Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

343 mt > conditions of Na+ imbalance > Flashcards

conditions of Na+ imbalance Flashcards

1
Q
  • Daily sodium intake _____ (Adequate Intake)

* Sodium is a primary driver of ______

A

1000-1500 mg
– About ½ a teaspoon of table salt
osmolality in the extracellular fluid compartment

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

how is Na+ actively transported out of cells

A

– Via the Na+-K+-ATPase pump

*Also involved in cell depolarization (nerves, muscles)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Kidneys are responsible for sodium _______

A

excretion
– Responsive to changes in serum sodium concentrations to maintain osmolality
– Will conserve sodium if required

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

• Sodium is a primary driver of osmolality in the extracellular fluid compartment

how do you calculate serum osmolality

A

– Serum Osmolality = (2 x [Na+]) + [Glucose] + [Blood Urea Nitrogen]
– Normal is 280-300 mOsm/kg

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

define hyponatremia

A

• extra note: Normal serum sodium concentration
– 135-145 mmol/L (mEq/L)

Low sodium concentration (<135 mmol/L)
most common electrolyte abnormality encountered
clinically

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

define hypernatremia

A

High sodium concentration (>145 mmol/L)
- always associated with hypertonicity and can cause
significant reduction in intracellular fluid volume

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

symptons of mild/chronic hyponatremia

A 
[Na+] 125-134 mmol/L
– Asymptomatic
– Impaired attention
– Gait changes
– Postural Changes
– Fall risk increased

Symptom severity may also depend on rate of change in [Na+] 9

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

symptoms of moderate/severe hyponatremia

A 
[Na+] <124 mmol/L
– Nausea
– Vomiting
– Headache
– Lethargy
– Altered mental status
– Seizures
– Respiratory arrest
– Risk of death increased
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

3 types of hyponatremia

A 
MEASURE SERUM OSMOLALITY
Low (<280 mOsm)
- Hypotonic hyponatremia (most common)
Normal (~280 mOsm)
-Isotonic hyponatremia]

hypertonic (elevated)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

what is isotonic hpyonatremia caused by?

SEE PICTURE ON SLIDE 10 OF NOTES

A 
AKA PSUEDONATREMIA
Artificially decreased c/o
• Elevated lipid level
• Elevated protein level
Reduces the proportion of water in the serum.\

Caused by other components in srum that could be elevated (lipid, proteins), water content in serium decreased, looks like there is low sodium level

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

what is hypertonic hyponatremia caused by?

A

Hyperglycemia
- Caused by presence of elevated amounts of other
effective osmoles
• Elevated glucose level

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

3 types of hypotonic hyponatremia

A

hypovolemic
euvolemic/isovolemic
hypervolemic

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

describe hypovolemic hypotonic hyponatremia

SEE TABLE FOR MORE

A
  1. Hypovolemic: loss of fluids that are hypotonic relative to serum
    ○ More water be lost than sodium
    ○ Serum levels go down because water loss more than sodium, body senses that sodium levels are high/concentration
    ○ Stimulate release of vasopressin frrom CNS
    ○ Vasopressin increases thirst and increases water reabsorption and sodium exretion
    ○ Hyponatremia nw develops as the sodium is being lost more than water
    ○ Pt may have orthosstatsis, change in bp whten they sit or stand rapid heartbeat, dry muc membranes
    ○ Do urine sample test, conc of urine
    ○ Also at whether kidnets are retaing sodium
    ○ If sodium lvls in urine are low, the case of Na loss is exrtrarenal, could be from GI source ro lungs
    ○ If urinary sodium is high, loss of sodium is likely renal
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

describe hypervolemic hypotonic hyponatremia

SEE TABLE FOR MORE

A
  1. Hypervolemic: low sodium level, low serum osmolality
    a. Fluid that should be retained within vascular space si moving out into interstitial space, fluid is collecting elsewhere (edema)
    b. Elevated urine concentration as body is trying to retain fluid as it thinks blood volume is low
    c. Sodium level is still low
    d. Body not perfusing kidneys well

due to heart failure, cirrhosis, nephrosis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

describe euvolemic/isovolemic hypotonic hyponatremia

SEE TABLE FOR MORE

A

a. Urine is normal, maybe low
b. Decrease in sodium conc is cuased by polydipsia, pt thristy all the time - elevated water volume relateive to sodium conc
c. IF URINE OSMOLALITY IS CONCENTRATED AND NA excretion IS > 20 mEQ need to look at other medical causes
* *** IF someone has elevated urince conc and elevated Na excretion, there are 2 possible conditions *hypovlemic, euvolemic/isovolemic)
- Extremely elevated, caused by diuretics
- Not extrenely elevated, look for drugs

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

what is hypovolemic caused by?

A
  • extrarenal losses, GI, skin, lung if Na excretion is low

- renal losses, diuretics, adrenal insuff if Na excretion is high

17
Q

what is euvolemic caused by?

A
  • primary poldipsia if UNa <20 mEq/L

- hypothyroidism, hypocortisolism, kidney failure, SIADH if UNa > 20 mEq/L

18
Q

what is hypervolemic hypotonic hyponatremia caused by?

A

heart failure failure
cirrhosis
nephrosis

19
Q

Syndrome of Inappropriate Secretion of Antidiuretic
Hormone (SIADH)

Disease Induced causes (3)

A

– Tumors (lung, pancreas)
– CNS disorders (head trauma, stroke,
meningitis, pituitary surgery)
– Pulmonary disease (TB, pneumonia)

20
Q

Syndrome of Inappropriate Secretion of Antidiuretic
Hormone (SIADH)

Drug Induced causes

A 
– Tricyclic antidepressants
– Phenothiazines
– Opioids
– Nicotine
– Carboplatin
– Cisplatin
– Bromocriptine
– NSAIDs
– Acetaminophen
21
Q

Syndrome of Inappropriate Secretion of Antidiuretic

Hormone (SIADH)

A

SIADH - body makes too much ADH and body retains too much water
Might be missed clinically
Cause of low sodium
Level of release is not as high as if somebody dehydrated
Urine conc is not as high as dehydration

22
Q

pt assessment

symptoms

A
  • asymptomiatic
  • neurologic, severity depends on magnitude, rate of onset
  • other symptoms depend on cause (dry mucus membranes, hypotension with hypovol)
23
Q

pt assessment

lab tests to look at

A

– Serum sodium concentration
– Plasma osmolality
– Urine analysis for osmolality and sodium concentration
– Glucose, lipid, renal function, thyroid function

24
Q

treating hyponatremia

goals (2)
what is ODS

A

Acute changes in serum osmolality can result in rapid and excessive
water movement out of cells
– Rapid decline in brain cell volume can cause osmotic demyelination syndrome (ODS)
• Hyperreflexia, para- or quadriparesis, parkinsonism, or death

Goals:
– Treat the underlying cause of hyponatremia
– Slowly correct the sodium and water imbalance

25
Q

Acute or Severely Symptomatic Hypotonic
Hyponatremia
- how to treat?

A

• Intravenous solution until severe symptoms resolve
– 3% NaCl (hypertonic saline)
– 0.9% NaCl (normal saline)
• Symptoms will usually resolve with a small increase in [Na+]
– e.g., 5% increase, or reaching 120 mmol/L
• To minimize risk of osmotic demyelination syndrome, the [Na+] should be corrected at a rate that does not exceed 6 to 12 mmol/L during the first 24 hours

26
Q

Hypovolemic Hyponatremia

- how to treat?

A
  • treat vomiting, diarrhea, asses need of direutics
  • reduce elevated vasopressin release by restoring intravascular volume
  • use solutions that remain in the extracellular / intravascular fluid compartment
  • Serum [Na+] will increase because the replacement solution stays in the ECF / intravascular fluid compartment not from the Na+ content of the solution
    – Oral replacement: water, WHO-ORS (oral rehydration salts), water+salt, sports drinks
    – Sodium chloride infusion (e.g., 0.9% NaCl solution)
27
Q

Hypervolemic Hyponatremia

- how to treat?

A

Treat the underlying cause of fluid retention
– Heart failure, nephrosis, cirrhosis
Fluid restriction (1000-1200 mL/day)
– Creates a negative water balance
Sodium restriction (1000-2000 mg/day)
Vasopressin receptor antagonists (tolvaptan, conivaptan*)
– V2 receptor: located on the distal nephron; blockade of vasopressinnbinding decreases water reabsorption from the collecting duct
⟹ large volume of water excretion, ↓urine osmolality, ↑serum [Na+]

28
Q

Euvolemic Hyponatremia

- how to treat?

A

• Correct the underlying cause if possible
– e.g., stop the drug that causes SIADH
• Fluid restriction (1000-1200 mL/day)
– Create a negative water balance
• Chronic SIADH may also require increased solute (NaCl tablet) intake +/- loop diuretic
• Vasopressin receptor antagonists

343 mt (15 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions