Ch.22Smith.ClinicalChemistry Flashcards
Fasting increases what form of bilirubin?
unconjugated bilirubin
Why are there variations in PCV with splenic contraction?
pain
excitement
catecholamine release
With blood loss usually see a decrase in both PCV/TP in what time frame?
24 to 48 hours
Extracellular fluid volume is determined by what electrolyte?
ECF: sodium
Intracellular fluid volume is determined by which electrolyte?
intracellular fluid potassium
Definition of hypertonic dehydration
water loss > loss of Na and K
What are examples of hypertonic dehydration?
hyeprnatremia
free water loss
feed/water deprivation
Define isotonic dehydraiton
water loss = loss of Na and K
Isotonic dehydration is caused by:
heavily sweating endurance horses
acute/ealry dairrhea
Define hypotonic dehydration
water loss less than loss of Na and K
Hypotonic dehydration causes
chronic diarrhea with access to fresh water
Intracellular fluid volume is what percentage of body weight?
40%
Extracellular fluid volume is what percentage of body weight?
20% BW
Sodium depletion occurs in what disease processes
vomiting
diarrhea
excessive sweating
adrenal insufficiency
What diseases of that lead to third spacing can cause hyponatremia?
peritonitis
ascites
bladder rupture
colon/viscus torsion
At what level are progressive neurologic signs seen with hyponatremia?
sodium <115 mEq/L
At what level does hyponatremia is severe/ can cause death?
sodium <100 mEq/L
What can cause falsely decreased sodium values?
marked hyperlipidemia or
hyperproteinemia
Common causes of hyponatremia
Relative water excess:
- Loss of sodium containing fluid (dec effective circulating vol)
- diarrhea
- excessive sweating
- blood loss
- fluid drainage: high-volume gastric reflux, high-volume pleural drainage
adrenal insufficiency
sequestration of fluid (third-space problems)
- peritonitis
- ascites
- pleuritis
- ruptured bladder
- torsion or volvulus of hte gut
False hponatremia: hyperlipidemia, hyperproteinemia, hyperglycemia
Uncommon causes of hyponatremia:
Water retention with normal effective circulating volume:
- psychogenic polydipsia
- renal disease
- inappropriate antidiuretic hormoen secretion
- use of diuretics
Common causes of hypernatremia
- pure water losses: panting, water deprivation
- sodium excess (wate restriction): salt poisoning, feeding only electrolytes, no free water
Uncommon causes of hypernatremia
water loss exceeds electorlyte oss:
- vomiting
- diarrhea
- burns
- intrinsic renal disease
- diuretics
- disbetes insipius: central neprhogenic
- hypertonic saline or sodium bicarbonate administraiotn
- mineralocorticoid excess
What percentage of potassium is in muscle cells and bone?
60-75% total body potassium
Where do herbivores receive potassium?
Herbivores have net intake of K that is regulated by kidneys
In Hypokaelmia, increased resting membrane potential leads to what clinical signs?
muscle weakness
impaire durien concentrating ability
arrhythmias
What are causes of depletion of total body potassium stores:
- Decreased intake and/or latered absorption
- INC GIT losses
- vagal indigestion, torsion of abomasum, ileus, diarrhea
- INC renal losses
- RTA (horses), diuretics, excess mineralocorticoid
- Early postpartum dairy cow
- anorexia and INC K losses
What will cause redistribution of potassium from ECF to ICF?
acute alkalosis
insulin or glucose amdinsitration
aggressive, rapid sodium bicarb administration–> alkalosis & profound hypoK
What is a cause of pseudohypokalemia?
severe lipemia
Causes of false hyperkalemia
- in vitro hemolysis
- prolonged storage of blodo (over 6 hours) w/o separation of serum or plasma
Common causes of hyperkalemia
- altered external balance
- hypovolemia w/ renal shutdown
- alterered internal balance
- metabolic acidosis
- virgorous exercise
- Uroperitoneum
Trimethoprim can cause hpyerkalemia through what mechanism?
Inhibits normal sodium reabsorption in cortical collecting duct
Alters transmembrane voltage–> impairs K secretion
Uncommon causes of hyperkalemia due to altered internal balance
- Hyperkalemic periodic paralysis in Quarter horses
- Diabetes mellitus
- tissue necrosis
- Renal disease
- Addison disease
Hyeprchloremic metabolic acidosis can occur in what disease in horses?
renal tubular acidosis
Disproportionate increases in chloride (in relation to sodium)
normal to low AG hyperchloremic met acidosis
compensation of primary resp alkalosis
Disproportionate decrease in chloride (in relation to sodium)
metabolic alkalosis
compensation for chronic primary respiratory acidosis
Hypochloremic metbaolic alkalosis,
loss or sequestration of chloride rich fluids occurs in what diseases?
displasced abomasum
reflux
diarrhea (Cl- absorbed in ileum, colon in horse)
heavy sweating in horses
diuertic use in horses
What is isotonic osmolality in healthy animals?
ECF ~300 mOsm
(280-310 mOsm in healthy animals)
Where does calcium live within the body and percentages?
99% total body Ca: teeth/bones
- 9% in cell membranes and endoplasmic reticulum
- 1% in serum
Serum calcium roles/function
- maintenance of neuromuscular exictability
- permeability of cell membranes
- conduction of nerve impulses
- muscle contraction
- clotting
Metabolism of calcium is regulated by:
- diet
- vitamin D + metabolites
- PTH
- Calcitonin
Serum Calcium adjusted by:
- intestinal absorption
- renal excretion (INC in horses)
- mobilization from bone
Ionized calcium fluctuates in what acid/base abnormalities?
DEC in alkalosis
**less H bound to albumin = more Ca bound
INC in acidosis
**excess H compete with Ca fo rnegative sites on albumin
At what level of hypocalcemia do dairy cows become recumbent?
<6 mg/dL
Systemic diaphragmatic flutter occurs d/t
phrenic nerves that fire synchronously with atrial depolarization
In renal injury what causes decrease in calcium?
acute renal tubular damage
**hroses, cattle, sheep
Hypocalcemia causes
H: hypoparathyroidism
A: Hypoalbuminemia
R: renal failure (not horses)
P: pancreatitis
I: intestinal malabsorption
S: spurious
A: alkalosis
L: lactation
E: ethylene glycol