Fluid and electrolytes

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Fluid and electrolytes
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(No Transcript)
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Solution Plasma Interstitial Intracellular Normal Saline Lactated Ringer's Solution
Cations
Sodium 142 144 10 154 130
Potassium 4 4.5 150 4
Magnesium 2 1 40
Calcium 5 2.5 3
Total cations 153 152 200 154 137
Anions
Chloride 104 113 154 109
Lactate 28
Phosphates 2 2 120
Sulfates 1 1 30
Bicarbonate 27 30 10
Protein 13 1 40
Organic acids 6 5
Total anions 153 152 200 154 137
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• Daily fluid requirements is 2-3 liters
• Insensible losses
• respiratory tract (500 to 700 mL/d)
• the skin (250 to 350 mL/d),
• feces (100 mL/d).
• Fever increases requirements to 500 mL/d per 1C
  (1.8F)

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hyponatremia

• Na lt 135
• Due to water gain or Na loss
• nausea, vomiting, anorexia, muscle cramps,
  confusion, and lethargy, and culminate ultimately
  in seizures and coma

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• Hypertonic hyponatremia (Posm gt295)
• Hyperglycemia
• Mannitol excess
• Glycerol therapy

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• Isotonic (pseudo) hyponatremia (Posm
  275295) Hyperlipidemia
• Hyperproteinemia (e.g., multiple myeloma,
  Waldenström macroglobulinemia)

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Hypotonic hyponatremia (Posm lt275)
Hypovolemic
Renal
Diuretic use
Salt-wasting nephropathy (renal tubular acidosis, chronic renal failure, interstitial nephritis)
Osmotic diuresis (glucose, urea, mannitol, hyperproteinemia)
Mineralocorticoid (aldosterone) deficiency
Extrarenal
Volume replacement with hypotonic fluids
GI loss (vomiting, diarrhea, fistula, tube suction)
Third-space loss (e.g., burns, hemorrhagic pancreatitis, peritonitis)
Sweating (e.g., cystic fibrosis)
Hypervolemic
Urinary Na gt20 mEq/L
Renal failure (inability to excrete free water)
Urinary Na lt20 mEq/L
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Urinary Na lt20 mEq/L
Congestive heart failure (perceived as low-flow state by kidneys, stimulates ADH)
Nephrotic syndrome (low serum protein secondary to urinary loss)
Cirrhosis (low intravascular oncotic pressure secondary to decreased protein production)
Euvolemic (urine Na usually gt20 mEq/L)
Syndrome of inappropriate secretion of antidiuretic hormone
Hypothyroidism (possible increased ADH or deceased glomerular filtration rate)
Pain, stress, nausea, psychosis (stimulates ADH)
Drugs ADH, nicotine, sulfonylureas, morphine, barbiturates, NSAIDs, acetaminophen, carbamazepine, phenothiazines, tricyclic antidepressants, colchicine, clofibrate, cyclophosphamide, isoproterenol, tolbutamide, vincristine, monoamine oxidase inhibitor
Water intoxication (psychogenic polydipsia, lesion in thirst center)
Glucocorticoid deficiency (glucocorticoids required to suppress ADH)
Positive pressure ventilation
Porphyria
Essential (reset osmostat or sick cell syndromeusually in the elderly)
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Table 21-4 Diagnostic Criteria for Syndrome of Inappropriate Secretion of Antidiuretic Hormone
Hypotonic hyponatremia
Inappropriately elevated urinary osmolality (usually gt200 mOsm/kg)
Elevated urinary Na (typically gt20 mEq/L)
Clinical euvolemia
Normal adrenal, renal, cardiac, hepatic, and thyroid functions
Correctable with water restriction
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Table 21-5 Causes of Syndrome of Inappropriate Secretion of Antidiuretic Hormone


Central Nervous System Disease Pulmonary Disease Carcinoma
Tumor Tumor Lung
Trauma Pneumonia Pancreatic
Infection Chronic obstructive pulmonary disease Thymoma
Cerebral vascular accident, subarachnoid hemorrhage Lung abscess Ovarian
Guillain-Barré syndrome Tuberculosis Lymphoma
Delirium tremens Cystic fibrosis
Multiple sclerosis
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treatment

• If hyponatremia is
• severe (lt120 mEq/L)
• develops rapidly (gt0.5-mEq/L decrease in serum
  Na per hour)
• associated with coma or seizures
• 3 hypertonic saline (25-100 cc) should be given
• The rise in Na should be no greater than 0.5
  to 1.0 mEq/L per hour.
• In the face of seizures, this can be increased to
  1 to 2 mEq/L per hour

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Complications of therapy

• central pontine myelinolysis
• Worse in chronic hyponatremia
• Occurs if hyponatremia is corrected too fast

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hypernatremia

• Serum sodium of 150 mEq/L
• Usually caused by decreased water intake but
  sometimes increased sodium intake

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adequate water intake
Inability to obtain or swallow water
Impaired thirst drive
Increased insensible loss
Excessive sodium
Iatrogenic sodium administration
Sodium bicarbonate
Hypertonic saline
Accidental/deliberate ingestion of large quantities of sodium
Substitution of salt for sugar in infant formula or tube feedings
Salt water ingestion or drowning
Mineralocorticoid or glucocorticoid excess
Primary aldosteronism
Cushing syndrome
Ectopic adrenocorticotropic hormone production
Peritoneal dialysis
Loss of water in excess of sodium
GI
Vomiting, diarrhea, intestinal fistula
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Renal loss
Central diabetes insipidus
Impaired renal concentrating ability
Osmotic diuresis (multiple causes)
Hypercalcemia
Decreased protein intake
Prolonged, excessive water intake
Sickle cell disease
Multiple myeloma
Amyloidosis
Sarcoidosis
Sjögren syndrome
Nephrogenic diabetes insipidus
Congenital
Drugs/medications
Alcohol, lithium, phenytoin, propoxyphene, sulfonylureas, amphotericin, colchicine
Skin loss
Burns, sweating
Essential hypernatremia
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Diabetes insipidus

• Failure of central or peripheral ADH
• Distinguish with vasopressin administration
• Central responds well
• Nephrogenic does not

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Central Nephrogenic
Neoplasms Familial
Pituitary surgery Hypercalcemia
Trauma Hypokalemia
Granulomas Renal disease
Idiopathic Drug induced
Hematologic disorders
Malnutrition
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Table 21-8 Clinical Signs of Hypernatremic States Related to Serum Osmolality
Osmolality (mOsm/kg) Manifestations
350375 Restlessness, irritability
375400 Tremulousness, ataxia
400430 Hyperreflexia, twitching, spasticity
gt430 Seizures and death
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treatment

• Cornerstone is volume replacement
• The reduction in Na should not exceed 10 to 15
  mEq/L per day.
• There is usually a total water deficiency in
  hypernatremia

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potassium

• 70-75 found in muscle tissue
• Foods high in potassium are baked potatoes,
  spinach, lima beans, dried prunes, tomatoes, and
  bananas.
• 90 excreted by the kidneys

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hypokalemia

• Serum K lt 3.5
• A rise in the pH of 0.10 generally causes a 0.5
  mEq/L decrease in serum K
• Most common causes
• intracellular shifts
• increased losses (GI)
• Diuretic therapy

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Signs and symptoms
Cardiovascular
Hypertension
Orthostatic hypotension
Potentiation of digitalis toxicity
Dysrhythmias (usually tachydysrhythmias)
T-wave flattening, U waves, ST depression
Neuromuscular
Malaise, weakness, fatigue
Hyporeflexia
Cramps
Paresthesias
Paralysis
Rhabdomyolysis
GI
Ileus
Renal
Increased ammonia production
Urinary concentrating defects
Metabolic alkalemia, paradoxical aciduria
Nephrogenic diabetes insipidus
Endocrine
Glucose intolerance
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treatment

• Oral is ideal
• Iv for severe hypokalemia
• 10 mEq/hr in peripheral IV
• No more than 40 mEq should be added to each liter
  of IV fluid, and infusion rates should be no
  greater than 40 mEq/h.

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hyperkalemia

• Serum K gt 5.5
• Main causes
• Hemolysis
• Acidosis
• Renal failure
• Potassium sparing diuretics
• Rhabdo/crush injury

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EKG changes


Table 21-12 ECG Changes Associated with Hyperkalemia
K (mEq/L) ECG Changes
6.57.5 Prolonged PR interval, tall peaked T waves, short QT interval
7.58.0 Flattening of the P wave, QRS widening
1012 QRS complex degradation into a sinusoidal pattern
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treatment

• CaCl 5-10 mL IV
• Ca gluconate 10-20 mL IV
• Sodium bicarb 50-100 mEq IV
• Insulin 10 units iv
• One amp D50 iv
• Albuterol breathing treatment
• Kayexalate 25-50 g PO or PR
• hemodialysis

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calcium

• Most abundant mineral in body
• PTH secreted by parathyroid gland in response to
  low Ca
• Works via
• Stimulates osteoclasts to increase bone
  absorption
• Kidney (increases absorption)
• Intestine (increases abdorption)

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calcium

• Ionized calcium is active
• 50 is bound to plasma proteins (albumin)
• A 1-gram decrease in albumin results in a 0.8
  milligram/dL decrease in total calcium, with no
  change in ionized fraction

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hypocalcemia

• Ionized calcium lt 2.0 mEq/L
• Common causes include shock, sepsis, renal
  failure, and pancreatitis
• Also hypoparathyroidism and drugs (loops)

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Signs and symptoms
General
Weakness, fatigue
Neurologic
Tetany
Chvostek sign, Trousseau sign
Circumoral and digital paresthesias
Impaired memory, confusion
Hallucinations, dementia, seizures
Extrapyramidal disorders
Dermatologic
Hyperpigmentation
Coarse, brittle hair
Dry, scaly skin
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Signs and symptoms
Cardiovascular
Heart failure
Vasoconstriction
Muscular
Spasms, cramps
Weakness
Skeletal
Osteodystrophy
Rickets
Osteomalacia
Miscellaneous
Dental hypoplasia
Cataracts
Decreased insulin secretion
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• Classic ekg finding is prolonged QT interval
• Treatment
• None or oral replacement if mild
• Iv for severe hypocalcemia
• Replace magnesium as well

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hypercalcemia

• Serum calcium gt 10.5 mg/dL
• Causes
• Malignancy and hyperparathyroidism (90)
• Drugs (lithium)
• Pagets disease of bone

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Signs and symptoms

• stones (renal calculi)
• bones (osteolysis)
• moans (psychiatric disorders)
• groans (peptic ulcer disease, pancreatitis, and
  constipation).

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Ekg findings

• depressed ST segments
• widened T waves
• shortened ST segments and QT intervals
• Treatment
• Fluid replacement
• Iv bisphosphonates
• Pamindronate 90 mg IV over 24 hours
• Calcitonin 4 units/kg SC

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hypomagnesiumemia

• Causes alcoholism, malnutrition, and those with
  cirrhosis, pancreatitis, or excessive GI fluid
  losses
• Symptoms Tetany, Muscle weakness, Cerebellar
  (ataxia, nystagmus, vertigo), Confusion,
  obtundation, coma, Seizures, Apathy,depression,
  Irritability, Paresthesias, Dysphagia, Anorexia,
  nausea, Heart Failure, Dysrhythmias, Hypotension,
  Hypokalemia, Hypocalcemia, Anemia

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Treatment

• 50 mEq oral
• Alcoholics and severe hypomagnesium may require
  8-12 mg iv per day

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Hypermagnesiumemia

• Rare in ED
• Causes
• Renal failure
• lithium ingestion
• volume depletion
• familial hypocalciuric hypercalcemia

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Table 21-22 Symptoms and Signs of Hypermagnesemia
Level (mEq/L) Symptom
2.03.0 Nausea
3.04.0 Somnolence
4.08.0 Loss of deep tendon reflexes
8.012.0 Respiratory depression
12.015.0 Hypotension, heart block, cardiac arrest
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references

• Ch. 21 Tintinalli