HYPONATREMIC RHABDO?!

Joseph Simonson, M.D*, Northwell Health System, manhasset, NY and Haider Nazeer, MD, Northwell HEALTH SYSTEM, Manhasset, NY

Meeting: Hospital Medicine 2017, May 1-4, 2017; Las Vegas, Nev.

Abstract number: 729

Categories: Adult, Clinical Vignette Abstracts

Case Presentation: A 60 year old woman with a history of hypertension and low back pain was brought it by family after she was found unresponsive in bed.  According to the patient’s family, at baseline the patient was a highly successful lawyer. Her husband and daughter reported that she stayed home from work the previous day because she experienced nausea and a small amount of vomiting. She had been taking percocet occasionally for her chronic back pain but was otherwise in her usual state of health. On admission, the patient was obtunted but had a non focal neurological exam. CT Head was negative for intracranial bleed. Urine and serum toxicology was unrevealing. The patient was found however to have a sodium of 114 with a creatinine kinase of 17,000 with normal renal function. The patient was admitted to the medical ICU. The patients serum osmolarity, urine osmolarity, and urine sodium were consistent with SIADH, her recent bout of worsening back pain with nausea were seen as the inciting events. The patient was treated with three percent sodium chloride. Her mental status improved to baseline and her sodium level normalized. Upon further questioning the patient reported no recent traumas, no extended falls, no immobility, no recent strenuous exercise and no recent new medications. Her creatine kinase trended down with IV fluids. 

Discussion: Hyponatremia, defined as a plasma sodium level < 135 mEq/l, is the most common disorder of body fluid and electrolyte balance encountered in clinical practice. Hyponatremia has many well known sequelae including nausea, vomiting, lethargy, seizure, and coma. One of the underreported sequela is rhabdomyolysis. Rhabdomyolysis is a syndrome  classically characterized by muscle necrosis with characteristically elevated creatinine kinase levels with or without impaired renal function. The causes of rhabdomyolysis are typically broadly grouped into 3 categories. (1)Traumatic, (2)Nontraumatic exertional, (3)Nontraumatic nonexertional.  The pathophysiology for these processes converge into one final path that compromises the adenosine triphosphate (ATP) synthesis and the functioning of the Na+/K+ and Na+/Ca++ pumps in muscle cell membranes. It is thought that Hyponatremia induced rhabdomyolysis centers around the effect of decreased levels of sodium on the Na+/Ca++ pump. Hyponatraemia reduces the gradient of Na+ input within the muscle cell and reduces the Ca++ output. This increase in intracellular Ca++ starts an enzymatic activation and cellular death process resulting in breakdown of muscle cells.

Conclusions: We present a case of hypotonic hyponatremia and subsequent development of rhabdomyolysis. Hyponatraemia is a rare cause of rhabdomyolysis and can go unnoticed if not suspected. When obvious causes are not elucidated during the history taking process, it is important to remember the profound effect electrolyte disturbances can have on the muscle cell membranes.

To cite this abstract:

Simonson, J; Nazeer, H . HYPONATREMIC RHABDO?!. Abstract published at Hospital Medicine 2017, May 1-4, 2017; Las Vegas, Nev. Abstract 729. Journal of Hospital Medicine. 2017; 12 (suppl 2). https://www.shmabstracts.com/abstract/hyponatremic-rhabdo/. Accessed September 22, 2019.

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