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Clin Med - Electrolytes

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drraythe's version from 2016-01-30 11:12

Electrolyte cases

Question Answer
CASE: Mare w/ intermittent mm twitching that occasionally progresses to recumbency, weakness & dyspnea.... hyperkalemia shows up on your lab tests? What are your Ddxs? What if you knew the mare was impressive bred?DDX: HYPP (hyperkalemic periodic paralysis) which is what Impressive had (affects sodium channels in muscle cells & the ability to regulate potassium levels in the blood.). It could also be from excessive K+ intake, mytonic conditions, or tetanus..
OTHER Ddx for hyperkalemia incld pseudohyperkalemia (hemolysis, age of sample), ↑ intake, transcellular shift, ↓ renal excretion (ARF, CRF, Addision's)
CASE: Holstein cow presents in recumbency following calving. Weak & unable to stand, muscle fasciculations of the triceps & facial muscles. She also had Dystocia(obstructed labor) & prolonged stage 2 labor, w/ retained fetal membranes, tachycardia. Which electrolytes do you think are affected? what are some Ddxs?HYPOCALCEMIA / HYPOMAGNESEMIA. Ddxs are milk fever, obturator nerve paralysis, pelvic fracture & severe ketosis
If you are considering hypocalcemia, what else must you consider?Mg++ levels
What 3 main things can lead to hypocalcemia?Dietary lack, renal failure, endocrine abnormalities (NOTE: lose a lot of electrolytes/Ca++ in milk also)
Where can a rumi lose Mg? Horse?Rumi in the saliva, horse in the sweat
What are 2 ways animals can lose Mg?(1) Imbalance btwn intestinal absorption & renal excretion
(2) Secreted in saliva (ruminants) & sweat (horses)
CASE: Gelding w/ Chronic intermittent lameness, Ocular discharge bilaterally, Enlargement of the facial bones, w/ a diet of poor quality hay & bran mash. What electrolytes are the problem? Ddxs?HYPOCALCEMA & HYPERPHOSPHATEMA. DDX incld Nutritional 2° hyperparathyroidism, Chronic renal failure & 2° hyperparathyroidism (dogs), hypercalcitosis, hypoalbuminemia
CASE: 2 day old calf w/ diarrhea & bradycardia, depressed, hypovolemic, inappetant, acidotic, low bicarb, On ECG: atrial stand still & tented T waves...which electrolyte do you think is involved? DDXs?HYPERKALEMA. Ddx is Metabolic acidosis associated w/ diarrhea, Repartitioning of electrolytes, dietary, renal dz, iatrogenic
Tx of metabolic acidosis?Sodium bicarbonate IV or orally
What are some complications you'll see w/ diarrhea?Metabolic acidosis, dehydration/hypovolemia, Loss or dilution of sodium (rate is important), Loss of free water & concentration of sodium (rate is important)
***WHAT IS CRAZY IMPORTANT TO KNOW WHEN YOU ARE TREATING HYPOKALEMA?************DO NOT EXCEED 0.5 Eq/kg/hour!*************** You can dilute hyperkalemia out quickly but you can’t give potassium quickly.
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Electrolytes

Question Answer
What is an electrolyte?“An electrolyte is a substance that ionizes when dissolved in suitable ionizing solvents such as water”
What are some examples of electrolytes?Salts, acids & bases (also Others incld: gases such as hydrogen chloride, biological & synthetic polymers (polyelectrolytes which contain charged fxnal groups) )
What are the most important electrolytes in the body?Sodium (Na+)
Chloride (Cl-)
Potassium (K+)
Calcium (Ca++)
Magnesium (Mg++)
Phosphate (PO4-)
Bicarbonate (HCO3-)
How do animals acquire electrolytes? What are ways there is an elevation in electrolytes the animal didn't have control over?(1) DIET
(2) IATROGENIC (fluids/medications)
(3) TISSUE BREAKDOWN
(4) False elevations on biochemistry(hemolysis/old sample)
How do animals eliminate the electrolytes? (incld basic explanation) (6)(1) Kidney (made to regulate ions)
(2) GI (diarrhea/vomiting)
(3) Sweating (HORSES)
(4) Salivating (COWS)
(5) Milk (salt, potassium, Ca, Mg....)
(6) Respiratory system (CO2, evaporation, Respiratory acidosis & Respiratory alkalosis, Compensation for Metabolic acid base derangements)
WHAT ARE THE MAJOR ECF CATIONS????Na+
K+
Ca++
Mg++
WHAT ARE THE MAJOR ECF ANIONS????Cl-
HCO3-

SO4-
HPO4-
WHAT ARE THE MAJOR ICF CATIONS????K+
Mg++
Na+
Ca++
WHAT ARE THE MAJOR ICF ANIONS????HPO4-
Protein

SO4-
HCO3-
Cl-
Electrolytes are Integral to most physiological fxns in the body...give some examples of where/how they are usedEnzymes
Cofactors
Transport proteins
Structural proteins
What cells/processes do electrolytes affect the most in the body?Neural cells
Muscle cells
Bone
Coagulation
Tissue necrosis
Why are electrolytes important to neural cells?Needed for action potential & synapse fxn
Why are electrolytes important to muscle cells?Needed for action potential, motor end plate fxn & Actin & myosin interaction... sm, skele & cardiac all need Ca++ for ContrActing (sm mm is most affected by Ca++)
Why are electrolytes important to bone?needed to be the mineralized bone component, Hydroxylapatite ([Ca5(PO4)3(OH)])
Why are electrolytes important to clotting?Ca++ is needed as a cofactor
Which electrolyte plays an important role in tissue necrosis?Ca++ is needed & triggers the release of other electrolytes also (K+ is important also)
The kidney is important in the balance of what electrolyte?NA:water balance
The respiratory center is important in the balance of what electrolyte?Acid & base balance (H+)
The parathyroid gland is important in the balance of what electrolyte?Ca & P
How does the electrolyte-water balance affect the behavior of a dehydrated animal?If there is a horse which is 5% dehydrated & it has a high concentration of salt in the blood, it will be very thirsty & drink. If another horse is twice as dehydrated & 10%, but the concentration of Na is low, then it WONT drink (one more reason hypovolemia is more dangerous than dehydration)
What is 1 of the only animals which can tell/know if there is an electrolyte/protein/fats/carbs imbalance & they can change their bh accordingly?Chicken!
Explain how K+, Mg+ & metabolic acidosis & alkalosis are relatedK+/Mg+ are 1° intracellular ions
In a metabolic acidosis, H+ starts to build up in the blood & it is imperative the keep the blood pH balanced, so the body exchanges the H+ to go into the cell & the K+ to go out, resulting in hyperkalemia & hypermagnesemia. In a metabolic alkalosis, the body takes the Mg+ & K+ which are in the blood & exchanges them for theH+ which is in the cells, in order to balance the pH. This can lead to hypomagnesemia & hypokalemia
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