A sheath assembly for an endoscope includes an elongate tubular body and a plug. The endoscope has a handle portion and a scope portion extending therefrom to a tip. The body includes first and second wall sections and extends along a longitudinal axis between first and second distal openings located at distal and proximal ends thereof, respectively. The first wall section extends radially about the longitudinal axis to define a scope lumen. The scope portion is receivable in the scope lumen with the distal and proximal ends. The second wall section extends radially about a portion of the first wall section and longitudinally between second distal and proximal end openings. The first and second wall sections define an integral suction lumen in fluid communication with a first source of negative pressure. The plug is mated with the distal end opening and includes a lens surface through which energy is transmissible.