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Case 1: Management of Hypernatremia

A 68-year-old male nursing home resident was brought to the emergency department by emergency medical services for altered mental status since early morning. As per nursing home staff, the patient had been experiencing poor oral intake and had been noted to be withdrawn from social activities over the past few days. Review of system was negative for nausea, vomiting, diarrhea, or fever. His medical history included hypertension, hyperlipidemia, osteoarthritis, and dementia. His medications included amlodipine, simvastatin, and multivitamins. Physical examination showed stable vital signs. However, the patient was cachectic, had dry mucous membranes, was alert and awake, and was able to follow commands but was confused. The rest of the examination was completely unremarkable. Significant laboratory data showed sodium of 167 mmol/L, chloride of 125 mmol/L, potassium of 4.0 mmol/L, and creatinine of 1.8 mg/dL (137.25 µmol/L). His cell count was normal. CT of the head showed no acute infarct, mass, or hemorrhages as well as no chronic microvascular changes. He was started on intravenous fluid and was transferred to the telemetry unit for electrolyte monitoring. How would you manage this case?

Case Review

The case presents a common scenario where an elderly nursing home resident with poor oral intake is admitted with acute altered level of consciousness due to poor eating and has responded to fluids. Hypernatremia should be managed cautiously in this case, and frequent monitoring of sodium level should be performed. Rapid correction can lead to central pontine myelinolysis.

Case Discussion

Hypernatremia is defined as a serum sodium concentration >145 mmol/L. It reflects a total body water deficit relative to total body sodium content caused by decreased water intake compared to water losses. The risk factors for development of hypernatremia include advanced age, mental or physical impairment, diuretic therapy, uncontrolled diabetes (solute diuresis), underlying polyuria disorders, nursing home resident, inadequate nursing care, and hospitalization.

Classification of Hypernatremia

Importantly, extracellular fluid (ECF) volume status should be assessed because it shows total body sodium content.

  • Hypovolemic hypernatremia: Decreased total body water (TBW) and sodium with a relatively greater decrease in TBW. It includes gastrointestinal losses (diarrhea, vomiting), skin losses (burns or excessive sweating), and renal loss (intrinsic renal disease, osmotic [glucose, urea, mannitol] and loop diuretics).

  • Euvolemic hypernatremia: Decreased TBW with near-normal total body sodium. It includes extrarenal losses from the respiratory tract (tachypnea) or skin (excessive sweating or fever), renal losses (central diabetes insipidus or nephrogenic diabetes insipidus), and other causes (inability to access water, primary hypodipsia, reset osmostat).

  • Hypervolemic hypernatremia: Increased sodium with normal or increased TBW. It includes hypertonic fluid administration (hypertonic saline, sodium bicarbonate, total parenteral nutrition) and mineralocorticoid excess (adrenal tumors, congenital adrenal hyperplasia).

Clinical Symptoms

Thirst is a major symptom with dehydration or clinical signs ...

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