Patho (U1.8): Fluid, Electrolyte, Acid-Base Imalances

intracellular compartment (ICF)

fluid inside cells and 2/3 of fluids in body

extracellular compartment (ECF)

fluid outside of cells and 1/3 of fluids in body

intravascular fluid (IVF)

ECF in blood vessels and 20% of ECF fluid

interstitial fluid (ISF)

ECF around cells and 80% of ECF fluidt

transcellular fluid

ECF fluid like cerebrospinal fluid

why do males have more fluid in their bodies than females?

more muscle mass means more fluids

younger children are predisposed to what as a result have large amounts of fluid?

dehydration

filtration

pushing fluid out of blood vessel into interstitial space from hydrostatic pressure

osmosis

pushing fluid into blood vessel from intersitial space from osmotic pressure

edema

excessive fluid in intersitial compartment causing swelling or enlargement of tissue

transudate edema

excess fluid in intersitial space as a result from increased hydrostatic pressure from increased blood pressure or decreased osmotic pressure from loss of plasma proteins such as albumin

what protein is important in transudate edema

albumin

exudate edema

increased capillary permeability due to inflammatory response or infection. histamine is released which dilates blood vessels, leaking chemicals into interstitial space

which protein is important in exudate edema

histamine

manifestations of transudate edema

pitting

manifestations of exudate edema

nonpitting, swelling, pain

dehydration

insufficient body fluid

diabetic ketoacidosis

complication of diabetes leading to frequent urination leading to loss of lfuid, electrolytes, glucose

third spacing of fluid

fluid shifts from blood into body cavity and can no longer return. caused by increased osmotic pressure or increased capillary permeablity

manifestations of dehydration

dry mucous membranes in mouth, decreased skin turgor (elasticity), decreased blood pressure (tachycardia), weak pulse, fatigue, increased hematocrit, decreased mental function

antidiuretic hormone (ADH)

secreted in response to dehydration to signal for increased osmolarity in kidney tubules

what is the urine like after ADH is released?

smaller urine volume with increased urine concentration

diabetes insipidus

deficiency of ADH causes high amounts of diluted urine which leads to increased thirst

central or neurogenic diabetes insipidus

trauma or complication to hypothalamus causes defect in release or synthesis of ADH

nephronic diabetes insipidus

damaged nephrons causes kidneys to not respond to ADH

SIADH

failure of negative feedback system that regulates ADH, leading to excess ADH and is caused by nervous system disorders

what does escess ADH lead to ?

increased ADH causes increased osmolarity (water intake) which prevents sodium reabsoprtion causing very concentrated urine

psychogenic polydipsia

compulsive water drinking caused by antipsychotic medications that increase ADH and is common with schizophrenia patients

sodium electrolyte

regulates osmolarity and is a primary ECF cation

aldoesterone

regulates sodium; secreted in response to low blood pressure

effects of aldoesterone to sodium

increases sodium reabsoprtion from urine into blood and also excretes potassium into urine

ANP

regulates sodium and is secreted in response to high blood pressure

effects of ANP on sodoum

increases sodium excretion into urine along with water

hyponatremia

plasma concentration of sodium is less than 135mEq/L caused by excessive sweat/vomitting, diretic drugs, low-salt diet, excess water intake, decreased aldosterone, increased ADH

effects of hyponatremia

hypotonic alteration (ECF is less concentrated), ISF becomes hypotonic as water moves out of blood and into cells

what is a common edema related to hyponatremia

cerebral edema

hypernatremia

plasma concentration of sodium is greater than 145 mEq/L caused by decreased ADH (diabetes insipidus), water diarrhea, ingesting lots of sodium without water

effects of hypernatremia

hypertonic alteration (ECF is more concentrated), dry mucous membranes, increased thirst

potassium electrolye

regulates fluid and sodium balance and is important intracellular cation

how does acid-base balance affect potassium serum levels

acidosis increases potassium levels and alkalosis decreases potassium levels

hypokalemia

plasma potassium concentration is less than 3.5 mEq/L and is caused by diarrhea, diuretic drugs, increased aldosterone, eating disorders

effects of hypokalemia

decreased neuromuscular funciton and possible paralysis

hyperkalemia

plasma concentration of potassium is greater than 5 mEq/L caused by renal failure, diuretics, leakage of potassium into ECF because of acidosis

effects of hyperkalemia

LIFE THREATENING, cardiac dysrhythmias, cardiac arrest

hyperkalemia on an EKG

wide QRS, long PR, tall and narrow T wave

calcium electrolyte

regulates nerves, muscle contractions, blood clotting and is an extracellular cation

what is calcium controlled by

PTH and calcitrol (vit D)

3 forms ECF calcium

protein-bound to albumin (40%), complexed (10%), ionized (50%)

hypocalcemia

plasma concentration of calcium less than 4.3 mEq/L caused by hypoparathyroidism (PTH/VitD signals calcium reabsorption into nephrons), low serum albumin, renal failure

effects of hypocalcemia

increased excitability of nerve membranes, tetany (spontaneous stimulation of muscle)

hypercalcemia

plasma concentration of calcium greater than 5.3 mEq/L caused by tumors that release calcium from bones, hyperparathyroidism (PTH/vitD release calcium into blood), excessive intake

effects of hypercalcemia

decreased neural excitability, decreased neruomuscular activity thus loss of muscle tone

magnesium electrolyte

intracellular ion and huge regulator

hypomagnesemia

plasma concentration of magnesium less than 1.8mg/dL caused by alcoholism

effects of hypomagesemia

increased neuromuscular activity, hypertension, cardiac dysrthytmia

hypermagenesemia

plasma magnesium concentration greater than 3mg/dL caused by renal failure

effects of hypermagnesemia

decreased neuromuscular activity

blood pH normal range

7.35-7.45

acidosis

ph is less than 7.35

respiratory acidosis

increased Co2 because of acute respiratory problems (pneumonia, obstruction) and chronic respiratory disorders

effects of respiratory acidosis

decreased breathing leading to increased co2 which lowers pH

compensation for respiratory acidosis

kidney conserves bicarbonate and lowers H+

metabolic acidosis

increased H+ in blood caused by chronic kidney disease, diabetic ketoacidosis (ketones are acidic)

effect of metabolic acidosis

impaired nervous system

compensation for metabolic acidosis

respiratory (hyperventilation to decrease co2 lvls), renal (conserve bicarbonates and remove H+)

alkalosis

pH is greater than 7.45

respiratory alkalosis

decreased co2 levels from hyperventilation, anxiety, fever, head injury, brainstem tumor

compensation for respiratory alkalosis

kidney conserves H+ and decreased bicarbonates

metabolic alkalosis

decreased levels of H+ in blood caused by decreased hydrochloric acid in the stomach

compensation for metabolic alkalosis

respiratory (hypoventilation to retain co2), renal (conserve H+ and rid of bicarbonates)

decompensation

primary regulatorys of pH has failed and requires intervention to maintain homeostasis

acid-base imbalance assessment in 4 steps

1.assess blood pH

2.assess PaCO2

3.assess bicarbonate levels

4.determine if compensation is taking place

A client with a history of heart failure is admitted with a

serum sodium level of 122 mEq/L. The nurse knows

that the client is at risk for which of the following fluid

shifts?

hyponatremia, fluid shifts from vascular compartment into interstitial compartment (into cell);

A nurse is reviewing the laboratory results for a

client with end-stage renal disease and notes a

serum potassium level of 6.5 mEq/L. The nurse

should assess for which of the following

electrocardiogram (EKG) changes?

hyperkalemia, peaked T-waves and widened QRS complex

What is the effect of increased ADH secretion

on blood volume?

ADH is secreted in response to dehydration so increased ADH would increase blood volume as it pulls water from urine into the blood

How do the kidneys compensate metabolic

alkalosis?

kidneys retain H+ while excreting bicarbonates