Long COVID: Neuropathies
Sep 14
The information provided here is for educational purposes only and is not intended as medical advice. It should not be used to diagnose, treat, cure, or prevent any medical condition. Instead, use it as a starting point for discussion with your healthcare provider. Always consult with a qualified healthcare provider before starting any new medication, supplement, device, or making changes to your health regimen.
Acute viral infection can be very challenging for both patients and their clinicians, but the infection is also contributing to various complications throughout multiple systems and organs in the body. Viral infection can have long-term consequences for both the central nervous system (CNS) and the peripheral nervous system (PNS). SARS-CoV-2-associated PNS complications affect many people with Long COVID, causing a variety of different neuropathies and symptoms. But what is peripheral neuropathy, how is it related to COVID, and what can you expect if you experience post-COVID neuropathy?
What is Peripheral Neuropathy?
The peripheral nervous system (PNS) is a complex communication network of nerves that transport signals from the central nervous system (CNS) to areas throughout your body. The messages that travel through the PNS can include everything from telling muscles to contract, letting you know that your feet are cold, or helping to control your heart and blood vessels. Peripheral neuropathy is an umbrella term for over 100 different types of conditions that involve damage to the peripheral nerves.
Nerve damage can cause nerve signaling disruption in three different ways: a complete loss of communication through the nerves, incorrect communication, or communication being sent when it shouldn’t. For example, if a person has a complete loss of nerve communication, they may experience numbness or a loss of feeling in the affected area. For those with incorrect communication, something that should not cause pain, such as a blanket, may become very painful when touching the skin. If the nerves send messages at incorrect times, one may experience muscle twitching or excessive sweating without activity.
Peripheral neuropathies can be mild to disabling, depending on the type and severity of the damage, as well as the type of nerve fibers affected. Symptoms can develop over days, weeks, or months and, in mild cases, can often improve on their own without the need for treatment. Unlike the nerves in your central nervous system, peripheral nerve cells continue growing throughout your life, so it is possible to completely recover from some peripheral neuropathies, though it can take years to fully repair.
What Nerves Are Affected?
Which peripheral neuropathy you have depends on the number of nerves affected. With mononeuropathy, only one nerve is damaged, as you see with carpal tunnel syndrome. Multiple mononeuropathy, also known as mononeuropathy multiplex, features nerve damage to two or more nerves in different areas of the body. With polyneuropathy, most of the nerves in the PNS are damaged and symptoms are widespread, such as with Guillain-Barre syndrome.
Types of Peripheral Neuropathy
Peripheral neuropathies are divided into categories based on the type of nerves affected. In most cases, neuropathies affect all types of nerve fibers to some degree, however, they can be isolated to one category. Symptoms of peripheral neuropathy are determined by the type of nerves affected and will vary between individuals. There are three main classifications when it comes to peripheral neuropathies: motor, sensory, and autonomic.
Motor Neuropathy – affects the motor nerves that relay messages to muscles that you control (e.g., walking, grasping, speaking).
Sensory Neuropathy – affects nerves responsible for touch and sensation (e.g., pain from a cut, temperature changes, light touch).
Autonomic Neuropathy – affects nerves that regulate involuntary functions (e.g., breathing, digestion, heart rate, blood pressure).
Symptoms of Neuropathy
Symptoms vary depending on nerve type and the severity of the damage. They also depend on whether large or small fibers are involved. Large diameter fibers are myelinated and damage often causes motor symptoms (and some sensory). Small fibers are unmyelinated and primarily subserve sensation and autonomic function.
Motor Nerve Symptoms
The most common symptom is muscle weakness (e.g., leg weakness making walking difficult). Other symptoms include:
Painful muscle cramps
Involuntary muscle contractions (fasciculations)
Decreased muscle tone
Loss of deep tendon reflexes
Possible muscle wasting (atrophy) with progression (e.g., in multifocal motor neuropathy)
Sensory Nerve Symptoms
Large fiber damage:
Decreased sensation to vibration or touch
Hands/feet may feel like wearing gloves/socks
Loss of reflexes
Problems with positional awareness affecting mobility
Small fiber damage:
Decreased sensation of pinprick in a localized area
Increased sensitivity to pain (hyperalgesia)
Pain from non-painful stimuli (allodynia), e.g., bedsheets causing pain
Decreased temperature sensation
Tingling, burning, pain in toes/feet
Temperature changes can provoke pain
Symptoms often worsen at night
Autonomic Nerve Symptoms
Autonomic symptoms depend on the nerves involved and can be debilitating (including POTS). They may affect multiple organ systems.
General symptoms:
Lack of/excessive sweating
Heat intolerance (often with activity)
Sexual dysfunction
Unexplained weight loss
Heart and lung symptoms:
High/low blood pressure; large changes on standing
Abnormal heart rate or rhythm
Chest pain
Dizziness/lightheadedness with position changes
Fainting
Exhaustion/fatigue
Shortness of breath with activity
Stomach and digestive symptoms:
Constipation or diarrhea
Early satiety (feeling full quickly)
Nausea after eating
Bowel incontinence
Trouble swallowing
Bloating
Vomiting undigested food
Bladder symptoms:
Difficulty starting urination
Incomplete bladder emptying
Urinary leakage
Causes of Neuropathies
Neuropathy has many causes; diabetes is the most common, but others include:
Autoimmune disorders (e.g., lupus, rheumatoid arthritis)
Infections (e.g., HIV, EBV, SARS-CoV-2)
Vitamin deficiencies
Metabolic disease
Heavy metal poisoning
Thyroid conditions
Nerve trauma
Certain medications (e.g., cancer, blood pressure)
Nerve compression (e.g., carpal tunnel)
Excessive cold exposure
Treatment Options for Neuropathy
Treatment depends on the nerves affected and underlying causes. Some neuropathies can be treated and even cured; others are managed to control symptoms and prevent further damage. Approaches can include controlling the underlying condition (e.g., diabetes), medications, dietary changes, immune suppression or immune-modulating treatments, transcutaneous electrical nerve stimulation (TENS), or surgical intervention.
Neuropathies and Long COVID
Many Long COVID patients are experiencing varying forms of neuropathy as a major symptom. Two main neuropathic conditions that we are seeing occur with Long COVID include postural orthostatic tachycardia syndrome (POTS) and Guillain-Barre syndrome (GBS). In addition, Long COVID patients hospitalized during their acute infection may experience neuropathy as a result of prone-position bedding while in the ICU. Those with pre-existing diabetes before their acute case of COVID have a higher risk of developing neuropathies with Long COVID or experiencing a worsening of their pre-existing neuropathy.