Diagnosing encephalitis – A brainy solution

Katie was a healthy teenager out shopping with her sister when she had a seizure that lasted two hours. She was rushed to the local hospital and eventually diagnosed with encephalitis – a life-threatening swelling of the brain.

Signs and symptoms

“One of the things that makes my illness so tricky is that I’m not aware that I’m getting ill. I was probably ill six to nine months before my first big seizure,” says Katie.

“Some of the signs are being aggressive and having panic attacks, my handwriting gets messy, I find it difficult to concentrate and my audio processing goes out the window.”

Shortly before her first major seizure, Katie had what is called an ‘absent seizure’ at school.

“It was like someone walking across my grave,” says Katie. “You can see everything happening but you’re not really there.”

Specialist care

Katie went on to experience more seizures at her local hospital. Her medical team decided that she needed specialist care and she was transferred to the intensive care unit at Great Ormond Street Hospital (GOSH).

“It’s a blessing that I can’t remember most of what happened to me,” says Katie. “The only thing I remember of my time in intensive care are vivid dreams, which were based on the things around me. I was there, but I wasn’t there. They call it a delirium.”

While uncommon, encephalitis can be life threatening and prompt treatment is essential in order to reduce the swelling and risk of permanent brain damage or death.

But diagnosis is complicated because encephalitis can be caused by many factors. Viral, bacterial or fungal infections can cause encephalitis, as can autoimmune conditions, where the patient’s immune system attacks their own brain.

Diagnostic challenges

Patients require drastically different treatment depending on the cause. If encephalitis is caused by an autoimmune condition, drugs may be prescribed to dampen the patient’s immune system. But when encephalitis is caused by a virus or bacteria, the immune response is essential for fighting the infection.

Katie remembers how stressful going through tests can be. “My condition is really rare,” says Katie. “I was told that my diagnosis was a process of elimination. They did hundreds of tests, including CT and MRI scans, lumbar puncture, EEG and blood tests.”

Dr Julianne Brown, a clinical scientist in the Microbiology, Virology and Infection Prevention and Control team at GOSH, is dedicated to improving the diagnosis of encephalitis.

“There’s thousands of viruses and you can’t test for them all,” says Dr Brown. “If you’ve got a brain biopsy or cerebral spinal fluid, they’re really precious samples as you can’t just keep taking them from patients. So you have to prioritise what you look for.”

Diagnosis through DNA

“Between three and six in every 10 cases of encephalitis go undiagnosed,” says Dr Brown, who hopes to improve the diagnosis of encephalitis by developing a technique known as  ‘deep sequencing’, supported by Great Ormond Street Hospital Children’s Charity funding.

Deep sequencing looks at the DNA in a sample and matches it up to all known viruses and bacteria. Dr Brown hopes the technique will offer patients an answer first time around, avoiding multiple tests. Rather than using the ‘needle in a haystack’ approach, clinicians can get a match to any of the known causes of encephalitis.

Managing the condition

A correct diagnosis has made a huge difference for Katie. “My type of encephalitis is caused by something going wrong with my immune system. Even though there was so much uncertainty around my condition and treatment, I knew I was in a special place at GOSH and that gave me a sense of security.”

The work that scientists like Dr Brown are doing is allowing young people like Katie to receive treatment faster and carry on with day-to-day life.

“I’ve had to learn to manage my expectations and prioritise my health, and that’s quite hard when you’re a teenager,” says Katie.

“GOSH has taught me to put one foot in front of the other and be grateful for everything you have. I’m brave, mature and responsible, and GOSH has given me that.”