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Metabolic Abnormalities

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Title: Metabolic Abnormalities


1
Metabolic Abnormalities
  • Surgical Fundamentals Lecture
  • Asha Bale, MD
  • 8/06/10

2
Overview
  • Symptoms, Etiology, Treatment
  • Sodium
  • Potassium
  • Magnesium
  • Calcium
  • Glucose abnormalities
  • Arrhythmias

3
Hyponatremia Nalt136
  • Most Common causes are Iatrogenic or SIADH
  • Sx CNS (increased ICP)
  • Sx usually dont occur until Nalt120
  • Causes
  • Na depletion (extracellular volume deficit)
  • Na dilution (Excess extracellular water)
  • Excess solute relative to free water (ie
    hyperglycemia)
  • Pseudohyponatremia

4
Na depletion
  • Decreased intake
  • Low sodium diet
  • Enteral feeds
  • Loss of Na containing fluids
  • GI losses (vomitting, NGT, diarrhea)
  • Renal losses (diuretics or primary renal disease)

5
Na Dilution
  • Excess extracellular water/Excess extracellular
    volume
  • Iatrogenic (IVF, free water)
  • High ADH (increases reabsorption of free water,
    causing increase in volume and hypoNa)
  • SIADH- low serum Na, high Urine Na and U Osm
  • Drugs causing water retention
  • Antipsychotics, tricylcic antidepressants, ACE
    inhibitors

6
Excess solute causing HypoNa
  • Excess solute relative to free water can cause
    hyponatremia
  • Untreated hyperglycemia
  • Glucose causes an osmotic force, shifting water
    from the Intracellular compartment to the
    Extracellular compartment (like dilutional
    hypoNa)
  • For every 100mg/dl increase in Glu, plasma Na
    decreased by 1.6
  • Mannitol

7
Pseudohyponatremia
  • Extreme elevations in plasma lipids and proteins
  • No true decrease in extracellular sodium relative
    to water

8
Hyponatremia Algorithm
  • Symptomatic or Asymptomatic?
  • Asymptomatic
  • Hypotonic (POsmlt280)
  • Hypervolemic- water restriction, diuresis
  • Hypovolemic- isotonic saline
  • Isovolemic- water restriction
  • Isotonic (POsm 280-285, hyperlipidemia)
  • Correct underlying disorder
  • Hypertonic (POsmgt280, hyperglycemia, hypertonic
    infusions like mannitol)
  • Correct underlying disorder
  • Symptomatic (treat aggressively)
  • 3 NaCl
  • Dont correct fast!
  • Stop when Na 120-125

9
Treatment of Hyponatremia
  • Water deficit(L) (serumNa-140 / 140) x TBW
  • TBW estimated as 50 of lean body mass in men and
    40 in women
  • Dont correct faster than 1mEq/h and 12mEq/d,
    avoids cerebral edema and herniation
  • Frequent neurologic exams

10
Treatment of Hyponatremia
  • Most cases- Free water restriction, if severe-
    administer sodium
  • If Neuro Sx, then use 3 NS to increase Na by no
    more than 1mEq/L per hour until Na level reaches
    130, or Neuro Sx are inproved
  • Rapid correction causes pontine myelinosis,
    seizures, death

11
Hypernatremia Nagt144 mEq/L
  • Caused by loss of water or a gain in Na in excess
    of water (hypervolemic, isovolemic, hypovolemic)
  • Can be assoc with increased, normal or decreased
    extracellular volume
  • Water shifts from ICF to ECF, causing cellular
    dehydration
  • Sx (neurologic) restlessness, irritability,
    seizures, coma, death

12
Hypervolemic Hypernatremia(Gain of water and
salt)
  • Iatrogenic
  • Administration of Na containing fluids, including
    Na Bicarb
  • Mineralocorticoid excess
  • U Nagt20meq/L, Uosmgt300mOsm/L
  • Hyperaldosteronism
  • Cushings Syndrome
  • Congenital Adrenal Hyperplasia

13
Normovolemic Hypernatremia(Loss of water)
  • Nonrenal Causes of water loss
  • GI
  • Skin
  • Renal Causes of water loss
  • Diabetes Insipidus
  • Diuretics
  • Renal Disease

14
Hypovolemic Hypernatremia(Loss of water and salt)
  • Renal water loss
  • DI (Low ADH) (high Serum Na, dilute urine, low U
    Na and U Osm)
  • Osmotic diuretics
  • Adrenal failure
  • Renal tubular diseases (UNalt20, UOsmlt300-400)
  • Nonrenal water loss (GI, Skin)
  • UNalt15, UOsm gt400)

15
Hypernatremia Algorithm
  • History, physical, electrolytes, BUN/Creatinine,
    Urine Na, UOsmolarity
  • Assess extracellular volume status
  • Hypovolemic (Loss of water and Na)
  • Restore extracellular volume, calculate water
    deficit
  • Isotonic saline until euvolemic, then hypotonic
    saline or D5W to correct HyperNa
  • Isovolemic (Loss of water)
  • D5W IV or water p.o.
  • Diabetes Insipidus- Vasopressin
  • Hypervolemic (Gain of Na and water)
  • Lasix and D5W or D51/4 NS
  • If renal failure? dialysis

16
Hyperkalemia
  • Normal K 3.5 to 5.0 meq/L
  • History, physical, EKG, chemistry, ABG
  • Sx GI (n/v, diarrhea), neuromuscular (weakness),
    cardiovascular (EKG changes, arrhythmias)
  • EKG changes
  • Peaked t waves
  • Flattened p wave
  • Prolonged PR interval
  • Widened QRS complex
  • Sine wave formation
  • V-fib

17
Hyperkalemia EKG Peaked t wavesFlattened p
waveProlonged PR intervalWidened QRS
complexSine wave formationV-fib
18
Hyperkalemia
  • Excess Potassium Intake
  • Oral, iv, blood transfusion
  • Increased Release of K from cells
  • Cell destruction/breakdown
  • Hemolysis, rhabdomyolysis, crush injuries, GI
    hemorrhage, acidosis
  • Impaired excretion by kidneys
  • Meds K sparing diuretics, ACE Inhibitors,
    NSAIDs
  • Renal Insufficiency, Renal Failure

19
Treatment of Hyperkalemia
  • Reduce total body K
  • Stop exogenous sources of K
  • Kayexalate
  • (Cation-exchange resin, binds K in exchange for
    Na)
  • PO or PR
  • Dialysis
  • Shift K from extracellular to intracellular
  • Glucose/Insulin, bicarbonate
  • Albuterol
  • Protect cells from effects of increased K
  • When EKG changes present, use Calcium chloride or
    calcium gluconate (5-10mL of 10 solution)
  • Use cautiously in patients on Digoxin- can cause
    Dig toxicity

20
Hyperkalemia Algorithm
  • History, PE, EKG, Chemistry, ABG
  • Klt6.5, no EKG changes?
  • Stop supplemental K and repeat K
  • Klt6.5, EKG changes?
  • Stop K, Kayexalate or Lasix, look for underlying
    cause
  • Kgt6.5 or EKG changes?
  • Calcium gluconate, Glucose Insulin, NaHCO3,
    Kayexalate, Lasix, Dialysis

21
Hypokalemia
  • Klt3.5 mg/L
  • Sx
  • Ileus, constipation
  • Weakness, fatigue
  • Cardiovascular
  • EKG changes u waves, t wave flattening, ST
    segment changes, arrhythmias

22
Etiology-Hypokalemia
  • Inadequate intake
  • Dietary, K free IVF, TPN with inadequate K
  • Excessive Renal Excretion
  • Hyperaldosteronism (waste K)
  • Meds
  • Diuretics which increase K excretion
  • Penicillin (promotes renal tubular loss of K)
  • Loss in GI Secretions
  • Diarrhea, vomiting, high NGT outputs

23
Etiology- Hypokalemia
  • Intracellular shifts
  • Metabolic Alkalosis
  • K decreases by 0.3 mEq/L for every 0.1 increase
    in pH above normal
  • Insulin therapy
  • Drugs causing Magnesium depletion will cause K
    depletion as well
  • Amphotericin, aminoglycosides, foscarnet,
    cisplatin
  • Replace Magnesium!

24
Treatment of Hypokalemia
  • Check K, electrolytes, renal function and urine
    output
  • Estimate for every 10 mEq K replaced, the serum
    potassium will increase by 0.1 mg/L
  • Potassium repletion
  • Oral (functioning GI tract, mild, asymptomatic
    patients)
  • KCl, K-dur
  • IV (Nonfunctioning GI tract, or severe
    hypokalemia)
  • No more than 20meq/H in an unmonitored setting
  • Can be up to 40meq/h replacement in monitored
    setting
  • Caution in patients with impaired renal function
  • Repeat K levels
  • KCl, KPhos

25
Magnesium Abnormalities
  • Magnesium found in the intracellular compartment
  • Of that found in the extracellular space, 1/3 is
    bound to albumin
  • Normal 1.3 to 2.1 mEq/L

26
Hypermagnesemia Mg gt2.2 mEq/L
  • Rare
  • Impaired renal function, excess intake with TPN,
    Excess use of laxatives or antacids
  • Sx n/v, weakness, lethargy, hypotension
  • EKG changes (similar to hyperkalemia)
  • Increase PR interval, widened QRS complex,
    elevated t-waves
  • Tx Ca 100-200mg IV over 5-10 mins., Dialysis,
    Remove Magnesium source

27
Hypomagnesemia
  • Renal excretion
  • Alcoholism, diuretics, Amphotericin B
  • GI Losses
  • Diarrhea, malabsorption, acute pancreatitis, DKA,
    primary hyperaldosteronism
  • Poor p.o. intake
  • Starvation, alcoholism, prolonged use of IVF, TPN

28
HypoMagnesemia
  • Sx neuromuscular and CNS hyperactivity, tremors,
    delerium, seizures
  • Sx similar to hypercalcemia
  • Associated with hypokalemia
  • EKG
  • Prolonged QT and PR intervals
  • ST segment depression
  • Flattened or inversion of p waves
  • Torsades de pointes
  • arrhythmias

29
Torsades de Pointes- hypomagnesemia
30
Treatment of Hypomagnesemia
  • Oral replacement if mild or asymptomatic
  • Magnesium Oxide
  • IV replacement if severe (lt1.0 mEq/L) or
    symptomatic
  • 2g Magnesium sulfate IV over 5 minutes followed
    by 10g during the next 24 hours (if renal
    function is normal)
  • If Torsades, give over 2 mins.
  • Also correct hypocalcemia, frequently associated

31
Hypercalcemia Cagt10.5
  • Serum Ca above normal range of 8.5 to 10.5 mEq/L,
    or an increase in the ionized calcium level above
    4.2 to 4.8 mg/dL
  • Primary hyperparathyroidism (outpatient)
  • Malignancy (inpatient)
  • Sx Neuro (confusion, depression), Musc
    (weakness, back pain), GI (n/v/ abd pain),
    cardiac, EKG changes

32
Hypocalcemia prolongs the QT interval by
stretching out the ST segment. Hypercalcemia
decreases the QT interval by shortening the ST
segment so that the T wave seems to take off from
the QRS complex
33
Treatment of Hypercalcemia
  • Most cases due to malignancy, if not check PTH
    level
  • PTH high? hyperparathyroidism
  • PTH normal or low? w/u for malignancy
  • Treatment is supportive, treat underlying cause
  • Tx when symptomatic (Hypercalcemic crisis)
    (serum level gt12mg/dL)
  • Replete volume deficit, then brisk diuresis with
    normal saline and Lasix
  • 1-2L NS over 1-2h, followed by 200-400mL/h with
    Lasix 20-80mg IV over 2-3h
  • Etidronate, phosphate, Mithramycin, steroids,
    Calcitonin, Dialysis

34
Hypocalcemia
  • Etiologies pancreatitis, massive soft tissue
    infections, renal failure, pancreatic and SB
    fistulas, hypoparathyroidism, Magnesium
    abnormalities, tumor lysis syndrome
  • Transiently after removal of a parathyroid
    adenoma
  • Malignancies assoc w/ increased osteoclastic
    activity
  • Massive blood transfusions (precipitation with
    citrate)
  • Sx parasthesias, muscle cramps, stridor, tetany,
    seizures

35
Treatment of hypocalcemia
  • Check albumin, check for abnormalities of Phos
    and Mag
  • Asymptomatic- give po or iv
  • Chronic
  • Add Calcium to IVF
  • Calcium p.o. (1500 to 3000mg per day, plus
    vitamin D)
  • Acute symptomatic
  • Need to give 200 to 300mg of Calcium
  • 20-30mL 10 Ca Gluconate OR
  • 5-10mL 10 Ca Chloride
  • Give slowly over several minutes
  • Can worsen HTN or Dig toxicity
  • Correct associated deficits in magnesium,
    potassium and pH

36
HyperphosphatemiaSerum Phos gt5mg/dL
  • Normal 2.7 to 4.5 mg/dL
  • Mostly seen in pt with renal failure
  • Hypoparathyroidism
  • Tx
  • Chronic- Low Phos diet, aluminum binding antacids
  • Acute- Dialysis

37
Hypophsphatemia
  • Decreased intake
  • Intracellular shift of phosphorus
  • alkalosis, insulin therapy
  • Increased phosphorus excretion
  • Sx muscle weakness (important for vent dependent
    pts)
  • PO- Nutraphos
  • IV- NaPhos, KPhos

38
Arrythmias
  • Ask Desk Clerk to CALL Senior Resident and/or
    Attending!
  • Symptomatic or Asymptomatic?
  • ABCs
  • Code Cart into room, call Anesthesia if needed
  • Vital signs, O2 Sat
  • Quick History/Physical Exam
  • EKG/Rhythm strip- Recognize the Arrhythmia
  • Place on a monitor, Supplemental Oxygen
  • ACLS Protocol- Stabilize Patient
  • ABG or ABE, electrolytes, cardiac enzymes
  • Treat Underlying Cause

39
Arrhythmia
40
Arrhythmia
41
Arrhythmia A-Fib
42
Arrhythmia
43
Arrhythmia SVT
44
Arrhythmia
45
Arrhythmia V-Tach
46
Arrhythmia
47
Arrhythmia
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