Volume Expansion and Hyponatremia Flashcards Preview

Renal and Urinary 2 > Volume Expansion and Hyponatremia > Flashcards

Flashcards in Volume Expansion and Hyponatremia Deck (19)
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1
Q

Primary renal Na retention

A

AKI (decreased GFR)
ACKD (marked deceased GFR)
Could also be from neprhotic syndrome (decreased IV volume, decreased flow to MD, activation of RAAS)

2
Q

Secondary Renal Na retention

A

Reduced effective arterial BP (heart failure/nephrotic syndrome/liver cirrhosis)

Sympathetic, RAAS, and AVP activation

Renal vasoconstriction with decreased GFR

Resistance to natriuretic peptides

3
Q

Hx of ECF expansion

A

Alcohol intake

Heart dz

Liver/kidney dz

Sx of heart failure

Foamy urine

4
Q

Exam of ECF exapnsion

A

Edema, increased JVP, S3 heart sound, basilar crackles, pleural effusion, liver cirrhosis

5
Q

Therapy in ECV expansion

A

Tx underlying syndrome

Low sodium

Fluid restriction if hyponatremic

Avoid NSAIDS as they are salt retainers

Diuretics - enhance Na excretion

Aggressive tx if pulmonary edema or hypervolemia induced HTN

6
Q

Hyponatremia

A

Serum sodium reflects plasma water content

Thus hyponatermia often associated iwth high AVP levels

7
Q

Hypotonic hyponatremia

A

loss of sodium in excess of water or more commonly replacement of fluid losses with Na poor water

Non-osmotic stimulation of AVP despite hypotonicity (volume rules over tonicity)

Water rentention by kidney

8
Q

Non-osmotic release of AVP

A

Decreased effective arterial blood volume through carotid sinus baroreceptors

Pain

Nausea

Pregnancy…lowers osmoregulatory threshold

Drugs

9
Q

Renal hyponatremia (hypovolemic)

Non-renal

A

Diuretics (HCTZ) and mineralocorticoid def…over 20 U na

Non renal - GI loss or sweat…under 20 U Na

10
Q

Evaluation of ECF depletion key

A

Postural hypotension (over 20 mmHg)

11
Q

Tx of hypovolemic hyponatremia

A

Avoid rapid correction to avoid osmotic demyelination syndrome

Replace with isotonic saline to correct the hypovolemia

12
Q

Causes of hyponatremia with ECF expansion

A

Retention of water>Na with low AVP ——KIDNEY problem

Retention of water>Na with high AVP level…reduced effective arterial blood volume
Heart failure (not enough blood)
Nephrotic syndrome (fluid leaving the IV space)
Cirrhosis of the liver (aterial tree dilated)

13
Q

WHy is AVP increased in hypervolemic states

A

Decreased effective arterial blood volume (through carotid barorecpeotrs)

Approximately 15% of cirulating blood is in arterial tree

14
Q

Therapy of hypervolemic hyponatremia

A

Tx underlying dz

Loop diuretics (decrease response to AVP)

Fluid restriction

AVP-V2 receptor antagonis is Na<125

15
Q

Euvolemia with hypotonic hyponatremia

A

High AVP, high U osm - SIADH, hypothyroidism, GC def, pregnanyc

Low AVP, low U osm - Primary polydipsia or beer potomania

16
Q

Sx of hypotonic hyponatremia

A

Sx largely due to cerebral edema (movement of water from hypotonic ECF)

General sx

CNS sx

GI sx

17
Q

Tx of SIADH

A

Fluid striction

High solute intake plus loop diuretics (decrease osmolar gradient and render AVP less effective)

Hypertonic saline…ODS (not over 10)

Arginine vasopressin V2 receptor antagonists

18
Q

Hypertonic hyponatremia

A

Hypertonic plasma

Movement of water from ICF to ECF

Also called dilutional hyponatremia

Causes - large amouint of high-osmolality molecules (glucose or mannitol)

19
Q

Isotonic hyponatremia

A

Severe hyperlpipidemia

Multiple myeloma