Lecture 15: Electrolytes and Acid-Base II Flashcards
1
Q
What physiologic processes are calcium important for
A
- Contraction of skeletal, cardiac, and smooth muscles
2, coagulation - Transmission of nerve impulses
- Essential for formation of bone and teeth
2
Q
hypercalcemia causes progressive depression of __
A
nervous system
3
Q
hypocalcemia causes nerve system to become more __
A
excited
4
Q
what are the 3 forms of calcium in total calcium in serum or plasma
A
- Free ionized ca2+
- Protein bound Ca2+
- Complexed ca2+
5
Q
which form of calcium is biologically active and contributes to pathological conditions
A
free ionized
6
Q
changes in __ and __ can impact level of protein bound ca2+
A
pH and albumin concentration
7
Q
how does an increase in H+ ions or decreased pH affect ionized calcium
A
less ca2+ bound to proteins—> increase iCa2+
8
Q
how does decreased H+ ions, higher pH affect ionized ca2+
A
more ca2+ bound to proteins, decreased ionized calcium
9
Q
why is it important to collect samples anaerobically when wanting to measure ionized calcium
A
exposure to air will pull out H+—> false decrease in ionized calcium
10
Q
hypoalbuminemia __ total calcium
A
decreases
11
Q
t or f: hypoalbuminemia impacts ionized calcium
A
false
12
Q
total calcium will be __ with hyperproteinemia
A
increase
13
Q
always look at __ and __ to see if they explain changes in calcium concentration
A
total protein, albumin
14
Q
what tubes should total calcium or ionized calcium be measured in
A
- Serum- red or white top tube
- Plasma- green top tube
15
Q
calcium and __exist in a reciprocal relationship
A
phosphorus
16
Q
what is equation for calcium: phosphorus product
A
Ca2+:phos product= tCa (P)
17
Q
if Ca:P product is >70 concern for __
A
soft tissue mineralization
18
Q
how does PTH affect calcium and phosphorus
A
increase calcium, decrease phosphorus
19
Q
how does calcitriol affect calcium and phosphorus
A
increase both
20
Q
how does calcitonin affect calcium and phosphorus
A
decrease both
21
Q
what are the ddx for hypercalcemia
A
- Hyperparathyroidism
- Osteolysis
3, granulomatous disease - Spurious (lab error)
- Idiopathic
- Neoplasia
- Young animals
- Addisons
- Renal disease
- Vitamin D toxicity
22
Q
what are the causes of primary hyperparathyroidism
A
- Functional parathyroid tumor
- Idiopathic hyperplasia
23
Q
what are lab findings with primary hyperparathyroidism
A
- Increase PTH
- Increase tCa2+ and ICa2+
- Decrease phosphorus
24
Q
what species can renal failure cause hypercalcemia
A
horses
25
how does vitamin D toxicity cause hypercalcemia
increase ca2+ and phosphorus absorption from intestine and facilitates PTH effect on bone
26
what lab findings are consistent with vitamin D toxicity
1. Decrease PTH
2. Increase total ca2+ and ionized Ca2+
3. Increase phosphorus
27
what is the most common cause of hypercalcemia in digs
1. Hypercalcemia of malignancy
28
what neoplasms are associated with hypercalcemia of malignancy
1. Lymphoma (#1)
2. AGASACA)
3. Multiple myeloma
29
what lab findings are consistent with hypercalcemia of malignancy
1. Normal to decrease PTH
2. Increase tCa2+ and ica2+
3. Normal phosphorus
4. +/- increase PTHrP
30
what are ddx for hypocalcemia
1. Hypoalbuminemia
2. Primary hypoparathyroidism
3. Renal hyperparathyroidism
4. Pancreatitis
5. Milk fever
6. Intestinal malabsorption (PLE)
7. Blister beetle (cantharidin) toxicosis in horses
8. Ethylene glycol
9. Nutritional secondary hyperparathyroidism
31
How does primary hypoparathyroidism lead to hypocalcemia
decreased PTH due to agenesis, surgical removal or atrophy
32
what are lab findings are consistent with primary hypoparathyroidism
1. Decrease PTH
2. Decrease tCa2+ and iCa2+
3. Increase phosphorus
33
what is cause of renal secondary hyperparathyrodism
1. Decrease GFR and decrease calcitriol
2. Leads to increase phosphorus and decrease calcium
3. Increase PTH release
34
what lab finding are consistent with renal secondary hyperparathyroidism
1. Increase PTH
2. Decrease iCa2+
3. Increase phosphorus
35
Answer kahoot
decrease PTHrP
36
what are roles of phosphorus in body
1. Key component of phospholipid ,membranes
2. Component of nucleic acids and ATP
3. Acid base regulation
4. Part of bone matrix
37
what are the 4 factors that determine serum phosphorus concentration
1. Renal disease
2. Gastrointestinal absorption
3. Resorption from bone
4. Shifting between ICF and ECF
38
what is most common cause of hyperphosphatemia
decreased urinary excretion- decrease GFR
39
what are some other causes of hyperphosphatemia
1. Hypervitaminosis D: increase GI absorption of phosphorus
2. Hypoparathyroidism: decreased renal excretion
3. Bone growth in young animals
4. Myopathies (leakage from damaged muscle cells)
5. Tumor lysis syndrome
6. Osteolysis
7. In vitro hemolysis
8. Ethylene glycol
40
what are some causes of hypophosphatemia
1. Primary hyperparathyroidism (increase PTH)
2. Hypercalcemia of malignancy
3. Inadequate dietary intake
4. Milk fever
5. Equine renal failure
41
what are the roles of magnesium in body
cofactor for mangy enzymes
42
what are the 3 main fractions of magnesium in the blood
1. Free ionized
2.. Protein bound
3. Non-protein anion bound
43
decrease pH cause __in magnesium, whereas increase pH and hypoprotinemia causes __in magnesium
increase, decrease
44
what are some causes of hypermagnesemia
1. Decrease GFR
2. Renal failure (ruminants)
45
what are some ddx for hypomagnesemia
1. Hypoproteinemia
2. Inadequate dietary intake
3. Enteric diseases
4. Excess urinary excretion (DM)
46
what is a classic presentation of hypomagnesemia in causes
grass tetany
47
answer kahoot
decrease GFR
48
blood gas evaluation gives info on __ and __
respiratory and metabolic acid base status
49
__blood is commonly used for blood gas evaluation
heparinized venous blood
50
why is it important to cap syringe or blood tube when doing blood gas evaluation
exposure to air causes CO2 to escape—> alkalosis (artifact)
51
what is normal pH range
7.35-7.45
52
what are the 3 mechanisms to protect pH
1. Buffers: HCO3-
2. Regulation by lungs: control partial pressure of CO2
3. Regulation by kidneys- control HCO3- and H+
53
how does hyperventilation affect pH
Increase removal of CO2–> decrease pCO2–> alkalosis
54
how does hypo ventilation affect pH
retention of CO2–> increase PCO2–> acidosis
55
in blood gas analysis respiratory factors affect __ and metabolic factors affect __
CO2, HCO3-
56
what is primary acid base disturbance
major abnormality that drives pH change
57
what is compensatory acid base disturbance
response by opposite system to mitigate altered pH
58
increased partial pressure CO2= hypercapnia or hypercarbia= __
respiratory acidosis
59
decreased partial pressure of CO2= hypocapnia or hypocarbia= __
respiratory alkalosis
60
increased bicarbonate =__
metabolic alkalosis
61
decreased bicarbonate = __
metabolic acidosis
62
Metabolic acidosis is characterized by
1. Decreased HCO3
2. Decreased pH
63
what are the mechanisms of metabolic acidosis
1. Excess H+ accumulation
2. Excess loss of HCO3- (GI or renal)
64
what is compensation for metabolic acidosis
increase ventilation and removal of CO2 (respiratory alkalosis)
65
respiratory acidosis is characterized by
1. Increase PCO2
2. Decrease pH
66
what are mechanisms for respiratory acidosis
1. Hypoventilation (anesthesia, pulmonary disease, pneumothorax)
67
what is compensation for respiratory acidosis
kidneys secrete H+ and conserve HCO3-
Metabolic alkalosis
68
metabolic alkalosis is characterized by
1. Increase HCO3-
2. Increase pH
69
what are mechanisms for metabolic alkalosis
1. Loss of H+ from body: vomiting, pyloric obstruction
2. Gain of HCO3- (rare)
70
what is compensation for metabolic alkalosis
hypoventilation to increase PCO2 (respiratory acidosis)
71
respiratory alkalosis is characterized by
1. Decrease PCO2
2. Increase pH
72
what are mechanisms for respiratory alkalosis
1. Hyperventilation
73
what is compensation for respiratory alkalosis
kidneys conserve H+ and increase HCO3- excretion (metabolic acidosis)
74
if the pH is between __ then there is adequate compensation
7.2-7.6
75
interpret blood gas
1.pH- acidosis
2. PCO2- low- respiratory alkalosis
3. HCO3- low- metabolic acidosis
Primary metabolic acidosis with compensatory respiratory alkalosis (adequately compensated)
76
interpret blood gas
1.pH= alkalemia
2. PCO2- low- respiratory alkalosis
3. HCO3- low- metabolic acidosis
Primary respiratory alkalosis with compensatory metabolic acidosis (inadequate)
77
interpret blood gas
1.pH= acidemia
2. PCO2= normal
3. HCO3= low- metabolic acidosis
respiratory not compensating
78
interpret blood gas
1.pH= alkalemia
2. PCO2- respiratory acidosis
3. HCO3- high- metabolic alkalosis
Primary metabolic alkalosis with compensatory respiratory acidosis (adequate)
79
interpret blood gas
1.pH= acidemia
2. PCO2= high- respiratory acidosis
3. HCO3- low- metabolic acidosis
Mixed respiratory and metabolic acidosis
