Fluid + Electrolyte Disorders Flashcards
Total Body Water (TBW) is distributed into:
Intracellular fluid (ICF) - 2/3 of TBW
Extracellular fluid (ECF) - 1/3 of TBW
- Transcellular
- Interstitial fluid (ISF)
- Intervascular fluid (IVF)
Intravascular Fluid of ECF
- the fluid in vessels and capillaries
- also called “plasma water”
Interstitial Fluid of ECF
- often called tissue space/fluid
- the fluid not inside vessels or cells
Transcellular Fluid of ECF
- isolated
- does NOT exchange easily with ISF or IVF spaces
What is Edema?
- palpable swelling due to the expansion of Interstitial Fluid Volume
- accumulation of excess fluid in ISF
Edema is caused by:
a disturbance in hydrostatic or osmotic pressure:
- increased capillary HYDROSTATIC pressure
- decreased capillary ONCOTIC pressure
- impaired lymphatic drainage
What is hydrostatic pressure?
the pressure required to push fluid OUT of vessels or capillaries
- out of IVF and into ISF
What is oncotic pressure? What is it directly correlated to?
- the pressure to SUCK fluid in
- helpful when dehydrated
- directly correlated to the amount of PROTEIN in the body
What is Starlings Law?
- official name for exchange of capillary fluid
- hydrostatic/oncotic exchange
Generalized vs. Dependent Edema
Generalized: fluid swelling all over body
Dependent: increased capillary pressure –> fluid accumulate in dependent body areas
- ex: ankles swollen from standing too long
Different ways to assess Edema
- touch using fingers - determine different stages
- weight gain
- measurement
How can increased capillary permeability cause Edema? What are some things that would cause increased capillary permeability?
increased capillary permeability can be caused by burns or localized inflammation
- damages outer layer of blood vessels
leads to loss of plasma proteins, which can cause:
- decreased capillary oncotic pressure
- higher tissue oncotic pressure
How does systemic decreased plasma protein production cause Edema?
less plasma protein –> decreased capillary oncotic pressure –> edema
capillaries don’t need to suck in as many proteins, which decreases overall pressure
How does increased capillary hydrostatic pressure cause edema?
as the ability to push fluid out of the capillaries increased, the fluid is pushed into the ISF
net movement/accumulation of fluid in ISF –> Edema
How does lymph vessel obstruction cause edema?
lymph system serves to move fluid out of the blood
- blockage –> no drainage –> accumulation of fluid inside ISF
- lymph vessels can’t absorb ISF, so more accumulates causing edema
What is Third Spacing?
- the movement of a large amount of bodily fluid FROM ECF –> INTO transcellular compartments inside serious cavities
- exchange of extracellular fluid between interstitial spaces, capillaries, and transcellular spaces of serious cavities
Where are serous cavities located and what are they closely linked with?
located in areas of continuous movement
- joints, bladder, etc.
closely linked with lymphatic drainage system
- blockages –> fluid buildup in serous cavities
Third space fluid contribute to ____ but not to ____ or _____
contribute to: body weight
not to: fluid reserve or function
Causes of third spacing:
- systemic inflammatory response syndrome
- severe liver failure
- 3rd degree burns
Volume Imbalance
Isotonic
- equal loss/gain of water and electrolytes (sodium)
Volume imbalances cause changes in:
mainly in ECF volume
osmolarity definition and types
relationship between molecules and water
hyperosmolar - more molecules, less water
hypoosmolar - less molecules, more water
Osmolarity Imbalance types
- hypertonic
- hypotonic
- unequal loss/gain of water and electrolytes
Osmolarity Imbalances causes changes in…
ICF volume
hyPERtonic fluid shift
ICF –> ECF
inside cell –> outside
deflates: think hyper –> so excited that it makes you tired and deflate
hyPOtonic fluid shift
ECF –> ICF
Example of increased capillary hydrostatic pressure
clot
venous obstruction
heart failure
How does Hypovolemia affect ECF?
- ECF volume deficit
- Isotonic (equal) fluid loss from ISF and IVF spaces
Common causes of Hypovolemia
- dehydration
- GI loss
- Third spacing (fluid trapped in serous cavities - technically dehydrated)
- sweat
- kidney failure
Effects of mild Hypovolemia
thirst
Effects of moderate Hypovolemia
- worsening thirst
- poor skin turgor
- decreased BP and urine output
- increased HR (orthostatic hypotension), HgB
- slow filling of peripheral veins
Effects of severe Hypovolemia
same as moderate plus:
- pallor
- worse drop in BP and urine output
- tachycardia (weak pulse)
- disorientation
Effects of potentially fatal Hypovolemia and range
Above 8% decrease
- anuria
- Hypovolemic shock (severe drop in BP)
How does Hypervolemia affect ECF?
- ECF excess
- Isotonic (equal) gain of water and sodium in ECF
Does tonicity change in Hypovolemia or Hypervolemia?
No –> changes mainly seen in ECF compartments
3 Common causes of Hypervolemia
- water retention from kidney dysfunction
- excess salt intake
- liver + heart failure
Effects of Hypervolemia
- increase in BP
- decrease in pulse
- venous distention (vein in side of neck)
often leads to edema:
- initially dependent
- may travel to lung –> pulmonary edema (fluid accumulation around lung, crackles)
Osmolarity Imbalances are due to:
- an overall excess or deficiency of sodium
less common cause: hyperglycemia in diabetes mellitus
What causes Hyponatremia?
- low plasma osmolarity –> water moves INTO the cell (ECF –> ICF)
- low sodium: LESS THAN 135 mEq/L
Serum Sodium Range
135 - 145 mEq/L
Hyponatremia etiologies
- Sodium loss
- GI loss: diarrhea, vomiting, sweating)
- Dilutional - too much H2O intake dilutes amount of Na in body
- Water retention
Hyponatremia manifestations
- muscle cramps
- decreased reflexes
- weakness/lethargy
- seizures
- coma
Hyponatremia treatment
based on cause:
- dilution: food restriction
- Na loss: stop the medication affecting kidneys
What is Hypernatremia?
- high plasma osmolarity causes water to shift ICF –> ECF
- serum sodium level is ABOVE 145 mEq/L
Hypernatremia is a key/cardinal sign of:
dehydration
true dehydration of cells
Hypernatremia etiologies:
- water loss
- sodium retention
Hypernatremia manifestations:
similar to Isotonic Fluid Volume Deficit
- thirst
- CNS changes: lethargy –> irritability –> seizures –> coma
- increased body temperature
- dry mucous membranes
- oliguria
Hypernatremia treatment
give fluids: sugar H2O
Serum Potassium Range
3.5 - 5.1 mEq/L
Potassium helps:
- muscle contraction (particularly cardiac)
- maintain level intracellular fluids
- maintain normal BP
What is Hypokalemia?
- when serum potassium levels are LESS THAN 3.5 mEq/L
Hypokalemia etiologies:
potassium deficit
- Loss in GI tract (nausea, vomiting, diarrhea)
- redistribution of K+ ions between ECF and ICF
- renal loss (heart failure, diuretics affecting kidneys)
Hypokalemia manifestations:
- fatigue
- muscle weakness or cramps
- decreased deep tendon reflexes
- flattened/depressed T waves on EKG
Hypokalemia treatment
- IV fluids
- K+ pills
- Bananas
If chronic –> special diet
What is Hyperkalemia?
- serum potassium level are ABOVE 5.1 mEq/L
- ICF –> ECF
Hyperkalemia etiologies
- decreased renal function
- too much K+ in ECF –> abnormal redistribution
- kidneys don’t secrete K+
Hyperkalemia manifestations
- above 8 = severe emergency
- muscle fatigue and weakness
- dyspnea: shortness of breath
- dysrhythmias
- Peaked T waves
Hyperkalemia treatment
medications that
- eliminate K+ through digestive GI tract
- cause K+ to shift from ECF back into ICF
Serum Calcium Range
8.6 - 10.6 mg/dl
Bones + Calcium function
- bones are storage unit for calcium
calcium helps:
- muscles contract
- nerve function
- stabilize neuromuscular response
Non-ionized calcium
- does not function well in body
- solidifies like bone matrix
Ionized calcium
stabilizes neuromuscular excitability –> decreases nerve cells’ sensitivity to stimuli
this is the form we measure in the serum
What is Hypocalcemia?
- serum calcium is LESS THAN 8.6 mg/dL
Hypocalcemia etiologies
- body’s impaired ability to pull Calcium from the bones
- abnormal calcium excretion from kidneys
Hypocalcemia manifestations’ severity depends on:
- underlying cause
- quickness of onset
- accompanying electrolyte disorders
- extracellular pH
Hypocalcemia Actue manifestations
- muscle cramps
- convulsions
- spasms
signs: Chvostek, paresthesia, Trousseau
Paresthesia
- relates to Hypocalcemia
- tingling around mouth and in extremities
Chvostek signs
- relates to Hypocalcemia
- tap cheek and causes uncontrollable mouth twitches
Trousseau signs
- relates to Hypocalcemia
- Take BP cuff off –> non-stop hand and arm spasms
Hypocalcemia Chronic manifestations
skeletal + skin manifestations
- bone pain, fragility, and fractures (from parathyroid hormone)
- dry + scaling skin
- brittle nails
- dry hair
- development cataracts
Hypocalcemia treatments
oral or IV calcium
What is Hypercalcemia?
- when serum calcium levels are ABOVE 10.6 mg/dL
Hypercalcemia etiologies
- Ca+ movement into circulation overwhelms the kidneys ability to remove excess ions –> increase
- increased bone resorption: body pulls more calcium from bones faster than it should (tell tale sign of cancer)
- prolonged immobility
- excess intake of calcium carbonate (tums)
- hyperparathyroidism: parathyroid gland releases too much hormone –> Ca level increases
Hypercalcemia manifestations
- decrease in neuromuscular excitability
- GI discomfort –> constipation, nausea, bloating
- slowing of peristalsis
- CNS effects
- cardiac effects: increase in contractability –> pumps too hard –> cardiac arrest
- renal calculi
Hypercalcemia treatment
fluid
specific diuretics - lasix
