Disorders of salt and water Flashcards
hypernatremia
water content of body fluid is deficient in relation to sodium content (>145)
either too much salt or not enough water
what does hypernatremia usually result from?
inadequate fluid intake or excess water loss.
causes: deficit of thirst hypotonic fluid loss urinary loss GI loss insensible loss burns diuretic theraphy osmotic diureses (hyperglycemia or mannitol administration) sodium excess DI
what population does Hypernatremia usually presnet?
elderly and infants w/ D
what are clinical features of hypernatremia?
neruological manifestations that result from alterations in the brain water content and include thirst, restlessness, irritability, disorientation, lethargy, delierium, convulsion, coma
-possible brain cell shrinkage that can cause damage to the supporting vasculature
what are some signs of hyper N
dry mouth, dry mucus membranes, lack of tears and decreased slivation, flushed skin, tachycardia, hypotension, fever, oliguria, anuria, hyperventilation, lethargy, hyperreflexia
what can you look at in children to test for dehydration?
clinical dehydration scale
diagnostic studies of hyperN
serum >145
when would urine sodium be decreased?
if hyper N is due to extrarenal losses
when is urine sodium increased?
if hyper Na is due to renal loss or sodium excess
when is urine dilute in hyper Na?
DI
tx of hyper na
inpatient
what is the medication route for hyperNa
free water (po preferred, but can do IV or SQ) as a %5 dextrose solution in water or saline
what should be treated first in hyperNa?
hypovolemia- w/ isotonic saline or lactated ringers
then hyper na
when should dialysis be implemened?
if sodium is greater than 200
what must you be cautious of when treating hyperNa?
pulmonary or cerebral edema!! especially in pts w/ DM
-don’t rapidly correct
hyponatremia
plasma sodium concentration of less than 135 , but sx may not ocur until less than125
what isthe most common electrolyte disorder seen in general hospital populatio?
hypoNa and its caused by hypotonic fluid administration
what can cuase hyponatremia w/ hypervolemia
CHF, nephrotic syndrome, renal filure, and hepatic cirrhosis
what can cause hyponatremia w/ euvolema
hypothyroidism, glucocorticold excess, SIADH
what is SIADH defined by?
hypotonic hypoNa, urine osmolality of greater than 100, normal cardiac, hepatic, thyroid, adrneal and renal fx, and the absence of extracellular fluid volume deficit
urine sodium is > 40
hypoNa w. Hypovolema?
renal or nonrenal sodium loss
what are clinical features of hyponatermia
lethargy, disorientation musce crmaps, anorexia, hicups, N, V, seizures
what are signs of hypona?
wekaness, agitation, hyporeflexia, orhtostatic hypotension, cheyne-strokes, delirium, coma, or stupor
what are cheyne-strokes?
characterized by progressively deeper, and sometimes faster, breathing followed by a gradual decrease that results in a temporary stop in breathing called an apnea. The pattern repeats, with each cycle usually taking 30 seconds to 2 minutes.[1] It is an oscillation of ventilation between apnea and hyperpnea with a crescendo-diminuendo pattern, and is associated with changing serum partial pressures of oxygen and carbon dioxide
what would lab studies would you do if expected hypoNa?
- serum sodium less than 135
- plasma osmolality is usually decreased (except in cases of fluid redistribution due to hyperlycemia or proteinemia
- urine sodium is either increased or decreased depending on cause
what diagnositic imagigin would you get is suspected SIADH?
CT- rule out CNS disorder
CXR- r/o lung pathology
tx of hypoNa?
inpt basis- iff less than 125,
what is the tx if hypovolemic hyponatremia?
isotonic saline
what can be used to tx sx hypona w/ sodium less than 120?
hypertonic saine
what ares some complications of rapid correction of hypona?
central pontine myelinolysis that can lead to neurological damage
what can be used when chronic hypona is unrepsondive to fluid restriction
demeclocycline- used to induce nephrogenic DI, but may cause nephrotoxicity in pts w/ chirrhosis
what drug can be used in euvolemic or hypervolemic hyponatremia?
vasopressin antagonist (conivaptan)
what are the ADR of Vaptans?
fever, hypokalemia, injury to IV ste, orhtostatic hyopthension
rare: anemia, a fib, confusion, cconstipation, dehydration, D, dry oth
what is SIADH?
syndrome of inappropriate ADH secretion- opposite of DI; too much ADH being made
- *normovolemic hypoNa
- pple resrb water (the quaporin effect) more than is homeostatie
what are sx of SIADH?
HTN and decreased serum sodium
tx of SIADH
can be drug induced, restrict fluid, demeclocycline, vasporessing resceptor antatgoinst
what drugs can cause SIADH?
nicotine, phenothiazines, tricyclins (stimulate release of ADH)
-desmopressin, oxytocin, protatglandin- increase the renal action of ADH
- chlorpropamide,
- carbamazepine
- cyclophosphamide
- vincristine
- omeprazole
- ecstasy
