A multi-stage pump comprising: a first set of pump stages directing fluid in a first direction (D1) from a first end of the multi-stage pump to a diffuser casing disposed at a central portion of the multi-stage pump ; a second set of pump stages directing the fluid expelled from the diffuser casing in a second direction (D2), opposite to the first direction (D1), from a second end of the multi-stage pump to the diffuser casing ; and the diffuser casing comprising: a first inlet that receives the fluid directed from the first set of pump stages , a first outlet that expels the fluid received by the first inlet toward the second end (1 10b) of the multi-stage pump , a second inlet that receives the fluid directed from the second set of pump stages , and a second outlet that directs the fluid to a chamber within the diffuser casing , wherein the diffuser casing receives the fluid from the first set of pump stages and directs the fluid toward the second end of the multi-stage pump and receives the fluid from the second set of pump stages within a chamber and directs the fluid in a radially outward direction (R) with respect to a first longitudinal axis (L 1 ) of the multi-stage pump , the diffuser casing further comprising a first vane disposed in a first internal passage extending from the first inlet to the first outlet , characterized in that the diffuser casing further comprises a second vane disposed in a second internal passage extending from the second inlet towards the chamber within the diffuser casing . a first set of pump stages directing fluid in a first direction (D1) from a first end of the multi-stage pump to a diffuser casing disposed at a central portion of the multi-stage pump ; a second set of pump stages directing the fluid expelled from the diffuser casing in a second direction (D2), opposite to the first direction (D1), from a second end of the multi-stage pump to the diffuser casing ; and the diffuser casing comprising: a first inlet that receives the fluid directed from the first set of pump stages , a first outlet that expels the fluid received by the first inlet toward the second end (1 10b) of the multi-stage pump , a second inlet that receives the fluid directed from the second set of pump stages , and a second outlet that directs the fluid to a chamber within the diffuser casing , a first inlet that receives the fluid directed from the first set of pump stages , a first outlet that expels the fluid received by the first inlet toward the second end (1 10b) of the multi-stage pump , a second inlet that receives the fluid directed from the second set of pump stages , and a second outlet that directs the fluid to a chamber within the diffuser casing , wherein the diffuser casing receives the fluid from the first set of pump stages and directs the fluid toward the second end of the multi-stage pump and receives the fluid from the second set of pump stages within a chamber and directs the fluid in a radially outward direction (R) with respect to a first longitudinal axis (L 1 ) of the multi-stage pump , the diffuser casing further comprising a first vane disposed in a first internal passage extending from the first inlet to the first outlet , characterized in that the diffuser casing further comprises a second vane disposed in a second internal passage extending from the second inlet towards the chamber within the diffuser casing . <EOS>