3.2 Clinical: Polyuria

Question 1

Vol. for Polyuria

Answer 1

Vol >3L/day

Question 2

Osmotic vs. Water diuresis

Answer 2

Osmotic: Ur osmolality>Serum Osmolality, Total solute>1000mOsm/day
Water: Ur osmolality<900 mOsm/day

Question 3

Hypertonic urine will occur in excessive water intake or excessive water loss

Answer 3

Excessive water intake

Question 4

Water deprivation test: What is the Uosm in primary polyuria?

Answer 4

Uosm>600mOsm/kg

Question 5

Water deprivation test: What is the Uosm and Posm in DI? Sodium concentration

Answer 5

Posm>300 and Uosm142 meq/L

Question 6

Central Vs. Nephrogenic DI

Answer 6

Central Baseline ADH is decreased. Uosm will increase>x2 when given ADH
Nephrogenic DI: Baseline plasma ADH increase, there is decrease response in ADH. Uosm will increase <x2 when ADH given

Question 7

Primary polydipsia: Causes

Answer 7

Middle age women; psychiatric illnesses (Phenothiazine); Hypothalamic lesions affecting thirst center–Sarcoidosis
{Na} <137 meq/L because of water overload

Question 8

Hypothalmaic lesion

Answer 8

Sarcoidosis

Question 9

Psychogenic drugs causing primary polydipsia

Answer 9

Lithium-Blocks Aquaporin in Principle cell

Phenothiazine–>Dry mouth

Question 10

Will excessive water intake or loss have hypernatremia

Answer 10

Excessive h2o loss

Question 11

Excessive H2O intake vs. Excessive H2O loss

Answer 11

Excessive intake: Hyponatremic or Normal Na concentration Hypertonic urine following H2O deprivation

Excessive loss: Hypernatremic or normal Na; Hypotonic urine following water deprivation

Question 12

Possible causes of central DI

Answer 12

Autoimmune, trama, familial, idiopathic, pituitary surgery, hypoxic encephalopathy

Question 13

Causes of Nephrogenic DI

Answer 13

Children: X-linked (ADH receptor V2); Mutation of aquoporin 2

Adults: Chronic Lithium use, Hypercalcemia, amyloidosis, Sjoren’s, Hypokalemia