F&e Popham Sodium

Front 1

Normal serum sodium: ____ meq/l
Normal plasma/serum osmolality: _____ osm
*sodium is main contributer to serum osmolality

Back 1

135-145 (just remember 140)

285-300 (just remember 300)

Front 2

Sx of Hyponatremia:
Symptoms relate to ___osmolality and subsequent brain cell _____
<125 - nausea/malaise
115-120 - headache/lethargy
<115 - seizures, coma
Usually reversible
More severe if it occurred fast/slow

Back 2

hypo
swelling
fast - brain needs time to adapt

Front 3

Sx of Hypernatremia:
Elevation in plasma osm
Extracellular ___osmolality causes brain cell _____
Lethargy, weakness, irritable, twitch, seizure, coma, death
Can see ruptured cerebral vessels due to _____ in brain volume

Back 3

hyperosmolality
dehydration
decrease

Front 4

Where is ADH released?
What are the 4 things that cause release of ADH?

Back 4

Posterior pituitary

Changes in plasma osmol
Non-osmotic signals from baroreceptors (hypovolemia, dec ECV)
Pain
Esophageal stimuli (NG tube)
.... also various meds

Front 5

If ADH present and water channels present, urine osmolality will be ____ and serum osmolality will be ___ as water moves

Back 5

high
low

Water being returned to blood

Front 6

If ADH is absent, water channels are absent, urine osmolality will be ___ and serum osmolality will be ____

Back 6

low
high

water is excreted in the urine

Front 7

Urine osm indicates if ADH and water channels are present
Urine sodium tells you what the kidney thinks about volume status:
High urine sodium?
Low urine sodium?

Back 7

High - kidney behaving as if body is volume expanded, getting rid of excess Na
Low - kidney behaving as if body volume is depleted, reclaiming Na and therefore H2O

Front 8

Uosm < 100 inicates what?
Uosm > 100 indicates what?

Back 8

No ADH prsent, urine is maximally dilute

Varying degrees of ADH activity, the higher the Uosm, the more ADH present

Front 9

Daily osmolar load from diet is about 500 mosm
Urine osmolality can range from 50-1000 mosm/l
What is the max and min daily urine output?

Back 9

Minimum:
500/1000 = 0.5 L/day
500/50 = 10 L/day

Front 10

How can you estimate plasma osmolality using Na?
What is normal for Posm?

Back 10

Na x 2 if glucose is normal

Normal Posm 285-300

Front 11

Pseudohyponatremia:
What is the cause of hyponatremia with normal Posm?
Hyponatremia with elevated Posm?

Back 11

Hyperlipidemia, Hyperproteinemia - lipids/protein take up more plasma space and reduces plasma water space, but Na+ still measured in total plasma space
Hyperglycemia, Hypertonic mannitol - water shifts out of cells to reestablish osmotic equilibrium so Na+ is more dilute in plasma water.

Front 12

Which stimulus is more powerful for ADH secretion? Osmotic or non-osmotic, and why?

Back 12

Non-osmotic (from baroreceptors in kidney/carotid/heart) maintain ECV at the expense of plasma osmolarity => it's better to have brain perfusion than perfect plasma osmolarity

THIS IS HOW YOU CAN BECOME HYPONATREMIC

Front 13

Hyponatremia with Uosm <100:
___ not being produced
Almost always due to what?
How do you treat?

Back 13

ADH
Primary polydipsia (excessive water intake)
Fluid restrict - body will quickly get rid of free water as no ADH is present

Front 14

Beer Potamania and Tea and Toast Syndrome:
Hyponatremia and low urine osmolality WITHOUT what?
Their normal osmolar load is ___ so they can clear ___ free water

Back 14

excessive fluid intake
Don't eat much
low osmolar load, clear less free water
100osm/day/50 mosm/l = 2 L/day
=> Develop hyponatremia even when fluid intake isnt that high

Front 15

Hyponatremia with Uosm >100:
ADH present or not?
It's release may be inappropriate from osmotic stimuli, but not if ___ depletion is present
What do you look at to determine this?

Back 15

It is present - urine is more concentrated
Extracellular volume - ADH release is appropriate if ECV depleted, but not if it's normal

Look at UNa+ to see how kidney is responding

Front 16

Use of UNa+ in hyponatremia with Uosm > 100:
UNa+ < 10 & volume depleted - what is the kidney doing? Why does hyponatremia develop?

Back 16

Kidney reabsorbing Na and H20 to reexpand volume. Hyponatremia develops because non-osmotic stimuli to ADH secretion (to increase ECV) overwhelm desire to keep Posm in range

Front 17

Use of UNa+ in hyponatremia with Uosm > 100:
Una+ < 10 and volume expanded - what signals are the kidney receiving, and from what conditions? What stimuli are dominating ADH secretion?

Back 17

Kidney receiving signals indicating poor perfusion despite overall volume excess (edema, CHF/cirrhosis/nephrosis) and is holding onto sodium
Non osmotic stimuli to ADH secretion cause reabsorption of free water without regard to Posm

Front 18

Hyponatremic and...
UNa+ > 10 and volume depleted: kidney is receiving wrong signals from what?
UNa+ > 10, volume expanded: volume appropriate or expanded, what is going wrong?

Back 18

Salt-wasting - diuretics, kidney damage, hormone problems
Brain or kidney is "confused" and still losing Na even in hypoosmolality

Front 19

What condition does a person have if they are Hyponatremic with UNa+ < 10, volume depleted

Back 19

GI losses (nausea/vomiting/diarrhea)
Skin losses (burns)
Diuretics
Pure cortisol deficiency

Front 20

What condition does a person have if they are hyponatremic with UNa+ > 10 and volume depleted?

Back 20

Salt wasting:
Adrenal insufficiency
diuretics
Hypokalemia with metabolic alkalosis after vomiting
Hypothyroidism

Front 21

What condition does a person have if they are hyponatremic with UNa+ <10, volume expanded

Back 21

Edematous states/poor perfusion:
CHF
Cirrhosis
Nephrotic syndrome

kidney/baroreceptors perceive volume depletion

Front 22

What condition does a person have if they are hyponatremic with UNa+ > 10, volume appropriate or expanded?

Back 22

Excess ADH production:
Syndrome of Inappriopriate ADh secretion (fixed ADH excretion with no regard to osmotic or volume stimuli)
Tumors, TB, pneumonia, asthma, drugs, esophageal process, pain ,neuropsych disorders
Chronic kidney disease

Front 23

SIADH:
If Uosm fixed at 350
Daily osmolar intake 500 osm
How much free water intake before hyponatremia develops?

Back 23

350/500 = 1.4 L/day

Front 24

How do you treat SIADH?

Back 24

Fluid restriction (hard to do)
or
Increase osmolar load - intake of high sodium or high protein diet - can clear more free water

Front 25

Rate of correction of hyponatremia:
first get out of danger range rapidly (to greater than ___)
Then don't correct more than __meq/L over 24 hours, or __meq/L/hour
General rule : if hyponatremia developed slowly, correct slowly, if rapid, fix rapidly w/ less complications

Back 25

120

12
0,5
Same for hypernatremia
Risk of Central Pontine Myelinolysis

Front 26

Emergency use of 3% NaCl to get out of danger range:
If hyponatremic seizures: ___cc 3% NaCl over 10 min, IV
If neurologic symptoms: 30-50 cc/hour over several hours

Back 26

100cc over 10 min

Front 27

What is Tolvaptan and how do you use it?

Back 27

ADH antagonist
Indicated for hypervolemic hyponatremia that can't tolerate 3% NaCl (CHF)
Used IV

Front 28

In what population do you usually see hypernatremia?

Back 28

Young, elderly, or altered mental status-
Unable to access free water.
thirst stimulus so profound that most are protected from hypernatremia if with water loss of up to 15 L/day

Front 29

Causes of Hypernatremia:
Sodium retention - rare, who would this be?
Water losses with inadequate intake - example?
Primary inadequate water intake

Back 29

Infusion of NaCl or salt water drinkers
Sweating, fevers, exercise, renal loss (diabetics), diarrhea, malabsorption, water loss into cells (seizures)
Hypothalamic dysfunction (primary hypodipsia)

Front 30

If Na >145, POsm will be >290, check ___
If it's >800 - primary hypodipsia, increased insensible/GI losses, or Na overload
If it's <300 - severe what?

Back 30

UOsm

Severe central or nephrogenic diabetes insipidus

Front 31

What's the difference between central and nephrogenic diabetes?
Unless acutely ill, usually not diagnosed by hypernatremia, but by what?

Back 31

Central - not releasing ADH, Nephrogenic - collecting tubules not responding to ADH
Can be partial or complete

Polyuria/polydipsia

Front 32

How do you treat diabetes insipidus:
Support/Diet
Drugs

Back 32

Low Na diet, moderate protein restriction (decrease osmolar load and minimize free water clearance)
Thiazide diuretic + low Na - induce mild volume depletion and decrease urine output by 50%
Give dDAVP for central DI

Front 33

Tx of Hypernatremia:
Calculate free water deficit and replact at rate to lower plasma sodium ___ meq/l/hr

0.5(70kg) x [(170/140) -1] = free water deficit of 7.5 L
Replace of 60 hours (30 meq deficit)
so what is the rate?

Back 33

0.5
7.5L/60 hours = 125 cc/hour

Front 34

Use POsm to confirm hypo or hyper _____
Use UOsm to find out what ___ is doing
Use UNa+ to find out what the kidney thinks of what?
Tx: use ___meq/L/hr

Back 34

hypo or hyperosmolality
ADH
body's volume status
0.5