Why can brain metastases cause a persistent headache?

The brain itself has limited sensitivity to pain, but its coverings, blood vessels, and nearby nerves can hurt when they are stretched or irritated. A metastatic deposit may trigger local inflammation and swelling. If swelling or the deposit takes up space, pressure can affect these structures and produce a headache that is new, persistent, or different from a person's usual pattern.

Headache may be worse after waking, with coughing, bending, or straining when pressure changes. Nausea, vomiting, visual changes, confusion, weakness, or a seizure can occur alongside a serious brain problem. Headache alone has many causes and does not establish that brain metastases are present.

Contact the oncology or medical team about a new headache, a pattern that is steadily changing, or pain that does not respond to the usual measures. The clinician may check vision, strength, coordination, reflexes, and alertness, then arrange brain imaging when appropriate. The results guide whether treatment should address swelling, the deposit, or the pain itself.

Keep a record of when the headache begins, where it is felt, what makes it worse, and any associated symptoms. Take medicines only as directed, and do not delay assessment by repeatedly treating a worsening headache at home. Rest in a safe position and ask for help if dizziness or weakness affects walking.

Seek emergency help for a sudden severe headache, new weakness or numbness on one side, difficulty speaking, loss of vision, severe confusion, collapse, or a first-time seizure. Repeated vomiting with a worsening headache also needs urgent assessment.

If you have known cancer, contact the treating team promptly for a new or progressively worsening headache, especially when it is worse in the morning or with coughing, bending, or straining. Do not drive yourself if you have visual changes, confusion, weakness, or a seizure.

Ask whether the headache pattern suggests raised pressure or another cause, whether brain imaging is needed, and which symptoms require emergency help. Discuss safe pain relief, treatment for swelling if relevant, and how to record changes between appointments.