Hypomagnesemia and seizures: what to know

Magnesium helps regulate electrical activity in nerves and muscles. When it is low, a person may develop tremor, muscle twitching, cramps, irritability, confusion, or seizures. Causes include prolonged vomiting or diarrhoea, poor intake, some medicines, alcohol-related illness, and problems affecting absorption or kidney handling. Low magnesium can occur alongside other electrolyte disturbances, so clinicians commonly check magnesium, potassium, calcium, glucose, and kidney function. A seizure has many possible causes; low magnesium is one possibility rather than a conclusion based on the event alone.

During a seizure, move nearby hazards away, cushion the head, loosen tight clothing, and turn the person onto their side when possible. Do not restrain them, put anything in their mouth, or give food or drink until fully alert. Note when it began and ended and what happened before and after. Emergency clinicians may give magnesium or other treatment based on examination and blood results; do not self-treat with high-dose supplements. Bring a list of medicines, supplements, recent illness, and alcohol use.

Call emergency services for a first seizure, a seizure lasting longer than expected, repeated seizures without recovery, injury, breathing difficulty, pregnancy, diabetes, or failure to regain awareness. Fever with severe headache, stiff neck, or confusion needs urgent evaluation because meningitis is among the conditions clinicians may need to exclude. Even when the person recovers, prompt medical assessment is needed to confirm the cause and prevent recurrence.

Ask which results were abnormal, what caused the magnesium loss, whether potassium or calcium also need correction, and whether a medicine should be changed. Ask how to recognise recurrence and when follow-up blood testing is needed.