THE IMPACT OF SECONDARY CARNITINE DEFICIENCY ON
SKELETAL MUSCLES IN CHILDREN UNDER VALPROATE THERAPY
M. EL-Ayouty1, A. Shaltout1,
A. Ghanem2, M. Abd El-Latef3, M. Shokeir1,
M. EL-Haggar1
Mansoura University, Mansoura, Egypt
To study the
effect of secondary carnitine deficiency on skeletal muscles in epileptic patients under valproic
acid (VPA) therapy, we have investigated 20 patients (10 males, 10 females
with their ages ranged from 6-15 ys.) for plasma free carnitine (PFC)
concentrations, plasma VPA levels, electromyographic studies and
microscopic examination of open biopsies of skeletal muscles. Ten healthy
controls of matched age and sex were tested for PFC and electromyographic
recording.
Sixteen out
of the 20 patients (80%) have chronic fatigue syndrome and eleven of them
have definite myopathic changes. PFC level was signifcantly lower in
myopathic patients when compared with nonmyopathic (P<0.0001) and control (P<0.0001) groups. PFC
level was significantly lower in patients with fatigue (P=0.005). The level
of PFC was significantly correlated negatively with the duration of VAP
therapy (P<0.001), at the meanwhile
, fatigue and myopathic changes were highly frequent in patients with long
duration of VAPtherapy (P<0.05 & P<0.001). Serum VAP level
was significantly higher in myopathic patients (P=0.009). EMG showed no
significant difference between patients and control (P>0.05).
In
conclusion, VPA therapy is associated with secondary carnitine deficiency
which may lead to myopathic changes in the skeletal muscles especially on
long-term therapy. So patients recieving VPA therapy are in need of regular
evaluation for PFC and serum VPA levels and for development of fatigue as
they may benfit from carnitine supplementaion, otherwise, change of anticonvulsant
may be mandatory.