Post infectious neurological symptoms

Post infectious neurological conditions are delayed effects of a previous infection, usually caused by a virus. The symptoms can vary widely from mild to more serious and in how they affect the nervous system.
In some cases, people experience ongoing symptoms that may involve the brain or nerves, such as fatigue, brain fog or dizziness. This pattern is seen in conditions like long COVID or myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS).

Less commonly, the immune system becomes overactive after an infection and begins to affect the nervous system directly. This can lead to autoimmune conditions, such as Guillain-Barré syndrome or encephalitis. Some other conditions, such as multiple sclerosis, may also follow infection, though the link is less well understood.

Post infectious neurological symptoms may not appear straight away. They can develop gradually over time, and the connection to a previous infection isn’t always clear, especially if the initial illness was mild or went unnoticed.

If you’ve been living with symptoms that don’t have a clear cause, seeing a neurological specialist can be an important step in getting answers — and getting back to feeling more like yourself.

There is a wide variety of symptoms caused by post infectious neurological conditions. Some are mild, whereas others can be debilitating or need urgent medical attention. 

• Fatigue
• Brain fog
• Cognitive impairment
• Headaches
• Neuropathy
• Movement disorders
• Sleeping problems

See a medical specialist if any of the above symptoms are familiar, especially if they’re persistent or getting worse.

Rarely, post-viral neurological conditions need urgent medical attention. See a doctor promptly if you or a loved one is experiencing more worrying symptoms like tingling, numbness, muscle weakness, sharp pains, seizures or difficulty breathing.

A wide range of infections have been linked to post infectious neurological conditions. Most are viral, including more common ones like COVID-19, Epstein-Barr virus (EBV), and HIV, as well as rare infections such as Zika virus, West Nile fever, and Ebola.

Not everyone who has one of these infections will go on to develop a complication, and it’s not always clear why some people experience post-viral symptoms when others do not. 
At Affidea neuraCare, we specialise in diagnosing and treating a range of neurological conditions that can arise after infections. Below are some key post infectious neurological syndromes and related conditions to be aware of.

Post-viral syndromes

Some people experience lingering symptoms for weeks or months after an infection, even after the virus has cleared. This is known as post-viral syndrome. It is not a neurological condition in itself, but may involve neurological symptoms such as fatigue, headaches, dizziness, or problems with memory and concentration, sometimes described as “brain fog”.

One example is long COVID, where symptoms may affect multiple systems in the body, including the nervous system, for a prolonged period after the initial infection.

ME/CFS

ME/CFS is a complex condition that often begins after a viral infection. It causes a range of long-term symptoms, including severe fatigue, unrefreshing sleep, dizziness, memory and concentration difficulties, and post-exertional malaise, where symptoms worsen after physical or mental activity.

There is still uncertainty about the biological mechanisms behind ME/CFS. It may involve chronic inflammation and problems in how the brain and body regulate energy. The World Health Organization classifies ME/CFS as a neurological condition, although it can affect many systems in the body. 

Many ME/CFS symptoms overlap with another neurological condition called fibromyalgia, which causes pain, fatigue, and sleep problems. The key differences are that ME/CFS often starts after a viral infection and causes post-exertional malaise, while fibromyalgia causes chronic widespread pain and tenderness. 

Guillain-Barré syndrome 

Guillain-Barré syndrome is a rare condition where the immune system attacks the peripheral nerves, often after a viral or bacterial infection. It causes symptoms such as weakness, numbness, pain, and in severe cases, temporary paralysis. It’s a medical emergency and requires urgent treatment. 

Autoimmune encephalitis

Autoimmune encephalitis occurs when the immune system attacks the brain, sometimes after a viral infection. This can cause symptoms such as confusion, seizures, cognitive impairment, unusual movements and sleep disturbances. 

Not all types of autoimmune encephalitis are caused by infection. Post infectious encephalitis is rare, but it can be serious and often requires treatment with immune-modulating therapies.

Related conditions 

In some other autoimmune neurological conditions, the link to a previous infection is less clear but may still play a role in triggering the immune system. In these cases, the infection is thought to act as a catalyst for the immune system to start attacking healthy tissue.

• Multiple sclerosis (MS) – where the immune system damages the protective covering of nerves in the brain and spinal cord
• Myasthenia gravis – a neuromuscular condition that affects how signals travel between nerves and muscles

These are among the conditions we investigate and treat at Affidea neuraCare.

If you’re experiencing new or unexplained neurological symptoms after an infection, it’s important to understand what’s causing them. At Affidea neuraCare, we offer detailed assessments to investigate possible links between past infections and your current neurological health.

Getting the right diagnosis helps us identify serious or progressive conditions early, guide appropriate treatment, and support your long-term wellbeing. Even if you’ve been searching for answers for some time, a thorough neurological assessment can be a turning point. 

Initial assessment

Your care begins with a consultation with one of our neurologists, who will explore your symptoms in depth and build a clear picture of your neurological health. This typically includes:

• A detailed discussion about your medical history, past infections, and any current or ongoing symptoms
• A neurological examination to assess reflexes, movement, strength, coordination and sensory function
• Blood tests to check for signs of inflammation, autoimmune activity or infection
• Cognitive screening, if symptoms include issues such as memory, attention or brain fog

Depending on your symptoms, you may also be referred for further testing straight away, especially if there are signs of an underlying neurological condition. 

Further investigations

As a Centre of Excellence in neurology, we use a range of advanced diagnostic tools at Affidea NeuraCare, which may include neuroimaging, nerve condition studies, and neuropsychological testing. 

Once we’ve identified the underlying cause, we work with you to create a personalized care plan. Treatments focus on reducing symptoms and may include cognitive behavioral therapy, graded exercise, and medications to relieve symptoms, such as pain, insomnia, and depression. We also offer access to emerging therapies and clinical trials, such as ozone therapy for ME/CFS. 

Blackburn, K et al. Post-infectious neurological disorders. 2020. 

Choutka, J et al. Unexplained post-acute infection syndromes. 2022. 

Encephalitis International. Autoimmune encephalitis. 2023. 

Johnson, T et al. Neurological syndromes driven by postinfectious processes or unrecognized persistent infections. 

Landry, R et al. The Probable Infectious Origin of Multiple Sclerosis. 

NHS. Chronic fatigue syndrome. 

NHS. Guillain-Barré syndrome. 

NHS. Long term effects of COVID-19. 2023. 

NHS. Myalgic encephalomyelitis (ME) or chronic fatigue syndrome (CFS). 2024.