A simple theoretical scheme based on a perturbative density functional approach using an approximate three-particle correlation function in conjunction with a sum rule relating the bulk pressure with the free energy functional of an inhomogeneous system has been proposed to study the structure of a model colloidal suspension (with screened Coulomb interaction) confined in a charged cylindrical pore. The calculated density profiles for the confined colloidal suspension for different values of the wall charges are shown to compare well with the available computer simulation results. The importance of the third order term has been demonstrated through the significantly better agreement of the present results as compared to those based on second order perturbative approach. The relative contribution of the third order term, however, is shown to depend on the screening parameter and hence the salt concentration in the suspension. The effect of the diameters of the cylindrical pores on the density profiles is also investigated.