Fluid and Electrolyte Imbalance Lecture 2 11/26/20151

Sodium Imbalance Normal value ( mEq/L) Sodium is a primary determinant of serum osmolarity. Increase in sodium lead to increase osmolarity Sodium also has a major role in water distribution. Sodium and water usually are lost and gained together Sodium is important in creation and transmission of nerve impulse and muscle contraction 11/26/20152

Sodium deficit ( Hyponatremia): defined as sodium level below 135mEq/L Can happened in 2 cases : Loss of sodium from blood in a proportion that is higher than loss of water Significant increase in water with no change in sodium content ( dilution hyponatremia) Hyponatremia can happened in both hypervolemia and hypovolemia 11/26/20153

Causes of hyponatremia Vomiting, sweating, diarrhea, fistula, use of diuretics if combined with loss sodium intake Deficiency of aldosterone ( up normal) Increase anti diuretic hormone( ADH) such as in syndrome of inappropriate antidiuritic hormone ( SIADH). 11/26/20154

Clinical manifestations of hyponatremia With minor change Poor skin turgor, headache, dry mucosa, orthostatic hypotension With a level of less than 115mEq/L neurologic changes such as alteration in mental status, increase intracranial pressure seizure and coma. Hyponatremia results in accumulation of water in brain tissue ( cerebral edema) due to osmotic gradient. 11/26/20155

Diagnostic findings in hyponatremia Decrease serum sodium ( less than 135mEq/L) Decrease urine sodium to less than 20mEq/L as the kidney try to conserve sodium Low urine specific gravity ( ) 11/26/20156

Management of hyponatremia Sodium replacement : increase oral intake Normal saline 0.9% or Ringer Lactate IV Sodium should not be increased in a rate higher than 12mEq/L Water restriction less than 800ml/24hrs in case of fluid excess such as (SIADH) 11/26/20157

Sodium excess (Hypernatremia ) High serum sodium more than 145mEq/L Cause by increase is sodium in different proportion than water Can happened in both hypervolemia and hypovolemia Causes Decrease fluid intake ( especially in unconscious patient). Administration of hypertonic saline solution Drowning in sea water 11/26/20158

Clinical manifestation of hypernatremia Neurologic manifestation as a result of increase plasma osmolarity and movement of water out of the cells. Restlessness, weakness, delusion hallucination Thirst Assessment and diagnostic findings Increase sodium higher than 145mEq/L and serum osmolarity higher than 300mOsm/kg 11/26/20159

Medical management of hypernatremia Administer hypotonic saline solution such as NS 0.45% Sodium level is reduced in a rate no faster than 0.5 to 1 mEq/L/ hr 11/26/201510

Potassium Imbalance Normal value in serum is 3.5-5mEq/L Potassium is a major intracellular electrolyte Influence both cardiac and skeletal muscle activity Potassium is very sensitive to change in serum level Kidney is the primary regulator of serum potassium with 80% excretion through kidney while the other 20% is excreted via bowle and sweat 11/26/201511

Potassium Deficit (Hypokalemia) Decrease in serum potassium less than 3.5mEq/L Causes include diuretics, Gastrointestinal loss as in vomiting and diarrhea, illeostomy. Increase aldosteron secretion Diuretics ( lasix) Increase insulin secretion as in diabetes I insulin increase entry of insulin into skeletal muscle and hepatic mucles 11/26/201512

Clinical manifestations of hypokalemia Fatigue, anorexia, nausea Muscle weakness, paresthesia, decrease bowel motility Inability of kidney to excrete urine Increase sensitivity to digitalis( digoxin) Electrocardiogram (ECG) changes flat T wave, inverted T wave, depressed ST segment elevated U wave 11/26/201513

Medical management of hypokalemia Potassium supplement: usually 40-80mEq/L High potassium diet as most fruits, legume, whole grain, milk, meat. Potassium chloride is a routine supplement and usually the concentration is 20mEq- 40mEq/ for each liter 11/26/201514

Potassium Excess (Hyperkalemia) Potassium decrease less than 3.5mEq/L Causes mainly is decrease renal excretion ( renal failure). Decrease aldosteron secretion. Side effect of medications such as heparin, ACE inhibitor (captopril), NSAID, potassium sparing diuretic such as spironalacton( aldacton) 11/26/201515

Clinical manifestations of hyperkalemia The most common is cardiac when the level is higher than 7mEq/L and early changes can be noted at a value 6mEq/L such as: Peaked narrow T wave St segment depression Shortened QT interval PR interval prolonged followed by disappearance of P wave. Prolongation of QRS complex that entails cardiac arrhythmia and cardiac arrest Muscle weakness may be paralysis related to depolarization block ( speech muscle and respiratory muscle 11/26/201516

Medical management of hyperkalemia Restriction of potassium Cation exchange resin ( Kayexalate): bind with potassium in the intestine and removed through stool. Administration of calcium gluconate ( to protect the heart but has no effect on the potassium level) Administration of sodium bicarbonate Administration of hypertonic dextrose solution with insulin: insulin bind potassium and sugare and move it to the cells 11/26/201517

Calcium Imbalance 99% of the total body calcium in the skeletal system Normal serum value for the total calcium is mg/dl ( mmol/L). The ionized calcium mg/dl) ( the lap give readings for both ionized and total) Calcium is absorbed in the food in the presence of gastric acidity and vitamin D Excretion mainly via feces with the reminder through urine 11/26/201518

Calcium deficit ( Hypocalcemia) Lower than mg/dl for the ionized or lower than 8.6mg/dl for the total Causes include hypoparathyroidism ( decrease parathormon cause less release of calcium from the bone) Inflammation of pancreas( pancreatitis) Renal failure ( because of increase in phosphate cause decrease in calcium) Inadequate vitamin D consumption 11/26/201519

Clinical manifestations of hypocalcemia Increase neuronal excitability resulting in Tetany: increase both sensory and motor peripheral nerve discharge. Symptoms of tetany include general tingling in fingers and feet, face, and around mouth Trousseau’s sign Chvostek’s sign Mental changes then Seizure ECG changes such as prolonged QT interval, prolonged St SEGMENT 11/26/201520

Diagnostic findings of hypocalcemia Serum calcium level and serum albumin level (because significant amount of calcium in blood is bonded to albumin) Medical management Increase dietary intake( milk, green leafy vegetables, canned salmon, sardines, and oyster IV supplement as calcium gluconate, or calcium chloride Vitamin D therapy ( increase absorption from the GIT 11/26/201521

Calcium Excess ( Hypercalcemia) Increase total calcium higher than 10.2mg/dl or ionized calcium higher than 5.1 mg/dl. Causes include malignancy and hyperparathyroidism ( increase parathormone) Clinical Manifestations Increase calcium lead to suppress neuronal activity at the neuromuscular junction which cause muscle weakness, incoordination, anorexia, and constipation. Increase urine output due to disturbed renal function Cardiac standstill in sever case when calcium is higher than 18mg/dl 11/26/201522

Medical management of hypercalcemia Administer high volume of NS0.9% to dilute the serum and increase urine output Phosphate may be given as it increase calcium excretion Lazix rarely given as it increase excretion Also rarely Calcitonin may be given as it move calcium from the blood to the bone. 11/26/201523