Lecture 23 - Electrolytes Flashcards
Plasma [Na+] is a major __________ fluid (ECF) ion. It is _______ eliminated from cells via ______ pump and has a major influence on ______.
For sodium Balance, it is needed a balance between intake & losses through: _____, _____, and _______ all affect plasma volume.
The ______ is the Main regulator of Na+ balance; Na+ resorbed in _____ tubule (water follows – d/t ADH); Exchanged for __ or __ (excreted in urine)
OSMORECEPTORS are in hypothalamus and sense increased _______ & secrete ____ & changes in thirst behavior
Plasma [Na+] is a major extracellular fluid (ECF) ion. It is actively eliminated from cells via sodium pump and has a major influence on osmolality.
For sodium Balance, it is needed a balance between intake & losses through: Urine, GIT, sweat all affect plasma volume.
The Renin- angiotensin-aldosterone system is the Main regulator of Na+ balance; Na+
resorbed in distal tubule (water follows – d/t ADH); Exchanged for H+ or K+ (excreted in urine)
OSMORECEPTORS are in hypothalamus and sense increased osmolality & secrete ADH & changes in thirst behavior
Sodium Regulation:
1. Adequate ______ (especially _________)
2. Renal tubular absorption via ___________
3. _________ absorption
4. Osmoreceptors that secrete _____ indirectly influence serum Na+ concentration
Sodium Regulation:
1. Adequate intake (especially herbivores)
2. Renal tubular absorption via ALDOSTERONE
3. Intestinal absorption
4. Osmoreceptors that secrete ADH indirectly influence serum Na+ concentration
List the mechanisms that alter sodium.
List the mechanisms of Hyponatremia.
- Intake
§ ________ Na Intake (_______)
§ ________ H2O Intake - Redistribution inside the body
§ Water shift s from ____ –> ____- _________ plasma osmolality (not due to Na)
§ Na shifts out of the ______ into an ______ - Edematous states like heart ______, _____ failure, etc.
- _________ plasma osmolality (not due to Na)
- Excretion
§ Na is lost in ______ of H2O (GI, renal, cutaneous)
- Intake
§ Decreased Na Intake (herbivores)
§ Increased H2O Intake - Redistribution inside the body
§ Water shift s fromICFàECF
* Increased plasma osmolality (not due to Na)
§ Na shifts out of the vasculature into an effusion
* Edematous states like heart failure, liver failure, etc. - Excretion
§ Na is lost in excess of H2O (GI, renal, cutaneous)
How can salt intake lead to Hyponatremia?
1.Intake
Decreased Salt Intake … (Herbivores, especially ruminants)
How can increased water intake lead to Hyponatremia?
Increased Water Intake:
1. Primary polydipsia (psychogenic water drinking)
2. Excessive administration of sodium-poor IVF (hypotonic fluids)
How can redistribution, specifically 3rd space syndrome, cause Hyponatremia?
3rd Space Syndromes
1. Extravascular fluid sequestration
2. Sodium in plasma moves into the “3 rd space”
→ plasma sodium decreases
- Peritonitis
- Ascites
- Uroabdomen
- Chylothorax
- GI sequestration
Third space syndromes occur when we have fluid moving from the vasculature into a “third space”. These commonly include the peritoneal and thoracic cavities.
The “first space” refers to the intravascular space (within vessels) and “second space” generally refer to the extravascular space (the interstitial and intracellular
spaces).
Fluid is sequestered in one of these third, or extravascular spaces and Na + moves from plasma down its concentration gradient and into that space – thereby
reducing plasma sodium
How can redistribution, specifically osmotic shift (from ICF to ECF), cause Hyponatremia?
Osmotic shift (from ICF to ECF)
1. __________: For every _____ mg/dL increase in glucose, ~2 mEq _______ in Na+
2. ______ administration
3. Occasionally with other diseases: ?
Basically it is the increased _________ Water. Hyperglycemia causes _________, and the water moves from _________ space to _________ space, which in turn produces a dilutional ______ in serum sodium level. Therefore, hyperglycemic patients are mostly mildly _________.
milliequivalent (mEq)
Mannitol is a diuretic
Osmotic shift (from ICF to ECF)
1. Hyperglycemia: For every 100 mg/dL increase in glucose, ~2 mEq decrease in Na+
2. Mannitol administration
3. Occasionally with other diseases: (PEN HisCock)
* Nephrotic syndrome
* Hepatic cirrhosis
* End-stage renal failure
* Congestive heart failure (CHF)
* Psychogenic polydipsia
Basically it is the increased Extracellular Water. Hyperglycemia causes hyperosmolality, and the water moves from intracellular space to extracellular space, which in turn produces a dilutional decrease in serum sodium level. Therefore, hyperglycemic patients are mostly mildly hyponatremic.
milliequivalent (mEq)
Mannitol is a diuretic
How can redistribution, specifically Excess Na+ Loss, cause Hyponatremia?
The most common cause of hyponatremia is… __________.
1. GIT: 3?
2. Renal loss:
* __________ (______):↓ ________
* ________, ________
* Prolonged ________
3. Cutaneous: _______, _______
tagged as important
The most common cause of hyponatremia is… Hypovolemia.
* GIT: vomiting, diarrhea, saliva
* Renal loss:
* Hypoadrenocorticism (Addison’s):↓ aldosterone
* Ketonuria, glucosuria
* Prolonged diuresis
* Cutaneous: sweating, burns
What are the consequences of Hyponatremia?
If other osmotically active substances are NOT increased: ___________
Cellular _______ (cellular ___________)
If other osmotically active substances are NOT increased:
Hypoosmolality
Cellular edema (cellular overhydration)
Clinical Manifestations of Cerebral Edema & Cell Lysis
_________ changes secondary to cellular _________
- ________, ________
- Altered ______, ________, ______, ______
Difficult to manage ________ therapy
Neurologic changes secondary to cellular dehydration
- Lethargy, weakness
- Altered mentation, obtundation, seizures, death
Difficult to manage rehydration therapy
What is the Diagnostic Pathway: Hyponatremia?
List the mechanisms of Hypernatremia.
- Intake
__________ Na Intake (?)
__________ H2O Intake (?) - Excretion
H2O is lost in _____ of Na (3? losses)
Hypernatremia: Mechanisms
- Intake
Increased Na Intake (hypertonic IVF)
Decreased H2O Intake (Dehydration) - Excretion
H2O is lost in excess of Na (GI, renal, insensible losses)
How can dehydration lead to hypernatremia?
Usually due to _________:
* __________ water intake
§ Inadequate water _____
§ ______ to drink
§ ______ thirst mechanism
Usually due to dehydration:
* Inadequate water intake
§ Inadequate water supply
§ Inability to drink
§ Defective thirst mechanism
How can excess Na+ intake or retention lead to Hypernatremia? What is a rare occurrence?
- Excess Na+ intake or retention:
§ Ingestion/ IV administration
§ Increased aldosterone <rare, rare, rare>
How can pure water loss lead to Hypernatremia?
- Pure water loss
§ ________/ high _____/ _____ stress
§ Diabetes ________ - ________ water loss
- Pure water loss
§ Panting/ high fever/ heat stress
§ Diabetes insipidus - Hypotonic water loss
What is the diagnostic pathway of Hypernatremia?
A diabetic patient is markedly hyperglycemic.
What do you expect the sodium concentration to be?
A. Increased (Hypernatremia)
B. Normal
C. Decreased (Hyponatremia)
C . Remember For every 100 mg/dL increase in glucose, ~2 mEq decrease in Na+
A diabetic patient is markedly hyperglycemic.
What is the mechanism that drives the change in Na+?
A. Decreased sodium intake
B. Dehydration
C. Loss of sodium (renal, GI, sensible)
D. Water shifts from the ICF to the ECF
D
Chloride
* Major __________ fluid (ECF) anion
* Important in transport of ______ and _____
* Anion involved in _____ _____ metabolism
Chloride
* Major extracellular fluid (ECF) anion
* Important in transport of electrolytes and water
* Anion involved in acid base metabolism
In a case of Hypochloremia, is loss of sodium and chloride proportional?
When we notice decreased chloride and sodium on the biochemical profile we always want to determine if losses of sodium and chloride are ________ – if they are, then we can generally rule out those serious conditions where chloride is lost or sequestered. To help us recognize those cases where there is disproportionate chloride loss we have a calculation we can perform – called “_________ _________.” We take the ______ value from the biochemical profile and multiply that value by the ______ of ____ sodium (the average of the _______ _______) divided by the patient’s _____ value from the biochemical profile
When we notice decreased chloride and sodium on the biochemical profile we always want to determine if losses of sodium and chloride are proportional – if they are, then we can generally rule out those serious conditions where chloride is lost or sequestered. To help us recognize those cases where there is disproportionate chloride loss we have a calculation we can perform – called “corrected chloride.” We take the chloride value from the biochemical profile and multiply that value by the quotient of mean sodium (the average of the reference interval) divided by the patient’s sodium value from the biochemical profile
Proximal GI obstruction = Cl - sequestration –like it could happen with a dog w. a tennis ball in duodenum, goat with coat in duodenum, Left displacement of the abomasum (LDA) in a cow.
Acidemia stimulates the type ____intercalated cells to secrete increased amounts of ___ and therefore ____, and the activity leads to increased ______ retention. Conversely, type B intercalated cells _________ Cl- when there is alkalemia or _____ excess and bicarb is being excreted in urine
Proximal GI obstruction = Cl - sequestration –like it could happen with a dog w. a tennis ball in duodenum, goat with coat in duodenum, Left displacement of the abomasum (LDA) in a cow. Acidemia stimulates the type A intercalated cells to secrete increased amounts of H+ and therefore Cl-, and the activity leads to increased bicarb retention Conversely, type B intercalated cells CONSERVE Cl- when there is alkalemia or HCO3- excess and bicarb is being excreted in urine
see below
A
see below
B
Normally:
____ & ____ balance maintains electroneutrality between ICF and ECF.
Normally:
H+ & K+ balance maintains electroneutrality between ICF and ECF.
1.During inorganic ACIDEMIA:
To preserve vascular pH, ___ move into the ICF. To maintain electroneutrality, ____ move to the ECF.
1.During inorganic ACIDEMIA:
To preserve vascular pH, H+ move into the ICF. To maintain electroneutrality, K+ move to the ECF.
- INSULIN DEFICIENCY:
Glucose pulls water _____ of the cell into the ___ Cell ______ (______), increases [___] in _____,
____ leaks into the vasculature
- INSULIN DEFICIENCY:
Glucose pulls water out of the cell into the ECF
Cell shrinks (dehydrates), increases [K+]ICF
K+ leaks into the vasculature
Cellular lysis: (i.e. _________, _____ _______
lysis syndrome): During massive cellular lysis,
____ is released from the cell into the vasculature
Cellular lysis: (i.e. rhabomyolysis, acute tumor
lysis syndrome): During massive cellular lysis,
K+ is released from the cell into the vasculature
What are the diagnostic pathways of Hyperkalemia?
What are the diagnostic pathways of Hypokalemia?
