Hyper/Hyponatremia Flashcards
What causes hypovolemic hypernatremia?
- most common
- renal losses (osmotic diuresis)
- insensible losses (sweat, fever, respiration)
- GI losses (diarrhea)
What causes euvolemic hypernatremia?
- renal losses (diabetes insipidus)
- variable hypothalamic disorder
What causes hypervolemic hypernatremia?
- hypertonic saline administration
- sodium bicarb administration
- primary hyperaldosteronism
Who will almost never present with hypernatremia?
alert patient with normal thirst mechanism and access to water
Who is at greater risk for hypernatremia?
-more common > 60 yo
What are 2 defense mechanisms the body has against hypernatremia?
- stimulation of ADH release (causes maximal urine concentration)
- thirst
Central Diabetes Insipidus
- loosing water freely
- occurs when secretion of ADH is impaired
Common Causes of Central DI
- head trauma
- hypoxic or ischemia encephalopathy
- idiopathic
Nephrogenic Diabetes Insipidus
-impaired ability to respond to ADH
Tx of Central DI
vasopressin
Tx of Nephrogenic DI
water PO
Clinical Manifestations of Hypernatremia
- neurologic
- lethargy, weakness, irritability
- hyperreflexia
- seizures, coma, death
- DI pts will c/o polydipsia, polyuria, nocturia
Diagnosis of Hypernatremia
- H&P
- recent fluid losses, altered mental status, thirst
- assess pt’s volume status
What is the serum osmolality level in hypernatremia?
always > 290 mOsm/kg in hypernatremia
pts with <200 have some form of DI
Tx of Hypernatremia
- rapid correction must be avoided b/c of brain’s adaptive response and risk of cerebral edema
- lower serum sodium concentration by 0.5 mEq/L per hour
Tx of Hypovolemia Hypernatremia
- normal saline solution initially to correct volume deficit
- then more hypotonic fluids
Tx of Hypervolemic Hypernatremia
- remove source of salt excess
- administer diuretics
- replace water
Tx of Euvolemic Hypernatremia
-water replacement alone (water PO or D5W IV)
Clinical Manifestations of Hyponatremia
- anorexia, nausea, lethargy
- more advanced: disoriented, agitated, seizures, depressed reflexes, focal neuro deficits
- coma and sz with serum sodium concentration <120 mEq/L
Physical Exam in Hyponatremia
- orthostatic vital signs
- check skin turgor, mucous membranes
- JVD, edema
- wedge pressure
Dx of Hyponatremia
- history
- meds, esp thiazide diuretics
- recent V/D or sweating with hypotonic fluid ingestion
- recent surgery
- psych illness (psych polydipsia)
- CHF, cirrhosis, nephrotic syndrome w/ renal failure
What causes hypovolemic hyponatremia?
- renal loss: diuretic use, salt wasting nephropathy, hypoaldosteronism
- GI loss: V/D, tube drainage
- skin loss: sweating, burns, CF
- peritonitis
What causes hypervolemic hyponatremia?
- CHF
- cirrhosis
- nephrotic syndrome
- acute and chronic renal failure
What causes euvolemic hyponatremia?
- ADH excess
- thiazide diuretics
- pain
- post-op state
- cortisol deficiency
- hypothyroidism
- decreased solute intake
What can happen with hyponatremia Tx failure?
- can cause central pontine myelinolysis (demyelination of pons)
- aka osmotic demyelination syndrome
- encephalopathy, AMS, seizures, weakness, dysarthria, HTN
- mutism, dysphagia, quadriparesis, delirium, coma, death
Tx of Hyponatremia
- eliminate the cause
- restrict water
- normal saline, restrict water
What will a mental health patient with psychogenic polydipsia have?
hyponatremia
Which patients may be unable to give a history?
hypernatremia
Hyperkalemia has peaked T waves. Are there any EKG changes with hyper or hyponatremia?
no!
