What should you know about brain fever?

People sometimes use brain fever to describe fever with a headache, weakness or changes in alertness. Clinicians instead assess the temperature pattern, duration, other symptoms and the person’s overall condition. Fever can accompany respiratory infections such as a common cold, acute bronchitis, bronchiolitis or COVID-19. It can also occur with skin infection, chickenpox, croup or less common infections such as brucellosis.

A fever does not by itself show which illness is present. Confusion, unusual sleepiness, a seizure, severe headache, light sensitivity or a stiff neck changes the level of concern because these symptoms can signal a serious problem affecting the nervous system.

Rest, drink fluids regularly, wear light clothing and check your temperature with a reliable thermometer if possible. Follow the label or a clinician’s instructions for any fever medicine, and check before giving medicine to a child. Do not combine products with the same ingredient. Stay home from close contact while you feel unwell and follow local advice if you may have a contagious infection.

Contact a clinician if fever persists, returns after improving, or occurs in a young infant, an older adult, someone pregnant, or a person with significant long-term illness or reduced immunity. Mention travel, animal exposure, new medicines and any rash.

Get emergency help for confusion, difficulty waking, a seizure, severe or rapidly worsening headache, stiff neck, trouble breathing, blue or grey lips, fainting, severe dehydration, or a widespread rash with serious illness. For a child, urgent assessment is also needed when they are unusually floppy, difficult to rouse, or breathing hard. Do not wait for a temperature reading if someone looks seriously unwell.

Ask: What might be causing this fever with my other symptoms? How should I monitor temperature and hydration? Which medicines are suitable for me or my child? Could I pass this illness to others? Which changes mean I should seek urgent care?