Neuropathic Pain Treatment at Drexel Neurology
Neuropathic pain occurs when nerve fibers are damaged, dysfunctional or injured. This causes a change in nerve function at and around the site of the injury. An example of neuropathic pain is complex regional pain syndrome (CRPS).
Symptoms of Neuropathic Pain
Common symptoms of neuropathic pain may include shooting and burning pain, or tingling and numbness. Often these symptoms worsen over time, rather than improving, and they may spread from the initial point of injury to the whole limb.
Diagnosing Neuropathic Pain
An electromyography (EMG) test measures the electrical activity of a muscle. It detects any signs of blocking or slowing down of responses to nerve stimulation. An EMG provides information about the muscle itself and shows how well the muscle receives stimulation from the nerve.
An EMG is often used to evaluate unexplained muscle weakness, twitching or paralysis, and to find the causes of numbness, tingling and pain. During an EMG, a physician or technician inserts a very fine needle, which serves as an electrode, through the skin into the muscle. With the electrode in place, the patient is asked to slowly contract the muscle—for example, by bending the arm—with gradually increasing force, while the electrical activity is being recorded. Patients may feel some discomfort after the test.
Nerve Conduction Studies (EMG/NCS)
A nerve conduction velocity test, also called a nerve conduction study, measures how quickly electrical impulses move along a nerve. A healthy nerve conducts signals with greater speed and strength than a damaged nerve. A nerve velocity test is often done at the same time as an electromyography test, in order to exclude or detect muscle disorders. During the test, flat electrodes are placed on the skin at intervals over the nerve that is being examined. A low-intensity electric current is introduced to stimulate the nerves.
Laser Doppler Perfusion Imaging (LDPI)
Laser doppler perfusion imaging (LDPI) records the movements of red blood cells and can estimate the blood flow to the overlying skin of the area in focus. LDPI is done to measure changes in blood flow to skin that can occur with autonomic neuropathies such as CRPS.
Quantitative Sensory Testing (QST)
Quantitative sensory testing (QST) is a method used to assess damage to the small nerve endings, which detect changes in temperature, and the large nerve endings, which detect vibration. QST is used to diagnose and assess the severity of nerve damage and to determine if a neuropathy is responding to treatment. Quantitative sensory testing uses a computer testing system to measure how the nerves involved react to vibration and changes in temperature.
Cutaneous (Skin) Nerve Biopsy
Cutaneous nerve biopsy is when a small sample of skin is taken to be analyzed microscopically to determine the health of the small nerves in skin. It is used to diagnose and monitor small fiber neuropathies. Cutaneous nerve biopsy allows doctors to visualize the small nerves in skin that cannot be studied electrically.
During cutaneous nerve biopsy the skin is anesthetized and a small circular needle is used to collect a piece of skin. There should be little or no pain after the injection of anesthesia. Some tenderness may occur after the biopsy.
A neuropsychological evaluation consists of paper-and-pencil or computerized tests that are used to determine brain function. Intelligence, memory, language function, and overall function are usually evaluated to see if there is an indication of loss of ability due to neuropathic pain syndromes.
Neuropsychological tests are administered privately with an examiner in a quiet office environment, free from distractions. This allows for an evaluation of a person at their highest level of concentration.
Treatment of Neuropathic Pain
Intravenous Infusions (IVs) of Ketamine for Complex Regional Pain Syndrome
Ketamine infusions are safe and effective for managing refractory complex regional pain syndromes (CRPS). Ketamine selectively relieves pain due to CRPS without causing prolonged sedation and respiratory depression. There is no problem with physical dependency, tolerance or constipation with ketamine.
Treatment includes an initial 3.5 hour infusion for ten days followed by two-day "boosters" every three months.
Booster infusions have proven effective in patients with severe, multiple extremity, intractable, complex regional pain syndromes (CRPS). Ketamine booster infusions are likely to lead to fewer emergency room visits for these extremely difficult and serious cases of CRPS.
The FDA-approved package insert supports the safety of ketamine: "[It] has a wide margin of safety; several instances of unintentional administration of overdoses of ketamine (up to ten times that usually required) have been followed by prolonged but complete recovery."
BOTOX® Injection for Dystonia
Dystonia, which can occur in patients who suffer from chronic pain conditions like CRPS, is involuntary movements and prolonged muscle contraction, resulting in twisting body motions and abnormal posture. These movements may involve the entire body, or only an isolated area. Symptoms may even be "task specific," such as writer's cramp. Dystonia can be inherited, occur sporadically without any genetic pattern, or be associated with medications or diseases.
Results from a key clinical study showed that after receiving BOTOX® treatment, the vast majority of people with cervical dystonia had improved head posture, neck pain that was less intense and happened less often, and an improved ability to function in certain daily activities.
Drexel Neurology's Neuropathic Pain Provider
Enrique Aradillas Lopez, M.D.
The information on these pages is provided for general information only and should not be used for diagnosis or treatment, or as a substitute for consultation with a physician or health care professional. If you have specific questions or concerns about your health, you should consult your health care professional.