Patient may be asymptomatic and Hyponatremia is incidentally found in ER on Routine Lab work. Or may have altered mental status. Lot of times, patients are either dehydrated (Diarrhea, vomiting, not drinking enough water) due to acute illness from other infections or have SIADH or are on HCTZ. Other patients could be having Cirrhosis, CHF, Hypothyroidism, malnutrition, using NSAIDS etc.
ER: Routine Labs (CBC, CMP, PT, PTT, EKG, CXR)
CT Head-if altered mental status (to rule out other problems)
If Na level is low enough with neurological symptoms, patient goes to ICU usually 120 and below with altered mental status
Others go to either Med-surg or Telemetry depending on severity and other comorbidities
Always look for Pseudohyponatremia-‘high GLP‘ –>Glucose (DKA), elevated Lipids, elevated Proteins.
Neuro-assessment q 4hrs
IV Fluids if patient is dehydrated vs Fluid Restriction (if you suspect SIADH)
Check Mg, P at least once
BMP every 4-6hrs so IV fluids can be stopped as soon as Na is correcting close to 8meq in 24hr period.
Nephrology evaluation for severe hyponatremia or if hyponatremia does not improve by the next day.
Tests to order: Serum Osmolality, Urine Osmolality, Urine Sodium, TSH, Uric Acid, Cortisol, Lipid panel
Do not correct more than 12 MEQ per day. Aim to correct Na by 8 per day (*Prevent Central Pontine Myelinolysis)
Sodium Chloride tablets 1g PO BID/TID.
Urea [URE-NA] Power Packet 15g PO TID
Sodium Bicarbonate PO or IV drip can be given if HCO3 is low [Metabolic Acidosis].
Usually the patients are from a facility like a NH, ECF, or are living alone and were lying on floor without help for several hours to few days. Rarely you may see Diabetes Insipidus patient.
As usual, always give Normal Saline IV if patient is hypotensive or else Give IV fluids like 1/2 NS, D5W if BP is normal.
The most important point is -Do not correct the above two too quickly.
Na may go up if you keep giving NS to a patient for days together in which case, stop IV NS and monitor or given some 1/2 NS.