Partial improvement after chemo?
“Some of my neuropathy improved after chemotherapy but my feet still feel (numb, tingly, painful, whatever)”
In another posting we looked into why chemotherapy induced neuropathy might persist even after treatment is completed.
I get my ideas of what to write about from the conversations I have with my patients. And since neuropathy is a complicated topic, I don’t foresee having troubles coming up with writing ideas for the near future (fingers crossed).
So this week when speaking to a new person who is in for a consultation, they asked why some of the symptoms of their neuropathy improved after the end of chemotherapy and other symptoms didn’t. I get asked that quite a bit. The answer could lie in the way the nerves work themselves. Now we are going to do a little nerve anatomy but it will be easy. The main part of a peripheral nerve (a nerve outside the brain and spinal column) is its cell body or nerve root, which sends nerve branches out to the rest of the body. The nerve roots in your neck and upper most back send branches down your arms to your fingers. The nerve roots in your lower back and pelvis to down your legs to your toes.
Everything is made there and then gets shipped to the rest of the nerves in a process call axoplasmic transport.
For nerves, the nerve roots are the grocery stores, the Home Depot, the gas station and the Target all rolled into one.
So who is at the end of this supply chain? The ends of the nerves in the feet/toes and the fingers. The fancy name for nerve damage that can happen because of this is, “length dependent sensorimotor polyneuropathy”. “Length dependent” means the longer a nerve is, the more vulnerable to damage. Since the nerves in the feet are the longest (They come aaaaaall the way from the low back), they are most likely to be involved.
One way to think about it is that the further away from the nerve roots you go, the harder it is for the body to fix nerve problems.
Keep in mind that compared to the rest of your body cells, nerves are HUGE! For example, if a skin cell, a white blood cell, a muscle cell, or what have you, is the size of a cat, a nerve cell would be as big as a blue whale! Many people kind of think of nerves as almost being microscopic, but hey aren’t. Your sciatic nerve by your butt is about as big around as one of your fingers. You have single nerve cells that run from your beltline all the way to your toes. We are talking huge nerves.
And they are all dependent on what is produced in the cell body, which is right next to your spine.
That seems to be a reasonable explanation as to why some symptoms (most commonly those in the legs or shins or whatever) tend to improve while leaving remaining symptoms down in the feet, toes, or fingertips.
• They are the furthest from “home base” of the nerve roots next to the spinal cord.
• Most vulnerable to damage.
• Hardest for the body to fix.
To me, this seems like a reasonable reason why there might be only partial improvement after cessation of chemotherapy.
Ps. If you are like me and want to know a little more about the nerve cells themselves here is a nice little page to peruse. Click Here