What lab tests are done for hyponatremia?

There are three essential laboratory tests in the evaluation of patients with hyponatremia that, together with the history and the physical examination, help to establish the primary underlying etiologic mechanism: urine osmolality, serum osmolality, and urinary sodium concentration.

How do you calculate sodium replacement in hyponatremia?

Formula for Sodium Correction

1. Fluid rate (mL / hour) = [(1000) * (rate of sodium correction in mmol / L / hr)] / (change in serum sodium)
2. Change in serum sodium = (preferred fluid selected sodium concentration – serum sodium concentration) / (total body water + 1)

How do you investigate hyponatremia?

Overall, serum osmolality and urinary sodium measurements are integral to the diagnosis and management of hyponatremia. Also required are clinical assessment and additional laboratory investigations that may include measuring urine osmolality, serum aldosterone, cortisol, and natriuretic peptide levels.

How can you distinguish between hypovolemic and hypervolemic hyponatremia?

Hypovolemic hyponatremia: decrease in total body water with greater decrease in total body sodium. Euvolemic hyponatremia: normal body sodium with increase in total body water. Hypervolemic hyponatremia: increase in total body sodium with greater increase in total body water.

How long does it take to correct hyponatremia?

In patients with severe symptomatic hyponatremia, the rate of sodium correction should be 6 to 12 mEq per L in the first 24 hours and 18 mEq per L or less in 48 hours. A bolus of 100 to 150 mL of hypertonic 3% saline can be given to correct severe hyponatremia.

How much water do you have to drink to get hyponatremia?

Symptomatic hyponatremia can occur when one drinks 3-4 L of water8). Severe hyponatremia occurs when too much water, more than what the kidney can excrete, is inhaled. The water excretion rate of a healthy adult is about 20 L/day and does not exceed 800-1,000 mL/hr9).

What can be done about drug induced hyponatremia?

Physicians may not always give proper attention in time to undesirable drug-induced hyponatremia. Effective clinical management can be handled through awareness of the adverse effect of certain pharmaceutical compounds on serum sodium levels.

How is serum osmolality measured in hyponatremic patients?

The initial approach to the hyponatremic patient is to measure the serum osmolality to determine whether the hyponatremia represents a true hypo-osmolar state.,, Although urea contributes to the absolute value of serum osmolality measured with an osmometer, it does not hold water within the extracellular space because of its membrane permeability.

Is there a link between SSRIs and hyponatremia?

Current evidence suggests a relatively higher risk of hyponatremia with SSRIs and venlafaxine, especially when combined with patient risk factors, warranting clinicians to be aware of this complicat … Hyponatremia is a potentially dangerous side effect of antidepressants and is not exclusive to SSRIs.

What is the lazy man’s algorithm for hyponatremia?

Hyponatremia: the lazy man’s algorithm Notice how at no stage is one invited to actually examine the patient. – Low urine osmolality Beer potomania, malnutrition The True hypovolemia Hyper-osmotic Measure Serum Osmolality Iso-osmotic Osmotic hyponatremia Hypo-osmotic Hyperlipidemia Mannitol Hyperglycemia