS) was 40.3 days, and mean rehabilitation length of stay (RLOS) was 75.9 days. Mean admission FIM (AFIM) was 40.1, mean discharge FIM (DFIM) was 69.9. Mean FIM gain was 29.8 and mean FIM efficiency was 0.39. Adult subjects with an AFIM > 30 at 5 weeks from onset of illness (n = 4) had a FIM LOS efficiency of 0.64 and all four were discharged home. None of the adult subjects with an AFIM < 30 at 5 weeks from onset of illness (n = 3, FIM efficiency = 0.14) were discharged home. A child with an AFIM < 30 (n = 1) had a FIM LOS efficiency of 1.24, made good recovery and was discharged home. FIM LOS efficiency of 0.64 in encephalitis is less, as compared to traumatic brain injury (TBI -1.27) and stroke (1.06).

The results of this study showed that, although subjects with encephalitis make functional gains in rehabilitation, the rate of recovery varies and is generally less than that for TBI and stroke. The study also suggests that FIM scores can be used for screening adult patients after encephalitis for admission to inpatient rehabilitation. Adult patients with an AFIM > 30, 5 weeks post onset of illness are likely to make reasonable progress and be discharged home. If replicated, these results suggest that despite low AFIM scores at 5 weeks from onset of illness (AFIM < 30), children may still make good progress and should be given a trial of in-patient rehabilitation.