Question

Describe the three causes of fluid deficit and the physiology for each. Examples are diabetes mellitus, diabetes insupidus, inadequate fluid intake, hemorrhage, nephrosis, burns, effusions, ascites, open wounds, excessive use of diuretics and excessive diaphoresis.

Answer 1

Causes of fluid deficit

1.loss of body sodium

2.blood loss from cuts or wounds

3.fluid loss from GIT.

4.excessive bleeding

5.polyuria

6.Burns

Diabetes mellitus-excess glucose which causes osmotic diuresis.leads to polyuria.

Diabetes insipidus -Defect in functioning of vasopressin or ADH causes polyuria.

Hemorrhage-The increased osmolality causes fluid to move extracellular from the cells.

Burns-coagulative necrosis of skin releases vasoactive peptides.Altered capillary permeability causes fluid loss.

Ascites-produced in liver cirrhosis.Increased pressure in liver forces fluid into stomach.

Effusion-fluid accumulation in anatomic spaces.occur due to blood vessel leakage or fluid from inflammation of pleura.

Excessive diuretics- diuretics increases fluid excretion and in excess amounts increases fluid loss.

Excessive diaphoresis-Excessive sweating causes loss of fluid from body.When body temperature increases set point in hypothalamus lowers casting darating.Excess sodium loss cause low water retention rate.

Open wounds-In open wounds evaporation causes fluid loss.Lack of a barrier causes water loss.