Results. We analyzed the light curves of 1670 stars with 242 epochs in the crowded central region of Terzan 5 in order to statistically detect variable stars in the field observed. We present a possible visual counterpart outburst at the position of the pulsar J1748-2446N, and the visual counterpart light curve of the low-mass X-ray binary CX 3. Additionally, we present the discovery of four semiregular variables. We also present updated ephemerides and properties of the only RR Lyrae star previously known in the field covered by our observations in Terzan 5. Finally, we report a significant displacement of two sources by similar to 0.62 and 0.59 arcsec with respect to their positions in previous images available in the literature.