Post on 24-May-2015
Electrolyte Disturbances Electrolyte Disturbances In ICUIn ICU
Dr. Fathia Hassan KhalilDr. Fathia Hassan Khalil
Body FluidsBody Fluids
• The average body water is 60% of TBW
• 65% in males & 55% in females
• In obese patient it decrease 5%
SodiumSodium
SodiumSodium
• Sodium is the major ion in ECF
• Normal value in blood is 135 : 145 mMol/L
Sodium is responsible forSodium is responsible for::
• 1- Maintaining plasma & ECF osmolality
• 2- Maintaining i.v. & ECF volume
• 3- Has physiologic role in generation of
• Membrane resting potential
• Action potential
• Glucose & a. a. transport.
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• Renal system
• Endocrine system
Sodium concentration is regulated by:
• Renal excretion of sodium is adjusted to equal the amount ingested.
• Urine sodium output 1 - 400 mEq/day
• The normal is 90 mEq/d
• In the kidney 96-99 % of the filtered sodium is reabsorbed– 67% in PCT by active process– 25% in thick ascending loop of Henel
passively (loop diuretics acted upon)– 5% in DCT & 3% in CD in exchange with K &
Cl (controlled by aldosteron).
HyponatremiaHyponatremia
HyponatremiaHyponatremia
• Hyponatremia means serum sodium less than 130 mEq/L
Less than 130 Mild
• Less than 125 Moderate
• Less than 115 Severe
• No linear correlation between degree of hyponatremia and symptoms.
• Symptoms depend upon the rapidity of occurrence of hyponatremia.
Because of difference between the regulation of total body volume and
sodium concentration, it is possible to have hypo- or hypernatremia in face of
hypo-, hyper-, or euvolemia.
Classification of HyponatremiaClassification of Hyponatremia
I- Hyponatremia with normal serum osmolality
II- Hyponatremia with high serum osmolality
III- Hyponatremia with low serum osmolality
I-Hyponatremia with normal serum I-Hyponatremia with normal serum osmolalityosmolality
• S. Osmolality: 280-295 mOsm/kg water
• Called Pseudohyponatremia
• Causes:– 1- Hyperlipidemia (every 4-6 gm/L increase in
lipids leading to 1mEq/L decrease in sodium.– 2- Hyperproteinemia e.g. multiple myeloma
(every 10gm/dl increase leading to 1mEq/L decrease in serum sodium).
II-Hyponatremia with High Serum II-Hyponatremia with High Serum OsmolalityOsmolality
S. Osmolality: > 295mosm/kg water
• Called Hypertonic Hyponatremia
Caused by increase impermeant solutes replacing sodium in the blood
• Causes:
1-Non sodium solutes e.g. glucose, mannitol, and some toxins (ethanol & urea).
2- Renal failure due to impaired water excretion.
Management of Hyponatremia with Management of Hyponatremia with normal & High S. Osmolality normal & High S. Osmolality
- Restoration of volume and free water deficit
- Treatment of non-sodium salts e.g. toxins
- Treatment of hyperglycemia or mannitol level
- Treatment of hyperlipidemia or hyperprotenemia.
III-Hyponatremia with III-Hyponatremia with HypoosmolalityHypoosmolality
• S. Osmolality : < 280 mosm/kg water
• It is the most common type
• It means that free water intake more than water loss
Types of Hyponatremia with Hypo-Types of Hyponatremia with Hypo-osmolalityosmolality
• Based on clinical assessment of total body water and sodium content it is classified into:
1. Hypovolemic hypoosmolar hyponatremia
2. Hypervolemic hypoosmolar hyponatremia
3. Euvolemic hypoosmolar hyponatremia
1-Hypovolemic Hypoosmolar 1-Hypovolemic Hypoosmolar HyponatremiaHyponatremia
• Causes:
• 1- Renal causes
• Diuretic use
• Renal tubular dysfunction
• Hypoaldosteronism
Urine sodium > 30mEq/L
Urine osmolality normal (300:400)
• 2- Non renal causes:
• G.I. loss
• Skin loss
• Dietery sodium restriction
• Third spacing
Urine sodium < 15mEq/L
Urine osmolality > 400 mosm/kg w
Manifestations of Hypovolemic Manifestations of Hypovolemic Hypoosmolar HyponatremiaHypoosmolar Hyponatremia
• Intra vascular volume depletion
• Hypotension
• Orthostatic hypotension
• Tachycardia
• Skin dehydration
Management of Hypovolemic Management of Hypovolemic Hypoosmolar HyponatremiaHypoosmolar Hyponatremia
• - Replace the volume depletion to depress ADH by isotonic crystalloid, or colloids and blood if not enough.
• -Replace free water with sodium by Water restriction and Furosemide
• Replace urine output by isotonic or hypertonic saline
22 - -Hypervolemic Hypoosmolar Hypervolemic Hypoosmolar HyponatremiaHyponatremia
• It is called dilutional hyponatremia
• Causes:
• CHF
• Liver cirrhosis
• Nephrotic syndrome
Manifestations of Hypervolemic Manifestations of Hypervolemic Hypoosmolar HyponatremiaHypoosmolar Hyponatremia
• Total body water increased and the patient is edematous but
• The effective circulatory volume is low.
• Urine sodium < 15 mEq/L
• Urine osmolality > 400 mosm/kg w
Management of Hypervolemic Management of Hypervolemic Hypoosmolar HyponatremiaHypoosmolar Hyponatremia
• The aim of management is to improve
• The effective circulating volume
• Renal function
• Cardiac function
• Distal tubular delivery of sodium*Combination of furosemide & ACE
Inhibitor.
3-Euvolemic Hypoosmolar 3-Euvolemic Hypoosmolar HyponatremiaHyponatremia
* Syndrome of inappropriate ADH secretion• Excess ADH secretion• Secretion stimulated by non-osmotic,
non-volumic factors e.g.:– Emotional stress– Endocrine disorders– CNS diseases– Excess hypotonic fluids– Drugs e.g. NSAID & Carbamezapine
• Urine Na > 30mEq/L, U. Osm > 400mosm
Management of Syndrome of Management of Syndrome of inappropriate ADH secretioninappropriate ADH secretion
• Treatment of the cause e.g. brain tumor resection
• Free water restriction
• Furosemide to get –ve water balance
• Replace fluid by isotonic or hypertonic saline
• Measure serum sodium every 6:12 h.
• * Water intoxication: e.g.
• Psychosis
• Heavy beer drinking
• Absorption of hypoosmolar fluids during prostate resection.
• Urine osmolality < 100 mosm/kg w
• Treated by water restriction
General Manifestations of General Manifestations of HyponatremiaHyponatremia
• Serum osmolality and cellular dehydration are the main insult done
• CNS cells are the most affected by changes in osmolality.
• CNS compensate for slow changes in osmolality affected severely in acute changes.
General Manifestations of General Manifestations of HyponatremiaHyponatremia
• In acute hyponatremia:
• -CNS manifestations:
• begin by lethargy & confusion up to seizures, cerebral edema & coma
• GI symptoms
• Muscle cramps & weakness
Management of HyponatremiaManagement of Hyponatremia
Management Based onManagement Based on::
*Treatment of the cause
*Restoration of serum sodium concentration
*Normalization of serum osmolality
Correction of Serum SodiumCorrection of Serum Sodium
Acute changes in sodium concentration should be treated rapidly, but
• Chronic changes should be treated more slowly.
In acute hyponatremia (<2 days):
Correct by no faster than 1 : 2 mMol/L/h
Serum sodium not increased more than 130 mEq/L and avoid hypernatremia
In presence of seizures or increase ICP the correction could be in 3 :4 mMol/L in the first hour or even 8 mMol/L
In chronic hyponatremia:
Correct by less than 12 mMol/L/day
The rapid correction may leads to:
Osmotic Demyelination Syndrome
Severe neurological deterioration after one to several days of rapid correction.
• The amount of sodium required to increase serum sodium concentration is calculated as the equation:
• Na required=
(Desired Na – Present Na) * TB Water
• TB Water =
• BW * 0.6 in male (0.5 in female)
• The desired sodium should not exceed 130mEq/L
• Hypertonic saline used only in severe hyponatremia
• Hypertonic saline should be stopped when:• Pt become asyptomatic• Plasma sodium increased by 20 mmol/L• Plasma sodium reached to 120:125mmol/L
HypernatremiaHypernatremia
HypernatremiaHypernatremia
• It means s. sodium >150 mEq/L
• It results from loss of free water or
• Gain of sodium ions in excess of water
Risky patients are:Risky patients are:
• The extreme of age for inability to drink
• Very sick patient
• Comatosed patient
• Severe vomiting
• Severe hypernatremia producing:
• Cellular dehydration
• Hyperosmolality in most cases
Classification of HypernatremiaClassification of Hypernatremia
I- Hypernatremia with hypovolemia
II- Hypernatremia with hypervolemia
III- Hypernatremia with euvolemia
I-Hypernatremia with hypovolemiaI-Hypernatremia with hypovolemia
• Causes:
• 1-Renal water loss e.g.
• Osmotic diuretics in excess
• Tubular renal disease
• Adrenal failure
• Impaired response to ADH & DI– U Na>20 mMol/L– U Osm<300:400 mOsm/kg water
• 2- Non-renal water loss e.g.
• GI loss e.g. diarrhea
• Skin loss, severe sweating
• Peritoneal dialysis– U Na < 15 mMol/L– U Osm > 400 mOsm/kg water
II-Hypernatremia with hypervolemiaII-Hypernatremia with hypervolemia
• Causes:
• 1- Iatrogenic (Na containing compounds)
• 2- Mineralocorticoid in excess e.g.
• Aldosteronism
• Cushing disease
• CAH– U Na >20 mMol/L– U Osm >300 mOsm/kg water
III- Hypernatremia with euvolemiaIII- Hypernatremia with euvolemia
• Causes:
• 1-Renal water loss e.g.
• DI
• Renal disease
• Diuretics– U Na variable– U Osm <290 mOsm/kg water
• 2- Non renal water loss e.g.
• Diarrhea
• Fever– U Na variable
– U Osm > 400 mOsm/kg water
Diabetes InsipidusDiabetes Insipidus
• I- Central DI
• Idiopathic DI
• Following head trauma
• Neurological disease
• 2-Nephrogenic DI
• Sickle cell nephropathy
• Chronic pyelonephritis
• Multiple Myeloma
Clinical Clinical FeaturesFeatures of Hypernatremia of Hypernatremia
• Neurological features:– Begin by irritability, to focal deficit up to
cerebral dehydration & hemorrhage
• Cardiovascular features– Manifestations of volume depletion up to
shock
• Renal features– Polyuria or oliguria up to renal insufficiency
Management of HypernatremiaManagement of Hypernatremia
• Acute hypernatremia treated rapidly
• While chronic state should be treated slowly to avoid neurological insults as seizures and cerebral edema
• Correction should not exceed 2mMol/L/h
Management of Hypernatremia:Management of Hypernatremia:
1- Treatment of the underlying cause
2- Volume repletion with isotonic salineHypotonic fluid used after volume repletion
Water deficit replaced over 24 : 48 h
3- Sodium overload :Removed by loop diuretics & renal dialysis in severe cases
4- Treatment of DI
- Hormonal replacement (Desmopressin)
- In nephrogenic DI desmopressin is not completely beneficial but
- Limitation of salt and water intake and
- Thiazide diuretics are the treatment of choice
PotassiumPotassium
PotassiumPotassium
• Serum potassium (k) range is
3.5 to 5mMol/L• But 98 % of total body k is intracellular
• Then decrement of 1 mMol of serum potassium concentration means a loss of about 200 : 300 mMol/L in body potassium store.
Functions of PotassiumFunctions of Potassium
• The main function is the stability of the action potential of the cell membrane.
• Then the main effect of serum hypokalemia is hyperpolarization of resting membrane potential affecting mainly:
• The heart producing arrhythmias and
• The brain affecting the nerve conduction
-Potassium also play a role as a cofactor in enzymatic reactions
-It maintain the normal cell volume
-It affects the IC hydrogen ion concentrations and participate in regulation of intracellular PH
HypokalemiaHypokalemia
HypokalemiaHypokalemia
• Hypokalemia means serum level less than 3.5 mMol/L
• Because potassium is primarily an intracellular ion, hypokalemia may occur in low, normal, or high total body potassium.
Causes of HypokalemiaCauses of Hypokalemia
• 1- Redistribution e.g.–Shift of potassium from ECF to ICF
– Insulin – Metabolic alkalosis– Catecholamines e.g. aldosteron – Periodic paralysis– Anabolism– Vitamin B12
• 2- Non-renal loss of potassium e.g.
– Gastrointestinal loss mainly diarrhea and repeated suction
– Discontinued diuretics with alkalosis
– Skin loss
33 - -Renal loss of potassiumRenal loss of potassium
The most common causes e.g.
* Diuretics:
It leads to increase renal tubular flow, aldosteron secretion & alkalosis
*Aldosteron: Causing potassium waisting in pressence of sodium ions
* Renal tubular damage:
From nephrotoxin drugs
*Diabetic ketoacidosis:
As a result of osmotic diuresis, and increased excretion of non-reabsorbable ketoacid anions.
Clinical Effect of HypokalemiaClinical Effect of Hypokalemia
1- Cardiovascular:
arrhythmias then conduction defects
2- Vascular: postural hypotension
3- Muscular: weakness up to cramps
4- Neurological:
hyporeflexia up to impaired mentation
5- Renal features:
Reduced glomerular filtration to renal damage
6- Gastrointestinal:
Paralytic ileus, nausea & vomiting
7- Metabolic features:
Glucose intolerance, metabolic alkalosis
Management of HypokalemiaManagement of Hypokalemia
• General measures:
-Treatment of underlying disease
- Correction of other electrolyte disturbance
-Discontinue offending drug
-Correction of acid base imbalance.
Monitoring for arrhythmias.
Potassium ReplacementPotassium Replacement
• Precautions:
• The maximal infusion in 10 : 40 mMol/h
• The minimal concentration given in peripheral big vessel is 60 mMol/liter fluid
• Potassium should be diluted in nonglucose solutions
• Avoid over infusion & hyperkalemia
Potassium ReplacementPotassium Replacement
• In severe cases i.e. s.k < 2 mMol/L, or ECG changes or muscle weakness:
• Give up to 40mMol/h in one litter normal saline iv.
• In mild to moderate cases i.e. s.k >2 mMol/L and no ECG changes:
• Give up to 10mMol/h iv.
HyperkalemiaHyperkalemia
HyperkalemiaHyperkalemia
• Hyperkalemia means serum potassium more than 5 mMol/L
• It may occur with low, normal or elevated total body potassium stores
• Pseudohyperkalemia results if potassium is released from cells in the test tube.
Most Common Causes of HyperkalemiaMost Common Causes of Hyperkalemia
• I- Decreased excretory capacity
• II-Excess intake of potassium
• III- Translocation from ICF to ECF
I- Decreased excretory capacityI- Decreased excretory capacity
1- Renal failure when GFR decreases below 10ml/min
2- Potassium sparing diuretics
3- Hypoaldosteronism
4 ACE inhibitors
5- NSAID
II-Excess intake of potassiumII-Excess intake of potassium
1- Iatrogenic excess potassium supplement
2- Stored blood
3- Salt substitutes
III- Translocation from ICF to ECFIII- Translocation from ICF to ECF
1- Acidosis
2- Severe catabolism & Rabdomyolysis
3- Insulin deficiency
4- Aldosteron antagonists
5- Digitalis toxicity
6-Hyperosmolality
Clinical features of HyperkalemiaClinical features of Hyperkalemia
* Cardiovascular:
1- Arrhythmias mainly VT & VF
2- Heart block
3- Delayed conduction
4- Ventricular standstill
Clinical features of HyperkalemiaClinical features of Hyperkalemia
• *Neuromuscular manifestations
1- Paresthesia
2- Muscle weakness
3- Flaccid paralysis
4- Mental confusion
Treatment of HyperkalemiaTreatment of Hyperkalemia
• General Measures:
– Treatment of underlying disease
– Restriction of exogenous potassium
– Removal of offending drugs
Treatment of HyperkalemiaTreatment of Hyperkalemia
• Mild Hyperkalemia:
• Restriction of potassium and liberalization of sodium and water are enough.
Treatment of HyperkalemiaTreatment of Hyperkalemia
• Severe Hyperkalemia:
1-Calcium 5 mMol IV over 5 min.
2-Sodium Bicarb. 50: 100 mMol over 5min.
3-Loop diuretics
4-Glucose and insulin
5-Hypertonic saline
Treatment of HyperkalemiaTreatment of Hyperkalemia
6- In resistant cases:
Potassium-binding resins in 50ml sorbitol 20: 30 g orally/4h
7- Inhaled or infused B2 blocker
8- Dialysis