39: Na & K Regulation Disorders Flashcards
two main systems that regulate serum osmolarity
- ADH
2. thirst mechanisms from osmoreceptor signals
two receptors that trigger ADH release
omsoreceptors in anterior hypothalamus, baroreceptors from BP
non-osmotic stimuli for ADH release
nausea, hypoxia, pain, meds, pregnancy
two things to order when assessing volume status of pt with hyponatremia
random urine Na level, urine osmolarity
extra lab value to order when considering SIADH
serum uric acid
order in which to order labs for hyponatremia
all simultaneously
five essential diagnostic criteria for SIADH
- decreased ECF osmolarity
- inappropriate urine concentration
- clinical euvolemia
- elevated urine Na
- absence of other cause (dx of exclusion)
three overarching causes of SIADH
carcinomas, pulmonary disorders, nervous system disorders
MC malignancy associated with SIADH
small cell lung cancer
how many days does it take for ODS to start showing sx
2-6 days
where does demyelination occur in osmotic demyelination syndrome
pontine and extrapontine neurons
symptoms of ODS
dysarthria, dysphagia, paraparesis, behavioral disturbnces, seizures, lethargy, confusion, coma, death
locked-in syndrome
occurs in some ODS patients - they are awake but unable to move or communicate
best way to Dx ODS
head MRI, may take up to 4 weeks to show abnormalities on MRI though
major intracellular vs extracellular cation
intra: K
extra: Na
