Electrolyte Abnormalities or “the H and Hs” by ert554898

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									Electrolyte Abnormalities


  Teresa Lianne Beck, MD
    Assistant Professor
  Emory Family Medicine
       August 4, 2011
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
     Calcium
     Magnesium
     Phosphorus
Hyponatremia
 Sodium: Normal 135 – 145 mg / dl
 Symptoms usually begin <120 mg /dl
     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
     GI losses
     Renal losses plus excess water ingestion
     Third space losses

  Tx: Isotonic saline
Hypotonic Hyponatremia
 Hypervolemia
     CHF
     Liver disease
     Nephrotic syndrome
     CKD

  Urine Na: < 20 mEq /liter except in CKD

  Tx: Salt restriction / water restriction / diuretics
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
 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
 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)
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
Hyponatremia
 How fast do we correct it?
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
 Sodium: Normal 135 – 145 mg / dl
 Clinical manifestations
   Tremors
   Irritability
   Ataxia
   Spasticity
   Mental confusion
   Seizures
   Coma
   Death
Hypernatremia
 Cause:
     Net sodium gain
     Net water loss
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
Hypernatremia
 Water depletion
   Hypotonic fluid losses


        Condition    Urine vol   Urine osm
        GI /         Low         High
        Insensible
        loss
        Renal        High        High
        loss
        Diabetes     High        Low
        Insipidus
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 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 hypernatremia
 Diabetes insipidus
  Sxs: Polyuria / Polydipsia / Low urine osm
     Central
          Tumor / Granuloma / Trauma / Surgery
     Nephrogenic
          Severe hypokalemia / hypercalcemia / CKD /
           Drugs (lithium / demeclocycline / amphotericin)
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 hypernatremia
 DI
      Treatment
           Central
              DDAVPP 5-10 mcg intranasally q day / bid
           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
     Fatigue
     Cramps
     Constipation
     Weakness / Paralysis
     Paraesthesias
     Arrhythmias
   Hypokalemia
    EKG abnormalites
          Flattened T waves
          ST depressions
          Prominent U waves




http://www.merck.com/media/mmpe/figures/MMPE_12END_156_02_eps.gif
Hypokalemia
 Causes
     Inadequate intake
     GI losses
     Renal losses
     Acid-base shifts
     Hypomagnesemia
     Hyperaldosterone
     Medications (diuretics)
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 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         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?
Hyperkalemia
 Symptoms
     Usually asymptomatic
     Muscle weakness / paralysis
     EKG abnormalities
          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
     Renal disease
     Intake increased (rare outside of renal
      disease)
 2. Shift of potassium from intracellular space
  to extracellular space
     DKA
Hyperkalemia
 Does the potassium level make sense in the
  patient?

Pseudohyperkalemia (hemolysis)
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
Hyperkalemia
 Treatment options
     Calcium gluconate
     NaHCO3
     Regular insulin
     Albuterol nebulizer treatment
     Kayexalate
     Dialysis
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.
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.
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.
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.
Hyperkalemia
 NaHCO3
     1 Amp (44.6 meq) IV over 5 minutes.
     Onset: 30 minutes
     Duration: 60-120 minutes
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.
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
 Normal Calcium: 8.9 – 10.3 mg/dl
 Calcium
     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:
      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
     Calcium orally       (1000 mg / day)
     Vit D orally
          Calcitriol 0.25 – 0.5 mcg / day
Hypocalcemia
 Magnesium can be effective as well
     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
     Increase urinary excretion
     Diminish bone resorption
     Diminish GI absorption
     Chelation of ionized Ca (EDTA)
     Dialysis
Hypercalcemia
 Treatment
     Increase urinary excretion
          NS @ 200 – 300 ml / hr to achieve UO = 100 ml
           /hr
          Lasix (if fluid overloaded state exists)
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
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
Hypercalcemia
 Treatment
     Decreased oral absorption (Need in sarcoid)
          Oral phosphate administration
          Prednisone
Hypercalcemia
 Treatment
     Sensipar (cinacalcet)
          Calcimimetic indicated for secondary
           hyperparathyroidism in ESRD
          Parathyroid carcinoma


     Dialysis
          Consider in severe cases
          Ca 18-20 mg / dl
Hypomagnesemia
 Normal: Magnesium 1.7 – 2.4 mg / dl
 Symptoms
     Neuromuscular irritability
     CNS hyperexcitability
     Cardiac arrhythmias
Hypomagnesemia
 Think about hypomagnesemia in the following
  situations:
     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)
          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
     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
     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
     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:
     Renal failure
     Hypoparathyroidism
     Rhabdomyolysis
     Tumor lysis syndrome
     Acidotic states
     Exogenous admin of phosphorus
Hyperphosphatemia
 Treatment:
     Dietary restriction 0.6 – 0.9 grams / day
     Oral phosphate binders
          Calcium acetate 2 tabs PO q AC
          Sevelamer (Renegal) 800 mg PO q AC
          May need to add aluminum containing product
           (aluminum hydroxide)
     Dialysis

								
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