HYPONATREMIA Flashcards
MANAGEMENT
- TREAT NEUROLOGICAL EMERGENCIES RELATED TO HYPONATREMIA WITH HYPERTONIC SOLUTION:
Indications: Na <120 mEq AND Seizures or Obtundation or Coma or Headache / Nausea / Vomiting, suspected cerebral herniation
100 ml of 3% hypertonic saline IV over 10 min
If symptoms persist, 1-2 additional boluses may be given
OR
8.4% Sodium Bicarbonate, 2 mL / kg
STOP ALL FLUIDS after the second bolus
Recheck serum sodium level 1-2 hr after each bolus
Goal: Increase Na by 4-6 mmol. Limit increase to no more than 6 mmol during first 6 hrs OR 8 mmol / L in first 24 hrs.
Saline Lock
DDAVP 1-2 ug SC / IV while using 3% Saline to prevent over correction. USE WITH CAUTION.
- DEFEND INTAVASCULAR VOLUME
HYPOVOLEMIC:
250-500 cc LR IV guided by BP
LR closer to hyponatremic patient, will not raise the Na as quickly
EUVOLEMIC:
NPO
Saline Lock
HYPERVOLEMIC:
NPO
Fluid Restriction
Sodium restriction
IV Furosemide
- PREVENT WORSENING OF THE HYPONATREMIA
Strict Fluid restriction
Saline lock the IV
- PREVENT RAPID OVERCORRECTION
Insert a foley catheter and monitor the ins and outs. Check urine output q hr
If urine output > 100 cc / hour, send a STAT urine osmolarity and urine sodium
If urine osmolarity < 100, consider administering 1 ug DDVAP IV
Continue steps 2-3 as per urine output
- CORRECT THE HYPONATREMIA: RULE OF 6’s
6 mmol in the first 6 hours for severe symptoms
Otherwise, 6-8 mmol / day
- ASCERTAIN THE CAUSE OF THE HYPONATREMIA
INVESTIGATIONS
Volume Status Exam
Serum {Na}
Serum Osmolality
Urinary Sodium (U Na)
Urine Osmolality (U Osm)
Cortisol
TSH
MONITOR
seizures
coma
respiratory arrest
DISPOSITION
Severe (Na < 120): Stepdown
Moderate (120-129): Hospitalist
DOCUMENTATION
CLINICAL FEATURES
Mild to Moderate Hyponatremia: MC Chronic
headache
fatigue
lethargy
nausea / vomiting
dizziness
confusion
ataxia
muscle cramping
Severe:
Seizure
Obtundation
Coma
Respiratory Arrest
i. Chief Complaint: look for conditions which can increase output or decrease intake such as vomiting and diarrhea, pain or altered level of awareness
ii. Meds: look for those that cause SIADH
Thiazide diuretics (most common)
Loop diuretics
Antipsychotics
Angiotensin-converting enzyme inhibitors
Angiotensin receptor blockers
Spironolactone
Selective serotonin reuptake inhibitors
patients who have been on chronic steroids may have adrenal insufficiency
iii. PMHx: look for history of end organ failure (CHF, liver failure, renal failure) or cancer (SIADH)
iv. Labs: Glucose (hyperglycemia), potassium (hyperkalemia may suggest adrenal insufficiency), TSH (hypothyroidism)
DDX
HYPEROSMOLAR HYPONATREMIA
Hyperglycemia
High Protein (myeloma, IVIG)
Hypertriglyceridemia
Exogenous osmoles
HYPERVOLEMIC HYPOTONIC HYPONATREMIA
Urine Na < 20:
CHF
Cirrhosis
Urine Na > 20:
CKD?
Nephrotic Syndrome
EUVOLEMIC HYPOTONIC HYPONATREMIA
Urine Na > 20: RATS
RTA IV
Adrenal Insufficiency (Addison’s) (early)
HypoThyroid
SIADH (MOST COMMON)
Water>Solute Intake:
Psychogenic Polydipsia (MOST COMMON)
Beer Potomania
Low-solute-diet (tea and toast)
Urine OSM Low
Urine Na Low
HYPOTONIC HYPOVOLEMIC HYPONATREMIA:
Renal vs. Non Renal Causes
Urine Na > 20: Renal
Diuretics
Hypoaldosterone (late)
Urine Na < 20: Non Renal
Diarrhea / Vomit
Reduced PO intake
Sweat / Burn