Updated on April 1, 2020.
Medical content reviewed by Dr. Joseph Rosado, MD, M.B.A, Chief Medical Officer
Focal neuropathy is a common neurological condition, caused by a wide array of injuries and diseases and manifesting with any number of associated symptoms. In the United States, about 20 million people suffer from some form of neuropathy — carpal tunnel syndrome, a specific type of focal neuropathy that affects the hands, has an overall prevalence of 3 to 5 percent by itself.
Despite how common focal neuropathy is, however, there are still limited diagnosis and treatment options for patients, especially those with more severe symptoms. While those with mild symptoms can often find relief with a brace and some mild painkillers, many patients with severe symptoms must pursue expensive or risky treatments like surgery or opioid analgesics. Some of these options are just not sustainable for people with certain types of focal neuropathy. For this reason, physicians have been analyzing the efficacy of marijuana for focal neuropathy, and have discovered promising results.
Read on to learn more about focal neuropathy and how cannabis can help manage the symptoms of neuropathy.
What Is Focal Neuropathy?
Neuropathy is a condition where one or more nerves get injured, resulting in problems in the nervous system. In focal neuropathy, only a few nerves at most are injured, confining the resulting symptoms to a small area of the body. Generally, focal neuropathies occur in the hand, head, torso or leg, resulting in different symptoms based on the location.
About 30 percent of neuropathy cases are idiopathic, which means they are of unknown cause. The remaining cases of neuropathy can be the result of several possible causes, including the following.
- Trauma: Physical trauma or pressure on the nerves is a common cause of neuropathy, though the cause itself doesn’t have to be traumatic. Compression, pinching, cutting, projectile injuries, strokes and electric discharge can all result in neuropathies. Most commonly, however, pressure from a cast, crutch or repetitive motion causes focal neuropathies. For example, carpal tunnel syndrome is most common in people with jobs where they spend hours resting their wrists on the edge of a desk and typing on a keyboard.
- Vitamin deficiency: Nutritional problems and deficiencies will often contribute to neuropathies, with a lack of B vitamins being the most common issue. Vitamin B12, vitamin A, vitamin E and vitamin B1 deficiencies can all result in neuropathy. It is particularly common in people with eating disorders and those with alcoholism.
- Diabetes: About 30 percent of neuropathies are linked to diabetes, and about half of all people with diabetes develop some neuropathy in their lifetime. That is mostly due to poor control of blood sugar Over time, high blood sugar and high levels of fat in the blood damage nerves and the small blood vessels that nourish them, leading to focal neuropathies.
- Genetic disorders: Friedreich’s ataxia, Charcot-Marie-Tooth syndrome and amyloid polyneuropathy are all examples of hereditary neuropathies.
- Metabolic and endocrine disorders: Besides diabetes, metabolic and endocrine issues like renal failure, liver failure, porphyria, amyloidosis, and hypothyroidism can all contribute to neuropathy.
- Toxic causes: When ingested in excess, certain drugs, organic and heavy metals may result in neuropathies. Too much vitamin B6 can also contribute to neuropathy. Fluoroquinolone drugs are particularly problematic in this case, as they can cause irreversible neuropathy.
- Inflammatory diseases: Guillain-Barré syndrome, systemic lupus erythematosus, leprosy, Sjögren’s syndrome, Lyme disease, and sarcoidosis can all lead to inflammation, which can compress nerves, causing neuropathy.
- HIV: Any condition that suppresses the immune system can increase the chances of developing neuropathy, and HIV is no exception. HIV neuropathy is a condition that affects more than a third of all people living with HIV.
- Tumors: Both malignant and benign tumors can press up against nerves as they grow, resulting in focal neuropathies.
- Others: Shingles, radiation, and chemotherapy can result in degeneration of nerves, causing various types of neuropathy.
Because there are so many potential causes, focal neuropathy is uniquely difficult to diagnose, making treatment even more problematic.
Symptoms of Focal Neuropathy
The specific symptoms of focal neuropathy depend primarily on the location and cause of the neuropathy. For example, with carpal tunnel syndrome, where the median nerve gets damaged through continuous compression, patients often feel pain and weakness in the affected hand. In focal neuropathies of the face, however, a patient may experience partial paralysis and numbness.
The most common symptoms of focal neuropathy include the following.
- Loss of function: The most common sign of focal neuropathy is a loss of sensation or control in the affected area. Generally, this will manifest as numbness, weakness, tremors or loss of fine motor control.
- Pain: Feeling pain is another common symptom of focal neuropathy, and usually manifests as an ache, tingling, itching, crawling or “pins-and-needles” sensation. In extreme cases, the pain may be acute enough to be debilitating and can require the use of painkillers.
- Sensitivity: Patients with focal neuropathy may notice an increase of sensitivity in the affected area, especially if the area contains bundles of nerve endings. This increase in sensitivity may result in more pain for the patient.
Any of these symptoms can be debilitating for patients if they persist long enough. While focal neuropathies that don’t involve trapped nerves may fade over time without treatment, those that do often linger, making treatment necessary for a patient to lead a normal life.
How to Treat Focal Neuropathy
With so many potential causes, the treatment of focal neuropathy has to begin with identifying the cause of the neuropathy. Once a doctor has determined the cause, they can move forward with a treatment plan, though diagnosis alone may require a complete review of a patient’s medical history and additional exams and tests. Unfortunately, even after figuring out the cause, neuropathic pain can be challenging to understand, so each patient may react differently to each type of treatment.
Current standard treatment options include the following.
- Splints: Patients can treat focal neuropathies that involve trapped nerves by wearing a splint or brace, which alleviates some of the pressure on the nerve. Often, doctors prescribe this remedy alongside medication, though the splint alone may be enough to relieve minor cases of focal neuropathy.
- Surgery: Some cases may require surgery to remove any obstructions placed on a nerve, such as a tumor or other anatomical anomaly. Usually, surgery is a last resort if other treatments do not work.
- Antidepressants: Several types of antidepressants act on the central nervous system in a way that has been found to help manage neuropathic pain. Tricyclic and certain SNRI antidepressants can be particularly useful in patients who do not suffer from depression.
- Anticonvulsants: Anticonvulsants and antiepileptic drugs have been found to have some positive effects in the management of neuropathic pain. These drugs block calcium channels on neurons, limiting the sensation of pain for patients.
- Opiate painkillers: Physicians commonly prescribe opioid narcotic treatments to help manage neuropathic pain. While these drugs are effective, the negative side effects, including the risk of dependency and severe constipation, have made doctors hesitant to prescribe opioids to patients.
- Topical anesthetic: For some types of neuropathy, physicians recommend treatment with a topical anesthetic such as lidocaine or capsaicin.
- Lifestyle changes: For some patients, lifestyle changes have proven to be very effective at managing neuropathic pain. Yoga, meditation and dietary changes specifically designed to stimulate the nervous system have historically been used to varying degrees of success, and some patients have even pursued dietary supplements, therapies and even specific types of massage to help ease their pain.
- Neuromodulators: Neuromodulators are implantable and non-implantable technologies, either electrical or chemical, that stimulate the motor cortex of the brain with a method called deep brain stimulation. Neuromodulators can accomplish this with spinal cord stimulators, implanted spinal pumps and electrodes.
- Other options: Additional options that have found some success include botulinum toxin type A, better known as Botox®, and NMDA antagonists such as ketamine.
With so many potential causes of focal neuropathy, patients usually end up using one or more of these various treatments to manage their symptoms. For the majority of people suffering from long-term pain due to focal neuropathy, opioid painkillers have become the standard treatment option, since they are effective at reducing pain quickly. However, risks and side effects associated with opioid narcotic treatments — including dependency — along with the current American opioid epidemic have led physicians to pursue other long-term solutions. That is where medical marijuana and cannabinoids have been of interest.
Medical Cannabis and Focal Neuropathy
Medical marijuana offers numerous benefits to patients with focal neuropathies. Several studies have supported the idea that the two primary compounds in medical cannabis, tetrahydrocannabinol (THC) and cannabidiol (CBD), are beneficial for treating neuropathies. Specifically, CBD is a powerful painkiller, and THC is helpful in managing pain and relaxation.
Medical marijuana for focal neuropathy exhibits the following benefits for patients.
- Pain management: Focal neuropathy often leads to sensitivity and pain in affected parts of the body. While opioids have historically helped patients manage this pain, their side effects have proven problematic. While some studies have suggested opioids are more effective at overall pain management than cannabis, medical cannabis for focal neuropathy offers pain relief without side effects. One study from the Journal of Pain studied the pain-relieving effects of vaporized cannabis for spinal cord injury patients and found cannabis treatment significantly improved their pain. Smoked cannabis has also been found to provide relief from neuropathy related to HIV, CRPS and nerve injuries. Pharmaceutical companies are also pursuing the possibilities of synthetic cannabinoids as painkillers, especially for neuropathic pain. Research has already demonstrated the synthetic oral cannabinoid Nabilone is an effective treatment option for neuropathy, and preliminary results for Sativex cannabinoid spray medicine show promising results in pain and sleep quality management.
- Neuroprotection: For patients suffering from focal neuropathy as a result of another condition, like diabetes or HIV, the potential neuroprotective qualities of marijuana are particularly attractive. One study showed cannabis could have a role as a neuroprotectant, discovering rats who ingested cannabis had a unique neuroprotective response after the substance activated their CB1 and CB2 receptors, helping them recover quickly from neurological lesions. Additionally, another experiment on diabetic mice suggested treatment with cannabidiol at the onset of diabetes had long-lasting neuroprotective benefits and might prevent people with diabetes from experiencing symptoms of neuropathic pain at all. While researchers have yet to replicate either of these studies with human subjects, they both show potential for the future of medical marijuana research and drug development.
These initial studies and results have encouraged many physicians in legalized states to pursue medical marijuana research and start prescribing it to their patients with neuropathic pain. Even though marijuana research has stalled at the federal level, and remains stalled in many states across the U.S., physicians continue to learn more about the benefits of marijuana for focal neuropathy every day.
Best Practices for Medical Cannabis for Focal Neuropathy
Physicians prescribing marijuana for focal neuropathy generally follow similar practices for the benefit of their patients. One doctor describes their prescription method and recommendations as follows.
- Use medical strains: Recreational marijuana and medical marijuana are very different in their balance of CBD to THC. While recreational marijuana contains a ratio that favors THC for its psychoactive effect, medical strains favor CBD. Higher amounts of cannabidiol and cannabinol are generally more helpful for pain management and neuroprotectivity, so strains with a higher CBD-to-THC ratio will be more effective at delivering painkilling effects. These strains will also have the added benefit of allowing patients to go about their lives normally without getting high. For specific suggestions, you can talk to a marijuana-friendly physician.
- Consider the dosage: With medical marijuana, it’s important to experiment with the dosage by starting out low and gradually increasing intake. Optimal dosages tend to vary from patient to patient based on their age, weight, and tolerance to THC and CBD, but a study published in the Journal of Pain found the average daily dosage for pain management by medical marijuana users was around 2.5 grams.
- Use a vaporizer: Traditional smoking of marijuana plant material can be harmful to the respiratory system, introducing tar, plant matter and vaporized fertilizers and pesticides to the lungs. All these materials can be carcinogenic in nature, and carry as much risk to the respiratory system as tobacco smoking. Generally, physicians recommend using a vaporizer, so the patient inhales mist instead of smoke. Patients who prefer to ingest their medication may also choose a tincture or edible option, though ingestion is more slow-acting.
In any case, you should always speak with your physician before introducing marijuana into your treatment plan. A marijuana-friendly doctor can direct you to the right strain and dosage for your needs.
Find Treatment Near You
Are you interested in pursuing medical marijuana as a treatment option for your focal neuropathy pain? MarijuanaDoctors.com can help you find the relief and support you need by assisting you in finding a quality physician and trusted dispensary close to your location. Use our search engine to find a doctor near you, or find your nearest trusted dispensary.
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