Post-concussion syndrome — an anecdote about the dangers of TBI heat sensitivity in the elderly

© 2020 Peter Free

 

13 August 2020

 

 

Occasionally, I write about medical aspects . . .

 

. . . associated with injuries and aging that the Lamestream ignores.

 

Today's blurb has to do with post-concussion syndrome's occasionally delivered heat sensitivity and intolerance.

 

 

Physiological background

 

If you are suffering from heat intolerance, after a considerable knock to your head — meaning a concussion (mild traumatic brain injury, mTBI) — read this from Flint Rehab:

 

 

The human body possesses a complex heat-regulating mechanism that keeps the body at a balanced temperature. This delicate process is controlled by the hypothalamus . . . .

 

The hypothalamus helps balance body fluids and controls the release of hormones that play a part in temperature regulation.

 

When the body gets too hot, the hypothalamus releases hormones that cause blood vessels to swell. This allows more heat to be carried by the blood to the skin, where the heat is then released into the air.

 

The hypothalamus also works with the middle layer of the skin, or dermis, which stores most of the body’s water in sweat glands. When the hypothalamus activates these glands, they bring that water to the surface of the skin. The water then evaporates from the skin and cools the body.

 

If the hypothalamus becomes damaged after a brain injury, the body cannot regulate its temperature. As a result, heat sensitivity can occur.

 

The symptoms of heat sensitivity after TBI can vary from person to person.

 

Some of the most common side effects include:

 

Feeling hot in mildly warm weather

Excessive sweating

Nausea

Not sweating enough

Mood swings when too hot

 

Excessive heat can also stop nerve fibers from working. This makes it difficult for messages to get to and from the brain, which can cause problems such as:

 

Confusion

Fatigue

Weakness

Balance and vision problems

 

Heat stroke [see here] occurs when body temperature gets too high, causing illness.

 

Heat stroke can be life-threatening.

 

© 2020 Flint Rehab, TBI and Heat Sensitivity: How to Stay Cool After Brain Injury, flintrehab.com (11 March 2020)

 

 

For studies demonstrating that . . .

 

. . . even mild TBI can negatively affect the autonomic nervous system, see:

 

 

Jon L. Pertab, Tricia L. Merkley, Alex J. Cramond, Kelly Cramond, Holly Paxton and Trevor Wue, Concussion and the autonomic nervous system: An introduction to the field and the results of a systematic review, NeuroRehabilitation 42(4): 397–427, doi: 10.3233/NRE-172298 (29 June 2018)

 

Dmitry Esterov and Brian D. Greenwald, Autonomic Dysfunction after Mild Traumatic Brain Injury, Brain Sciences 7: 100; doi:10.3390/brainsci7080100 (11 August 2017)

 

 

My anecdote

 

What follows is intended as a heads-up to people, especially older people (like me), who are encountering post-concussion heat intolerance.

 

The take-away message is, "This condition ain't necessarily trivial."

 

By way of pertinent background, I've had dozens of concussions. The last head bash, a mountain bike fall, occurred about 4 months ago.

 

Among other noticeable injuries, I fractured the superior orbital portion of my skull. The force of the head slam was considerable. Most of it bypassed my non-full-face helmet.

 

Among other battered brain symptoms, I have since developed a potentially dangerous heat intolerance.

 

I've had post-concussion heat sensitivity before, but not to this magnitude.

 

What's disconcerting is how quickly the inability to dissipate warmth creeps up on me.

 

It always catches me by surprise. With the foreseeable result that I'm already more incapacitated than a sensible person would allow himself and herself to become.

 

 

Specifics

 

The current go-round has me having difficulty working for more than an hour in (for example) the vegetable garden and yard — in as little as 75-80 degree Fahrenheit California weather.

 

Come 90 degrees, I'm in deep muck.

 

Symptoms take this form:

 

 

hypotension (markedly lowered blood pressure)

 

dizziness (not related to the lowered blood pressure)

 

impaired balance (even when cognitively using visual anchor points)

 

nausea

 

extreme and long-lasting fatigue

 

recognition that staying in even mild warmth might be fatal

 

and

 

a general unawareness of what my bruised brain is up to.

 

 

Metaphorically, I can feel my skull matter cooking. That's an oddly indescribable feeling.

 

 

An example of how the sequence of symptoms develops

 

Admittedly, I am absurdly task oriented and tend to get so focused, that I lose track of physiological warning signs.

 

My first warning usually manifests as a combination of nausea and orthostatic hypotension. In lay terms, the latter usually means feeling dizzy when standing up.

 

 

Note

 

Orthostatic hypotension is not at all new to me. It's been characteristic, since childhood.

 

I've learned to squat (to keep from passing out) and gain some cognitive control of the condition, before standing up again.

 

Rehydrating fixes recurrences for me.

 

Under my post-concussion circumstances, however, reduced blood pressure has nothing to do with reacting to dehydration.

 

Instead, the autonomic nervous system has stopped responding appropriately to physiologic circumstances. I have yet to find a cognitive way to control this.

 

 

After noticing hypotension and nausea, I also notice that my walking has suddenly become unbalanced. Unless I give it full conscious attention.

 

Those concussion-related balance problems exist over and above the effects of the vestibular system damage that I experienced some years ago. The vestibular effects, which are significant, I control with visual reference points. Like twirling dancers do.

 

The post-concussive heat effect, in contrast, goes beyond my (now unconscious) ability to control it by visually referring to anchor points in the environment. This makes heat intolerance syndrome mildly disconcerting — in that I have to pay real attention just to walking without falling over.

 

At about this point (in becoming aware that I have been hot for too long), I begin to notice the brain-cooking "feeling".

 

I detect that my body is incapable of off-loading heat gain quickly enough to prevent bad things from happening.

 

At only 78 or so Fahrenheit degrees (at maybe 60-70 percent humidity), such feebleness seems unbelievable.

 

Ordinarily, I tolerate exercising in southern US warmth. For instance, living in South Texas for 2 of the last 3 years. In short, these brain "things" can take one by surprise.

 

Fatigue becomes noticeable, during the very short walk back into the house.

 

Whether accurate or not, I have the sense that continuing to work outside, in the "heat", is going to put me on the ground and in a not-so-healthy state.

 

Recuperation, indoors, takes a minimum of three hours at 76 to 77 degrees. I have to sit or lie down.

 

Dizziness continues. I sometimes find myself having to hold onto kitchen counters and chairs. Walking stably requires bouts of attention. These difficulties come and go erratically. Like waves.

 

There is also a peculiar sense of the brain not being or acting as one is accustomed to. The "really not me" sense usually lasts the rest of the day. It's an effect that goes noticeably beyond the "not me" consciousness that concussions routinely bring with them (in my experience).

 

Even after the described recovery period, going back outside (during the same day) always demonstrates itself to have been a bad idea.

 

 

Ironically

 

After writing that last line, I went outside again in 104 degree (15 percent humidity) warmth. Vegetable garden seedlings had sucked up all the water I gave them, just this morning.

 

Returning indoors, after only 20 minutes, nevertheless, left me with the now familiar unbalanced and fainty problem.

 

 

The point is that one probably cannot completely will oneself . . .

 

. . . through this sort of thing.


Ya gonna pay.

 

 

In that, it is like what I call post-concussion "dead battery syndrome"

 

That's the post-concussed situation in which one runs completely out of energy and literally cannot will oneself to go on — no matter how trivial one's energy output needs to be to finish whatever job (or activity) one has undertaken.

 

The condition is caused (in my experience) by the injured brain's inability to sort and process incoming stimuli. It shuts down higher level activity. Even if you don't want it to.

 

You basically have to lie down, wherever you are (preferably in quietly dim conditions) and let your figurative brain battery trickle re-charge in uninterrupted silence.

 

I find that anything that requires the brain to find or notice patterns is debilitating under those conditions.

 

I'm not kidding. Dead battery syndrome and I are very intimately acquainted. You can read about how limiting this aspect of concussion recovery can be, here.

 

Post-concussion heat intolerance limits us the same way. One has to plan for and work around it.

 

 

The moral? — Post-concussion heat sensitivity is potentially dangerous

 

Be wary, after knocking your head.

 

Brain injuries remind us that the conscious "I" does not know much and is not in charge.