56 yo M with hyponatremia


  • Evaluation and management of hyponatremia


A 56 yo M with a history of a DDRT for APCKD ~ 6 years ago presents with 3 days of high fevers, diffuse myalgias and arthralgias. He denies any localizing infectious symptoms including abdominal pain over his graft or dysuria. ROS is otherwise notable for thirst, though he denies poor PO intake, vomiting, or diarrhea.

His PMH (full history and medications) is notable for a relatively uncomplicated post-transplant course but has had several UTIs in the past that are thought to be related to chronic urinary retention. 

On exam, he is febrile to 39C, HR 109, BP 120-140s/80s, RR 16, SaO2 99% on RA. He is diaphoretic but otherwise well appearing with no focal findings on exam. His initial labs are notable for a Na of 121, Cr of 1.6 (from a baseline of 1.3) and WBC of 11.6 with a left shift. Click here for full exam and labs.

What additional work-up would you want? (~5-10 min) 


In the OSH ED, he received 2L of NS and 1 dose of ceftriaxone. You are now seeing him ~ 10 hours after initial presentation and he is still febrile, tachycardic and diaphoretic. His repeat labs show:

  • Na of 130 (at 10 hrs) → 132 (at 14 hrs)
  • Cr down to 1.3 (baseline)
  • K still normal at 4.0
  • Foley in with 2 L out in the first 1 hour (over the next 24 hours puts out 14L of UOP)
  • Serum Osm is still low at 257
  • Urine Osm is 90, Urine Na is 26

Vancomycin was added based on prior culture sensitivities, which all grew out CoNS resistant to oxacillin.

Click here to skip to hyponatremia review

What do you make of his urine studies?

How would you manage his sodium?


Pathophysiology Review: 

Diagnostic Work-up and Management: 

Take me back to the case!



  1. Verbalis, et al. 2007. Hyponatremia Treatment Guidelines 2007: Expert Panel Recommendations. The American Journal of Medicine. 120(11A): S1-S21.
  2. Sterns, RH, et al. 2013. Management of Hyponatremia in the ICU.  CHEST. 144(2): 672-279.
  3. Barrisford, GW & Steele, GS.  Acute urinary obstruction. In: UpToDate, Libman, H (Ed), UpToDate, Waltham, MA. (Accessed on May 25,2017)
  4. Sterns, RH.  Overview of treatment of hyponatremia in adults. In: UpToDate, Forman, JP (Ed), UpToDate, Waltham,  MA. (Accessed on May 25, 2017)
  5. Buffington, MA & Abreo, K. 2016. Hyponatremia: A Review. Journal of Intensive Care Medicine. 31(4) 223-236
  6. Hoorn, EJ & Ziestse, R. 2017. Diagnosis and Treatment of Hyponatremia: Compilation of the Guidelines. Journal of the American Society of Nephrologists. 28:1340-1349.