Electrolyte question

[cardiac~lover]

When studying the differences of hypo- and hypernatremia, I'm confused as to why hyponatremia(low sodium) would cause hypertension. I know that when sodium shifts out of the cells, water goes in to compensate causing edema, increased blood volume and thus increased blood pressure. But doesn't high salt cause hypertension? Can anyone get this straight in my head? Ready to pull my hair out over sodium. Everything seems backwards. I don't understand "where sodium goes water follows" when hypo is sodium loss and water excess and hyper is sodium gain and water loss. HELP!!!!!:crying2:

[Daytonite, BSN, RN]

hyponatremia does not cause hypertension. it causes hypotension. look at the list of signs and symptoms associated with each. also see the weblinks for the major cations of f&e posted on the pathophysiology/ a & p/ microbiology/ fluid & electrolyte resources sticky of this forum: https://allnurses.com/forums/2016228-post24.html

sodium

sodium is a major cation in the extracellular space. it promotes neuromuscular function and reflects the balance between dietary sodium intake and renal excretion.

normal adult:

• 135-145 meq/liter
  
  
• (135-145 mmol/liter)
  
  

normal urine sodium:

• 27-287 meq/24 hrs
  
  
• (27-287 mmol/24 hrs)
  
  

panic (critical) values

:

• below120 meq/liter
  
  
• above 160 meq/liter

hyponatremia:

• is due to:
  • decreased sodium intake:
    
    • insufficient dietary intake
      
    • deficient sodium in iv fluids
      
    • n/g feeding with inadequate fluid
      

    [*]increased sodium loss:

    • addison's disease
      
    • fever
      
    • diarrhea
      
    • vomiting
      
    • excessive use of diuretics
      
    • chronic renal insufficiency
      
    • nephrotic syndrome
      

    [*]excessive body water gains:

    • excessive oral intake
      
    • excessive iv water intake
      
    • chf
      
    • siadh (syndrome of inappropriate secretion of adh)
      
    • osmotic dilution
      

    [*]third-space losses of sodium:

    • ascites
      
    • peripheral edema
      
    • pleural effusion
      
    • ileus or mechanical bowel obstruction
      
    • hidden fluid in body cavities

  [*]signs and symptoms:

  • increased pulse (tachycardia)
    
  • weak, thready peripheral pulses
    
  • flat neck veins
    
  • increased respiratory rate
    
  • decreased blood pressure (hypotension)
    
  • decreased body weight
    
  • thick, slurred speech
    
  • anorexia
    
  • nausea/vomiting/abdominal cramps
    
  • oliguria
    
  • anuria
    
  • lethargy/malaise
    
  • headache
    
  • confusion
    
  • muscular twitching
    
  • seizures
    
  • coma
    
  • respiratory arrest

hypernatremia:

• is due to:
  • increased sodium intake:
    
    • excessive dietary intake of sodium or water
      
    • excessive saline in iv therapy
      
    • excessive infusion of isotonic iv solutions
      

    [*]decreased sodium loss:

    • cushing's syndrome
      
    • hyperaldosteronism
      
    • decreased water output due to renal disease
      

    [*]excessive body water loss:

    • excessive sweating
      
    • extensive burns
      
    • dehydration
      
    • diabetes insipidus
      
    • osmotic diuresis
      

    [*]other causes of increased water:

    • azotemia
      
    • heart failure
      
    • pulmonary edema
      
    • lactic acidosis
      
    • long term administration of adrenocortidal hormones

  [*]signs and symptoms:

  • elevated blood pressure (hypertension)
    
  • elevated pulse (tachycardia)
    
  • elevated temperature
    
  • elevated respiratory rate, possible dyspnea
    
  • increased body weight
    
  • bounding peripheral pulses
    
  • moist mucous membranes
    
  • moist respiratory secretions
    
  • crackles in lungs on auscultation
    
  • fever
    
  • edema (may be pitting)
    
  • dry skin
    
  • thirst
    
  • weakness
    
  • restlessness/agitation
    
  • disorientation
    
  • delusions
    
  • hallucinations
    
  • lethargic when undisturbed
    
  • irritable when stimulated
    
  • muscle irritability
    
  • diminished or absent dtrs
    
  • high pitched cry in infants
    
  • seizures
    
  • coma (due to swelling of brain cells)
    
  • respiratory arrest due to increased osmotic pressure

[cardiac~lover]

Thank you so much for that post. I feel retarded for even asking that :) Thank you though!

[Daytonite, BSN, RN]

This stuff is complicated and confusing. I failed my first attempt at the national certification in Intravenous Therapy by 2 questions--both in the section on electrolytes.