Abstract: SA-PO392
Fellow's Nocturnal "Natremic" Dilemma; True, Pseudo, or Both: Implications on Dialysate Sodium
Session Information
- Genetic and Diagnostic Trainee Case Reports
November 09, 2019 | Location: Exhibit Hall, Walter E. Washington Convention Center
Abstract Time: 10:00 AM - 12:00 PM
Category: Trainee Case Report
- 902 Fluid and Electrolytes: Clinical
Authors
- Andrievskaya, Maria, Henry Ford Hospital, Detroit, Michigan, United States
- Khan, Bilal shahzad azam, Henry Ford Hospital, Detroit, Michigan, United States
- Soman, Sandeep S., Henry Ford Hospital, Detroit, Michigan, United States
Introduction
Hyponatremia is the most common electrolyte disturbance in patients admitted to the hospital. We report a case of combined true- and pseudohyponatremia in a patient who was on continuous renal replacement therapy (CRRT).
Case Description
A 46-year-old female with a history of end stage renal disease (ESRD) secondary to lupus was admitted to intensive care unit with peritonitis and septic shock. The patient weighted 50 kg, with calculated Watson’s volume of 26 L. She was started on CRRT due to hemodynamic instability. Her serum sodium (SNa) levels were stable around 129-130 mmol/L while on CRRT with a CRRT dialysate Na of 132 (to avoid over-correction). This was thought to be related to a hypotonic solution she was receiving (D20 for severe hypoglycemia). Overnight, the SNa was noted to drop to 122 mmol/L while she was receiving CRRT with no added hypotonic solutions administered. On call nephrology fellow was contacted urgently to establish the cause of this acute worsening of SNa.
On medication review it was found that the patient received intravenous immunoglobulin (IVIG) for immune thrombocytopenia in the evening prior to the SNa of 122 mmol/L. That fact raised a suspicion of pseudohyponatremia. Further workup revealed serum Osmolality of 281 mOsm/kg and anion gap of 1. Whole blood electrolytes were obtained and showed sodium level of 129 mmol/L.
Discussion
IVIG can cause hyponatremia by multiple mechanisms. Pseudohyponatremia results from increased percentage of protein in plasma, with a normal plasma water Na concentration. IVIG therapy can also result in true hyponatremia, arising from sucrose-induced translocation of water from the intracellular compartment (ICF) to the extracellular compartment (ECF). Even in the presence of underlying true hyponatremia, nephrologist should be cognizant of possibility of additional pseudohyponatremia. Therapeutic strategies should target whole blood Na in these situations.