Why it almost always starts at the feet.
The National Institute of Neurological Disorders and Stroke describes peripheral neuropathy as the many conditions that damage the peripheral nervous system — the signal network linking your brain and spinal cord to everywhere else. NINDS sorts those nerves into three jobs: motor nerves move muscles, sensory nerves carry touch, temperature, and pain, and autonomic nerves run things you never think about, such as digestion, heartbeat, and gland function. Which job is affected is why one person reports burning feet and another reports lightheadedness on standing.
The pattern is not random. Many of these neuropathies are length-dependent, as NINDS explains: the nerve endings farthest from the brain — the ones in the feet — are where symptoms show up first or worst, and in severe cases they can spread upward toward the center of the body. That is why symptoms tend to arrive in both feet at once rather than in one spot, and why the hands often come later, if at all.
Diabetes leads the list, but it is not the whole list.
NINDS names diabetes as the country's leading cause of this nerve damage. The National Institute of Diabetes and Digestive and Kidney Diseases puts the scale of it at roughly one-third to one-half of people with diabetes, describes the damage as typically affecting the feet and legs and sometimes the hands and arms, and attributes it to high blood glucose and high blood fats such as triglycerides.
The rest of the list matters because several entries are findable with ordinary testing. MedlinePlus names vitamin B12 deficiency, alcohol use disorder, cancers and chemotherapy, autoimmune diseases such as rheumatoid arthritis and lupus, certain medicines, toxic exposures like lead and mercury, infections including Lyme disease and HIV, kidney or liver disease, physical injury, and inherited genetic conditions. B12 is worth its own sentence: MedlinePlus reports that long-term B12 deficiency can cause nerve damage, that it may be permanent if treatment does not begin promptly after symptoms start, and that numbness and tingling of the hands and feet and loss of balance are among its symptoms.
The same page lists what drives a deficiency: pernicious anemia, strict vegetarian diets, malabsorption from Crohn or celiac disease, stomach or intestinal surgery, alcohol use, and medicines including metformin and antacids. If you take one, that is a question for the clinician who prescribes it, not a reason to stop on your own.
And sometimes the answer does not arrive: MedlinePlus is candid that in certain cases the cause is not known. An honest "we have not found it yet" is a different thing from a search that was never run.
Weakness that is new or climbing needs to be seen now.
Slow numbness over years and weakness that is spreading this week are not the same problem. NINDS describes Guillain-Barré syndrome as beginning suddenly and building in intensity over hours, days, or weeks until certain muscles cannot be used at all — often starting at the feet, with weakness moving up through the legs, arms, face, and the muscles used to breathe. People with it are usually admitted to the hospital and cared for in intensive care because of what that weakness can do.
So if weakness is new, worsening quickly, or climbing up your body — or if breathing or swallowing becomes difficult — seek medical care immediately rather than booking anything. Get to an emergency department or call 911. It does not belong in a clinic queue.
Finding the cause is the work.
NINDS acknowledges that peripheral neuropathy can be difficult to diagnose given how widely symptoms vary. The evaluation it describes starts with questions about your symptoms, your work environment, toxic exposures, and alcohol use, then an examination testing sensation of touch, vibration, and temperature. Blood tests can detect diabetes, vitamin deficiencies, liver or kidney dysfunction, other metabolic disorders, infections, and signs of abnormal immune activity. Nerve conduction studies measure the strength and speed of signals along specific motor and sensory nerves, and can show whether the damage sits in the nerve fiber itself or in its myelin covering.
All that effort points at one thing. MedlinePlus puts it directly: it is important to treat any conditions causing nerve damage, and in certain cases that will allow nerves to heal over time. Whether it applies to you depends on the cause — which is exactly why the testing exists.
If you want to ask about care here.
Gates Brain Health is a functional neurology practice in Reno, Nevada, led by Dr. Randall Gates, D.C., DACNB. People living with numbness, burning, and balance concerns do call. Whether this practice fits your situation gets decided in a conversation and an evaluation — not on this page — and nothing here stands in for your primary care provider, a neurologist, or the clinician managing your diabetes or your medicines.
The practice publishes a free consultation as a first step; what an examination involves is set out on the treatment page rather than repeated here. To ask about one, call (775) 507-2000, Monday through Friday, 8:00 AM to 5:00 PM. There is no website form or scheduler, so please keep the medical details for the phone call.
- Which of the common causes have already been checked for me, and with what test?
- Have my B12 and blood sugar been looked at, and how recently?
- Would you tell me if a neurologist or an urgent evaluation is the better next step?
- What would you expect to change for me, and what would you expect not to?