Hypernatremia

If hypernatremia is corrected too quickly in the setting of chronic hypernatremia, the lowering of the serum osmolality can lead to water movement into the brain cells causing brain edema.

CT scan of the brain shows diffuse sulcal effacement and slight blurring of grey-white differentiation consistent with global cerebral edema.[Figure caption and citation for the preceding image starts]: CT brain showing diffuse sulcal effacement and slight blurring of grey-white differentiation consistent with global cerebral edema. There is no evidence of herniationDr Hari Trivedi, Department of Radiology, San Francisco General Hospital, University of California; used with permission [Citation ends].

May develop due to rapid administration of dextrose-containing fluids.

More likely to occur in patients with diabetes, those with physiologic stress, or when high infusion rates are used.

Patients should be monitored for the development of hyperglycemia and associated dextrose-induced osmotic diuresis, which can worsen the hypernatremia.

If hypernatremia is worsened by the patient’s inability to metabolize the glucose load, a less concentrated solution of dextrose (e.g., dextrose 2.5% in water), or even pure water, may be given.

Inpatient glycemic management

Myelinolysis (also known as osmotic demyelination syndrome) has been described rarely in patients with hypernatremia (it is more common in patients with rapid correction of hyponatremia).[66]Sterns RH. Disorders of plasma sodium - causes, consequences, and correction. N Engl J Med. 2015 Jan 1;372(1):55-65. http://www.ncbi.nlm.nih.gov/pubmed/25551526?tool=bestpractice.com [117]Yanagawa Y, Jo T, Yoshihara T, et al. A patient with demyelination, laminar cortical necrosis, and rhabdomyolysis associated with hypernatremia. Am J Emerg Med. 2013 Jan;31(1):269.e3-5. http://www.ncbi.nlm.nih.gov/pubmed/22795431?tool=bestpractice.com [118]Han MJ, Kim do H, Kim YH, et al. A case of osmotic demyelination presenting with severe hypernatremia. Electrolyte Blood Press. 2015 Jun;13(1):30-6. https://synapse.koreamed.org/DOIx.php?id=10.5049/EBP.2015.13.1.30 http://www.ncbi.nlm.nih.gov/pubmed/26240598?tool=bestpractice.com [119]Bhatia S, Kapoor AK, Sharma A, et al. Cerebral encephalopathy with extrapontine myelinolysis in a case of postpartum hypernatremia. Indian J Radiol Imaging. 2014 Jan;24(1):57-60. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4028916 http://www.ncbi.nlm.nih.gov/pubmed/24851006?tool=bestpractice.com ​​

Hypernatremia-induced osmotic demyelination can lead to permanent neurological dysfunction.[118]Han MJ, Kim do H, Kim YH, et al. A case of osmotic demyelination presenting with severe hypernatremia. Electrolyte Blood Press. 2015 Jun;13(1):30-6. https://synapse.koreamed.org/DOIx.php?id=10.5049/EBP.2015.13.1.30 http://www.ncbi.nlm.nih.gov/pubmed/26240598?tool=bestpractice.com

Brain MRI shows a symmetric central pontine lesion with trident shape and areas of restricted diffusion.[Figure caption and citation for the preceding image starts]: Brain MRI showing a symmetric central pontine lesion (arrows), sparing the peripheral fibers, with a typical trident shape and areas of restricted diffusion. Suggests osmotic demyelination syndrome. Note the symmetric thalamic lesions (open arrows) in images B and CBMJ Case Reports 2012, doi: 10.1136/bcr:11.2011.5198 [Citation ends].

Hypernatremia can lead to rhabdomyolysis; however, this is not common.[75]Lindner G, Funk GC, Schwarz C, et al. Hypernatremia in the critically ill is an independent risk factor for mortality. Am J Kidney Dis. 2007 Dec;50(6):952-7. http://www.ncbi.nlm.nih.gov/pubmed/18037096?tool=bestpractice.com [117]Yanagawa Y, Jo T, Yoshihara T, et al. A patient with demyelination, laminar cortical necrosis, and rhabdomyolysis associated with hypernatremia. Am J Emerg Med. 2013 Jan;31(1):269.e3-5. http://www.ncbi.nlm.nih.gov/pubmed/22795431?tool=bestpractice.com [120]Naik KR, Saroja AO, Narayanappa G. Electromyographic and histological features of postpartum hypernatremic rhabdomyolysis. Ann Indian Acad Neurol. 2013 Oct;16(4):664-7. https://journals.lww.com/annalsofian/Fulltext/2013/16040/Electromyographic_and_histological_features_of.41.aspx http://www.ncbi.nlm.nih.gov/pubmed/24339601?tool=bestpractice.com ​​[121]Mastro-Martínez I, Montes-Arjona AM, Escudero-Lirio M, et al. Severe rhabdomyolysis secondary to severe hypernatraemic dehydration [in Spanish]. Rev Chil Pediatr. 2015 Jul-Aug;86(4):279-82. http://www.ncbi.nlm.nih.gov/pubmed/26298299?tool=bestpractice.com

Muscle dysfunction has also been reported.[122]Hiromatsu K, Kobayashi T, Fujii N, et al. Hypernatremic myopathy. J Neurol Sci. 1994 Apr;122(2):144-7. http://www.ncbi.nlm.nih.gov/pubmed/8021697?tool=bestpractice.com [123]Denman JP. Hypernatraemia and rhabdomyolysis. Med J Aust. 2007 Nov 5;187(9):527-8. http://www.ncbi.nlm.nih.gov/pubmed/17979621?tool=bestpractice.com

Rhabdomyolysis

Hypernatremia can affect cardiac contractility.[75]Lindner G, Funk GC, Schwarz C, et al. Hypernatremia in the critically ill is an independent risk factor for mortality. Am J Kidney Dis. 2007 Dec;50(6):952-7. http://www.ncbi.nlm.nih.gov/pubmed/18037096?tool=bestpractice.com

Extreme hypernatremia (i.e., serum sodium concentration >190 mEq/L) has been reported to cause ECG changes such as sinus tachycardia, short PR interval, prolonged QT interval, and diffuse ST depression.[124]Kazanji N, Al Assad W, Gjeorgjievski M, et al. Extreme hypernatremia (254 mmol/L) and electrocardiogram findings. Int Urol Nephrol. 2015 May;47(5):871-2. http://www.ncbi.nlm.nih.gov/pubmed/25862238?tool=bestpractice.com [125]Arambewela MH, Somasundaram NP, Garusinghe C. Extreme hypernatremia as a probable cause of fatal arrhythmia: a case report. J Med Case Rep. 2016 Oct 1;10(1):272. https://jmedicalcasereports.biomedcentral.com/articles/10.1186/s13256-016-1062-9 http://www.ncbi.nlm.nih.gov/pubmed/27716387?tool=bestpractice.com

Hypernatremia-related insulin resistance and decreased hepatic gluconeogenesis and lactate clearance have been reported.[75]Lindner G, Funk GC, Schwarz C, et al. Hypernatremia in the critically ill is an independent risk factor for mortality. Am J Kidney Dis. 2007 Dec;50(6):952-7. http://www.ncbi.nlm.nih.gov/pubmed/18037096?tool=bestpractice.com

An association between hypernatremia and metabolic alkalosis has also been described.[126]Lindner G, Schwarz C, Grüssing H, et al. Rising serum sodium levels are associated with a concurrent development of metabolic alkalosis in critically ill patients. Intensive Care Med. 2013 Mar;39(3):399-405. http://www.ncbi.nlm.nih.gov/pubmed/23160772?tool=bestpractice.com

Evaluation of metabolic alkalosis