Electrolyte Abnormalities
Teresa Lianne Beck, MD
Assistant Professor
Emory Family Medicine
August 4, 2011
Goals
 Review of common electrolyte abnormalities
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Normal ranges
Clinical manifestations of hypo- or hyperstates
Causes
Treatment options
Goals
 What will spend time on today…
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Sodium
Potassium
Calcium
Magnesium
Phosphorus
Hyponatremia
 Sodium: Normal 135 – 145 mg / dl
 Symptoms usually begin <120 mg /dl
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Nausea
Lethargy
Muscle cramps
Psychosis
Seizure
Coma
Death
Hyponatremia
 Diagnosis based on assessment of serum
osmolality and volume status
Hyponatremia
 Serum Osmolality

Osmolality (calculated) =
2 (Na) + Gluc / 18 + BUN /2.8
Hyponatremia
 Normal Osmolality (280 – 295 mOsm / kg)
Isotonic pseudohyponatremia
Hyperproteinemia (>10 mg / dl)
Hyperlipidemia (severe)
Hyponatremia
 High Osmolality (>295 mosm / kg)
Hypertonic hyponatremia
Hyperglycemia
Na: 1.6 mEq / liter decrease per
100 mg/dl increase in glucose
Mannitol excess
Glycerol therapy
Am J Med 1999 Apr;106(4):399-403
Hyponatremia
 Low serum osmolality (<280 mOsm / kg)
Hypotonic hyponatremia
Need to assess volume status next in these
patients.
Hypotonic hyponatremia
 Hypovolemia
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GI losses
Renal losses plus excess water ingestion
Third space losses
Tx: Isotonic saline
Hypotonic Hyponatremia
 Hypervolemia
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CHF
Liver disease
Nephrotic syndrome
CKD
Urine Na: < 20 mEq /liter except in CKD
Tx: Salt restriction / water restriction / diuretics
Hypotonic Hyponatremia
 Isovolemia
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Glucocorticoid insufficiency
Hypothyroidism
Psychogenic polydipsia
Medications (amitriptyline / cyclophosphamide
/ carbamazepine / morphine)
SIADH
Nausea / pain / emotional stress
Diuretic use with potassium depletion
Isovolemic Hypotonic Hyponatremia
 SIADH
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Syndrome of inappropriate antidiuretic
hormone
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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
 Acute tx
 Severe hyponatremia (<110 mEq / liter)
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IV lasix
NS with 20 – 40 mEq / liter KCL
Rarely 3% saline will be needed
 Chronic tx
 Mild hyponatremia
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Water restriction to approx 1000 ml / day
Demeclocycline 300 mg PO bid if water restriction
not working (contraindicated in liver disease)
SIADH
 Chronic treatment (cont)
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Vasopressin receptor antagonists
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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
Hyponatremia
 How fast do we correct it?
Hyponatremia
 Treatment principles
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Not too fast (pontine myelinolysis)
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Symptomatic
 Initial 1 - 2 mEq / L / hr x two hours, then
 0.5 mEq / L / hr
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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
 Sodium: Normal 135 – 145 mg / dl
 Clinical manifestations
 Tremors
 Irritability
 Ataxia
 Spasticity
 Mental confusion
 Seizures
 Coma
 Death
Hypernatremia
 Cause:
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Net sodium gain
Net water loss
Hypernatremia
 Volume expansion (net sodium gain)
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Cause
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Hypertonic saline / NaHCO3 administration
Primary hyperaldosteronism
Cushing’s syndrome
Tx: Diuretics
D5W to replace fluid loss after diuretics
Hypernatremia
 Water depletion
 Hypotonic fluid losses
Condition
Urine vol
Urine osm
GI /
Insensible
loss
Low
High
Renal
loss
High
High
Diabetes
Insipidus
High
Low
Hypovolemic hypernatremia
 Treatment

Calculate free water deficit
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TBW (liters) = 0.6 x current total body weight (kg)
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Desired TBW (liters) =
Measured Na (mEq/l) x current TBW / Normal Na
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Body water deficit (liters) =
Desired TBW – current TBW
Hypovolemic hypernatremia
 If hemodynamic compromise, then replace
initially with NS
 Otherwise use ½ NS or D5W
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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 hypernatremia
 Diabetes insipidus
Sxs: Polyuria / Polydipsia / Low urine osm
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Central
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Tumor / Granuloma / Trauma / Surgery
Nephrogenic
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Severe hypokalemia / hypercalcemia / CKD /
Drugs (lithium / demeclocycline / amphotericin)
Hypovolemic hypernatremia
 DI
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Differentiation of central and nephrogenic
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Trial of water deprivation
Failure to concentrate urine confirms DI
Subsequently given arginine vasopressin
 Central DI (urine concentration increases)
 Nephrogenic DI (no increase)
Hypovolemic hypernatremia
 DI
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Treatment
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Central
 DDAVPP 5-10 mcg intranasally q day / bid
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Nephrogenic
 Correction of underlying cause if possible
 Genetic abnl / lithium / hypercalcemia
 Thiazide diuretic / salt restriction can help
Hypokalemia
 Normal K level: 3.5 – 5.0
 Clinical manifestations
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Fatigue
Cramps
Constipation
Weakness / Paralysis
Paraesthesias
Arrhythmias
Hypokalemia
 EKG abnormalites
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Flattened T waves
ST depressions
Prominent U waves
http://www.merck.com/media/mmpe/figures/MMPE_12END_156_02_eps.gif
Hypokalemia
 Causes
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Inadequate intake
GI losses
Renal losses
Acid-base shifts
Hypomagnesemia
Hyperaldosterone
Medications (diuretics)
Hypokalemia Treatment
 Oral therapy
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Mild hypokalemia
Ability to tolerate oral replacement
Increase dietary intake
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Potatoes / Bananas
KCl preps (i.e. KDur)
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Preps can be used in range 8 – 20 mEq
Monitor K level and adjust dose as needed
Correct cause
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
 Potassium
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Normal 3.5 – 5.0
Elevated potassium level should be evaluated
as to the following:
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What is the cause?
Is the cause an acute or chronic issue?
Are there accompanying EKG changes?
Hyperkalemia
 Symptoms
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Usually asymptomatic
Muscle weakness / paralysis
EKG abnormalities
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Peaked T waves
ST depression
1st degree AVB
QRS widening
“Sine wave sign”
Hyperkalemia
 EKG changes
Hyperkalemia
 Think about the cause
 1. Too much total potassium
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Renal disease
Intake increased (rare outside of renal
disease)
 2. Shift of potassium from intracellular space
to extracellular space
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DKA
Hyperkalemia
 Does the potassium level make sense in the
patient?
Pseudohyperkalemia (hemolysis)
Hyperkalemia
 When do we treat
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Patient assessment
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Cause
Chronicity
Degree of potassium elevation
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<6.0 Does not need acute invasive tx
>6.0- 6.5 Kayexalate +/- other modalities
>6.5 Consider more acute modalities
Hyperkalemia
 Treatment options
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Calcium gluconate
NaHCO3
Regular insulin
Albuterol nebulizer treatment
Kayexalate
Dialysis
Hyperkalemia
 Calcium gluconate
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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.
Hyperkalemia
 Calcium gluconate
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Precautions
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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.
Hyperkalemia
 Beta agonist
 Albuterol nebulizer treatment
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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
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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.
Hyperkalemia
 Insulin
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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.
Hyperkalemia
 NaHCO3
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1 Amp (44.6 meq) IV over 5 minutes.
Onset: 30 minutes
Duration: 60-120 minutes
Hyperkalemia
 Alternate approach to NaHCO3 / Insulin:
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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.
Hyperkalemia
 Kayexalate
(Na – K exchange resin)
 PO dosing: 15 -30 gram
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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
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Mix with 50 ml of 70% sorbitol and 100 ml tap
H20
Retain in rectum x 30 minutes minimum but
ideally 2+ hours
Hypocalcemia
 Normal Calcium: 8.9 – 10.3 mg/dl
 Calcium
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40% bound to albumin
15% bound to other serum anions
45% is ionized in serum
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))
Hypocalcemia
 Clinical signs of low calcium:
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Tetany / Carpopedal spasm
Trousseau’s sign
Chvostek’s sign
Lethargy / confusion
Seizures
Heart failure
EKG: Prolonged QT
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
Hypocalcemia
 Asymptomatic
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Calcium orally
Vit D orally
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(1000 mg / day)
Calcitriol 0.25 – 0.5 mcg / day
Hypocalcemia
 Magnesium can be effective as well
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Magnesium sulfate 2 gram IV bolus followed
by 1 gram / hr gtt
Hypercalcemia
 Calcium range: 8.9 – 10.3 mg / dl
 Symptoms
 Anorexia
 N/V
 Constipation
 Polyuria
 Nephrolithiasis
 Weakness
 Confusion
 Coma
 EKG: Shortened QT interval
Hypercalcemia
 Causes
 Primary hyperparathyroidism
 Malignancy
 Sarcoidosis
 Vitamin D toxicity
 Hyperthyroidism
 Thiazide diuretics
 Milk-alkali syndrome
 Renal failure
 Familial hypocalciuric hypercalcemia
 Immobilization
Hypercalcemia
Hypercalcemia
 Treatment
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Increase urinary excretion
Diminish bone resorption
Diminish GI absorption
Chelation of ionized Ca (EDTA)
Dialysis
Hypercalcemia
 Treatment
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Increase urinary excretion
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NS @ 200 – 300 ml / hr to achieve UO = 100 ml
/hr
Lasix (if fluid overloaded state exists)
Hypercalcemia
 Treatment
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Decrease bone resorption
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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
Hypercalcemia
 Treatment (Decrease bone resorption)
 Bisphosphonates
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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
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Pamidronate
 Alternative
 Dose: 60-90 mg IV over 2 hours
Hypercalcemia
 Treatment
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Decreased oral absorption (Need in sarcoid)
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Oral phosphate administration
Prednisone
Hypercalcemia
 Treatment
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Sensipar (cinacalcet)
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Calcimimetic indicated for secondary
hyperparathyroidism in ESRD
Parathyroid carcinoma
Dialysis
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Consider in severe cases
Ca 18-20 mg / dl
Hypomagnesemia
 Normal: Magnesium 1.7 – 2.4 mg / dl
 Symptoms
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Neuromuscular irritability
CNS hyperexcitability
Cardiac arrhythmias
Hypomagnesemia
 Think about hypomagnesemia in the following
situations:
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Alcoholism
Hypokalemia
Hypocalcemia
Chronic diarrhea
Ventricular arrhythmias
Hypomagnesemia
 Differentiate urinary from GI losses
 FeMg =
(UrMg * PCr) *100
(0.7*PMg*UCr)
<2% = GI loss
>2% = Renal loss
Hypomagnesemia
 Treatment

Severe (<1.0)
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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
 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
Hypermagnesemia
 Treatment
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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
 Phosphorus: Normal 2.6-4.5 mg / dl
 Symptoms
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Weakness
Respiratory insufficiency or myocardial
depression
Neurologic symptoms may vary, ranging from
simple paresthesias to profound alterations in
mental status
Hypophosphatemia
 Causes
 Hyperglycemic states
 Alcoholism
 Respiratory alkalosis
 GI abns
 Alum / Mg containing antacids
 Hyperparathyroidism
 Renal wasting
Hypophosphatemia
 Treatment

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Treat underlying cause
Replete if severely low

Below 1 mg / dl in DKA
 IV KPhos
 PO Neutraphos
Hyperphosphatemia
 Phosphorus: Normal 2.6 – 4.5 mg /dl
 Symptoms (due to hypocalcemia): CNS
hyperexcitability, CV
 Causes:
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Renal failure
Hypoparathyroidism
Rhabdomyolysis
Tumor lysis syndrome
Acidotic states
Exogenous admin of phosphorus
Hyperphosphatemia
 Treatment:
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Dietary restriction 0.6 – 0.9 grams / day
Oral phosphate binders
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Calcium acetate 2 tabs PO q AC
Sevelamer (Renegal) 800 mg PO q AC
May need to add aluminum containing product
(aluminum hydroxide)
Dialysis