Electrolytes & BUN Flashcards
what are the lab values which are included in an BMP
- sodium (Na)
- potassium (K)
- chloride (Cl)
- CO2
- BUN (blood urea nitrogen)
- creatitine (Cr)
- glucose
also…
- Anion gap
- calcium (Ca)
what is the role of sodium within the body
- major role in regulated blood pressure
- muscle and nerve function are also regulated by sodium contents
- sodium is the MAJOR extracellular cation (+)
- controls fluid volume becuase wherever sodium goes, water follows (thus BP control)
- excreted by the kidneys (therefore, poor kidney function can elevate potassium levels)
- excreted through sweat too (to a lesser extent)
what is the role of potassium within the body
- controls muscle and nerve impulses at the level of thresholds and channels
- the MAJOR INTRAcellular cation (+)
- excreted mainly by the kidneys
- minial excreting through sweat and GI losses (diarrhea, vomiting)
what is the role of chloride in the body
- chloride maintains acid-base balances
- maintains nerve impulses
- maintains fluid balance
- maintains stomach acid
- excreted within the urin
- a MAJOR EXTRAcellular anion (-)
what is the role of carbon dioxide in the body
- it serves as an indirect role to measure bicarb
- excreted via the lungs
- involved in pH regulation, repiratory drive, and helps Hgb attract O2
Signs and Symptoms of Hyponatremia
- what are the earlier signs: at what Na level?
- what are some later signs: at what Na level?
at a Na < 130
- nausea: becuase of cerebral edema: with less salt outside the cells: there is less pull of fluid out; thus more flow into cells creating the feeling of nausea
- malaise
at a Na < 120
- headache
- lethargy
- obtundation
- seizure
- coma
- respiratroy arrest
other symptoms of hyponatremia
- asymptomatic
- fatigue
- nausea
- dissiness
- gait abnormalities
- forgetfulness
- confusion
- muscle cramps
- lethargy
seizure & coma: acute exacerbations
are some questions you need to ask to evaluate your pt and their hyponatremia?
decide if the patient is also hyperglycemic?
- if hyperglycemic: correct sodium via (measured sodium + 1.6(glucose-100)/100)
are they post-op (especially GU) ?
have they been given mannitol, glycerol or IV immunoglobulin?
do they have…
- elevated lipemic serum
- jaundice
- plasma cell dyscrasia
want to assess if they are isotonic or hypertonic hyponatremia
what are some causes of hypotonic hyponatremia
think high levels of fluid volume: diuluting the sodium and other solutes
- polydipsia
- low dietary intake of sodium
- advanced renal impairment
- diuretic -induced hyponatremia
- volume depleltion (hypovolemic)
- heart failure/cirrhosis (hypervolemic, but low sodium)
- SIADH
- CNS abnormality
- drugs
- malignancy
- hormonal deficiency
- exercise induced (marathon!)
drugs: antidepressants, anti seizures, antipsychotis, anticancer, antidiabetes, vasopressin-like
Diagnostics to do for hyponatremia
- BMP
- LFTs: AST,ALT, bilirubin, albumin
- serum osmolality : gives idea of what solutes are in the blood at what concentration
- urine sodium : determines if the cause of the hyponatermia is due to renal or extrarenal causes (renal we will see hypovolemic hyponatermia with a high level or urine sodium, extra-renal will see low levels of sodium in the urine)
- urine osmolality : the amount of solutes within the urine
repeat urine osm and sodium after adequate sodium is given via IV will help determine if its a volume issue or a thyroid and signally issue
Treatment of hyponatremia
what happens if you correct too quickly?
what is our goal sodium
goal is to correct the sodium level = increasing sodium level by 1mEq/L/hr
- fluid restriction
- sodium tablets
in general: avoid correcting the sodium level too quicky: this could cause flash pulmonary edema or osmotic demyelination syndrome
in acute hyponatermia you can give IV saline 3% to rise the sodium level by 5mEq/L
Goal Sodium : 130
treat underlying cause!
Signs and Symptoms of Hypernatremia
plasma serum concentration > 145 mEq/L
- thrist
- lethargy
- irritability
- fever
- urinary symptoms (oligouria, polyuria, nocturia)
- twitching
- confusion
- seizures
- hyperreflexia
- coma
as the sodium concentration increases in the serum; fluid is drawn out of the cells; they shirnk and produce the seen symptoms (especially within the brain
Hypernatremia
- diagnosis
- acurate history
- BMP
- Urine Osmolality (should be over 600)
normal 500-800
a decreased urine osmolality & plasma = central or nephrogenic diabetes insipudus (becuase so much fluid is being lost form the serum, high sodium in the serum)
an increase urine osmolality 600 (normal) = think of extrarenal losses of water (GI losses common if the urine sodium is < 25)
major causes of hypernatremia
- inappropriate water consumption; and sweat loss
- GI losses
- central or nephrogenic diabetes insipidus ( no response of the body to uptake water leds to increased water loss thus more sodium per water)
- osmotic diuresis (glucose, urea, mannitol)
- CNS dysfunction
- sodium overload (in the hospital!!)
Treatment of hypernatremia
Acute (< 48 hours)
- sodium posioning risk, diabetes insipidus or severe hyperglycemia (because of the osmostic diuresis that occurs with hyperglycemia)
give 5% dextrose in water IV because adding glucose into the body helps the osmostic pressure to pull fluid back into the body and balance out the sodium
- do at a faster rate: 3-6mL/kg/hr
Chronic ( > 48 hours) most common
- 5% dextrose in water IV
- do at 1.35mL/height x kg
