CIS - Disorders of Salt and Water Imbalance - McCormick

Question 1

Hyponatremia

Answer 1

Results from the intake and subsequent retention of water
Most often from inability to suppress ADH
Uncommon exception is primary polydipsia
Can be pseudo - lab error or hyperglycemia (dilution)

Question 2

2 Types of true hyponatremia

Answer 2

1. Dilute urine, low ADH
   - ex. psych polydipsia
2. Conc urine, high ADH
   - ex. SIADH

Question 3

If you give a pt with Central DI ADH, what happens?

Answer 3

Increased urine conc and problem is corrected

–problem is with production of ADH - NOT how it interacts with body like nephrogenic DI

Question 4

Hypernatremia

Answer 4

Hypertonicity
Usually due to unreplaced water loss, NOT Na gain
Extrarenal or renal

Question 5

What impact does lithium have?

Answer 5

Limits ability of V2 receptors to generate cAMP resulting in diminished biological activity of ADH

Question 6

2 common caused of nephrogenic DI?

Answer 6

Hypercalcemia (malignancies)

Hyperkalemia (acidosis)

Question 7

Common causes for central DI?

Answer 7

Head trauma
Postpartum hypophysistis
Pituitary tumor

Question 8

A stressed out medical student, Stefan Vilcoxippi, has become so stressed out that he no longer has a 4.0 and decided to drop out of KCU. He goes home to West Virginia and gets a new job in coal mining. He toils all day and goes home to smoke 2 packs of cigarettes a day while he cries into his bourbon, lamenting his inability to buy expensive panties now. After years and years of this debauchery, he goes to a previous classmate, Dr. DianNe Spring, for medical testing. She notices that his lab work shows high ADH and low plasma osmolality. What is Stefan’s diagnosis?

Answer 8

Oat cell carcinoma.

Question 9

Possible causes of SIADH?

Answer 9

Pulmonary TB
CHF
CNS issues
Mechanical ventilation
Drugs (not cocaine)

Question 10

Effective circulating volume

Answer 10

the part of the ECF that is in the arterial system and effectively perfusion tissues

Question 11

Hypervolemia

Answer 11

Excessive gain of salt and water volume overload
-edema formation
Ex. CHF

Question 12

BUN/Cr > 20/1

Answer 12

Prerenal

Ex. reduced renal perfusion due to hypovolemia

Question 13

BUN/Cr < 10/1

Answer 13

Intrarenal

Reduced reabsorption of BUN

Question 14

Hypovolemia

Answer 14

Volume depletion - loss of salt and water in excess of intake