PCWP pulmonary capillary wedge pressure, CVP central venous pressure, BUN blood urea nitrogen

¥Normal serum uric acid.

¥Increased fractional excretion of urate.

¥This can be differentiated from SIADH as mentioned in Table 55.2.

Management

¥Treat the underlying causes of CSW like subarachnoid hemorrhage.

¥Put the central line to assess volume status.

¥Volume replacementÑmatch urine loss.

¥ Amount of sodium required = sodium deÞcit × total body water (See step 8). ¥ Blood product if anemia is present.

Step 12: Hyperosmolar hyponatremia

Consider hypertonic mannitol or other osmotic agents and hyperglycemia.

¥Stop infusion.

¥HyperglycemiaÑstop or decrease glucose administration.

¥Give insulin and ßuids.

¥Target a drop in glucose concentration of 75Ð100 mg/dL/h.

Step 13: Iso-osmolar hyponatremia

Consider pseudohyponatremia (drip arm sample, hyperlipidemia, paraproteinemia); usually asymptomatic and no treatment is required.

Suggested Reading

1.Ferguson-Myrthil N. Novel agents for the treatment of hyponatremia: a review of conivaptan and tolvaptan cardiology in review. Cardiol Rev. 2010;18(6):313Ð21.

The article describes the role of conivaptan and tolvaptan in the treatment of hyponatremia.

2.Verbalis JG, Goldsmith SR, Greenberg A, Schrier RW, Sterns RH. Hyponatremia treatment guidelines 2007: expert panel recommendations. Am J Med. 2007;120(11A):S1ÐS21.

A comprehensive guideline-based approach for the management of hyponatremia.

3.Irwin RS, Rippe JM. Irwin and RippeÕs intensive care medicine. 6th ed. Philadelphia: Lippincott Williams & Wilkins; 2006. p. 898Ð912.

4.Adrogue HJ, Madias NE. Hyponatremia. N Engl J Med. 2000;342:1581Ð9.

Pictorial description of extracellular fluid and intracellular fluid compartments under normal conditions and during states of hyponatremia.