Fluids and Electrolytes

Question 1

Osmotic Pressure

Answer 1

Pulling force created by particles (i.e. plasma proteins) that do not pass through capillary pores
Capillary colloidal pressure is greater than interstitial colloidal pressure

Question 2

Hydrostatic Pressure

Answer 2

Fluid pushing force inside the capillary

Inside capillaries hydrostatic pressure and capillary filtration pressure are equal

Question 3

S/S of Dehydration

Answer 3

Increased thirst
Dry mouth
Tired or sleepy
Decreased urine output
Urine is low volume and more yellowish than normal
Headache
Dry skin
Dizziness
Few or no tears

Question 4

Sodium, Na+2

Answer 4

135-145 mEq/L
- the most abundant cation in ECF
- functions: maintain water balance, nerve
impulse transmission, regulate acid-base
balance, and participate in cellular
chemical reactions.
- regulated by dietary intake & aldosterone
secretion

Question 5

Hyponatremia

Answer 5

Na+ < 135 mEq/L 
  sodium loss (GI, renal,
  &amp; skin losses: sweating);
  pshychogenic 
  polydipsia (drinking water increase); water
  intoxication; SIADH (Excess ADH)

Question 6

Hyponatremia S/S

Answer 6

lethargy, edema, headache,
disorientation,
seizures, coma.
Pure Na loss: hypovolemia
Dilutional: Hypervolemia

Question 7

Hypernatremia

Answer 7

Na+ > 145mEq/L
Causes: Excess salt intake, aldosterone secretions, Diabetes Insipidus, increased sensible & insensible water loss, water deprivation (hypertonic/hypernatremic)

Question 8

Hypernatremia S/S

Answer 8

thirst, dry & flushed skin, dry & sticky m.m., postural hypotension, fever, CNS: agitation, decreased reflexes, convulsions, restlessness, & irritability.

Question 9

Hypocalcemia

Answer 9

Ca2+< 8.5 mg/dL
Rapid administration of blood containing citrate, hypoalbuminemia, hypoparathyroidism, vitamin D deficiency, alkalosis, pancreatitis, Chronic Renal Failure (Vitamin D not activated), chronic alcoholism

Question 10

Hypocalcemia S/S

Answer 10

numbness & tingling of fingers and circumoral (around mouth) region, hyperactive reflexes, +Trousseau’s (nerve excitability/tetany of fingers during BP) & +Chvostek’s sign (Stroking cheek), muscle cramps, fractures (if chronic). ECG: prolonged ST & QT…

Question 11

Hypercalcemia

Answer 11

Ca2+> 10.5 mg/dL

Hyperparathyroidism, Cancer, Paget’s disease, osteoporosis, prolonged bed rest, thiazide diuretics.

Question 12

Hypercalcemia S/S

Answer 12

Anorexia, abdominal pain & constipation, muscle weakness, hypoactive reflexes, lethargy, flank pain (if kidney stones), ECG: shortened QT & ST segment

Question 13

Hypokalemia

Answer 13

K+ < 3.5 mEq/L
Causes: Use of K+ wasting diuretics (most), polyuria, GI losses (vomiting, diarrhea, NG/colostomy outputs), alkalosis, Tx of DKA with insulin.

Question 14

Hypokalemia S/S

Answer 14

Skeletal muscle weakness 
U wave/ ECG changes (PR Interval increase)
Constipation, ileus
Toxic effects of digoxin
Irregular, weak pulse
Orthostatic hypotension
Numbness (paresthesias)

Question 15

Chvostek sign

Answer 15

is a clinical sign of existing nerve hyperexcitability (tetany) seen in hypocalcemia. It refers to an abnormal reaction to the stimulation of the facial nerve.

Question 16

Trousseu sign

Answer 16

a test for latent tetany in which carpal spasm is induced by inflating a sphygmomanometer cuff on the upper arm to a pressure exceeding systolic blood pressure for 3 minutes. A positive test may be seen in hypocalcemia and hypomagnesemia.

Question 17

Hyperkalemia

Answer 17

K > 5 mEq/L
Renal failure, fluid volume deficit, massive cellular damage (burns & trauma), acidosis (esp DKA), rapid infusion of stored blood, use of K+-sparing diuretics, salt substitutes.

Question 18

Hyperkalemia S/S

Answer 18

ECG changes (tall, tented T wave), paresthesias, muscle weakness, abdominal cramping, diarrhea.

Question 19

Renin/ADH/Aldosterone/Angiotensin

Answer 19

1. Low blood pressure/blood flow is sensed by the Juxtaglomerular apparatus in the kidney (which are cells next to the glomerulus). This is because a decrease in Na+ will reduce the amount of water in the blood, thus the blood will have a lower pressure. This follows the principle of osmosis, which states that water will diffuse to areas that have highly concentrated solutes.
2. In response to this, the glomerulus releases a hormone known as renin into the blood stream.
3. Renin then moves to the liver, where it converts an inactive peptide (protein) angiotensinogen to an active angiotensin I.
4. Angiotensin I then travels to the lungs where an enzyme known as the Angiotensin Converting Enzyme (ACE), converts Angiotensin I to Angiotensin II. One effect Angiotensin II has on the body is in its ability to constrict blood vessel, thus increasing blood pressure. Another function of it is to stimulate the adrenal glands on top of the kidneys to produce the hormone Aldosterone.
5. Aldosterone stimulates the reabsorption of sodium (Na+) in the distal convoluted tubules. Increasing sodium reabsorption means that water and chloride will follow, thus increasing blood volume.
6. An increase in blood volume may also trigger the release of a hormone known as Atrial Natriuretic Hormone, which inhibits the release of Aldosterone, keeping the body’s water and sodium levels at the homeostatic levels. This last step is known as a negative feedback loop.