A brain abscess, also known as a cerebral abscess or CNS abscess, is an abscess within the brain tissue caused by inflammation and collection of immune cells and infected material originating from local or remote infection sources.

A brain abscess is a rare, life-threatening infection of the brain. Local sources may include ear infections, a dental abscess, infection of the paranasal sinuses, or epidural abscess, while remote sources may include infections in the lung, heart or kidney.

A brain abscess may also be the result of a head trauma or surgical procedure. In children cerebral abscesses are usually linked to congenital heart disease.

Brain abscesses may affect people of any age, but more commonly occur in people in their 30s and 40s. Traditionally, they were disproportionately diagnosed in young people – changes in vaccination practices, treatment of child infections, and the AIDS pandemic shifted the average age of infection upwards. Males have double the risk of developing a brain abscess compared to females.

Bacteria, fungi or viruses may enter brain tissue and cause an abscess – a pus-filled swelling – to develop. The most common reported symptoms include an elevated body temperature, headache, confusion, weakness – and even paralysis on one side of the body. Symptoms vary, depending on where in the brain the abscess is located.

As the inflammation can damage the brain, as well as undermine its oxygen and blood supply, a cerebral abscess may be a very serious condition. If left untreated the patient may die. If the abscess ruptures (bursts) the risk of brain damage and death is even greater. A cerebral abscess is a medical emergency which requires immediate treatment with antibiotics and surgery (to drain the pus or remove the abscess entirely).

The National Institutes of Health (NIH), USA, informs that between 1,500 and 2,500 cases of brain abscesses are reported in the USA each year. According to the National Health Service (NHS), UK, approximately between 2 and 3 people in every million develop an abscess annually in the United Kingdom – it is a very rare infection. The NHS adds that modern diagnostic and surgical techniques have significantly improved the prognosis (outlook) for patients – approximately 10% of patients today die; a much lower figure than a few decades ago. The majority of patients recover completely. However, if the abscess ruptures into the ventricular system, the mortality rate may be 80%.

Written by Christian Nordqvist