Brainscape's Knowledge GenomeTM

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


See full index

Foundations II- Nephrology > Electrolytes > Flashcards

Electrolytes Flashcards

1
Q

What regulates serum sodium?

A

thirst

ADH

RAAS system

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

What’s included on an electrolyte panel?

A 
Na 
K 
Cl 
CO2
Ca

*Mg and phosphate need to be ordered separately

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

What is the most common electrolytes abn. in hospitalized pt?

A

hyponatremia

danger zone Na below 125

can be acute or chronic

can be seen in assoc. with pulmonary disease of CNS disorder

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

What are some clinical manifestations of hyponatremia?

A 
Headache, dizziness
Nausea, vomiting
Lethargy
Weakness
Confusion 
Hypoventilation, respiratory arrest
Seizures
Coma
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What are some causes for hyponatremia?

A

Pseudohyponatremia
Redistributive hyponatremia

Hypovolemic hyponatermia
Hypervolemic hyponatremia
Euvolemic hyponatremia

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

What is pseudohyponatremia?

A

Falsely low serum sodium

Serum Na<135 but NORMAL osmolality

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

When does pseduohyponatremia occur?

A

Occurs with hyperlipidemia and hyperproteinemia

-Can also occur with obstructive jaundice & multiple myeloma

lab artifact!! call lab to confirm

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

What is redistributive hyponatremia?

A

Hyperosmolar state; “relative hyponatremia”

Caused by osmotically active solutes in extracellular space that draw H2O from cell diluting

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

What is a common cause of redistributive hyponatremia?

A

hyperglycemia

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

How do you calculate redistributive hyponatremia?

A

Add 1.5mEq/L to sodium value for every 100mg/dl serum glucose > 100mg/dl

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

What are some renal losses responsible for Hypovolemic Hyponatremia?

A

diuretics

osmotic diuresis

addison’s disease

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

What are some non-renal losses responsible for Hypovolemic Hyponatremia?

A

External GI: vomiting, diarrhea, NG suction, fistula
Internal GI: pancreatitis, peritonitis
Burns

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

Tx for hypovolemic hyponatremia?

A

replace fluid losses (with isotonic fluid, ie. NS), and treat the underlying cause

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Causes for hypervolemic hyponatremia? tx?

A

Hepatic cirrhosis, CHF, Renal failure

diuretics, dialysis, fluid restriction

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

Causes for euvolemic hyponatremia?

A

SIADH

Primary polydipsia
Often psychogenic
Urine maximally dilute

Hypothyroidism

Adrenal Insufficiency

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

Tx for euvolemic hyponatremia?

A

fluid restriction,

treat underlying cause.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Describe SIADH

A

Syndrome of Inappropriate Antidiuretic Hormone Secretion

This impairs free water excretion but sodium continues to be excreted normally

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Hallmark findings in SIADH?

A

Concentrated urine (>100mOsm/kg) with low serum osmolality and euvolemia

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

SIADH usually occurs in…

A

hospital setting

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Tx for SIADH?

A

Fluid restriction

Treatment of underlying pathology

For refractory cases +/-
Hypertonic saline
Demeclocycline
Urea
Lithium
“Vaptans”
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

How do we eval for hyponatremia?

A

good H &P

labs: UA- Na and osmolarity, serum osmolarity, CMP

secondary labs: TSH, serum cortisol

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Tx for hyponatremia?

A

Depends on underlying cause

If Na<125 or symptomatic hospitalize!

Chronic hyponatremia must be managed with extreme care
-slow cautious correction

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Why do we need to be careful about correcting Na?

A

Rapid increase in serum sodium can lead to cerebral pontine myelinolysis (CPM)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

What can be used to tx hyponatremia?

A

hypertonic solutions

traditional tx: chronic hyponatremia =demeclocycline

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

How often should you check serum Na while correcting?

A

q2hrs

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

What is Central pontine myelinolysis?

A

CPM is a poorly understood entity characterized by focal demyelination in the pons and extra- pontine areas – it is irreversible!!

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

Sxs of central pontine myelinolysis?

A

Dysarthria, dysphagia, seizures, altered mental status, quadriparesis, hypotension

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

Work up for hyponatremia?

A

Check serum osmolarity

  • if high&raquo_space; hyperglycemia
  • if low&raquo_space; check urine osmolarity

if urine osmolarity is low&raquo_space; water intoxication
if high&raquo_space;need to check volume status

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

What is hypernatremia?

A

A hypertonic disorder due to serum sodium >145mEq/L

“Too little water relative to salt”

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

Clinical features of hypernatremia?

A 
Often asymptomatic
Thirst, signs of volume depletion
AMS, weakness
Neuromuscular irritability
Focal neurologic deficits
Seizures or coma
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

Causes for hypernatremia?

A

Too little dietary water

Too much dietary salt

Excessive water loss from the body

32
Q

Work up for hypernatremia?

A

check urine osmolality!

if less than plasma osmolality (<300) = central or nephrogenic DI

If intermediate (300-600) = osmotic diuresis or DI

If high (>600) : dehydration most likely secondary to extrarenal water loss

33
Q

Normal response to hypernatremia?

A

thirst, increase fluid intake

concentrates urine

34
Q

What is diabetes insipidus?

A

Nonosmotic urinary water loss in setting of elevated serum sodium: urine is dilute when it should be concentrated

35
Q

Describe central DI

A

due to impaired secretion of antidiuretic hormone (ADH)

36
Q

Describe Nephrogenic DI

A

lack of kidney response to ADH, causing continued water loss even though patient is low on water. Adequate ADH is present.

37
Q

Tx for nephrogenic DI?

A

Thiazide diuretic
Amiloride (potassium sparing diuretic)
Chlorpropamide (antidiabetic oral agent)
NSAIDs have been tried (including Indomethacin)

38
Q

Tx for hypernatremia?

A

hospitalize if severe

stop water loss

replace water deficit
-but not too quickly!

39
Q

How can you calculate water deficit? What is this used for?

A

normal TBW-Current TBW

Normal: .6 x body weight in kg

current: normal serum x normal TBW

to replace free water in hypernatremia

40
Q

Serum Potassium is a…

A

major IC cation

41
Q

hypokalemia is common in…

A

pts receiving diuretics

42
Q

Clinical presentation of hypokalemia?

A 
Weakness, fatigue
Muscle cramps
Hyporeflexia
Flaccid paralysis (ascending)
Cardiac arrhythmia
Hypercapnia
43
Q

ECG findings for hypokalemia?

A

Flattened T waves

Prominent U waves

Premature Ventricular
Contractions (PVC’s)

Depressed ST segments

44
Q

What are the 3 dif. mechanisms that can causes hypokalemia?

A

transcellular shifts- drugs, delirium tremens…

renal losses - diuretics MC cause

extra-renal losses- V/D, burns, Mg deficiency

45
Q

Tx for hypokalemia?

A

replace K (oral preferred!) and underlying cause

telemetry monitoring if inpt

IV for those not able to eat/emergencies

46
Q

Can you push IV K?

A

NO, should be given slowly

give with lido if using peripheral IV

47
Q

How do you replace K?

A

For every 0.1 mEq/L below 4mEq/L,
Give 10 mEq/L

(10 for ever .1 you want to increase)

48
Q

What is hyperkalemia?

A

Defined as K > 5 mEq/L, severe > 6.5 mEq/L

In the absence of renal failure or other identifiable cause, actually quite rare

49
Q

Clinical presentation for hyperkalemia?

A

Relatively asymptomatic
Muscle weakness
Begins in legs and ascends to trunk and arms
“ascending flaccid paralysis”
ECG changes: potentially life threatening arrhythmias

50
Q

ECG findings in hyperkalemia?

A

Peaked T waves >
widen QRS >
junctional rhythm> ventricular fibrillation

K > 6 more likely to cause severe cardiac arrhythmias

51
Q

Causes of hyperkalemia?

A

Factitious-hemolysis

Impaired K excretion- renal failure

Drugs- K sparing diuretics, ACE/ARBs,NSAIDS, Bactrim

Increased intake

52
Q

Other causes for hyperkalemia?

A

conditions which move K+ from intracellular to extracellular space:

-tissue damage, acidosis, decreased insulin

53
Q

Tx for emergent hyperkalemia?

A
  1. IV calcium
  2. Maneuvers to shift K from ECF to ICF
    - -sodium bicarb
    - -Insulin IV + D50W
  3. other potential options: nebulized albuterol, IV lasix, dialysis
54
Q

Less urgent tx for hyperkalemia?

A

Kayexalate

  • exchanges Na for K in the gut
  • causes lots of diarrhea

Lasix

correct underlying cause

55
Q

How is serum calcium measured?

A

otal Ca = free (ionized) + protein-bound

Used to evaluate metabolism and monitor patients with hyperparathyroidism, malignancies and renal failure

56
Q

There is an inverse relationship btwn Ca and…

A

phosphate

57
Q

Most Ca is in the…

A

bone

58
Q

What are the dif. Ca forms?

A

ionized

complexed

protein-bound (albumin)

59
Q

A decreased in serum Ca triggers the release of….

A increase in serum Ca triggers the release of…

A

PTH from parathyroid gland, which acts to increase Ca in the blood by:

calcitonin from the thyroid gland, which acts to decrease Ca in blood by: Inhibiting bone resorption

60
Q

hypercalcemia..

A

Calcium > 10.1

Relatively common, most cases are mild and self-limiting

61
Q

presentation for hypercalcemia?

A

Stones, Bones, Abdominal Moans,

and Psychiatric Groans”

62
Q

Primary causes for hypercalcemia?

A

malignancy and hyperparathyroidism

other causes: meds

63
Q

What labs should you check for hypercalcemia?

A

Serum Ca

PTH and rPTH

TSH

Protein electrophoresis

64
Q

Tx for hypercalcemia?

A

***volume expansion

  • Calcitonin > lowers levels rapidly
  • Pamidronate
  • Zoleronic Acid

Others: fallium nitrate, prednisone, dialysis

65
Q

Presentation for hypocalcemia?

A 
Increased neuromuscular: excitability (tetany)
Paresthesias (peri-oral, extremities)
Hyperactive reflexes, carpopedal spasms
Chvostek’s sign
Trousseau’s sign

Cardiovascular effects:
ECG changes (prolonged QT interval); arrhythmia
Hypotension

66
Q

What is tetany?

A

involuntary sustained contractions

67
Q

Chvostek’s sign?

A

tapping facial nerve against the bone just anterior to the ear results in contraction of facial muscles

68
Q

Trousseau’s sign?

A

occluding brachial artery for 3 minutes with BP cuff induces carpal spasms.

69
Q

Causes for hypocalcemia?

A

hypoalbuminemia, large blood tranfusion, hypomagnesemia, hypoparathyroidism, renal failure, intestinal malabsorption/Vit D def.

70
Q

Neuromuscular changes in hyper v. hypocalcemia

A

decreased excitability (weakness)

increases excitability (tetany)

71
Q

Phosphate

A

used to investigate parathyroid and calcium abnormalities

72
Q

Causes for hyperphosphatemia

A 
Renal failure
Hypoparathyroidism
Hypocalcaemia
Rhabdomyolysis
Exogenous Phosphorus
73
Q

causes for hypophosphatemia?

A 
Decreased intestinal absorption
Hyperparathyroidism
Chronic alcoholism
Severe diarrhea
Cellular shift
-Insulin
-Refeeding Syndrome
74
Q

Describe Mg

A

Normal value: 1.3 – 2.1 mEq/L (adult)

Involved in neuromuscular and cardiac function

bound to ATP, excreted by kidneys

75
Q

Mg is intimately tied to…

A

Ca and K

76
Q

Hypomagnesium inhibits…

and impairs…

A

PTH activity which can cause hypocalcemia

and impairs ability of the kidneys to conserve K

Foundations II- Nephrology (7 decks)

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