Lecture 14: Electrolytes and Acid-Base I Flashcards
1
Q
TBW accounts for __% of adult mammals BW
A
60%
2
Q
what are 2 functions of fluid in body
A
- Transport many substances
- Electrolytes dissolved in fluid
3
Q
___ contains 2/3 of TBW and __ contains 1/3 TBW
A
ICF, ECF
4
Q
what two compartments make up ECF
A
- Intravascular fluid
- Interstitial fluid
5
Q
what are some places where interstitial fluid is stored
A
- Intercellular fluid
- Third spaces
- GI tract fluid
- Synovial fluid
- CSF
6
Q
what controls volume/hydration status
A
- Water intake- thirst
- Renal output
7
Q
___= decreased TBW
A
dehydration
8
Q
how do we identify dehydration in our patients
A
- Decrease BW
- External signs- skin tent, prolonged CRT, retraction of eyes, tacky MM, signs if shock
- Clinpath parameters- increased PCV/HCT, azotemia, hyperproteinemia, increased USG, increase electrolytes
9
Q
___= increased TBW
A
overhydration
10
Q
how do we identify overhydration in our patients
A
- Increase body weight
- Accumulation of fluid in extracellular spaces- edema, ascites, hydrothorax, excess fluid therapy
11
Q
t or f: it is possible for patients to be hypovolemic and have increase TBW
A
true- accumulation of fluid in third spaces or GIT
12
Q
distribution of water between compartments is determined by __
A
quantity of osmotically active particles in each compartment
13
Q
Na+ is most important for __compartment
A
ECF
14
Q
K+ is most important for ___ compartment
A
ICF
15
Q
what are the 3 types of dehydration
A
- Hypertonic
- Isotonic
- Hypotonic
16
Q
what occurs in hypertonic dehydration
A
- Net loss of hypotonic fluid
- Water loss»_space; Na+ loss
- Increased Na+ and Cl-
17
Q
what are some ddx for hypertonic dehydration
A
- Water deprivation
- Diabetes insipidus
- Excessive insensible losses
- Renal loss of water
- Osmotic diarrhea
18
Q
what occurs in isotonic dehydration
A
- Net loss of isotonic fluids
- Water loss= Na+ loss
- Na+ and Cl- don’t change
19
Q
what are some ddx for isotonic dehydration
A
- Alimentary loss-diarrhea
- Renal loss
- Cutaneous loss
20
Q
what occurs in hypotonic dehydration
A
- Net loss of hypertonic fluid
- Water loss < Na+ loss
- Na+ and Cl- decrease
21
Q
what are some ddx for hypotonic dehydration
A
- Addisons
- Third spacing
- Secretory diarrhea
22
Q
define osmolality
A
number of particles of solute per kg of water
23
Q
what is normal ECF osmolality
A
280-310 mOsm/kg
24
Q
what is the osmolal gap
A
measured osmlality- calculated osmolality
25
what is the primary ddx for increased osmolal gap >10
ethylene glycol toxicity
26
what is the effective osmolality of a solution
concentration of solutes that causes shift of H20 across a semipermeable membrane
27
__freely passes between eCF and ICF, thus does not contribute to toxicity
urea
28
since urea passes freely between ECF and ICF, not contributing to toxicity, therefore changes in __ do not cause water shifts between eCF and ICF
BUN
29
answer kahoot
A dehydrated dog with diabetic ketoacidosis (increase glucose, dehydrated- increase BUN)
30
what is the primary cation in ECF
Na+
31
what is primary anion in ECF
Cl-
32
Electrolytes and H20 balance are primarily controlled via __, __, ___ and __
kidneys, GIT, skin and airways
33
what is the most important cation for renal conservation of water
Na+
34
sodium is primarily acquired through __
diet
35
sodium excreted in __, __ and __
feces, urine and sweat
36
what are the 2 factors that influence serum sodium levels
1. Blood volume
2. Plasma osmolality
37
what hormones/systems regulate blood volume and therefore sodium levels
1. RAS
2. Aldosterone
3. ADH
4. ANP
38
how does hyperosmolality affect water reabsorption
thirst center activated and ADH released—> increase drinking and water reabsorption
39
what are some ddx for hyponatremia
1. Loss of sodium- Pee, poop and third space
2. Water excess
3. Movement of water from ICF to ECF
4. Shifting Na+ from intravascular to extravascular space
5. Shifting of NA+ from ECF to ICF
40
what are some GI causes of hyponatremia
diarrhea, hypersalivation
41
what are some renal causes of hyponatremia
1. Addisons
2. Prolonged diuresis
3. Hypoaldosteronism
4. Na+ wasting renal disease
42
what are some third space causes of hyponatremia
1. Hemorrhage
2. Exudation
3. Uroabdomen
4. Repeated draining of chylomicrons effusions
43
what are some causes of water excess leading to hyponatremia
1. Edematous disorders- CHF, hepatic cirrhosis, nephrotic syndrome
2. Psychogenic PD
3. Hypotonic fluid administration
44
what can cause movement of water from ICF to eCF leading to hyponatremia
1. Hyperglycemia (DM)
2. IV mannitol infusion
45
what can cause shifting of NA+ from intravascular to extravascular space leading to hyponatremia
uroabdomen
46
What are 2 ddx for hypernatremia
1. Decreased TBW
2. Increased total body sodium
47
what can cause decreased TBW leading to hypernatremia
1. Insufficient water intake
2. Water loss- panting, fever, hyperventilation, diabetes insipidus
3. Renal osmotic diuresis
4. Osmotic diarrhea
48
what can cause increase total body Na+ leading to hypernatremia
1. Salt poisoning
2. Hypertonic saline infusion
3. Hyperaldosteronism
49
what electrolyte is important component of secretory fluids: gastric fluid, sweat, saliva
Cl-
50
Concentration of Cl- primarily controlled by __
kidneys
51
what are some causes of selective hypochloremia
1. Vomiting
2. Pyloric obstruction
52
What lab work finding do you expect to find with vomiting and pyloric obstruction
hypochloremic metabolic alkalosis
53
How do we determine if Cl- is lost in excess of sodium
corrected chloride= (Normal Na+/ measured Na+) x Cl-
54
how do you interpret Cl- losses if corrected Cl- is within RI
Cl- is being lost in conjunction with Na+
55
how do you interpret corrected Cl- losses below RI
loss of Cl- in excess of sodium
56
do corrected chloride calculation
Chloride: 75 (RI: 98-110)
Sodium: 125 (RI: 135-148)
corrected Cl= (141/125) x 75=84.6 85mmol
Corrected Cl- below RI= selective hypochloremia
57
answer kahoot
Vomiting
58
hyperchloremia is most often present with ___ or if there is decreased bicarbonate= __
hypernatremia or secretional metabolic acidosis
59
what are ddx for selective hyperchloremia
1. GI loss of HCO3-: diarrhea
2. Salivation- cattle- esophageal obstruction
3. Renal loss of HCO3: renal tubular acidosis
60
K+ is obtained via __
diet
61
K+ primarily lost or excreted via __ due to __
kidney due to aldosterone
62
K+ can be exchanged between ECF and ICF for __
H+
63
how would insulin and epinephrine affect K+
stimulate uptake into cells—> decrease K+
64
how would a metabolic acidosis affect K+
Exchange H+ for K+—> increase K+
65
how would a metabolic alkalosis affect K+
decrease K+
66
what are the 3 ddx for hypokalemia
1. Decreased intake
2. Increased loss
3. Shifting from ECF to ICF
67
what would cause increase loss of K+
1. GI loss- vomiting, abomasal disorders, diarrhea
2. Renal loss- polyuria, diuretics, hyperaldosteronism, renal tubular acidosis
3. Profuse sweating or prolonged exercise
68
what would cause shifting of K+ from ECF to ICF causing hypokalemia
1. Metabolic alkalosis
2. Insulin therapy
69
what are the causes of hyperkalemia
1. Decreased urinary excretion- urinary tract obstruction, uroabdomen, renal failure, addisons (lack aldosterone)
2. DM
3. Metabolic acidosis
4. HYPP in horses
5. Repeated drainage of chylous effusions
6. Whipworms infection
7. Pseudohyperkalemia
8. Hemolysis
70
how would DM cause hyperkalemia
insulin deficiency—> lack of K+ movement into cells
71
what are the ddx for Na:K ratio < 25
1. Decreased renal excretion of K+: addisons, renal failure, post-renal obstruction, uroabdomen
2. Diarrhea caused by whipworms infection
3. Repeated drainage of chylous effusion
72
what are the 2 subtypes of metabolic acidosis
titrational and secretional
73
TCO2 = __
HCO3
74
increased TCO2= __
metabolic alkalosis
75
decreased TCO2= __
metabolic acidosis
76
if TCO2 is normal could be __
mixed acid base disturbance
77
what is the anion gap equation
AG= (Na + K+)- (Cl+ HCO3)
78
an increased anion gap is indicative of __
titrational metabolic acidosis
79
what are ddx for increased anion gap/ titrational metabolic acidosis
KULE
1. Ketones- negative energy balance, DKA
2. Uremic acids- renal failure
3. Lactic acids- decreased perfusion, dehydration, hypoxia
4. Ethylene glycol
80
what are the 2 causes of a decreased anion gap
1. Hypoalbunemia
2. Hypercalcemia
81
answer kahoot
Hyperlactatemia
82
metabolic acidosis characterized by a decrease in __
TCO2/HCO3-
83
what are biochemical findings consistent with titrational metabolic acidosis and what are ddx
1. Low TCO2/HCO3-
2. Cl- within RI
3. High AG
Ddx: KULE, hyperalbuminemia
84
what are biochemical findings for secretional metabolic acidosis
1. Low TCO2/HCO3-
2. Cl- within RI or increased
3. Normal AG
85
what are some causes of secretional metabolic acidosis
1. Diarrhea
2. Duodenal vomiting
3. Renal tubular acidosis
86
metabolic alkalosis is characterized by increase in __
TCO/HCO3-
87
what are biochemical findings for metabolic alkalosis
1. Increase TCO2
2. Decreased Cl- in excess of Na+ (hypochloremic metabolic alkalosis)
88
what are some causes of metabolic alkalosis
1. Vomiting
2. Abomasal stasis
3. Proximal duodenal obstruction
4. Horses- gastric reflux
89
answer kahoot
Dog with marked dehydration from heat stroke (dehydration—> increase lactic acid—> titrational acidosis)
90
what is paradoxical aciduria
urine pH is acidic in face of metabolic alkalosis
91
what species is paradoxical aciduria most commonly seen in
ruminants
92
what 3 things are required to cause paradoxical aciduria
1. Hypovolemia
2. Hypochloremia
3. Hypokalemia
93
what is tx for paradoxical aciduria
correct NaCl deficit with appropriate fluids and K+ supplementation
94
what type of acid base disturbance would you expect in patient with renal disease that is also vomiting or vomiting patient with DKA
mixed titrational metabolic acidosis and hypochloremic metabolic alkalosis
95
what are the typical biochem findings for mixed acid base disturbances
1.normal TCO2/HCO3
2. Low corrected Cl-
3. High anion gap
96
what are two situations where you should be suspicious of mixed acid base disturbance
1. When AG gap is high, but TCO2 is normal
2. When Cl- is lost in excess of Na+ but TCO2 is normal
