Imported: Renal: 24. Thomas : Sodium Disorders I & Ii

Front 1

What controls total body water? 2

Back 1

ADH & thirst control center

Front 2

What controls Na?

Back 2

Aldosterone

Front 3

____ _____ determination is essential in the evaluation of sodium derangements

Back 3

Volume Status

Front 4

hyponatremia is a serum level of?

Back 4

Na<135

Front 5

Nausea, vomiting
Lethargy, confusion
Seizures
Coma

hyper/hyponatremia?

Back 5

hypo

Front 6

why does hyponatremia normally not cause symptoms (especially neurological)?

Back 6

increase ADH, increase water in the extracellular space.

then water gets sucked into the cell which leads to cell swelling (which is bad)

the brain then kicks out other effective osmoles in the cell to maintain the equalibrium...

now you don't get cell swelling

Front 7

The Brain’s adaptation to slowly developed or chronic hyponatremia?

Back 7

And increase in ADH and water retention causes an acute lowering of ECF osmolality.
This leads to movement of water into cells which could cause cell swelling.
However, the increase in brain water is much less marked than expected because there is a prompt loss of both electrolyte and organic osmolytes, such as myo-inositol, after the onset of hyponatremia.
This volume regulatory response protects the brain against cerebral edema,

Front 8

A marathon runner overhydrates and becomes hyponatremic. Can they develop brain edema with neurological symptoms?

Back 8

Yes

from slamming too much water and swelling up the cells

Front 9

A 43-year-old patient with type 1 diabetes mellitus has a serum glucose of 700 mg/dL (normal fasting 70-130 mg/dL). What does this do to water in the intracellular (IC) and extracellular (EC) compartment, total body water (TBW) and total body sodium?

Back 9

The water shifts from IC to EC

TBW is unchanged

Total body Na is unchanged

Front 10

in a pt who is hyperglycemic, for every 100 mg/DL in glucose above 100, serum Na will appear how many meq lower than the actual value?

Back 10

1.6

Front 11

corrected Na=?

Back 11

Corrected Na = 1.6 [(Pt glucose-100) ÷ 100] + pt Na

Front 12

Example: Patient’s Na is 127, glucose is 700 ****

Corrected Na = ?

Back 12

Corrected Na = 1.6 [(700-100) ÷ 100] + 127
= 1.6 [(600) ÷ 100] + 127
= 1.6 (6) + 127
= 9.6 + 127
= 136.6

Front 13

Do you treat someone with pseudohyponatremia?

Back 13

no, it just appears to be hyponatremic, normally it is due to hyperglycemia

Front 14

What will the serum osmolality be in a person with hypovolemic hyponatremia?

Back 14

Hypotonic

Front 15

Please give the chart to figure out what type of volume loss you have

Front 16

the following are what type of causes of Hypovolemic hyponatremia? what will the UNa, FeNa, and FeUr be like?

GI Losses
Vomiting
Diarrhea
Nasogastric Suction
High output Ostomy
burns

Back 16

Extrarenal Causes

UNa ≤ 20
FeNa ≤ 1%
FeUr ≤ 35%

Front 17

the following are what type of causes of Hypovolemic hyponatremia? what will the UNa, FeNa, and FeUr be like?

Diuretics
Salt-wasting Nephropathy
Mineralocorticoid Deficiency

Back 17

Renal Losses


UNa ≥ 20
FeNa ≥ 2%
FeUr ≥ 50%

Front 18

What is the mechanism of hyponatremia in mineralocorticoid deficiency?

Back 18

decrease volume
↓
insufficient aldosterone release
↓
insufficient Na and water reuptake
↓
insufficient volume expansion

Front 19

What is the mechanism of hyponatremia in mineralocorticoid deficiency?

Back 19

decrease volume -->

insufficient aldosterone release-->

insufficient Na and water reuptake -->

insufficient volume expansion

Front 20

Tx for Hypovolemic Hyponatremia

Back 20

-volume resuscitation
-treat offending cause if possible

Front 21

Na deficit =?

Back 21

TBW x (wt kg) (desired Na – pt Na)

TBW = 0.6 male
= 0.5 female or elderly

for desired Na, correct by 10

Front 22

Sample Sodium Deficit and Fluid Replacement Calculation

55-year-old male, ideal wt 80 kg, Pt Na = 115 mEq/L

Na deficit =

Back 22

we want to correct by 10 so desired Na is 125


Na deficit = TBW (wt kg) (desired Na – pt Na)
= 0.6 (80) (125-115)
= 48 (10)
= 480 mEq

Front 23

what is an important consideration for using 3% saline?

Back 23

3% saline is usually reserved for emergency situations only (such as when a patient is seizing from hyponatremia) due to the fact that the sodium could correct too rapidly.

Front 24

What happens to the ECF and ICF when the serum sodium is corrected too quickly? 2

Back 24

Fluid shifts from ICF to ECF

shrinkage of brain cells

Front 25

what is one of the major problems with over correcting Na too quickly?

Back 25

Central Pontine Myelinolysis

Relative glial dehydration and myelin degradation and/or oligodendroglial apoptosis
Demyelination that results in a “locked in” syndrome, quadriparesis and/or speech disturbances

Front 26

TRUE/FALSE

for every 100 mg/dL in glucose above 100, serum Na will appear 1.6 meq higher than actual value

Back 26

False

it will be 1.6 meq LOWER than the actual value

Front 27

Lab findings of FeNa <1 and UNa <20 would be consistent with which of the following:

Mineralocorticoid deficiency
Vomiting
Diuretics

Back 27

Vomiting

Front 28

Signs and symptoms of volume overload

Problem is decreased effective circulating volume

Body response is ADH release and increased thirst

this is seen in what?

Back 28

Hypervolemic Hyponatremia

Front 29

what are UNa and FeNa levels like in Hypervolemic Hyponatremia

Back 29

UNa <20
FeNa <1

Front 30

pts with
-CHF
-Liver Failure
-Nephrotic Syndrome

will likely have what problem with Na?

Back 30

Hypervolemic Hyponatremia

Front 31

tx for Hypervolemic Hyponatremia

Back 31

-Fluid restriction
-Na restriction
-Loop diuretics

Front 32

A 66-year-old male with CHF. Which of the following will help to increase blood volume and maintain blood pressure in this patient?

increase or decrease ADH

Back 32

increase ADH

Front 33

How is this excess ADH affecting the water in his extracellular fluid (ECF) compartment and intracellular fluid (ICF) compartment?

Back 33

Increase water in ECF

and it shifts from ECF to ICF

Front 34

Would you expect a HF patient to be symptomatic from his hyponatremia?

Back 34

nope... it is usually a chronic problem

Front 35

In a HF patient, how fast will the hyponatremia develop?

Back 35

weeks/months

Front 36

TRUE/FALSE

Patients with hypervolemic hyponatremia are volume overloaded in both the intravascular and extravascular spaces.

Back 36

False

**Not enough fluid in intravascular space**

Front 37

TRUE/FALSE

Patients with hypervolemic hyponatremia are volume overloaded in both the intravascular and extravascular spaces.

Back 37

False

Front 38

what does a Uosm<100 imply?

Back 38

implies maximally dilute urine

Front 39

what are the Uosm like in primary polydipsia, beer potomania, tea and toast diet?

what are these seen with?

Back 39

<100

Euvolemic Hyponatremia

Front 40

what are the Uosm like in SIADH, hypothyroidism, and glucocorticoid deficiency?

what are these seen with?

Back 40

>100

Euvolemic Hyponatremia

Front 41

psychiatric disorder
-patients drink massive amounts of fluid (>12 liters/day)
-maximal urine volume ≈ 12 L/day, so excess water is retained

what is this known as, and what type of Na disorder does it cause?

Back 41

Primary Polydipsia

causes Euvolemic Hyponatremia: Uosm < 100

Front 42

-relatively large volume ingested in face of low solute load
-usually these patients only ingest ≈ 250 meq/day, so maximal urine output is ≈ 4L/day (250 meq/day ÷ 60meq/L = 4L/day)
-net result is anything over 4L is retained

what is this known as, and what type of Na disorder does it cause?

Back 42

Beer Potomania/Tea and Toast Diet

causes Euvolemic Hyponatremia: Uosm <100

Front 43

ADH is underlying mechanism of what?

Back 43

Euvolemic Hyponatremia: Uosm >100

Front 44

Hypothytroidism and glucocorticoid deficiency can cause what type of Na disorder?

Back 44

Euvolemic Hyponatremia: Uosm >100

Hypothyroidism
- ↓ CO= ↓ BP = ↑ ADH
- if suspected, check TSH

Glucorticoid Deficiency
-CRH crossreacts/activates ADH
-associated nausea and vomiting = ↓BP = ↑ADH
-if suspected, may check random cortisol or perform cosyntropin stimulation test

Front 45

Person comes in, smoker, has Cxray, has a nodule, their Na is 125.. What is the mechanism?

Back 45

Paraneoplastic syndrome because of SIADH

Front 46

what must be ruled out to diagnose an SIADH euvolemic hyponatremia

Back 46

* Thyroid and Adrenal Disorders must be ruled out first to make this diagnosis*

Front 47

compare Uosm with Sosm in SIADH euvolemic hyponatremia

Back 47

-Uosm usually greater than Sosm

Front 48

TRUE/FALSE

Sosm > Uosm points to a diagnosis of SIADH.

Back 48

FALSE

Front 49

Which one of these does not belong?

Primary Polydipsia
SIADH
Tea and Toast Diet
Beer Potomania

Back 49

SIADH

this has Uosm>100

Front 50

A 53-year-old man presents with 4-6 days of vomiting and feels tired and weak. He is usually well and takes no medications on a regular basis.

Physical examination shows a ill-appearing man in no acute distress. Vital signs reveal a blood pressure of 100/70 with a 20 mm Hg decline in SBP after assumption of the upright posture. The skin turgor is moderately reduced and the estimated jugular venous pressure is less than 5 cm H2O.
Lab show high BUN, Cr
low Na, low Cl
What does the urine Na of 8 mEq/L tell you?

Back 50

Extra-renal cause of hyponatremia

Front 51

Nephrogenic Diabetes Insipidus
-ADH ineffective at V2 receptors

can cause what?

Back 51

hypernatremia

Front 52

-Diarrhea
-Osmotic Laxatives
-Sorbitol, lactulose

-Malabsorption
-Lactose Intolerance

can cause?

Back 52

hypernatremia

Front 53

Central causes of hypernatremia include which of the following:

Sarcoid
Tumors
Stroke
MS

Back 53

Sarcoid
Tumors
Stroke

Front 54

Elderly in NH
-Demented
-Physically Impaired
-Intubated Patients
-Excessive Exercise

can cause?

Back 54

Hypernatremia

Front 55

when do you calculate a free water deficit? what is the formula?

Back 55

when you have hypernatremia

Free Water (L) = TBW (wt kg) [(pt Na ÷ desired Na) – 1]

TBW male = 0.6
female, elderly = 0.5

Front 56

Free Water Calculation

Patient Data:
Na 157 Wt 75 kg Age 80 Gender Male

Free Water (L)=

Back 56

Free Water (L)= TBW (wt kg) [(pt Na/desired Na) – 1]
Free Water (L) = 0.5 (75) [(157/147) – 1]
= 37.5 [(1.068) – 1]
= 37.5 (0.068)
= 2.55

Front 57

An 85 year old female with end-stage dementia is brought to the ED from the nursing home after she was found to be very somnolent. Initial vitals in ED are significant for BP of 86/40 and pulse of 104. On PE, mucus membranes are dry and tacky, and there is reduced skin turgor noted. Labs reveal serum Na of 158 mEq/L.
What are possible mechanisms for her hypernatremia?

Back 57

nursing home: no access to H20

demented: maybe forgets to drink

could have had a stroke

Front 58

If all you had was the urine osmolality and plasma sodium, how could you tell the difference between hypovolemic hypernatremia and central diabetes insipidus?

Back 58

Hypernatremia has high serum Na and high urine osmolality

Diabetes insipidis has high serum Na and low urine osmolality

Front 59

If all you had was the urine osmolality and plasma sodium, how could you tell the difference between hypovolemic hypernatremia and central diabetes insipidus?

Back 59

Hypernatremia has high serum Na and high urine osmolality

Diabetes insipidis has high serum Na and low urine osmolality

With diabetes insipidus, you have too little ADH (central) or too little ADH effect (nephrogenic) – hence not able to absorb water in the collecting duct – so there is a very dilute urine or low urine osmolality.

With hypovolemic hypernatremia – this would be a stimulus for ADH secretion, so water would be absorbed in the collecting duct causing a more concentrated urine or high urine osmolality. You needed to answer both answers for full credit.

Front 60

TRUE/FALSE

Hypernatremia is always corrected by calculating the free water deficit and replacing it

Back 60

False

remember if there is an underlying disorder treat that first

Front 61

TRUE/FALSE

Central Diabetes is treated with Loop Diuretics.

Back 61

false!

desmopressin normally