Electrolytes (Patho) - EG

Intracellular fluid (ICF)

2/3 of total body fluid

Extracellular fluid (ECF)

• interstitial fluid

• intravascular fluid

• transcellular fluid (TSF)

• 1/3 total body fluid

Tonicity

• isotonic

• hypotonic

• hypertonic solutions

Osmolarity

osmosis

Fluid sources

• oral intake

• intravenous solutions (iso-, hypo-, or hypertonic)

Fluid losses

• urine

• feces

• insensible losses

Regulatory hormones

• antidiuretic hormone (ADH)

• aldosterone

• atrial natriuretic peptide

Fluid balance

regulation of body’s fluid compartments to maintain a stable internal environment

What functions does fluid affect?

• cellular metabolism

• temperature regulation

• delivery of oxygen and nutrients to cell

Types of fluid excess

• third spacing

• edema

• anasarca

• hypervolemia or fluid volume excess

• water intoxication

Causes of fluid excess

• excessive sodium or water intake

• inadequate sodium or water elimination

Filtration

fluid exits capillary since capillary hydrostatic pressure (35 mm Hg) is greater than blood colloidal osmotic pressure (25 mm Hg)

No net movement

no net movement of fluid since capillary hydrostatic pressure (25 mm Hg) = blood colloidal osmotic pressure (25 mm Hg)

Reabsorption

fluid re-enters capillary since capillary hydrostatic pressure (18 mm Hg) is less than blood colloidal osmotic pressure (25 mm Hg)

Pitting edema

• indentation in the affected areas

• excess fluid mainly composed of water

Non-pitting edema

• associated w/ conditions affecting the thyroid or lymphatic system

• buildup composed of proteins, salt and water

Common risk factors for edema

• medications

• obesity

• low protein levels

• pregnancy

• sitting/standing in same position too long

Treatment for edema

• mild: resolve on its own / elevate affected limbs

• severe: diuretic prescribed to help eliminate excess fluid through urine

• chronic: compression socks to promote circulation

Manifestations for fluid excess

• edemas: peripheral, periorbital, cerebral and anasarca

• dyspnea

• tachycardia

• hypertension

Diagnosis for fluid excess

• through history, physical examination, daily weights, measurement of intake and output

• lab results: blood chemistry, urine analysis, complete blood count

Treatment of fluid excess

• administering diureticcs

• restricting sodium and fluids

• maintaining high Fowler’s position

Types of fluid deficits

• dehydration

• hypovolemia or fluid volume deficit

• can occur independently w/o electrolyte defects

Causes of fluid deficit

• inadequate fluid intake

• excessive fluid or sodium losses

Fluid deficits lead to…

• increased level of blood solutes

• cell shrinkage

• hypotension

Diagnosis for fluid deficit

• blood test (CBC and chemistry panels)

• urine test (creatinine, urine sodium concentration, urine pH)

• X-ray or MRI

• daily weights

• measurements of intake and output

Manifestations of fluid deficit

• altered level of consciousness

• hypotension

• dry mucous membranes

• decreased skin turgor

Treatment for fluid deficit

• managing underlying cause

• fluid replacement

Electrolyte balance

• cations

• anions

• play a role in muscle and neural activity, and acid-base and fluid balance

Sodium normal range

• 135-145 mEq/L

• most significant cation and prevalent electrolyte of extracellular fluid

• mainly acquired through diet

• excreted through the kidneys and GI tract

Sodium functions

• controls serum osmolality and water balance

• plays a role in acid-base balance

• facilitates muscles and nerve impulses

Sodium homeostasis

• positive ion or “cation” —> Na

• most outside cells —> extracellular fluid

• concentration: 135 mEq/L —> Na relative to water in body

Hypernatremia

• >145 mEq/L

• serum osmolarity increases, resulting in fluid shifts

Causes of hypernatremia

• excessive sodium

• deficient water

Hypernatremia manifestations

• dry and sticky mucous membranes

• dysphagia

Hypernatremia diagnosis

through history, physical examination, and lab results

• blood chemistry and urine analysis

Hypernatremia treatment

fluid replacement and diuretics

Hyponatremia

• sodium <135 mEq/L

• serum osmolarity decreases

Causes of hyponatremia

• deficient sodium

• excessive water

Hyponatremia manifestations

• anorexia

• GI upset

Hyponatremia diagnosis

through history, physical examination and lab results

• blood chemistry and urine analysis

Hyponatremia treatment

limit fluids and increase dietary sodium

Hyponatremia electrolyte disturbance

• increase in serum levels of ADH, renal sensitivity to ADH and free water intake

• decrease in solute intake

Hyponatremia: SALT LOSS

• Stupor/coma

• Anorexia

• Lethargy

• Tendon reflexes

• Limp muscles

• Orthostatic hypotension

• Seizures

• Stomach cramping

Electrolyte balance: chloride

• normal range: 98-108 mEq/L

• mineral electrolyte and major extracellular anion

• obtained through dietary intake

• excreted through kidneys

• plays a role in acid-base balance

Hyperchloremia

• chloride > 108 mEq/L

Hyperchloremia causes

• increased chloride intake or exchange

• decreased chloride excretion

  **manifestations reflect underlying cause**

Hyperchloremia diagnosis

through history, physical examination and lab results

• blood chemistry, urine analysis and arterial blood gases measurement

• SAME AS HYPOCHLOREMIA

Hyperchloremia treatment

• identifying and managing underlying cause

• diuretics

• bicarbonate

Metabolic acidosis

• headache

• decreased BP

• hyperkalemia

• muscle twitching

• warm, flushed skin

• nausea, vomiting, diarrhea

• compensatory hyperventilation

Metabolic acidosis causes

• DKA

• severe diarrhea

• renal failure

• shock

Hypochloremia

chloride <98 mEq/L

Hypochloremia causes

• decreased chloride intake or exchange

• increased chloride excretion

  **manifestations reflect underlying cause**

Hypochloremia treatment

• identifying and managing underlying cause

• sodium replacement (oral or intravenous)

• ammonium chloride

• saline irrigation of gastric tubes

Metabolic alkalosis

• restlessness/lethargy

• tachycardia

• compensatory hypoventilation

• confusion

• nausea, vomiting, diarrhea

• tremors, muscle cramps

Metabolic alkalosis causes

• severe vomiting

• excessive GI suctioning

• diuretics

• excessive NaHCO3

Potassium

• normal range: 3.5-5 mEq/L

• primary intracellular cation

• mainly obtained through diet

• excreted through the kidneys and GI tract

Potassium plays a role in…

• electrical conduction

• acid-base balance

• metabolism

Hyperkalemia

potassium >5 mEq/L

Hyperkalemia causes

• deficient excretion

• excessive intake

• increased release from cells

• acute or chronic kidney disease

• tissue breakdown —> crush injury

Hyperkalemia manifestations

• paresthesia

• muscle weakness

• dysrhythmias

Hyperkalemia diagnosis

through history, physical examination and lab results

• blood chemistry, 12-lead EKG, arterial blood gas

Hyperkalemia treatment

• correcting acidosis (sodium bicarbonate)

• calcium glutinate for dysrhythmias

• decreased dietary intake

• increased excretion (dialysis, IV solutions, meds), insulin

Hypokalemia

potassium <3.5 mEq/L

Hypokalemia causes

• excessive loss

• deficient intake

• increased shift into the cell

• abuse of laxatives

• metabolic alkalosis

• diuretics (loop and thiazides)

Hypokalemia manifestations

• paresthesia

• leg cramps

• cardiac arrest

Hypokalemia diagnosis

through history, physical examination and lab results

• blood chemistry, 12-lead EKG, arterial blood gas measurement

Hypokalemia treatment

• identifying and managing the underlying cause

• potassium replacement (oral or intravenous)

Calcium

• normal range: 4-5 mEq/L

• mostly found in bone and teeth

• has inverse relationship w/ phosphorous

• synergistic relationship w/ magnesium

• main source = dietary intake

What is calcium regulated by?

• vitamin K

• parathyroid hormone

• calcitonin

What does calcium play a role in?

• blood clotting

• hormone secretion

• receptor functions

• nerve transmission

• muscular contraction

Hypercalcemia

calcium >5 mEq/L

• osteoclastic bone resorption

Hypercalcemia causes

• increased intake or release

• deficit excretion

Hypercalcemia manifestations

• dysrhythmias

• lethargy

• muscle weakness

• SAME AS HYPERMAGNESEMIA

Hypercalcemia diagnosis

through history, physical examination and lab results

• blood chemistry and 12-lead EKG

• SAME AS HYPOCALCEMIA

Hypercalcemia treatment

• identifying/managing underlying cause

• managing symptoms

• increasing mobility

• administering IV fluids

Hypocalcemia

calcium <4 mEq/L

Hypocalcemia causes

• excessive losses

• deficient intake

• hypomagnesemia

• hypoparathyroidism

• vitamin D deficiency

Hypocalcemia manifestations

• dysrhythmias

• positive Trousseau’s and Chvostek’s signs

• SAME AS HYPOMAGNESEMIA

Hypocalcemia treatment

• identifying and managing underlying cause

• calcium replacement (oral or intravenous)

• decreasing phosphorous

Hypocalcemia symptoms

• numbness around mouth

• muscle cramps

• paresthesias

• vomiting

• seizures

• decreased cardiac function

Hypocalcemia ECG

• lengthened ST

• lengthened QT

• may cause Torsades de pointes

Hypercalcemia ECG

• shortened ST

• shortened QT

Phosphorous

• normal range: 2.5-4.5 mg/dL

• mostly found in bones (small amounts in bloodstream)

• mainly obtained through diet

• excreted through the kidneys

Phosphorous plays a role in…

• bone and tooth mineralization

• cellular metabolism

• acid-base balance

• cell membrane formation

Hyperphosphatemia

phosphorous >4.5 mg/dL

Hyperphosphatemia causes

• deficient excretion

• excessive intake or cellular exchange

Hyperphosphatemia manifestations

rarely seen alone

• SAME AS HYPOPHOSPHATEMIA

Hyperphosphatemia diagnosis

through history, physical examination and blood chemistry

Hyperphosphatemia treatment

• identifying/managing underlying cause

• aluminum hydroxide or aluminum carbonate

• treating hypocalcemia

Hypophosphatemia

phosphorous <2.5 mg/dL

Hypophosphatemia causes

• excessive excretion or cellular exchange

• deficient intake

Hyperphosphatemia diagnosis

through history, physical examination and blood chemistry

Hyperphosphatemia treatment

• identifying and managing the underlying cause

• phosphorous replacement (oral or intravenous)

Magnesium

• normal range: 1.8-2.5 mEq/L

• an intracellular cation

• mostly stored in the bone and muscle

• mainly obtained through diet

• excreted through kidneys

Magnesium plays a role in…

• muscle and nerve function

• cardiac rhythm

• immune function

• bone strength

• blood glucose management

• blood pressure

• energy metabolism

• protein synthesis

Hypermagnesemia

magnesium >2.5 mEq/L

Hypermagnesemia causes

• renal failure

• excessive laxative and antacid use

Hypermagnesemia diagnosis

through history, physical examination and blood chemistry

• SAME AS HYPOMAGNESEMIA

Hypermagnesemia treatment

• diuretics

• dialysis

• intravenous calcium

Hypomagnesemia

magnesium <1.8 mEq/L