Clin Path exam 4

Total body water is what % of body weight

60

Total body water is split into ICF and ECF, what % of BW is ICF

40

Total body water is split into ICF and ECF, what % of BW is ECF

20

ECF is made up of

interstitial fluid and plasma

What % of BW is plasma

5

Is fluid located predominantly intracellularly or extracellularly

intracellularly

Major extracellular cation

Na+

Major intracellular cation

K+

Significant cell lysis increases what ion concentrations in the blood

K+ and PO4-

What might cause increased serum K+ and PO4-

tumor lysis syndrome, rhabdomyolysis, and severe tissue damage

Concept that says total boy cations and anions must be balanced

electroneutrality

What cations like to exchange with each other

K+, Na+, and H+

What anions like to exchange with each other

Cl- and HCO3-

Electroneutrality means when an anion increases what must happen

other anions must decrease or cations must increase

Angiotensin 2 effects

Na+ resorption, aldosterone secretion, increased thirst

Aldosterone causes resorption of

Na+ and Cl-

Aldosterone causes excretion of

K+ and H+

ADH causes insertion of aquaporins into the collecting duct and causes

water retention

Overall the RAAS system is activated in response to hypovolemia and causes

Na+ and water retention

What is released in response to hypervolemia

ANP

What does ANP do

inhibits renin and aldosterone

The secretion of ANP in response to atrial distension caused by hypervolemia causes excretion of

Na+ and water

Where are osmoreceptors located

hypothalamus

Osmoreceptors tightly regulate osmolality, what % change in osmolality stimulates a maximum ADH response

1-2%

Hyperosmolarity stimulates

ADH and thirst to retain water and dilute the solute

Hypoosmolarity inhibits

ADH and thirst response to excrete more water

What osmole contributes most to plasma osmolality

Na+

Ineffective osmoles

urea and K+

Is calculated or measured osmolality found on a serum chemistry panel

calculated

What fluid/electrolyte issue should always be addressed 1st when there are contradicting resposnes

hypovolemia

Order of precedence that you should address fluid/electrolyte issues

1. hypovolemia

2. hyperosmolality

3. hypervolemia

What should you correct 1st in a hypovolemic and hyperosmolar patient

hypovolemia

What should you correct 1st in a hyperosmolar and hypervolemic patient

hyperosmolality

Causes of hypernatremia

water deprivation, impaired thirst response, diabetes insipidus, osmotic diuresis, osmotic diarrhea, paintball toxicosis, panting, hyperventilation, salt poisoning (play doh, seawater), baking soda (sodium bicarbonate) administration

water loss>Na+ loss and Na+ excess can lead to

hypernatremia

A pig showing neurological signs has had their water source frozen and then fixed. What is causing the neuro signs

rapid correction of hypernatremia causes cerebral swelling

An animal ingests play doh or seawater, what are you concerned about

hypernatremia

What clinical signs can be seen in animals with Na+ levels >170 mg/dL

neurologic signs

Hypernatremia causes the brain to

shrink and rupture cerebral vessels

Sudden rehydration with hypotonic water after hypernatremia causes

cerebral swelling

At what pace should you correct hypernatremia

slowly

Causes of hyponatremia

GI loss (v/d, sequestration, whipworms, excess salivation), renal loss (hypoadrenocorticism, Na+ wasting nephropathy), 3rd space loss, cutaneous loss (sweating), edematous disorders, hyperglycemia, lipemia

Na+ loss>H2O loss, H2O excess, hyperglycemia, and lipemia cause

hyponatremia

Pseudo-hyponatremia

lipemia causes false hyponatremia

What can shift water from ICF→ECF

hyperglycemia

Cl- should always be interpretted with

Na+

If Na+ and Cl- move together Cl- will move for the

same reason as Na+

If Na+ and Cl- move separately

acid-base disorder

How do you determine is Na+ and Cl- are moving together

corrected chloride

Because most K+ is intracellular, serum K+ is

not a good indicator of total body K+

Hyperkalemia clinical signs

bradycardia, atrial standstill, asystole, death

Hypokalemia clinical signs

muscle weakness, inability to breathe, death

Causes of hyperkalemia

oliguric/anuric renal disease, urethral obstruction, uroabdomen, decreased tubular flow (hypovolemia), hypoadrenocorticism, supplementation

A male orange cat comes in with bradycardia and anuria what is going on

hyperkalemia due to a urethral obstruction

Hypoadrenocorticism is associated with what Na+ and K+ changes

Hyponatremia and hyperkalemia

Metabolic acidosis causes what change in K+

hyperkalemia

K+ moves into the cell with glucose after activation of Glut4 transporters. This means an insulin deficiency would cause what change in K+

hyperkalemia

Severe tissue damage/rhabdomyolysis would cause hyper or hypokalemia

hyperkalemia

What causes pseudohyperkalemia

extreme thrombocytosis, hemolysis, EDTA contamination

Hyperkalemia and hypocalcemia in a sample may be indicative of

EDTA contamination

What dog breeds are known for high K+ in RBCs

asian dog breeds

EDTA contaminated blood will have what electrolyte abnormalities

hyperkalemia and hypocalcemia

Metabolic alkalosis will cause what change in K+

hypokalemia

Causes of hypokalemia

K+ poor fluids, renal loss (CKD, post obstructive diuresis, diuretics, DKA, polyuric state), GI loss (gastric vomiting, SI diarrhea), skin loss, metabolic alkalosis, increased insulin, endotoxemia,

A blocked cat recently got unblocked and now is polyuric, what electrolyte abnormality are you worried about

hypokalemia

Insulin moves K+ into cells, therefore increased insulin would cause

hypokalemia

Metabolic alkalosis has more H+ inside cells than in blood, therefore K+ is moved where while H+ is moved into blood

into the cell→hypokalemia

Metabolic acidosis has more H+ in the blood, therefore K+ is moved where while H+ is moved into cells

into the blood→hyperkalemia

Hypokalemia or K+ WRI is seen with acidosis, what does this suggest

low total body K+

Hyperkalemia or WRI K+ is seen with alkalosis, what does this suggest

High total body K+

Low Na:K ratio causes

Renal disease, Addison’s disease, gastroenteritis, uroabdomen

A high or low Na:K ratio is seen with Addison’s disease

low

RAGU is an acronym used to remember the causes of

low Na:K ratio

Na:K <27

suspicious for Addison’s

Na:K <19

highly associated with Addison’s

Addison’s disease is associated with a decrease in what mineralocorticoid that in turn causes hyperkalemia and hyponatremia

aldosterone

A full acid base evaluation requires a

blood gas and chemistry

In order to diagnose respiratory acidosis or alkalosis what diagnostic panel do you need

blood gas

2 types of metabolic acidosis

secretional and titrational

TCO2 is synonymous with

HCO3-

Low HCO3- tells you

metabolic acidosis

Titrational metabolic acidosis is characterized by low HCO3- and

increased anion gap

Secretional metabolic acidosis is characterized by low HCO3- and

high chloride

Metabolic alkalosis is characterized by high HCO3- and

low chloride

Low chloride and high HCO3-

metabolic alkalosis

High chloride and low HCO3-

secretional metabolic acidosis

High anion gap and low HCO3-

titrational metabolic acidosis

Corrected chloride above reference interval

secretional metabolic acidosis

Corrected chloride below reference interval

metabolic alkalosis

Corrected chloride within reference interval

chloride is moving with sodium

Chloride increases with sodium

hypernatremia

Chloride decreases with sodium

hyponatremia

Most common cause of secretional metabolic acidosis

secretory diarrhea

pseudo-hyperchloremia is caused by

potassium bromide treatment

Hyperchloremic or non-gap metabolic acidosis is another name for

secretional metabolic acidosis

Most common cause of metabolic alkalosis

vomiting

A cow with hypochloremia and metabolic alkalosis most likely has

LDA or RDA

Vomiting, upper GI sequestration, diuretics, bovine renal failure, and equine excessive gastric reflux can all cause metabolic alkalosis and hypochloremia. What are examples of upper GI sequestration

LDA, RDA, pyloric obstruction, hemorrhagic bowel syndrome in cattle, proximal enteritis in horses

Bovine renal failure can cause what acid/base abnormality

metabolic alkalosis

Vomiting is the #1 cause of what acid/base disorder

metabolic alkalosis