A post-operative patient with abdominal distension and absent bowel sounds most likely has paralytic ileus, a functional obstruction caused by temporary bowel motility paralysis after surgery. Unlike mechanical obstruction, there is no physical blockage but rather a cessation of peristalsis, leading to accumulation of gas and fluids. Paralytic ileus commonly presents with diffuse abdominal distension, absent bowel sounds, and minimal localized tenderness. Early recognition is crucial to avoid unnecessary interventions. It is typically managed conservatively with supportive care, such as fluid management and correction of electrolytes.

Reference: Schwartz's Principles of Surgery, Brunicardi et al., 11th Edition.