kidney(hypothalamic feedback mechanism), ADH, RAAS
What are the homeostatic mechanisms for retaining Na? (3)
Na/K/ATPase pump
ECF & ICF osmolality is maintained by _________.
Serum osmolality
_______ regulates ADH secretion.
b
ADH is secreted by the _________.
a) hypothalamus
b) posterior pituitary gland
detects decreases in circulating volume through baroreceptors & afferent arteriole
How does the RAAS regulate sodium retention?
a
A loss of Total Body water. (TBW)
a) Dehydration
b) Hypovolemia
b
A loss of ECF volume only.
a) Dehydration
b) Hypovolemia
a
Which results in hypertonicity?
a) Dehydration
b) Hypovolemia
hospitalization, NH residents, exercise-induced, medication-induced, parenteral nutrition
What are the risk factors associated with hyponatremia? (5)
a phenomenon in which the calculated lab values show hyponatremia when the patient has normal serum Na levels; caused by large amounts of proteins & lipids.
Explain Pseudohyponatremia.
caused by excessive amounts of serum glucose that moves water from ICF compartment to the ECF; diluting the existing sodium
Explain Hypertonic Hyponatremia.
b
Which can result in polyuria & polydipsia?
a) hypovolemic hyponatremia
b) hypertonic hyponatremia
c) Pseudohyponatremia
d) Euvolemic Hyponatremia
e) Hypervolemic Hypotonic Hyponatremia
will diffuse into all of the fluid compartments
If we give a patient D5W, how will it be distributed in the body?
will stay in the ECF compartment
If we give a patient NS, how will it be distributed in the body?
NS will remain in ECF; D5W will distribute to all other compartments
If we give a patient D5W-1/2 NS, how will it be distributed in the body?
2 Na + Glucose/18 + BUN/2.8
Calculated Osmolarity Formula?
assess serum osmolality
What is the first step in treating hyponatremia?
central venous access device
How must 3% NaCl be administered?
(NaIV-Nas)/ (TBW+volumeIV)
Change in Na Serum formula?
0.5 mEq/L per hour
What is the rate for changing sodium?
osmotic demyelination syndrome
What can occur if we correct sodium too fast?
ODS
-a rare neurological disorder that primarily affects the central nervous system, particularly the myelin sheath that surrounds nerve cells in the brain.
nausea, malaise, headache, lethargy, restlessness, seizure
Symptoms of Acute-Hyponatremia? (6)
water restriction
How would a patient with Euvolemic Hyponatremia be treated?
isotonic fluids
How would a patient with Hypovolemic Hyponatremia be treated?
NS, lactated ringers
Which fluids are Isotonic? (2)
water/sodium restriction; diuretics, VRAs
How would a patient with Hypervolemic Hyponatremia be treated? (3)
vasopressin 2; collecting duct
ADH stimulates _________ receptors of the ________; causing water to flow back into the bloodstream to correct volume deficits.
rifampin, carbamazepine, st.john's wort
Which drugs can induce(decrease drug concentrations) CYP3A4? (3)
azoles, clarithromycin, grapefruit juice
Which drugs can inhibit (increase drug concentrations) CYP3A4?
can cause hypernatremia; first dose started in hospital;
What is the BBW for Tolvaptan?
dominant polycystic disease; can cause hepatic failure
Patients with what condition must use Tolvaptan with caution? Why?
Samsca
Tolvaptan
Jynarque
Tolvaptan (DPD)
b
Which is available via IV?
a) Tolvaptan
b) Conivaptan
a
Which is more selective?
a) Tolvaptan
b) Conivaptan
carbamazepine, antipsychotics, SSRIs, chlorpropamide, NSAIDs
What medications can cause SIADH? (5)
100mg/dL; 1.5-1.9 mEq/L
Every _______ increase in glucose will cause sodium to fall by ______.