Yes, a sinus infection can spread to the brain.
What Is a Sinus Infection?
A sinus infection occurs when mucous that is unable to drain becomes infected with bacteria. It is brought on by a common cold, which inflames the sinuses. If the mucous that results from the cold is unable to drain, it can become trapped behind the nasal passages and become infected by the bacteria that are present in the nasal lining. If the bacteria begin to multiply in the environment, a sinus infection can result.
If it spreads to the brain, it could lead to coma or death.
Serious Side Effects of Sinus Infection
Serious side effects of a sinus infection are relatively rare but it is possible that the infection can spread through the sinus wall and into the brain causing a brain abscess or meningitis. Meningitis is an inflammation of the membranes of the brain and spinal cord. If left untreated, meningitis can result in death in a very short time. Early warning signs of meningitis include flu-like symptoms, stiff neck, confusion, and fever.
Sinus infections can also spread to the bones of the face and skull or to the eye socket.