Polyneuropathy is when multiple peripheral nerves become damaged, which is also commonly called peripheral neuropathy. Peripheral nerves are nerves outside of the brain and spinal cord. They relay information between the central nervous system (CNS), and all other parts of the body. The brain and spinal cord are part of the CNS.
Polyneuropathy affects several nerves in different parts of the body at the same time. In cases of mononeuropathy, just one nerve is affected. Polyneuropathy can affect nerves responsible for feeling (sensory neuropathy), movement (motor neuropathy), or both (sensorimotor neuropathy). It may also affect the autonomic nerves responsible for controlling functions such as digestion, the bladder, blood pressure, and heart rate.
A variety of medical conditions and other factors can cause polyneuropathy, including: diabetes, alcohol abuse, autoimmune conditions, bacterial or viral infections, bone marrow disorders, exposure to toxins, hereditary disorders, hypothyroidism, kidney disease, liver disease, medications, poor nutrition, and physical trauma or injury.
Jayne Leonard, What’s to Know About Plyneuropathy?, Medical News Today (updated Apr. 29, 2017), https://www.medicalnewstoday.com/articles/317212.php