What are the clinical manifestations of hyponatremia?

• A. Fever and chills
• B. Increased appetite
• C. Weight loss
• D. Nausea/vomiting, abdominal cramping, lethargy, headaches, seizures, respiratory arrest, and coma

Answer: (D)

Low serum sodium lowers plasma osmolarity, causing water to move into brain cells and leading to brain swelling. This cerebral edema disrupts neural function and produces neurologic symptoms that can escalate quickly as sodium falls or the rate of decline accelerates. The hallmark manifestations are nausea, vomiting, and abdominal cramping early on, followed by lethargy, headaches, and eventually more severe neurologic signs such as seizures, respiratory arrest, and coma. In severe cases, the brain’s swelling and increased intracranial pressure can manifest as life-threatening events like respiratory failure.

Among the options, the combination of nausea/vomiting, abdominal cramping, lethargy, headaches, seizures, respiratory arrest, and coma best reflects the clinical picture of hyponatremia. Fever and chills point toward infection rather than hyponatremia, while increased appetite or weight loss do not describe hyponatremia’s typical presentation.