Osmotic demyelination syndrome: novel risk factors and proposed pathophysiology

Fatal osmotic demyelination following urgent start hemodialysis in a patient with normal serum sodium

End stage kidney disease (ESKD) patients in the developing countries often present late for dialysis initiation with advanced uremia and life-threatening complications. Urgent start dialysis in such emergent situations exposes the patient to risk of uremia related complications as well as iatrogenic insults. We report the case of a middle-aged man with ESKD who presented late with acute pulmonary edema and hyperkalemia and developed osmotic demyelination syndrome following urgent start hemodialysis. Osmotic demyelination syndrome in this patient is noteworthy since there was no accompanying hyponatremia, the most commonly recognized antecedent. We propose that rapid lowering of serum osmolality by aggressive hemodialysis is sufficient to incite osmotic demyelination syndrome in patients who have long-standing uremia and high blood urea level. Malnutrition resulting from uremia might be a compounding factor in this scenario. Our patient had a characteristic initial presentation of osmotic demyelination syndrome with locked-in-state which later progressed to respiratory failure and death.

Intensive Care Management of Severe Hyponatraemia-An Observational Study

Background and Subject: Hyponatraemia is a common electrolyte disorder. For patients with severe hyponatraemia, intensive care unit (ICU) admission may be required. This will enable close monitoring and allow safe management of sodium levels effectively. While severe hyponatraemia may be associated with significant symptoms, rapid overcorrection of hyponatraemia can lead to complications. We aimed to describe the management and outcomes of severe hyponatraemia in our ICU and identify risk factors for overcorrection. Materials and Methods: This was a retrospective single-centre cohort that included consecutive adults admitted to the ICU with serum sodium < 120 mmol/L between 1 January 2017 and 8 March 2023. Anonymised data were collected from electronic records. We included 181 patients (median age 67 years, 51% male). Results: Median admission serum sodium was 113 mmol/L (IQR: 108-117), with an average rate of improvement over the first 48 h of 10 mmol/L/day (IQR: 5-15 mmol/L). A total of 62 patients (34%) met the criteria for overcorrection at 48 h, and they were younger, presented with severe symptoms (seizures/arrythmias), and had lower admission sodium concentration. They were more likely to be treated with hypertonic saline infusions. Lower admission sodium was an independent risk factor for overcorrection within 48 h, whereas the presence of liver cirrhosis and fluid restriction was associated with normal correction. No difference was identified between the normal and overcorrected cohorts for ICU/hospital length of stay or mortality. Conclusions: In some patients with severe hyponatraemia, overcorrection is inevitable to avoid symptoms such as seizures and arrhythmias, and consequently, we highlight the key factors associated with overcorrection. Overall, we identified that overcorrection was common and concordant with the current literature.

[Consensus recommendations on the diagnosis and treatment of hyponatremia from the Austrian Society for Nephrology 2024]

Hyponatremia is a disorder of water homeostasis. Water balance is maintained by the collaboration of renal function and cerebral structures, which regulate thirst mechanisms and secretion of the antidiuretic hormone. Measurement of serum-osmolality, urine osmolality and urine-sodium concentration help to diagnose the different reasons for hyponatremia. Hyponatremia induces cerebral edema and might lead to severe neurological symptoms, which need acute therapy. Also, mild forms of hyponatremia should be treated causally, or at least symptomatically. An inadequate fast increase of the serum sodium level should be avoided, because it raises the risk of cerebral osmotic demyelination. Basic pathophysiological knowledge is necessary to identify the different reasons for hyponatremia which need different therapeutic procedures.

Severe osmotic demyelination syndrome with cortical involvement in the context of severe hyponatremia and central diabetes insipidus: an uncommon presentation of an unusual combination

BACKGROUND

Osmotic demyelination syndrome (ODS) with cerebral cortical involvement is a rare complication of severe hyponatremia correction. Careful management of hyponatremia is crucial, particularly in patients with risk factors, such as alcohol use disorder and diabetes insipidus.

CASE

A patient in his 40s with a history of alcohol use disorder and central diabetes insipidus developed ODS after a 24 mEq/L osmolar increase during the treatment of hyponatremia. The patient's condition progressed into locked-in syndrome and then improved to spastic tetraparesis after cortical basal ganglia ODS improved.

DISCUSSION

The differential diagnosis of cortical demyelination includes laminar cortical necrosis, being the interpretation of Apparent Diffusion Coefficient (ADC) MRI sequence is a useful tool.This case underscores the need to investigate and improve diagnosis and treatment strategies in patients with ODS. It also emphasises the significance of careful hyponatremia correction and frequent monitoring, particularly in patients with known risk factors for ODS.

A Case of Alcohol Withdrawal-Induced Central and Extrapontine Myelinolysis

A 40-year-old female with a history of chronic alcohol use disorder presented with an acute intractable left-sided headache for three days and progressively worsening unsteady gait requiring a wheelchair to ambulate. The patient had a history of chronic alcoholism since 2019 but reported abstinence since September 2021. One month after quitting alcohol, she experienced a sudden deterioration in bilateral extremity neuropathy, forgetfulness, difficulty writing, and severe mood swings, which continued to worsen until her presentation in July 2022. Laboratory tests, including complete blood count and electrolyte levels, were within normal ranges. A previous MRI performed during the investigation for alcoholic neuropathy a few months before she quit drinking showed no abnormalities. However, a subsequent MRI during work-up for the current acute symptoms revealed significant signal abnormalities involving the central pons, bilateral cerebral peduncles, and medullary pyramids, consistent with chronic central pontine myelinolysis (CPM) with extrapontine myelinolysis (EPM) extending into the peduncles. The patient received treatment with folate and multivitamins and was scheduled for outpatient follow-up with physical therapy for rehabilitation. This case highlights CPM as a consequence of alcohol withdrawal and emphasizes the importance of timely diagnosis and appropriate management in such patients.

Osmotic Demyelination After Rapid Correction of Hyperosmolar Hyperglycemia

Osmotic demyelination syndrome (ODS) is seen due to an overt rise in serum osmolality, most often during rapid correction of chronic hyponatremia. We present the case of a 52-year-old patient who presented with polydipsia, polyuria, and elevated blood glucose with rapid correction of glucose levels under five hours and developed dysarthria, left-sided neglect, and unresponsiveness to light touch and pain in the left extremities on the second day of hospitalization. MRI revealed restricted diffusion in the central pons, extending into extrapontine areas suggestive of ODS. Our case highlights the importance of cautious correction of serum hyperglycemia and monitoring serum sodium levels in patients with a hyperosmolar hyperglycemic state (HHS).

Administration of 3% Sodium Chloride and Local Infusion Reactions

Three-percent sodium chloride (3% NaCl) is a hyperosmolar agent used to treat hyponatremic encephalopathy or other cases of increased intracranial pressure. A barrier to the use of 3% NaCl is the perceived risk of local infusion reactions when administered through a peripheral vein. We sought to evaluate reports of local infusion reactions associated with 3% NaCl over a 10-year period throughout a large healthcare system. A query was conducted through the Risk Master database to determine if there were any local infusion reactions associated with peripheral 3% NaCl administration throughout the entire UPMC health system, which consists of 40 hospitals with 8400 licensed beds, over a 10-year time period from 14 May 2010 to 14 May 2020. Search terms included infiltrations, extravasations, phlebitis, IV site issues, and IV solutions. There were 23,714 non-chemotherapeutic and non-contrast-associated intravenous events, of which 4678 (19.7%) were at UPMC Children’s Hospital. A total of 2306 patients received 3% NaCl, of whom 836 (35.8%) were at UPMC Children’s Hospital. There were no reported local infusion reactions with 3% NaCl. There were no reported local infusion reaction events associated with 3% NaCl in a large healthcare system over a 10-year period. This suggests that 3% NaCl can be safely administered through a peripheral IV or central venous catheter.