Hi Friend
If you live with Fibro, ME/CFS, or MCAS, you know the feeling of "Brain Fire." It’s that combination of crushing brain fog, light sensitivity, and a sensory overload that makes a simple conversation feel like standing behind a jet engine.
For years, patients were told this was "psychosomatic." But we now have a name for the biological "ghost" driving this: Microglial Activation.
The Nanny vs. The Soldier
Inside your brain and spinal cord, you have a specialized group of immune cells called Microglia. In a healthy state, these cells act like "nannies." They are graceful and branched, moving through your neurons to prune old connections, clear out cellular debris, and keep your brain chemistry balanced.
But Microglia have a second job: they are the primary defenders of your Central Nervous System.
When they perceive a threat, they undergo a physical transformation. They retract their branches, turn into a blob-like "amoeboid" shape, and become "Soldiers." In this state, they stop cleaning and start firing. They pump out inflammatory cytokines, glutamate (which makes your nerves hypersensitive to pain), and reactive oxygen species.
The "Ghost" in the Machine: Microglial Priming
Here is the problem: once Microglia are "turned on" by a major stressor, they don't always go back to being nannies. They become primed.
Think of a "primed" microglial cell like a security guard with his finger shaking on the trigger. He is hyper-reactive. Now, even a tiny stressor—a late night, a high-histamine meal, or a minor argument—causes these cells to dump a massive amount of "neuro-poison" into your system. This is why you "crash" so much harder than other people.
What turned them on in the first place?
You weren't born with this neuro-inflammation. It was a process. For our community, the "switch" is usually flipped by a combination of:
The Peripheral Leak: When you have Leaky Gut or Mast Cell Activation (MCAS), inflammatory messengers (like LPS or Histamine) travel through the blood. They can actually cross the Blood-Brain Barrier and "scream" at the Microglia to stay in attack mode.
The Hidden Load: Chronic "stealth" infections like Epstein-Barr (EBV), Borrelia, or even mold toxicity act as a constant biological alarm bell.
Vagus Nerve Tension: In EDS (Ehlers-Danlos), the physical instability of the neck (CCI) can irritate the nerves that tell the brain "we are safe," leaving the Microglia stuck in "danger mode."
The Glutamate Loop: Inflamed microglia produce glutamate, which keeps you in a state of "wired but tired," making it impossible for your brain to enter the deep, restorative sleep it needs to reset those very cells.
How do we turn them off?
The goal isn't just to "calm down"—it’s to provide the biochemical environment that allows these cells to return to their "Nanny" state. This requires addressing the gut, stabilising mast cells, and using specific neuro-protective strategies to dampen the "fire."
In my 1-1 clinic, we look past the "fog" to find your specific triggers, any underlying causes and tailored treatments. Bookings available here
Tomorrow we will dive deeper into one of the main drivers, MCAS.
Stay Well
