Week 4 - Lecture 1a - Altered Electrolyte Balance Flashcards Preview

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Flashcards in Week 4 - Lecture 1a - Altered Electrolyte Balance Deck (36):
1

cells function depends on what

continuous supply of nutrients
removal of waste products
physical and chemical homeostasis of surrounding fluids

2

Water

universal solvent

3

solutes

what is dissolved in water
- classified as non electrolytes and electrolytes

4

non electrolytes

most organic
-do not dissolve in water: glucose, lipids, creatinine, and urea
-no charged particles created

5

electrolytes

dissociate into ions in water
e.g. inorganic salts, all acids and bases, some proteins
ions conduct electrical current

electrolytes have a greater osmotic power than non-electrolytes
greatest ability to cause fluid shifts

6

electrolyte concentration

expressed in miliequivalents per litre (mEq/L)

mEq/L = ion concentration *mg/L) / atomic weight of ion (mg/mmol) x

7

extracellular and intracellular fluids

each fluid compartment has distinctive pattern of elctrolyte

8

extracellular fluid

major cation : Na+
major anion : Cl-

9

intracellular fluid

Low Na+ and Cl-
Major cation : K+
Major anion : HPO 4^2-

10

electrolyte balance

electrolytes are salts, acids, bases, some proteins
electrolyte balance usually refers only to salt balance

1. salts control fluid movements
2. provide minerals for excitability
3. secretory activity
4. membrane permeability

salts enter body by ingestion and metabolism
lost via perspiration, feces, urine, vomiting

11

altered sodium balance

most abundant cation in the extracellular fluid

only cation exerting significant osmotic pressure

- controls extracellular fluid volume and water distribution

-changes in Na+ levels
- affects plasma volume
- blood pressure
- extracellular and intracellular fluid volumes

12

Sodium balance altered

Na+ leaks into cells
- pumped out against electrochemical gradient
Na+ moves back and forth between the extracellular fluid and body secretions (eg. digestive secretions)

Concentration of Na+
- determines osmolality of extracellular fluid
- influences excitability of neurons and muscles
-Remains stable due to water shifts out of or into intracellular fluid

Content of Na+
- total body content of Na+ determines extracellular fluid volume and therefore blood pressure

13

Hyponatraemia (low sodium)

serum sodium <135mEq/L
cause
- vomiting
- diarrhoea
-sweating

manifestations are related to cellular swelling
- muscle twitching, weakness
-hypotension
- tachycardia
- oliguria
- anuria (no urine output)
-altered neuronal function (nausea, vomiting, lethargy)

14

Hypernatraemia (high sodium)

serum sodium > 145mEq/L

cause
- related to sodium gain or water loss
- excessive dietary intake
-water movement from the intracellular to the extracellular compartment
- intracellular dehydration

15

manifestations of hypernatraemia

intracellular dehydration
agitation, restlessness, decreased level of consciousness
hypertension
tachycardia
edema
weight gain

16

Importance of potassium

extracellular fluid has higher concentration of Na+ than intracellular fluid
- balanced chiefly by chloride ions (Cl-)

Intracellular fluid has higher concentrations of K+ than the extracellular
- balanced negatively charged proteins

K+ plays most important role in membrane potential

17

What is hypokalaemia

low potassium(<3.5 mEq/L)

18

Manifestations of hypokalaemia (low potassium)

dizziness, muscle weakness, and leg cramps

cardiac arrhythmia, hypotension, thirst, nausea, anorexia, poorly concentrated urine, polyuria

19

What is hyperkalaemia

high potassium (>5mq/L)

20

manifestations of hyperkalaemia

cardiac arrest

abdominal cramping, flaccid paralysis

21

what is hypochloremia

low chlorine (<98mEq/L)

22

manifestations of hypochloremia (low chlorine)

increased muscle tone, twitching, weakness, and tetany
shallow, depressed breathing
respiratory arrest
mental confusion

23

what is hyperchloremia

high chlorine (>108mEq/L)

24

manifestations of high chlorine (hyperchloremia

hyperchloremic metabolic acidosis rapid breathing
deep, rapid breathing
weakness, headache, and diminished cognitive activity
cardiac arrest

25

What is hypocalcemia

low levels of calcium (<8.5mg/dL)

26

manifestations of low calcium (hypocalcemia

enhanced neuromuscular irritability
anxiety, irritability and seizure
muscle twitching, cramps, spasms, tetany and laryngospasm
hypotension
cardiac arrhythmia

27

What is hypercalcemia )

elevated calcium levels (>10.5mg/dL)

28

Manifestations of elevated calcium levels (hypercalcemia)

decreased neuromuscular irritability
confusion, fatigue, headache, and irritability
constipation, nausea and vomiting
cardiac arrhythmia

29

What is hypomagnesemia

low magnesium levels (<1.5mEq/L)

30

manifestations of low magnesium levels (hypomagnesemia)

tetany, muscle cramping, seizures, cardiac arrhythmia, hypotension

31

What is hypermagnesemia

elevated levels of magnesium (>2.5mEe/L)

32

Manifestations of elevated magnesium (hypermagnesemia

reduced neuromuscular transmission and excitability
flaccid paralysis, diminished reflexes, muscle weakness
hypotension, respiratory depression

33

What is hypophosphatemia

low levels of phosphate (<2.5mg/dL)

34

manifestations of low phosphate (hypophosphatemia

muscle weakness, tremor, and paresthesia
weight loss
bone deformity

35

What is hyperphosphatemia

elevated levels of phosphate >4.5mg/dL

36

manifestations of hyperphosphatemia

no associated manifestations