Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

DiBartola - Gautier > Chapter 5 - Disorders of Potassium > Flashcards

Chapter 5 - Disorders of Potassium Flashcards

1
Q

What is the major extracellular cation?

A

Na+

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

What is the major intracellular cation?

A

K+

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

What is the concentration of K+ in the intracellular fluid?

A

140mEq/L (variation in RBCs)

Muscle: 400 mEq/L

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

What is the concentration of Na+ in the intracellular fluid?

A

10mEq/L

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

As much as 95% or more of total body K is located within the cells. What area contains the most?

A

Muscle

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

What maintains the relationship between the ECF and ICF potassium concentrations?

A

Na/K ATPase

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

Na/K ATPase pumps ____ out of cells and ____ into cells.

A

Na, K

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

Na/K ATPase pumps in what ratio?

A

3Na/ 2K

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

A net _____ charge is within the cell and a net _______ charge is outside the cell.

A

Negative/ positive

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

What is the Nernst equation?

A

Resting cell membrane potential

Em = -61Log10 [Ki]/[Ko]

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

Hypokalemia ___________ the resting membrane potential

A

Increases/ makes more negative/ makes it less excitable

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

Membrane excitability is affected by potassium, but can also be affected by what two other things?

A

Calcium and acid-base balances

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

Ionized hypocalcemia _________ membrane excitability.

A

Increases (allows self perpetuating Na permeability to be reached with lesser degree of polarization)

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

Membrane excitability is ______ with alkalemia and ________ by acidemia.

A

Increased, decreased

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

T/F: Transport of K in the small intestine is active, while transport of K in the colon is passive.

A

False (passive in the small intestine and active in the colon)

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

Where is K removed from the body from?

A

Kidneys and GI tract

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

In dogs, what percent of K intake is eliminated via the kidneys?

A

90-98%

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

What 2 hormones promote cellular uptake of K in the liver and muscle by increasing the activity of Na/K ATPase?

A

Insulin and epinephrine

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

What type of acidosis is more likely to cause any clinically relevant change in serum K concentration during acute acid-base disturbances?

A

Mineral acidosis

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

T/F: Metabolic acidosis of at least 2-3 days duration is associated with increased urinary K excretion and mild hypoK.

A

True

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What can help differentiate between renal and non-renal sources of potassium loss?

A

Fractional excretion of potassium

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

What are the common causes of hypokalemia / metabolic alkalosis, hypokalemia / metabolic acidosis, respectively?

A

Hypokalemia / metabolic alkalosis: vomiting of stomach contents, diuretic administration

Hypokalemia / metabolic acidosis: diarrhea caused by small intestinal disease, chronic renal failure, distal renal tubular acidosis

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

Causes of hypokalemia: Translocation (ECF to ICF)?

A 
alkalemia
insulin/glucose containing fluid
catecholamine
albuterol overdosage
hypothermia
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

Effects on muscle

  1. less than 3.0 mEq/L
  2. less than 2.5 mEq/L
  3. less than 2.0 mEq/L
A
  1. muscle weakness
  2. increased CK
  3. frank rhabdomyolysis
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
True/False: chronic hypokalemia leads to metabolic acidosis in both dogs and cats
True
26
True/False: hypokalemia renders the myocardium refractory to the effects of class 1 antiarrhythmic agents (lidocaine, quinidine, procainamide). Therefore, serum potassium concentration should be measured and hypokalemia should be corrected in dogs with ventricular arrhythmia unresponsive to antiarrhythmic therapy
``` True Lidocaine: class 1b Quinidine: class 1a Procainamide: class 1a ```
27
What are the main features of hypokalemic nephropathy?
1. Renal vasoconstriction- decrease RBF and GFR | 2. PU/PD from impaired responsiveness of the kidneys to ADH
28
Explain 3 categories of hypokalemia
1. decreased intake 2. translocation of K from ECF to ICF 3. excessive loss of potassium by either the GI or urinary route
29
How much potassium is needed for maintenance fluid therapy?
15-30 mEq/L
30
True/False: Rattlesnake envenomation is associated with hypokalemia
True. Mild hypokalemia was reported in 78% of dogs suffering from rattlesnake envenomation.
31
What is the presumed mechanism of hypokalemia from beta2 adrenergic agonist overdose?
Rapid uptake of extracellular potassium by muscle and liver (stimulate Na-K pump embedded in the cell membrane)
32
What breed of cat is reported to have familial disorder characterized by episodes of sudden translocation of potassium from ECF to ICF?
Burmese
33
T/F: hypokalemia is common in cats with CKD, whereas most dogs with CKD have normal serum potassium concentration
True
34
What is the mechanism of hypokalemia induced by administration of loop or thiazide diuretics?
Blocks Na-Cl receptors in the distal convoluted tubule 1. increased flow rate in distal tubule (decreased sodium reabsorption) 2. increased secretion of aldosterone secondary to volume depletion (PUPD)
35
What is the additive of choice for parenteral potassium supplementation and why?
KCl. Chloride repletion is essential if vomiting or diuretic administration is the underlying cause of hypokalemia.
36
KCL should not be infused at rates greater than _____?
0.5 mEq/kg/hr
37
What are the reasons for normo- or hyperkalemia in DKA cases?
1. effects of insulin deficiency 2. hyperosmolality on serum potassium concentration 3. Hypovolemia
38
In the proximal tubule, how is K reabsorbed?
Solvent drag via paracellular route
39
In the thick ascending limb of the LoH, most K reabsorption happens by what route?
Paracellular
40
T/F: The transepithelial electrical potential difference is lumen positive in the early proximal tubule.
False, the lumen is positive
41
T/F: In the thick ascending limb of the LoH, the transepithelial electrical potential difference is lumen positive.
True, the lumen is strongly positive
42
Transcellular reabsorption of K is facilitated by what in the luminal membrane?
Na-K-2Cl cotransporter
43
Transcellular reabsorption of K is facilitated by what in the basolateral membrane?
K channels and and K-Cl cotransporters
44
What cotransporter do thiazide diuretics inhibit?
Na-Cl cotransporter
45
What cells in the connecting tubule and collecting duct are responsible for K secretion?
Principal cells
46
Name 3 diuretics of the principal cells and what they work on.
1. Amiloride- directly block electrogenic Na channel 2. Triamterene- directly block electrogenic Na channel 3, Spironolactone- antagonized aldosterone's effect on the electrogenic Na channel
47
Where are a-intercalated cells located?
Connecting tubule, CCD and outer medullary collecting duct
48
Where are B-intercalated cells located?
Cortical collecting duct
49
Where are the Cl-HCO3 countertransporters located in the a-intercalated cells?
Basolateral membrane
50
What three main factors affect K secretion in the distal nephron?
1. Magnitude of chemical concentration gradient for K between the tubular cells and tubular lumen 2. Tubular flow rate 3. Transmembrane potential difference across the luminal membranes of the tubular cells
51
What is the most important hormone affecting urinary K excretion?
Aldosterone
52
What two things directly stimulate the secretion of aldosterone?
Hyperkalemia | Angiotensin II
53
What two things directly inhibit aldosterone release?
ANP | Dopamine
54
What three things indirectly promote aldosterone secretion?
ACTH Hyponatremia Increased extracellular pH
55
What is the primary effect of aldosterone?
Increase the number of open Na cells in the luminal membrane of principal cells
56
T/F: Aldosterone increases the activity and number of Na-K ATPase pumps in the basolateral membrane of the principal cells.
True
57
In what two ways does aldosterone influence H secretion?
1. Directly promotes H secretion in H secreting type a-intercalated cells through stimulation of the H-ATPase present on the luminal membrane. 2. Promotes H secretion in the distal tubule by stimulating electrogenic Na reabsorption in principal cells, increasing lumen negativity which favors enhanced H secretion
58
T/F: Low Na intake is associated with decreased renal K excretion.
True
59
T/F: Acute mineral metabolic alkalosis decreases urinary excretion of K.
False, it causes metabolic acidosis
60
Chronic metabolic acidosis does what to urinary excretion of K?
Increases urinary excretion of K
61
What is a normal K concentration in dogs and cats?
3.5-5.5mEq/L
62
Why does serum K concentration exceed plasma concentrations?
Platelets release K during clotting
63
T/F: There is a positive correlation between platelet count and serum K concentration in cats
False, the positive correlation is in dogs
64
T/F: In normal adult canine and felines, hemolysis is not associated with hyperK.
True
65
Which has higher K concentrations: | Neonatal dogs or adult dogs
Neonatal
66
Which has higher K concentrations: Dogs with thrombocytopenia or thrombocytosis
Thrombocytosis
67
Which has higher K concentrations: Canine red cells stored in citrate for 4 days or 40 days
40 days
68
Which has higher concentations: Canine RBC or reticulocytes
Reticulocytes
69
Which has higher K concentrations: Canine RBC with Na-K ATPase present or absent
Present
70
What breeds tend to have a high K phenotype for their RBC? (3 breed naturally, and 2 breed with a disease)
Naturally: Shibas, Akitas, Jindos Disease: Phosphofructokinase deficiency- Springers and whippets
71
Some dogs with the high K phenotype for their RBC can accumulate a lot of glutathione in their RBC. What food should they avoid?
Onions- they have a predisposition for oxidative damage

DiBartola - Gautier (11 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions