Renal: 15. Hamra : Pathophysiology Of Electrolyte Disorders (Really Only Na)

Front 1

Too much H20 (relative to Na):

Back 1

Hyponatremia

Na < 135 mmole/L

Front 2

Too little H20 (relative to Na):

Back 2

Hypernatremia

Na > 144 mmole/L

Front 3

define osmolality and tonicity

Back 3

Osmolality: reflects the concentration of all solutes

Tonicity: reflects the concentration of solutes that will cause a water shift

Front 4

please explain the difference btw true and relative hypovolemia

Back 4

True (absolute) Hypovolemaia
: true loss of ECF volume

Relative Hypovolemia:
container is larger due to vasodilation (increased capacitance of the compartment)

Front 5

Hemorrhage
GI fluid loss
Diuretic
Burns

are examples of what kind of hypovolemia

Back 5

True Hypovolemaia

Front 6

Drugs
Sepsis


are examples of what kind of hypovolemia

Back 6

Relative Hypovolemia
( ↑ capacitance of the compartment)

Front 7

renal disease, mineralocorticoid excess

are examples of what type of hypervolemia?

Back 7

Primary

Front 8

cardiac failure, cirrhosis

are examples of why type of hypervolemia?

Back 8

Secondary

Front 9

Major regulators for Na? 5

Back 9

Na: hormonal regulators

Aldosterone
ADH (AVP): antidiuretic hormone
ANP: atrial natruretic peptide
Sympathetic nervous system
Angiotensin II

Front 10

where does Aldosterone work?

Back 10

Na channel (and ATP dependent Na K channel) at the collecting duct

Front 11

Angiotensin II and NE work where?

Back 11

Proximal tubule, work on the Na/H pump in the lumen and ATP dependent Na/K channel at the interstitium

Front 12

wher does ADH work?

Back 12

adds aquaporin channels in collecting duct

also works in thick ascending limb

Front 13

what increases urea transport in the IMCD

Back 13

ADH

this concentrates the urine

Front 14

effect of ADH?

Back 14

brings in Na and H20

Front 15

effect of ANP?

Back 15

dumps Na and H2O

Front 16

please list if an increase/decrease of the following will cause an increase in ADH

Osmolality
volume
angiotensin

which is most important

Back 16

increase osmolality

decreased volume

increased angiotensin


VOLUME WILL TRUMP

Front 17

for hypervolemic hyponatremia

What is the plasma Na?

Relative change in H2O and Na

Plasma Osmolality

Una

Uosm

Back 17

Plasma Na < 136 mm/L
↑↑ H2O, ↑ Na
↓ plasma osmolality
Urinary Na: <20 mm/L
Uosm: high to isosmotic

Front 18

The following are an example of what type of hyponatremia?

….CHF
…..Decompensated cirrhosis with ascites
….advanced renal failure
…..Nephrotic syndrome

Back 18

Hypervolemic Hyponatremia

note these are all edema states

Front 19

if you have edema states, what type of hyponatremia will you have

Back 19

Hypervolemic Hyponatremia

Front 20

decreased effective arterial blood volume will do what to:

Thirst
ADH
SNS
RAAS

Back 20

INCREASE THEM ALL

want to increase H2O and Na retention

Front 21

for hypovolemic hyponatremia

What is the plasma Na?

Relative change in H2O and Na

Plasma Osmolality

Una

Uosm

Back 21

Plasma Na < 136 mm/L
↓H2O, ↓↓Na
↓ plasma osmolality
Una: Extrarenal cause- <20mm/L...Renal cause- >20mm/L
Uosm: low to high

Front 22

The following are an example of what type of hyponatremia?

GI loss, Bleeding, urine, skin

Back 22

Hypovolemic Hyponatremia

Front 23

What are the two major extra renal causes of hypovolemic hyponatremia? what is the Una like?

Back 23

GI loss (vomiting, diarrhea)

Excessive sweating

Una < 20 mm/L

Front 24

what are the 3 major renal causes of hypovolemic hyponatremia? what is the Una like?

Back 24

Diuretics (thiazides specifically)
Salt-wasting neuropathy
Mineralocorticoid deficiency

Una > 20 mm/L

Front 25

why is urinary sodium low in extrarenal causes of Hypovolemic Hyponatremia?

Back 25

lets say you have excessive sweating

so there is then a Na retaining response

so since you have fluid loss with na loss you will have increased thirst and ADH

Front 26

why is urinary sodium high in renal causes of Hypovolemic Hyponatremia?

Back 26

say you are on a thiazide diuretic

you will have a renal Na wasting event

thus you will have decreased volume that will cause increased thirst and ADH

you will excrete an isosmotic or concentrated urine

Front 27

SIADH is the classic example of what

Back 27

Normovolemic (Euvolemic) Hyponatremia

Front 28

for Normovolemic (Euvolemic) hyponatremia


Plasma Osmolality

Pna

Una

Uosm

What is the mechanism underlying this? (the key)

Back 28

↓Plasma osmolality
↓ Pna
↑↑Una > 40 mm/L
Uosm: high (in SIADH, hypothroidism) low in (primary polydipsia, beer potomania, tea/toast diet)

Key is that there is neither a volume or osmolar signal to increase ADH

Front 29

if you see Una>40 mm/L what do you have?

Back 29

Normovolemic (Euvolemic) Hyponatremia

Front 30

in what Na problem is there neither a volume or osmolar signal to ↑ ADH
**

Back 30

Normovolemic (Euvolemic) Hyponatremia

Front 31

Primary polydipsia
Beer potomania
Tea and toast diet

are examples of what type of hyponatremia?

Back 31

Normovolemic (Euvolemic) Hyponatremia with low Uosm

Front 32

H2O
Na
Pna
Posm
and normal response

for hypervolemic hypernatremia

Back 32

↑ H2O
↑↑Na
Pna > 144 mm/L
Posm: high
Normal response:
increase H2O intake
Excrete a maximally concentrated, minimum volume urine (read ADH)

Front 33

Hypertonic saline excess

Hypertonic NaHCO3 solution

examples of what

Back 33

Hypervolemic Hypernatremia

Front 34

classic example of Normovolemic Hypernatremia

Back 34

Diabetes Insipidous (too little ADH)

Front 35

please give the

H2O
Na
and Plosm

for Normovolemic Hypernatremia

Back 35

Decreased H2O
<-->Na
increase Plosm

Pure net H2O loss with no change in body Na

Front 36

for hypovolemic hypernatremia

H2O
Na
Plosm

Back 36

↓↓H2O
↓ Na
↑ Plosm

Front 37

if you have a hyponatremia and it is associated with diuretics, which is it?

if you have a hypernatremia, which diuretic is it associated with?

(name the Natremia and the assoc diuretic)

Back 37

Hypovolemic hyponatremia: thiazides

Hypovolemic Hypernatremia: Loops

Front 38

the following are extrarenal examples of what?

GI loss (vomiting,
diarrhea)

Excessive sweating

Burns

Back 38

Hypovolemic Hypernatremia

Front 39

The following are renal examples of what?

Loop diuretic

Osmotic diuretic

Back 39

Hypovolemic Hypernatremia