Fluid and Electrolytes

Fluid and Electrolytes

1. Manifestations=IMPORTANT

   • EDEMA

2. Terms to Know

   • Osmosis
     • Movement of water across a semipermiable membrane 
   • OsmolaRity
     • Used to describe fluids outside the body  go Run around OUTSIDE
   • Osmolality
     • Used to describe fluids INSIDE the body
   • Isotonic
     • Equal, neither shink or swell
   • Hypotonic
     • Lower osmolaity (inside) than the intracellular fluid. Cells swell because the water moves from outside (less solutes/diluted) to the more concentrated place in the cells
   • Hypertonic
     • Greater osmolality and cells shrink becuase the water is pulled out in order to try and dilute the solution outide of the cell. 

3. Important Notes!!!

   • Intracellular vs. Extracellular
     • Intra=2/3
     • Extra=1/3
       • - Interstitial tissue spaces -Plasma (vascular) -Transcellular
         • Transcellular= portion of water contained w/n epithilial lined spaces (CSF, pleural spaces, peritoneal and joints). Smallest component 
   • Rapid changes in osmolality from treatment can cause osmotic demyelination syndrome: Includes destruction of the myelin sheath of the axons passing through the brain stem) • Osmotic demyelination syndrome can cause serious neurologic injury and death

4. Imbalances, Regulations, Clinical maifestations

   • Solutes
     • Sodium
       • Hyponatremia
         • <135 mEq/L
         • excessive sodium loss or excessive ater gain
         • Etiology
           • Fluid loss such as vomiting, diarrhea, fistulas, diaphoresis, and diuretic therapy • Adrenal insufficiency • SIADH • Excessive water gain • Water pulled into cells due to decreased extracellular sodium levels and increased cellular fluid concentration
         • Assessment findings
           • Anorexia Muscle crampsNausea&nbsp;Altered level of consciousness: lethargy, disorientation, HA, confusion, convulsions (Na+ level &lt;115 mEq/L &nbsp;
         • Lab Studies
         • Treatments
           • Treat the underlying cause(s) &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;Sodium replacement (oralorIV) with diuretic medication(Lasix)&nbsp; Limit water intake &nbsp;&nbsp;Discontinue medications that contribute to SIADH&nbsp;
       • Hypernatremia
         • >145 mEq/L
         • Sodium Excess
         • Etiology
           • Water loss from diarrhea, fever, hyperventilation, Diabetes Insipidus &nbsp;&nbsp; &nbsp; &nbsp; &nbsp; Inadequate water replacement (decreased intake in the elderly, cognitively impaired, or comatose patients)&nbsp;&nbsp; &nbsp; &nbsp; &nbsp; &nbsp;Inability to swallow &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;Excessive oral or parenteral sodium intake&nbsp;&nbsp; &nbsp; &nbsp; &nbsp; &nbsp;Water pulled from cells b/c of increased extracellular sodium level and decreased cellular fluid concentration&nbsp;
         • Assessment Findings
           • Thirst&nbsp; Dry skin and mucous membranes &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; Elevated body temperature &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;Lethargy and restlessness&nbsp;
         • Lab Studies
           • Elevated serum osmolality &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;Elevated urine specific gravity&nbsp;
         • Treatments
           • Correct the underlying cause &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;Fluid replacement to correct the dehydration (oral or IV) &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;Complication of sustained hypernatremia is dehydration of brain and nerve cells &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;Treatment requires controlled, gradual correction of sodium and water levels in order to avoid serious neurologic complications&nbsp;
           • note:If hypernatremia is corrected too fast, water will move into the brain cells causing cerebral edema and potentially severe neurologic impairment.
     • Potassium
       • Filtered by the glomerulous
       • Major intracellular electrolyte
       • Potassium levels affect nerve and muscle excitability
       • Hypokalemia
         • etiology
           • Inadequate dietary potassium intake &nbsp; &nbsp; Excessive loss due to: Treatments such as&nbsp; 1.amphotecerin B 2. diuretics, steroid therapy 3. parenteral therapy without potassium replacement 4.gastric suctioning 5.colostomy, and ileostomy&nbsp; GI Disorders (diarrhea, vomitting, fistulas) Metabolic alkalosis Hyperaldosteronism &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;&nbsp; &nbsp; &nbsp;
         • assessment findings
           • -anorexia -fatigue -muscle weakness -paresthesia
         • EKG= flattened T-Wave, Prominent U wave, depressed ST segment
         • <3.5 mEq/l
         • Treatments
           • &nbsp;-Increase the intake of oral potassium through food (meats, dried fruits, orange juice, bananas) -Oral potassium supplements&nbsp;-IV potassium &nbsp; &nbsp;
       • Hyperkalemia
         • >3.5 mEq/l
         • Etiology
           • &nbsp;Pseudohyperkalemia from hemolysis of blood sample Decreased renal excretion due to renal failure&nbsp; Hypoaldosteronism&nbsp;&nbsp;Acidosis&nbsp;Severe tissue trauma (burns,massive infection,sepsis)&nbsp;Excessive intake of potassium supplement&nbsp;&nbsp; &nbsp;
         • assessment findings
           • •Muscle weakness, paresthesias, possibly paralysis • Nausea &nbsp; • EKG changes: Tall, narrow and symmetrically peaked T-wave, short Q-T interval, widened QRS complex, disappearing P-wave &nbsp; &nbsp;
         • Treatments
           • Depends on the degree of serum potassium concentration and whether there are EKG and neuromuscular manifestations&nbsp; Decreasing potassium ingestion and absorption&nbsp;Increasing renal excretion Increasing cellular uptake&nbsp;Persons with kidney failure may require hemo or peritoneal dialysis&nbsp;
     • Calcium
       • Normal=8.5-10.5
       • Bone strength and stability
       • Membrane potentials and excitability
       • contraction of all muscle types
       • Clotting
       • Second messanger in many hormone and neurotransmitter pathways
       • Extracelllular Calcium Controls Nerve Firing
         • Hypocalcemia
           • <8mg/dL
           • Nerves fire more easily
           • Causes
             • Primary or surgical hypoparathyroidism due to thyroidectomy&nbsp; Pancreatitis&nbsp; Inadequate intake or synthesis of Vitamin D&nbsp;Renal failureDrug therapy (aminoglycosides, corticosteroids, caffeine) &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;Insufficient Calcium intake&nbsp;
           • Clinical Manifestations
     • Phosphorus
       • Normal= 2.5-4.5
       • Bone and ATP formation
       • glucose, fat, protein metabolism
       • In DNA, RNA, and phospholipids
       • Acid- base Buffer
       • RBC, WBC, platelet function
       • Hypophosphatemia
         • <2.5 mg/dL
         • Manifestations: Neural, Musculoskeletal, Blood
           • NEURAL Intentional tremor Ataxia Paresthesias Confusion, stupor, coma Seizures MUSCULOSKELETALJoint stiffnessBone painOsteomalaciaBLOODHemolytic anemia&nbsp;Platelet dysfunction with bleeding tendency&nbsp;Impaired white blood cell function
       • Hyperphosphatemia
         • Laboratory values
           • Serum phosphorus &gt;4.5 mg/dL
         • Manifestations: Neuromuscular, cardiovascular
           • NEUROMUSCULAR&nbsp; ParesthesiasTetanyCARDIOVASCULARHypotension&nbsp;Cardiac arrhythmias&nbsp;
     • Magnesium
       • Normal= 1.3-2.1mg/dL
       • Cofactor in enzymatic reactions
         • ATP generation DNA replication Messenger RNA (mRNA) production and translation&nbsp;
       • Blocks K+ exit from cardiac cells
       • Smooth muscle relaxant
       • Hypomagnesemia
         • <1.3 mg/dL
         • Neural and muscle effects
           • Paresthesias Ataxia, dizziness, muscle fasiculations, tetany, confusion , disorientation&nbsp;
         • Cardiovascular effects
           • Tachychardia Hypertension&nbsp; Cardiac arrhythmias
       • Hypermagnesemia
         • >2.1 mg/dL
         • Neural and Muscle effects (decreased)
           • Lethargy Hyporeflexia Confusion Coma
         • Cardiovascular effects
           • Hypotension&nbsp; Cardiac arrythmias cardiac arrest
   • Other Diseases/Disorders
     • Thirst
     • ADH
     • Fluid Volume