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Electrolyte Abnormalities. 3 July 2008 Justin A. Glass, MD Emory Family Medicine. Goals. Review of common electrolyte abnormalities Normal ranges Clinical manifestations of hypo- or hyper- states Causes Treatment options. Goals. What will spend time on today… Sodium Potassium

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electrolyte abnormalities

Electrolyte Abnormalities

3 July 2008

Justin A. Glass, MD

Emory Family Medicine

goals
Goals
  • Review of common electrolyte abnormalities
    • Normal ranges
    • Clinical manifestations of hypo- or hyper- states
    • Causes
    • Treatment options
goals3
Goals
  • What will spend time on today…
    • Sodium
    • Potassium
    • Calcium
    • Magnesium
    • Phosphorus
hyponatremia
Hyponatremia
  • Sodium: Normal 135 – 145 mg / dl
  • Symptoms usually begin <120 mg /dl
    • Nausea
    • Lethargy
    • Muscle cramp
    • Psychosis
    • Seizure
    • Coma
    • Death
hyponatremia6
Hyponatremia
  • Diagnosis based on assessment of serum osmolality and volume status
hyponatremia7
Hyponatremia
  • Serum Osmolality
    • Osmolality (calculated) =

2 (Na) + Gluc / 18 + BUN /2.8

hyponatremia8
Hyponatremia
  • Normal Osmolality (280 – 295 mOsm / kg)

Isotonic pseudohyponatremia

Hyperproteinemia (>10 mg / dl)

Hyperlipidemia (severe)

hyponatremia9
Hyponatremia
  • High Osmolality (>295 mosm / kg)

Hypertonic hyponatremia

Hyperglycemia

Na: 2.4 mEq / liter decrease per

100 mg/dl increase in glucose

Mannitol excess

Glycerol therapy

Am J Med 1999 Apr;106(4):399-403

hyponatremia10
Hyponatremia
  • Low serum osmolality (<280 mOsm / kg)

Hypotonic hyponatremia

Need to assess volume status next in these patients.

hypotonic hyponatremia
Hypotonic hyponatremia
  • Hypovolemia
    • GI losses
    • Renal losses plus excess water ingestion
    • Third space losses

Tx: Isotonic saline

hypotonic hyponatremia12
Hypotonic Hyponatremia
  • Hypervolemia
    • CHF
    • Liver disease
    • Nephrotic syndrome
    • CKD

Urine Na: < 20 mEq /liter except in CKD

Tx: Salt restriction / water restriction / diuretics

hypotonic hyponatremia13
Hypotonic Hyponatremia
  • Isovolemia
    • Glucocorticoid insufficiency
    • Hypothyroidism
    • Psychogenic polydipsia
    • Medications (amitriptyline / cyclophosphamide / carbamazepine / morphine)
    • SIADH
    • Nausea / pain / emotional stress
    • Diuretic use with potassium depletion
isovolemic hypotonic hyponatremia
Isovolemic Hypotonic Hyponatremia
  • SIADH
    • Syndrome of inappropriate antidiuretic hormone
      • Hypotonic hyponatremia
      • Clinical euvolemia
      • Inappropriately elevated urine osmolality (>200) in face of low serum osmolality
      • Urine Na >20 mEq / liter
      • Normal renal function / TSH / cortisol
siadh
SIADH
  • Acute tx
    • Severe hyponatremia (<110 mEq / liter)
      • IV lasix
      • NS with 20 – 40 mEq / liter KCL
      • Rarely 3% saline will be needed
  • Chronic tx
    • Mild hyponatremia
      • Water restriction to approx 1000 ml / day
      • Demeclocycline 300 mg PO bid if water restriction not working (contraindicated in liver disease)
siadh16
SIADH
  • Chronic treatment (cont)
    • Vasopressin receptor antagonists
      • Conivaptan (Vaprisol) IV prep
        • 20 mg infusion over 30 min, then gtt of 20 mg/24 hrs
        • Maximum dose 40 mg/24 hrs gtt
        • Maximum duration is 4 days
hyponatremia17
Hyponatremia
  • How fast do we correct it?
hyponatremia18
Hyponatremia
  • Treatment principles
    • Not too fast (pontine myelinolysis)
      • Symptomatic
        • Initial 1 - 2 mEq / L / hr x two hours, then
        • 0.5 mEq / L / hr
      • Asymptomatic
        • 0.5 mEq / L / hr
        • Max in 24 hours: 10 meq total rise
        • Max in 48 hours: 18 meq total rise

Am J Med. 2007 Nov;120(11 Suppl 1):S1-21.

hypernatremia
Hypernatremia
  • Sodium: Normal 135 – 145 mg / dl
  • Clinical manifestations
    • Tremors
    • Irritability
    • Ataxia
    • Spasticity
    • Mental confusion
    • Seizures
    • Coma
    • Death
hypernatremia21
Hypernatremia
  • Cause:
    • Net sodium gain
    • Net water loss
hypernatremia22
Hypernatremia
  • Volume expansion (net sodium gain)
    • Cause
      • Hypertonic saline / NaHCO3 administration
      • Primary hyperaldosteronism
      • Cushing’s syndrome

Tx: Diuretics

D5W to replace fluid loss after diuretics

hypernatremia23
Hypernatremia
  • Water depletion
    • Hypotonic fluid losses
hypovolemic hypernatremia
Hypovolemic hypernatremia
  • Treatment
    • Calculate free water deficit
      • TBW (liters) = 0.6 x current total body weight (kg)
      • Desired TBW (liters) =

Measured Na (mEq/l) x current TBW / Normal Na

      • Body water deficit (liters) =

Desired TBW – current TBW

hypovolemic hypernatremia25
Hypovolemic hypernatremia
  • If hemodynamic compromise, then replace initially with NS
  • Otherwise use ½ NS or D5W
    • Aim to decrease Na by 0.5 mEq / liter / hr
    • Correct one half of the water deficit in 24 hrs
    • Correct other half over next 24-48 hours
hypovolemic hypernatremia26
Hypovolemic hypernatremia
  • Diabetes insipidus

Sxs: Polyuria / Polydipsia / Low urine osm

    • Central
      • Tumor / Granuloma / Trauma / Surgery
    • Nephrogenic
      • Severe hypokalemia / hypercalcemia / CKD / Drugs (lithium / demeclocycline / amphotericin)
hypovolemic hypernatremia27
Hypovolemic hypernatremia
  • DI
    • Differentiation of central and nephrogenic
      • Trial of water deprivation
      • Failure to concentrate urine confirms DI
      • Subsequently given arginine vasopressin
        • Central DI (urine concentration increases)
        • Nephrogenic DI (no increase)
hypovolemic hypernatremia28
Hypovolemic hypernatremia
  • DI
    • Treatment
      • Central
        • DDAVPP 5-10 mcg intranasally q day / bid
      • Nephrogenic
        • Correction of underlying cause if possible
        • Thiazide diuretic / salt restriction can help
hypokalemia
Hypokalemia
  • Normal K level: 3.5 – 5.0
  • Clinical manifestations
    • Fatigue
    • Cramps
    • Constipation
    • Weakness / Paralysis
    • Parasthesias
    • Arrhythmias
hypokalemia31
Hypokalemia
  • EKG abnormalites
    • Flattened T waves
    • ST depressions
    • Prominent U waves
ekg changes in hypokalemia
EKG Changes in Hypokalemia

http://www.merck.com/media/mmpe/figures/MMPE_12END_156_02_eps.gif

hypokalemia33
Hypokalemia
  • Causes
    • GI losses
    • Renal losses
    • Acid-base shifts
hypokalemia treatment
Hypokalemia Treatment
  • Oral therapy
    • Mild hypokalemia
    • Ability to tolerate oral replacement
    • Increase dietary intake
      • Potatoes / Bananas
    • KCl preps (i.e. KDur)
      • Preps can be used in range 8 – 20 mEq
      • Monitor K level and adjust dose as needed
      • Correct cause
hypokalemia treatment35
Hypokalemia Treatment
  • IV repletion
    • Severe hypokalemia
    • Inability to tolerate oral repletion

Max Concentration: 60 mEq / liter

Note pain is common at > 40 mEq /liter

Rate: 10 mEq / hr (20 mEq / hr with tele)

Monitor response and decrease conc / rate as appropriate.

hyperkalemia
Hyperkalemia
  • Potassium Normal 3.5 – 5.0
    • Elevated potassium level should be evaluated as to the following:
      • What is the cause?
      • Is the cause an acute or chronic issue?
      • Are there accompanying EKG changes?
hyperkalemia37
Hyperkalemia
  • Symptoms
    • Usually asymptomatic
    • Muscle weakness / paralysis
    • EKG abnormalities
      • Peaked T waves
      • ST depression
      • 1st degree AVB
      • QRS widening
      • “Sine wave sign”
hyperkalemia38
Hyperkalemia
  • EKG changes
hyperkalemia39
Hyperkalemia
  • Think about the cause
  • 1. Too much total potassium
    • Renal disease
    • Intake increased (rare outside of renal disease)
  • 2. Shift of potassium from intracellular space to extracellular space
    • DKA
hyperkalemia40
Hyperkalemia
  • Does the potassium level make sense in the patient?

Pseudohyperkalemia

hyperkalemia41
Hyperkalemia
  • When do we treat
    • Patient assessment
      • Cause
      • Chronicity
    • Degree of potassium elevation
      • <6.0 Does not need acute invasive tx
      • >6.0- 6.5 Kayexalate +/- other modalities
      • >6.5 Consider more acute modalities
hyperkalemia42
Hyperkalemia
  • Treatment options
    • Calcium gluconate
    • NaHCO3
    • Regular insulin
    • Albuterol nebulizer treatment
    • Kayexalate
    • Dialysis
hyperkalemia43
Hyperkalemia
  • Calcium gluconate
    • IV formulation is 1000 mg / 10 ml (10% soln)
    • Dose: 10 ml over 2-5 minutes IV with EKG monitoring
    • Action: Stabilization of cardiac cells. Does not lower potassium. Used for hyperkalemia with EKG changes.
    • If EKG changes do not immediately resolve, dose can be repeated in 5 minutes.
hyperkalemia44
Hyperkalemia
  • Calcium gluconate
    • Precautions
      • Do not infuse with bicarbonate (precipitation of calcium carbonate)
      • Do not use routinely with digitalis as hypercalcemia can augment digitalis toxicity. Limit use to patients with widened QRS.
hyperkalemia45
Hyperkalemia
  • Beta agonist
    • Albuterol nebulizer treatment
      • 2-4 ml of 0.5% soln (10-20 mg dose)
      • Note a usual nebulizer tx for RAD is 2.5 mg
      • Peak effect in 90 minutes
    • Epinephrine IV infusion
      • 0.05 mcg / kg / min IV infusion
      • Peak effect in 30 minutes
      • I would be hesitant to use this when an albuterol neb is easy and less risky.
hyperkalemia46
Hyperkalemia
  • Insulin
    • Regular insulin 10 units IV plus one D50 Amp over 5 minutes. This will give patient 25 grams of glucose.
    • Follow this with a D 5 containing IV maintenance fluid for several hours.
    • Effect within 15 minutes. Peak effect 60 min. Duration 3-4 hours.
hyperkalemia47
Hyperkalemia
  • NaHCO3
    • 1 Amp (44.6 meq) IV over 5 minutes.
    • Onset: 30 minutes
    • Duration: 60-120 minutes
hyperkalemia48
Hyperkalemia
  • Alternate approach to NaHCO3 / Insulin:
    • Put 2 Amps NaHCO3 in 1 liter D10 W.
    • Give 300 ml over first 30 minutes, then change to 250 ml / hr until finished.
    • Give Regular insulin 25 units SQ with starting the IVF.
hyperkalemia49
Hyperkalemia
  • Kayexalate (Na – K exchange resin)
    • PO dosing: 15 -30 gram
      • Can be used as a dry powder
      • Can be mixed with 60-120 ml of a 20% sorbitol soln to avoid constipation
    • PR dosing: 50 grams
      • Mix with 50 ml of 70% sorbitol and 100 ml tap H20
      • Retain in rectum x 30 minutes minimum but ideally 2+ hours
hypocalcemia
Hypocalcemia
  • Normal Calcium: 8.9 – 10.3 mg/dl
  • Calcium
    • 40% bound to albumin
    • 15% bound to other serum anions
    • 45% is ionized in serum
hypocalcemia52
Hypocalcemia
  • Correct for low albumin
  • 0.8 mg / dl drop in Calcium for every 1 g / dl drop in Albumin
  • Corr Ca = Meas Ca + (0.8 * (4.5 – Meas Alb))
hypocalcemia53
Hypocalcemia
  • Clinical signs of low calcium:
    • Tetany / Carpopedal spasm
    • Trousseau’s sign
    • Chvostek’s sign
    • Lethargy / confusion
    • Seizures
    • Heart failure
hypocalcemia54
Hypocalcemia
  • Treatment of symptomatic cases
    • Calcium gluconate (10% soln) which contains 100 mg elem calcium / 10 ml.

1. Give two ampules IV over 10 minutes

then

2. Add six ampules to 500 ml D5W and infuse

at 1 mg / kg / hr

hypocalcemia55
Hypocalcemia
  • Asymptomatic
    • Calcium orally (1000 mg / day)
    • Vit D orally
      • Calcitriol 0.25 – 0.5 mcg / day
hypocalcemia56
Hypocalcemia
  • Magnesium can be effective as well
    • Magnesium sulfate 2 gram IV bolus followed by 1 gram / hr gtt
hypercalcemia
Hypercalcemia
  • Calcium range: 8.9 – 10.3 mg / dl
hypercalcemia58
Hypercalcemia
  • Symptoms
    • Anorexia
    • N/V
    • Constipation
    • Polyuria
    • Nephrolithiasis
    • Weakness
    • Confusion
    • Coma
    • EKG: Shortened QT interval
hypercalcemia59
Hypercalcemia
  • Causes
    • Primary hyperparathyroidism
    • Malignancy
    • Sarcoidosis
    • Vitamin D toxicity
    • Hyperthyroidism
    • Thiazide diuretics
    • Milk-alkali syndrome
    • Renal failure
    • Familial hypocalciuric hypercalcemia
    • Immobilization
hypercalcemia60
Hypercalcemia
  • Differential
hypercalcemia61
Hypercalcemia
  • Treatment
    • Increase urinary excretion
    • Diminish bone resorption
    • Diminish GI absorption
    • Chelation of ionized Ca (EDTA)
    • Dialysis
hypercalcemia62
Hypercalcemia
  • Treatment
    • Increase urinary excretion
      • NS @ 200 – 300 ml / hr to achieve UO = 100 ml /hr
      • Lasix (if fluid overloaded state exists)
hypercalcemia63
Hypercalcemia
  • Treatment
    • Decrease bone resorption
      • Calcitonin 4 units SQ or IM q 12 hours
        • This approach works rapidly (4 hrs) and lowers Ca by 1-2 mg / dl
        • Tachyphylaxsis develops after 48 hours
        • Note that nasal dosing does not lower calcium
hypercalcemia64
Hypercalcemia
  • Treatment (Decrease bone resorption)
    • Bisphosphonates
      • Zoledronic Acid
        • Hyperglycemia of malignancy
        • Dose: 4 mg IV over 15 minutes
        • Onset 2-4 days (use saline or calcitonin initially)
        • Effect is longlasting (several weeks)
        • 88% pts normalized calcium
        • Can be repeated q 1-4 weeks as needed
      • Pamidronate
        • Alternative
        • Dose: 60-90 mg IV over 2 hours
hypercalcemia65
Hypercalcemia
  • Treatment
    • Decreased oral absorption (Need in sarcoid)
      • Oral phosphate administration
      • Prednisone
hypercalcemia66
Hypercalcemia
  • Treatment
    • Dialysis
      • Consider in severe severe severe case
      • Ca 18-20 mg / dl
hypomagnesemia
Hypomagnesemia
  • Normal: Magnesium 1.7 – 2.4 mg / dl
hypomagnesemia69
Hypomagnesemia
  • Think about hypomagnesemia in the following situations:
    • Alcoholism
    • Hypokalemia
    • Hypocalcemia
    • Chronic diarrhea
    • Ventricular arrhythmias
hypomagnesemia70
Hypomagnesemia
  • Differentiate urinary from GI losses
  • FeMg = (UrMg * PCr) *100

(0.7*PMg*UCr)

<2% = GI loss

>2% = Renal loss

hypomagnesemia71
Hypomagnesemia
  • Treatment
    • Severe (<1.0)
      • IV Magnesium sulfate 2 grams IV over 1 hr
    • Mild – moderate
      • PO Magnesium
        • Magnesium chloride (Slo-Mag) 2 tabs PO q day
        • Magnesium oxide (Mag-Ox 400) 2 tabs PO q day
hypermagnesemia
Hypermagnesemia
  • Magnesium: Normal range 1.7-2.4
  • Seen in renal failure with concomitant tx with magnesium containing antacids / laxatives
  • Seen in preeclampsia treated with Magnesium sulfate
  • Notable if Mg >4.0
hypermagnesemia73
Hypermagnesemia
  • Treatment
    • Stop the exogenous magnesium
    • HD may be needed in the setting of renal failure
    • Calcium gluconate (10%) 1-2 ampules IV can be given as a bridge to setting up dialysis
hypophosphatemia
Hypophosphatemia
  • Phosphorus: Normal 2.6-4.5 mg / dl
  • Causes
    • Hyperglycemic states
    • Alcoholism
    • Respiratory alkalosis
    • GI abns
    • Alum / Mg containing antacids
    • Hyperparathyroidism
    • Renal wasting
hypophosphatemia76
Hypophosphatemia
  • Treatment
    • Treat underlying cause
    • Replete if severely low
      • Below 1 mg / dl in DKA
        • IV KPhos
        • PO Neutraphos
hyperphosphatemia
Hyperphosphatemia
  • Phosphorus: Normal 2.6 – 4.5 mg /dl
  • Causes:
    • Renal failure
    • Hypoparathyroidism
    • Rhabdomyolysis
    • Tumor lysis syndrome
    • Acidotic states
    • Exogenous admin of phosphorus
hyperphosphatemia78
Hyperphosphatemia
  • Treatment:
    • Dietary restriction 0.6 – 0.9 grams / day
    • Oral phosphate binders
      • Calcium acetate 2 tabs PO q AC
      • May need to add aluminum containing product (aluminum hydroxide)
    • Dialysis
armand trousseau
Armand Trousseau
  • Trousseau’s Sign of Latent Tetany
  • Trousseau’s Sign of Malignancy