Fluid Electrolyte Imbalances Flashcards
Which electrolytes would you find in the ECF? ICF?
ECF: Na+, Cl-, HCO3-
ICF: K+, Mg, Phosphates
Total Body water volume is can be broken down into what compartments?
Intracellular fluid & Extracellular fluid.
*Interstitial fluid and plasma make up the extracellular fluid
Water movement from ECF to ICF regulated by?
- Starling forces: hydrostatic pressure(capillary and interstitial) and osmotic pressures(plasma protein and interstitial protein).
- Osmolality
By what route can you give 3% normal saline?
in central line only!! This will destroy peripheral veins. this is very hypertonic.
What are the IV solutions & what is in each?
- D5W (sugar and water)
- Normal Saline (water and NaCl)
- Lactated ringers ( Na+, Cl-, lactate, Ca2+, K+)
- Albumin
- Blood Products:
–packed RBC
–FFP
Describe Na and Water balance in the following:
-hypervolemia
- hypovolemia
- hyponatremia
- hypernatremia
- edema
Hypervolemia:
- too much water
- too much Na+
Hypovolemia:
- not enough water
- too little Na+
Hyponatremia:
- too much water
- not enough Na+
Hypernatemia_
- too little water
- excess of Na+
Edema:
-too much Na+ w/ water retention in the interstitial space
Determing the severity of edema
PITTING
- 2mm = +1
- 4mm = +2
- 6mm = +3
- 8mm = +4
Skin Turgor
Dry mucous membranes
Tachycardia
Tx of Mild dehydration and moderate hypovolemia?
Dehydration:
- fluids with some electrolytes
- AVOID fluids with high sugar concentration (b/c draws fluid out_
- stop activities that create ongoing loss.
Mod. Hypovolemia:
-get a full hx, sx, oral replacement
Sodium
- normal value
- considered hyponatremic
- value to start tx
- panic value
normal: 135-148meq/L
hyponatremic: less than 135meq/L
Start tx: 120-130 dependent upon sx and situation
Panic: less than 120meq/L
WHat is normal lab value:
- serum osmolality
- urine osmolality
- sodium
- cl
- specific gravity
Serum Osmolality: 285-295mOsm/kg
Urine Osmolality: 24hr specimen=500-800mOsm/KgH20
random specimen= 50-1200mOsm/KgH20
Sodium: 135-145mEq/L
Cl: 95-105mEq/L
Specific Gravity: 1.003-1.030
high= dehydration
low= diabetes insipidus
Clinical Manifestations of Hyponatremia:
- chronic
- Acute
Chronic: fatigue, nausea, dizziness, confusion, lethargy, muscle cramps, gait disturbances, forgetfulness.
*Cerebral adaptation
Acute: fatigue, malaise, HA, lethargy, coma, seizures, resp arrest
*cerebral over hydration related to degree of hyponatremia. Neuronal cell expansion and cerebral edema….death.
What is one SE of correcting hyponatremia too fast?
osmotic demyelination
Hyponatremia may be further classified as:
- Hypovolemic
- Normovolemic
- Hypervolemic
what are some causes of each volume status?
Hypo: GI losses, renal losses(thiazides)
Normo: SIADH, low Na+ intake
Hyper: CHF, cirrhosis
Hyponatremia may be caused by:
a. inability to suppress ADH
b. appropriate suppression of ADH secretion
…what are some examples of each.
inability to suppress b/c:
- true volume depletion (GI/renal loss)
- decreased tissue perfusion
- syndrome of inappropriate ADH secretion
Appropriate suppression of ADH:
- polydipsia*
- low dietary solute intake
- advanced renal failure.
Treatment of Hypovolemic Hyponatremia?
Tx: normal saline/isotonic saline
*usually volume replacement orally or IV if more severe.
Tx Hypervolemic Hyponatremia?
- restrict fluids 1000-1200ml/day
- restrict sodium 1000-1200 mg/day
- utilize loop diuretics to remove excess fluid
SIADH
-what is this?
- describe the volume,tonicity, and Na concentration
- causes
- tx
What: too much anti-diuretic hormone
Describe: Hypervolemic hypotonic hyponatremia
Causes:
-drugs: carbamazepine, SSRIs, haloperidol, thorazine
-disease: Malignancies, CNS disorders, post surgery, pulm infections
Tx:
- treat the underlying cause
- fluid restriction is mainstay***
- may use oral salt tablets
- loop diuretics
Tx of SEVERE Hyponatremia, what are they at risk for?
what are some tx precautions?
At risk for brain herniation!
Tx:
- 3% hypertonic saline
- measure Na every hour.
Precautions:
-develop osmotic demyelination if increase Na too quickly.
Hypernatremia
- common causes
- describe whats happening in acute and chronic
- tx
Common causes:
- loss of water**(insensible and sweat, GI losses)
- Addition of hypertonic solution
- Sodium overload (intake or admin of hypertonic Na solution)
Acute:
-rapid decrease in brain volume can rupture cerebral veins leading to SAH, demyelinating brain lesions
Chronic:
-brain adapts by pulling water from CSF and increasing the uptake of solutes by cells which also increases the amount of water in the cells.
Tx:
-replace free water with D5W (b/c if you gave them free water it would mess up their brain)
-*add normal saline IF hypovolemic
Diabetes Insipidous
- describe Na concentration
- may be central or nephrogenic, describe the cause of each and the tx
Hypernatremia
Central:
Cause: not enough ADH
Tx: Desmopressin (ADH like activity) and fluid restriction
Nephrogenic:
Cause: kidney resistant to ADH.
Tx: Thiazide diuretic to decrease ECF and Na+, also sodium restriction.
When deciphering calcium lab values what other lab value must you consider?
ALBUMIN!!!!!!!!
if albumin level is not normal you need to correct for that..
Hypercalcemia
- causes
- sx
- tx
Cause:
-cancer and primary hyperparathyroidism (Benign adenoma is MC cause)
-Drugs: thiazide diuretics, calcium supplements, lithium
Sx:
- EKG changes
- N/V, anorexia, constipation
- Polyuria/dypsia
- neuro/psych sx
-untreated manifestations:
–metastatic calcification
–nephrolithiasis
–renal failure
Tx: Hypercalcemic Crisis
- saline and loop diuretics
- bisphosphonates
- osteoclast inhibitors: calcitonin
- dialysis
*Tx of hyperparathyroidism is surgically remove the glands.
Hypocalcemia
- causes
- sx
- ekg changes
Causes:
-hypoparathyroidism, Vit D deficiency, loop diuretics, phosphates
Sx:
-tetany, paresthesias around mouth** hallmark sx
Ekg:
-QT prolongation
Loop diuretics have what effects on Ca, Mg, and K…and Na.
Ca: decrease reabsorption…hypocalcemia
Mg: decrease reabsorption…hypomagnesemia
K: decrease reabsorption…hypokalemia
Na: decrease reabsorption…hyponatremia
Tx Acute Symptomatic HypoCalcemia
IV calcium salts (elemental)
*magnesium if hypomagnesaemia present
Tx Chronic Hypocalcemia
- oral calcium supplements (1-3g elemental Ca/day
- if not responding add Vit D 1000 IU/ day
Hyperphosphatemia
- causes
- tx
- sx
- emergent tx
Cause:
-decreased excretion d/t low GFR
-chemotherapy & rhabdo
Tx:
- GI binders…IV calcium salts.
- usually in renal failure:
- -diet restriction
- -phosphate binding gel (selvelamer)
- -avoid alluminum containing antacids-can cause bone dz
Sx:
- dysrhythmias, HTN
- muscle cramps
- seizures, tetany
- N/V/D
- acute renal failure, edema
Emergent: dialysis
Hypophosphatemia
- sx
- Tx
Sx:
-rare, long term may have proximal muscle weakness and osteomalacia
Tx:
Severe/Symptomatic:
-IV phosphorus: sodium PO4, Potassium PO4
Mild/Mod:
- Neutra-Phos
- Neutra-Phos K
Hypomagnasemia
- causes
- sx
- EKG
- Tx
Cause:
-increased excretion (diuretics,alcoholism)
- Impaired absorption (GI dz)
- Reduced Intake
- drugs: aminoglycosides, cisplatin, cyclosporine
Sx:
-muscle cramps, tetany, seziures, coma, hypocalcemia
EKG: wide QRS, afib, ventricular arrhythmias
Tx: if symptomatic or less thatn 1.0mEg/Ml
- IV MgSO4 if symptomatic/severe
- Oral replacement if mild/mod.
Hypermagnesemia
- Tx
IV calcium – strictly to antagonize neuromuscular and cardiovascular effects of magnesium.
- renal failure: hemodialysis
- normal renal function: diuresis w/ fluid and loop diuretics
Hypokalemia
-causes
-EKG
-
Causes:
-Drugs: beta 2 agonists, loop diuretics, ACEi, thiazides, insulin, high dose PCN, amphotericin B
-Medical: metabolic acidosis, vomiting, diarrhea
EKG: U waves
Hypokalemia Tx:
-loop/thiazide induced
-severe or symptomatic
Loop/thiazide:
-Potassium supplement oral
Sever/Symptomatic:
-IV K+ in saline bag
Hyperkalemia
- causes
- sx
- EKG
- Tx
Causes:
- increased K+ intake
- decreased excretion
- aldosterone resistance
Sx:
-ascending muscle weakness
EKG:
-eiffel tower peaked QT waves, shortened QT interval
as it becomes more severe… QRS & QT prolongation p waves may disappear..may lead to vfib or asystole
Tx:
-if abnormal EKG: Calcium gluconate IV,
D5W then insulin,
consider bicarb if acidotic
- if renal failure:
- -dialysis
- -K+ binders (Sodium polystyrene sulfonate)
loop diuretic if not volume depleted and kidneys okay.
