Final answer:
Diabetes insipidus results in polyuria and polydipsia because of insufficient ADH production or ADH receptor mutations, preventing water retention by the kidneys and leading to dehydration and electrolyte imbalances.
Step-by-step explanation:
Diabetes insipidus is associated with polyuria (frequent urination) and polydipsia (frequent intake of water) due to the underproduction of antidiuretic hormone (ADH) or a mutation in the ADH receptor. When ADH levels are insufficient, the kidneys cannot retain water which leads to the production of a large volume of dilute urine. This increased urination can lead to dehydration, prompting an excessive consumption of water to compensate.
Severe cases of diabetes insipidus can cause electrolyte imbalances due to the inability to retain water despite increased fluid intake. This is because the ADH is not high enough to trigger water reabsorption in the kidneys, which is necessary to decrease the solute concentration in the blood.