Journal of General Internal Medicine

, Volume 23, Issue 2, pp 202–205

Pseudohyponatremia in a Patient with HIV and Hepatitis C Coinfection

  • Brian T. Garibaldi
  • Scott J. Cameron
  • Michael Choi
Case Reports/Clinical Vignettes

DOI: 10.1007/s11606-007-0446-3

Cite this article as:
Garibaldi, B.T., Cameron, S.J. & Choi, M. J GEN INTERN MED (2008) 23: 202. doi:10.1007/s11606-007-0446-3


Pseudohyponatremia refers to low serum sodium in the presence of normal plasma tonicity. Whereas pseudohyponatremia secondary to hyperlipidemia is a commonly recognized occurrence, falsely low sodium levels secondary to elevated protein are less frequently observed. We present in this paper the case of a man coinfected with HIV and hepatitis C who had pseudohyponatremia from hypergammaglobulinemia. As hypergammaglobulinemia is a frequent occurrence in both HIV and HCV, we suggest that pseudohyponatremia is an important and likely underdiagnosed phenomenon in this patient population. Clinicians need to be aware of the electrolyte exclusion effect and become familiar with the techniques used by their local laboratory in the measurement of serum electrolytes. Pseudohyponatremia should also be included in the differential diagnosis of an elevated osmolal gap, as the falsely lowered sodium level will lead to a falsely low calculated serum osmolality.


pseudohyponatremia HIV hepatitis C electrolyte exclusion effect 

Copyright information

© Society of General Internal Medicine 2007

Authors and Affiliations

  • Brian T. Garibaldi
    • 1
  • Scott J. Cameron
    • 2
  • Michael Choi
    • 3
  1. 1.Department of MedicineThe Johns Hopkins HospitalBaltimoreUSA
  2. 2.Department of Pathology, Clinical Chemistry DivisionThe Johns Hopkins HospitalBaltimoreUSA
  3. 3.Department of NephrologyThe Johns Hopkins HospitalBaltimoreUSA

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