A patient on antidepressant therapy develops a seizure and has epilepsy. Which electrolyte abnormality is most likely to have contributed to the seizure?

A patient on antidepressant therapy develops a seizure and has epilepsy. Which electrolyte abnormality is most likely to have contributed to the seizure?

• A. Hypocalcemia
• B. Hyponatraemia
• C. Hypernatremia
• D. Hypoglycemia

Answer: (B)

Electrolyte disturbances can alter neuronal excitability, and hyponatremia is a classic trigger for seizures. Antidepressants, especially SSRIs, can cause SIADH, leading to dilutional hyponatremia. When sodium levels fall, plasma osmolality decreases and water shifts into brain cells, causing cerebral edema and increased neuronal excitability, which can precipitate seizures. This is why hyponatremia is the most likely contributor in a patient on antidepressant therapy who experiences a seizure and has epilepsy. Hypocalcemia, hypernatremia, or hypoglycemia can also provoke seizures in different contexts, but they are less specifically linked to antidepressant use and to this scenario.

Electrolyte disturbances can alter neuronal excitability, and hyponatremia is a classic trigger for seizures. Antidepressants, especially SSRIs, can cause SIADH, leading to dilutional hyponatremia. When sodium levels fall, plasma osmolality decreases and water shifts into brain cells, causing cerebral edema and increased neuronal excitability, which can precipitate seizures. This is why hyponatremia is the most likely contributor in a patient on antidepressant therapy who experiences a seizure and has epilepsy.

Hypocalcemia, hypernatremia, or hypoglycemia can also provoke seizures in different contexts, but they are less specifically linked to antidepressant use and to this scenario.