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Nephrology Board Review > Hypernatremia > Flashcards

Flashcards in Hypernatremia Deck (20)
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1

hypernatremia is a problem w/

WATER deficit

2

clinical shortcut to calculate free water deficit

pt [Na+] minus 140 divided by 3

3

free water clearance calculation

urine volume - ((urine osm/plasma osm) x urine volume)

4

electrolyte free water clearance calculation

urine volume - ((urine Na+ + K+/plasma Na+) x urine volume)

5

polyuria from water diuresis

> 3 l/day d/t;
- polydipsia
- hypotonic solution
- impaired urinary concentration (central or nephrogenic DI)

6

polyuria from solute diuresis

> 3 l/day d/t;
- isotonic solution
- osmotic diuresis (DM, mannitol)
- solute diuresis (diuretics)

7

if polyuria (UOP > 3 l/day) next step

check urine Osm

8

if polyuria and urine Osm < 100 mosm/kg, ML diagnosis

- primary polydipsia
- central or nephrogenic DI

9

if polyuria and urine Osm < 100 mosm/kg (water diuresis), next step

water deprivation test

10

if polyuria and urine Osm 100-300 mosm/kg (mixed polyuria), ML diagnosis

- partial DI (central and nephrogenic)
- simultaneous water and solute intake
- CKD

11

if polyuria and urine Osm 100-300 mosm/kg (mixed polyuria), next step

water deprivation test or 24-hour urine collection (urine Na+, K+, glucose, and urea)

12

if polyuria and urine Osm > 300 mosm/kg (solute diuresis), ML diagnosis

- hyperglycemia
- azotemia
- high solute intake

13

if polyuria and urine Osm > 300 mosm/kg (solute diuresis), next step

water deprivation test or 24-hour urine collection (urine Na+, K+, glucose, and urea)

14

if primary polydipsia water deprivation test (WDT) result

will be able to concentrate urine

15

if DI WDT result

still have water diuresis; unable to concentrate urine

16

after WDT, DDAVP response test; expected response if central DI

urine concentrates

17

after WDT, DDAVP response test; expected response if nephrogenic DI

NO response; unable to concentrate urine

18

causes of nephrogenic DI

- congenital = V2 receptor mutation
- medications = Li+, amphotericin, etc
- electrolyte abnormalities = hypokalemia, hypercalcemia
- intrinsic renal diseases = polycystic kidney disease, medullary cystic disease, SCD, obstruction

19

gestational DI

- placenta produces vasopressinase usually in 3rd trimester

20

causes of central DI

- congenital (Wolfram syndrome)
- head trauma
- suprasellar tumors (either primary or metastatic)
- granulomatous disease (TB, sarcoid, etc)
- Histiocytosis
- vascular (cerebral thrombosis, Sheehan syndrome, etc)