Electrolytes & BUN Flashcards

1
Q

what are the lab values which are included in an BMP

A
  • sodium (Na)
  • potassium (K)
  • chloride (Cl)
  • CO2
  • BUN (blood urea nitrogen)
  • creatitine (Cr)
  • glucose

also…
- Anion gap
- calcium (Ca)

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2
Q

what is the role of sodium within the body

A
  • 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)
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3
Q

what is the role of potassium within the body

A
  • 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)
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4
Q

what is the role of chloride in the body

A
  • chloride maintains acid-base balances
  • maintains nerve impulses
  • maintains fluid balance
  • maintains stomach acid
  • excreted within the urin
  • a MAJOR EXTRAcellular anion (-)
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5
Q

what is the role of carbon dioxide in the body

A
  • it serves as an indirect role to measure bicarb
  • excreted via the lungs
  • involved in pH regulation, repiratory drive, and helps Hgb attract O2
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6
Q

Signs and Symptoms of Hyponatremia
- what are the earlier signs: at what Na level?
- what are some later signs: at what Na level?

A

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

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7
Q

other symptoms of hyponatremia

A
  • asymptomatic
  • fatigue
  • nausea
  • dissiness
  • gait abnormalities
  • forgetfulness
  • confusion
  • muscle cramps
  • lethargy

seizure & coma: acute exacerbations

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8
Q

are some questions you need to ask to evaluate your pt and their hyponatremia?

A

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

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9
Q

what are some causes of hypotonic hyponatremia

A

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

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10
Q

Diagnostics to do for hyponatremia

A
  • 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

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11
Q

Treatment of hyponatremia

what happens if you correct too quickly?

what is our goal sodium

A

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!

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12
Q

Signs and Symptoms of Hypernatremia

A

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

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13
Q

Hypernatremia
- diagnosis

A
  • 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)

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14
Q

major causes of hypernatremia

A
  • 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!!)
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15
Q

Treatment of hypernatremia

A

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

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16
Q

Clinical Manifestations of Hypercalcemia

A

renal signs
- poyluria
- polydipsia
- nepthrocalcinosis
- nephrogenic DI
- acute & chronic renal insufficiency

GI signs
- anorexia
- N/V
- constipation
- pancreatitis
- peptic ulcer disease

MSK
- muscle weakness
- bone pain
- decreased bone density

Neuro
- inability to concentrate
- fatigue
- coma
- confusion

Cardiac
- shortened QT interval
- bradycardia
- HTN

17
Q

What are some reasons for hypercalcemia

A

parathyroid mediated processes
- MEN syndrome
- familial or primary hyperparathyroidism

non-parathyroid mediated
- secreting PTHrP (malgnancy)
- increased calcitriol (secondary to malignacy)

others
- lithium
- thiazides
- adrenal insufficiency
- parenteral nutrition

hyperthyroid and malignancy are the most common causes

18
Q

Diagnostics for hypercalcemia

A

confirm the presence of the hypercalcemia

  • get corrected calcium = serum calcium + 0.8 x (4-serum albumin)
  • good history
  • measure PTH
    if PTH high = think primary hyperparathyroidism
    if mid = find evidence to r/o hypocalciruic hypercalcemia (rare)
    low = look for causes like vit D and PTH-related proteins
19
Q

Management of hypercalcemia
- mild
- moderate
- severe

A

Mild = pts. with asymptomatic or have mild symptoms
calcium < 12 mg/dL
- no immediate treatment needed; advise to avoid calcum…..
- lithum
- thiazides
- volume depleteion (make sure theyre hydrated)
- inactivity
- calcium and vit D supplements
- high dietary calcium

Moderate = calcium between 12-14
- if chronic and aysmptomatic: treat like mild
- if acute and symptomatic: treat like severe

Severe = calicum > 14
- if symptomatic…
- give IV ISOTONIC salie
- calcitonin
- bicarbonate

20
Q

Clincal Signs of Hypocalcemia

A

Acute Signs
- paresthesias
- muscle twiching
- trousseaus signs
- seizures
- prolonged QT
- hypotension
- heart ailure
- arrythmias
- papilledema

Chronic
- etopic calcification
- extrapryamidal signs
- parkinsonism
- dementia
- dry skin
- subcapsular cataracts

21
Q

Conditions which may cause hypocalcemia

A

hypoparathyroidism
- cataracts form
- cognitive impairment
- dystonia
- dementai
- psychosis
- moodiness

pseudohypoparathryoidism
- skeletal abnormalites
- intellectual impairment
- hormone insufficiens

Vit D deficiency
- rickets
- osteomalacica

rare could ahve autosomal dominat hypocalcemia

22
Q

Managment of hypocalcemia

A

for severe symptoms (tetany, seizures, prolonged QT)
- IV calcium
- then calcium gluconate (oral)

for mild/asymptomatic hypocalcemia
- oral calcium supplements
- calcuim carbonate or citrate

dont forget to give vitamin D and magnesium!!

23
Q

clinical signs of hyperkalemia

A

Severe with K >7.0
- ascending muscle weakness
- paralysis
- cardiac arrythmias & abnormalities….
- RBBB/LBBB
- AV block
- bradycardia
- sinus arrest
- VT
- Vfib
- asystole
- death

24
Q

Causes and Etiologies of Hyperkalemia

A
  1. ingestion of excess K (but this is rare: normally the body will regulate this and push it into the cells via insulin & use aldosterone to increase Na reabsorbtion and K secretion)
  2. imparied urinate secretion (aldosterons impaired secretion or response, acute/chronic kidney disease, decrease in Na or H20)

other causes
- metabolic acidosis
- insulin deficiency, hypergycemia or hypesomlarity
- beta blocker
- exercise
- hemolyzed specimen sample!! (false +)

25
diagnosis of hyperkalemia EKG findings
- history and physical - EKG!!! to see if any changes - BMP - evaluate hypoaldosteronsim EKG findings - tall peaked T waves - shortened QT interval - legthened ORS == leads to asystole - absent P waves
26
Management of Hyperkalemia emergency and otherwise
**Emergency** - IV insulin (add dextrose but not if they're hyperglycemic) - hemodialysis - albuterol - diuretics - GI cation exchangers **other** - dietary modification - diuretics - bicarbonate - GI cation exchangers (binders)
27
Hypokalemia signs and symptoms
**seen as a K < 3.5** - severe muscle weakness or rhabomyolysis - kidney dysfunction - hypertension EKG changes - PACS - bradycardia - Atrial or ventricular tachycardia - AV blocks - PVCs
28
Diagnosis of hypokalemia EKG findings
history and physical BMP EKG with - ST depression - **Decreased amplitude of T waves** - increase amp. of U waves - prolonged QT - assess acid base status: bicarb, albumin, chloride, pH urin, VBGABG, electrolytes - assess urine K: 24 hour or a urine potassium to cr ratio - urine Na and chloride too
29
why does hypokalemia occur
- GI losses (like vomiting/diarrhea) - urinary losses ( diueretics, MRAs, kidney disease, polyuria, some drugs) - decreases intake of K - aldosteronsim (increased excretion) reasons for uptake into cells and therefore less in serum - increased pH - insulinemia - increase beta adrenergic (NE and N) - hypokalemia paralysis (rare) - increaed in blood cell production others - increase sweating - dialysis - plasmapheresis
30
Management of hypokalemia
mild/moderate K= 3-3.4 - oral potassium (Kchloride or phosphate) - k sparing diuretics severe K= < 2.5-3 - correct rapidly with oral or IV potassium - monitor K for rebound hyperkalemia - contiuous EKG
31
What is BUN and Creatitine
BUN: measures the urea nitrogen in the blood - urea nitrogen is a waste from when the liver breaks down protein - excreted by the kidneys Creatinine - a waste product of creatine catabolsim from muscles - excreted in the kidneys
32
Reasons for elevated BUN
- kidney dysfunction - high protein intake - GI bleed - catabolic (breakdown) states like fever, steroid use, bruns - rhabdomyolysis - dehydration - CHF - shock - dimished blood volume - Urinary tract obstruction - bladder dysfunction
33
Reasons for elevated creatinine
- high protein intake - rhabdomyolysis - GI bleed - exercise: strenuous - hypovolemia - drugs - renal disease or failure - surgery - shock