Brainscape's Knowledge GenomeTM

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


See full index

CPRII- Renal Exam > Electrolyte Disorders - Hyponatremia > Flashcards

Electrolyte Disorders - Hyponatremia Flashcards

1
Q

Def. hypoN and RFs

A

-Serum Na <135.

CHF
Cirrhosis
nephrotic syndrome
PNA legionella
post-op
ICU
older pt
meds
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

2 main systems that regulate sodium?

A
  • ADH system (amount of ADH is indirectly related to amount of urine produced!)
  • thirst mechanism.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What is normal Na

A

280-290 mOsm/L

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

What two stimuli trigger ADH to be released? the goal here would be to make urine that is NOT dilute

A
  1. Osmotic stimuli: osmoreceptors detect high osmolarity in serum –> concentrate urine to get rid of extra solutes
  2. Non-osmotic stimuli: baroreceptors detect low BP or blood volume –> concentrate urine to conserve fluid
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What are other non-osmotic stimuli that trigger ADH release

A 
Baroreceptors
Nausea
Hypoxia
Pain
Opiates &amp; Antidepressants
Pregnancy
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Pathogen. of HypoN: what happens when you have decreased serum osmolarity i.e. too much free water retention?

A
  • Thirst suppression and suppression of ADH release

- ADH suppression= more urine= dilute urine

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

Pathogen. of HypoN: what happens when you have increased serum osmolarity i.e. too little free water?

A
  • Thirst stimulation and stimulation of ADH release

- ADH release=little urine=concentrated urine

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

Defective urine diluting ability (so all you’re doing is concentrating your urine!) + excess water intake = ?

A

Hyponatremia

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Defective urine concentrating ability + inadequate water intake = ?

A

Hypernatremia

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

What results in hyponatremia?

A

Increases in TBW, not really from actual Na changes. Increased TBW due to excessive intake or decreased renal excretion …

(renal one is usually due to inability to suppress ADH…if you can’t suppress ADH you produce less urine thus increasing TBW and diluting out your Na)

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

Timing of acute v. chronic hyponatremia

A

Acute: <48h
Chronic: >48 h or unknown amount of time

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

Sx of hyponatremia

A

Usually present at <125mEq/L

HA, fatigue, dizziness, nausea, gait instability/falls, confusion, psychosis, seizures, coma due to cerebral edema

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

Whats the 2 step systematic approach to dx hypoN

A
  1. Measure serum osmolarity to determine if hypoN is hypotonic (true), isotonic or hypertonic (secondary)
  2. If it is hypotonic, assess fluid volume status because each volume status correlates w/ diff. etiologies.
    2a. Measure random urine Na level and urine osmolarity to weed out etiology. If considering SIADH, take serum uric acid. If low, could be SIADH.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What’s special about the labs in hyponatremia?

A

Must be drawn simultaneously ideally before any tx is given b/c that could alt. lab values

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

Hypovolemia PE

A 
HypoTN
Orthostatics 
Tachy
Poor cap refill
Increased skin turgor
Dry mucosa/fissuring
Flat JV
Decreased urine output
>50% collapse of IVC during inspo on ECHO
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Hypervolemia PE

A

HTN, Edema, JVD, Dilated IVC on ECHO

17
Q

Etiology:

  • Hypovolemic
  • Urine osm>300
  • Urine Na>20
A

RENAL FLUID LOSS

  • diuretic excess
  • adrenal insufficiency
  • osmotic diuresis
  • post obstructive diuresis post hydronephrosis
  • RTA
  • cerebral salt wasting
  • salt losing nephropathy
18
Q

Etiology:

  • Hypovolemic
  • Urine osm>300
  • Urine Na<20
A

EXTRARENAL FLUID LOSS

  • V/D
  • 3rd spacing (burns, pancreatitis)
  • Blood loss
  • Sweating
  • Lung losses
19
Q

Etiology:

  • Euvolemic
  • Urine osm<100
A

Psych issue causing primary polydipsia

20
Q

Etiology:

  • Euvolemic
  • Urine osm>300
  • Urine Na>20
A

-SIADH (tumor i.e. paraneoplastic syndrome pf #1 SCLC, CNS/pulm, SSRI, Nausea, Pain, hypoxia)

  • Hypothyroid
  • Adrenal insufficiency
  • Thiazides (one of the most common causes!!!)
21
Q

Etiology:

  • Hypervolemic
  • Urine osm>300
  • Urine Na<20
A

Nephrotic syndrome
CHF
Cirrhosis

all these lead to a defective circ. volume –> RAAS activation

22
Q

Etiology:

  • Hypervolemic
  • Urine osm>300
  • Urine Na>20
A

Acute or chronic kidney failure (will have low GFR)

23
Q

How is SIADH dx?

A

Exclude cortisol def., hypothryoid, other causes

24
Q

Most common causes of SIADH

A

SCLC!
Post-op!
Pulmonary disorders
Nervous system disorders

25
Q

What drugs are associated w/ SIADH

A 
Antidepressants
Anticonvulsants
Antipsychotics
Cyclophosphamide for cancer
Opiates
MDMA
26
Q

Correction of acute hyponatremia

A

Can have rapid correction w/ little risk of ODS

27
Q

Correction of chronic hyponatremia

A

-Raise by 8-10 mEq/L/day w/ no more than 18mEq/L in first 48 hours

28
Q

If a pt is seizing (a complication of hypoN), what should you do?

A

Give HYPERTONIC SALINE (3%) to quickly raise Na by 3-4 mEq/L and stop sizure. Then slowly raise to normal.

29
Q

How to fix an overcorrection of Na?

A
  • D5W i.e. free water
  • DDAVP i.e. desmopressin
  • D5W and DDAVP
  • Discontinue therapies that are raising Na
30
Q

Tx for hypovolemic hypoN (both renal and extrarenal)

A
  • Isotonic saline if w/o sx

- Hypertonic saline if w/ sx

31
Q

Tx of euvolemic hypoN due to primary polydipsia

A
  • Water restriction

- Hypertonic saline if w/ sx

32
Q

Tx of euvolemic hypoN due to SIADH

A
  • Water restriction
  • Furosemide
  • Salt or urea tabs
  • Vaptans to inhibit ADH in kidney
  • Demeclocycline

-Other tx: thyroid replacement, prednisone, discontinue thiazine

33
Q

Tx of hypervolemic hypoN (both etiologies)

A

Water restriction and Furosemide

34
Q

Sx of ODS

A
  • Dysarthria and dysphagia
  • Paralysis
  • Behavior issues
  • Pseudobulbar palsy
  • Seizures
  • Lethargy
  • Confusion
  • Coma (*locked-in syndrome…terrifying)
  • Death
35
Q

Dx of ODS

A

MRI Head. Initial normal MRI does not R/O ODS b/c it can take 4 weeks for MRI abnormalities to be seen.

36
Q

Steps of developing ODS

A
  1. Normal brain w/ normal osmolality
  2. Sudden onset of hypotonic state
  3. Water moves ECM to ICM b/c there are more solutes IN the cells
  4. Rapid adaptation: we try to fix the edema by having Na, K, and Cl leave our cells so water will follow
  5. Slow adaptation: organic osmolytes leave
  6. BRANCH POINT:
    - proper therapy: slow increase of osmolytes and Na, K, Cl, etc.
    - overcorrection: cells shrink, axonal shear damage, BBB disruption all lead to demyelination

CPRII- Renal Exam (6 decks)

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