Pain is referred to as not only an unpleasant sensory experinence but also an emotional one. Though hated by all, pain is a natural indicator that lets us know about injury or trauma. Pain is also oftentimes a good indicator of a patient’s mental health state. Patients with comorbidities, such as those suffering from diabetes, often experience different pain sensations. Diabetic patients often experience lesser pain sensations, for example, which in turn makes them more prone to serious injuries.
However, chronic pain is a different story. It is an issue that can seriously complicate your daily life. There are many diverse forms of pain including the pain arising from muscles, bones, and nerves being the most common.
Pathophysiology Of Pain
The obnoxious stimulus involves both the central and peripheral nervous systems. It is classified into two different categories:
- Nociceptive pain (physiologic pain)
- Neuropathic pain
Nociceptive Pain
This is the most common type of pain and is caused by a harmful stimulus. The pain is perceived by the nociceptors present in the skin, muscles, and bones, etc. Physical injury such as bruises, burns, fractures, or underlying medical conditions (such as arthritis) causes nociceptive pain.
Neuropathic Pain
Such pain arises from damage or impingement of nerves. The unrelenting pain is felt as shooting or burning pain. Malfunctioning of the nervous system or damage to the nerves can lead to neuropathic pain.
How Does Ketamine Work In Providing Pain Relief?
Ketamine has a wide variety of effects on the body. This noncompetitive antagonist of N-methyl-D-aspartate (NMDA) receptors possesses anti-hyperalgesic and analgesic properties. NMDA receptors receptors are specialized receptors present in the brain and the spinal cord. These receptors play an important role in memory formation, neuronal connections, and cognition. Overexcitation of these proteinaceous receptors is seen in neurodegenerative disease.
Ketamine binds to the NMDA receptor (phencyclidine site on the postsynaptic channels) which leads to a reduction in the frequency of opening of ion channels. This blocking of NMDA channels leads to analgesic effects that provide pain releif.
Chronic Pain
Treating chronic pain is a difficult task for many clinicians. Ketamine is effective in providing analgesia when given in small doses. A study done in 2020 reveals that ketamine can be effective in the management of both acute and chronic pain.
This article discusses the impact of ketamine on the different types of pain disorders. Chronic pain is always associated with some sort of underlying medical condition. In most cases, the disease is incurable, and only symptomatic relief from pain is provided.
For pain to be classified as chronic pain, it often has to be felt for at least 12 weeks. Occasional body aches and pains, while unpleasant, do not classify as chronic pain.
Types Of Chronic Pain
The most common types of cause chronic pain are given below:
Low-Back Pain
Chronic low back pain is a seriously debilitating disease that hampers day-to-day activity. It is reported that 20% of patients suffering from acute back pain develop a chronic form that may last for a year or so.
Arthritis Pain
Arthritis is a condition of joint swelling that causes chronic pain. There are two common types of chronic arthritis i.e. osteoarthritis (caused by degeneration of joints) and rheumatoid arthritis (caused by joint attack of auto-antibodies).
Post-Surgical Pain
Pain after surgery is a common phenomenon and, in some cases, may persist for long periods of time. Cancer removal surgeries may also result in chronic pain.
Post-Trauma Pain
Pain after an injury or trauma can take a chronic form. Fractures and burn injuries can leave a scar and chronic pain which can severely debilitate you.
Cancer Pain
Pain arising from a tumor or cancer in the body can last for a long time. The removal or inactivation of a tumor can also result in chronic cancer pain.
Underlying Medical Conditions
Certain underlying medical conditions can cause chronic pain. Some of these conditions are given below:
- Chronic fatigue syndrome
- Rheumatoid arthritis
- Fibromyalgia
- Temporomandibular joint dysfunction
- Inflammatory bowel disease
Ketamine For Chronic Pain
In a study carried out on rats, ketamine infusions were linked to evident ant-rheumatoid arthritis properties. The pain relief and reduction in inflammation with ketamine use were evident. Another case study found that a rheumatoid arthritis patients reported complete relief of all symptoms after 10 consecutive ketamine hydroxide IV infusions.
As per a randomized, controlled study, low-dose ketamine infusion proved to provide an efficient analgesic effect in persistent postsurgical pain after breast cancer surgery. Another study published in SAGE journals proposed that ketamine can be a beneficial medical intervention in the management of chronic postsurgical pain (CPSP).
Low dose ketamine (0.2 mg/kg) provides a rapid and significant reduction in pain in the emergency department. The study suggested that ketamine’s results were superior to morphine. Another study advocated the use of ketamine for the management of traumatic pain. A 2019 review also found that the NMDA antagonist effect of ketamine leads to impressive analgesia in cases of chronic pain.
Cancer pain is a prevalent type of chronic pain. A meta-analysis of 6 studies concluded that ketamine is efficacious in reducing chronic pain arising due to cancer/tumor. Another study promoted the use of ketamine infusions for rapid pain relief from cancer pain.
If you suffer from chronic pain, please call (310) 928-6863 to schedule a free consulation to see whether you’re a good candidate for Ketamine Infusions!
Complex Regional Pain Syndrome (CRPS)
Complex regional pain syndrome or CRPS is a relatively uncommon chronic pain condition. CRPS arises after an injury to the limbs and results in an excess and prolonged pain felt in the arms and the legs. In the majority of cases, the pain felt in CRPS is unrelated to the original injury.
Signs And Symptoms
It manifests itself in the following form:
- Pain in the affected limb
- Persistent burning sensation in the arm or leg
- The skin of the affected limb shows changes in temperature and color (hot with a blotchy red appearance)
- Nail and hair growth are altered
- The affected area is inflamed and swelling is seen
- Stiffness in joints and reduced range of motion
- Muscle loss
Types Of Complex Regional Pain Syndrome
The syndrome is divided into two different types:
Type 1
This type of complex regional pain syndrome is the most prevalent, occurring in 90% of CRPS cases. The condition is also known as reflex sympathetic dystrophy (RSD). Type 1 CRPS is the result of an injury that doesn’t damage the nerves directly.
Type 2
Type 2 CRPS is characterized by nerve injury of the limbs (arms and legs). The disease is also referred to as causalgia. It is comparatively rare but has symptoms similar to type 1.
Pathophysiology Of Complex Regional Pain Syndrome
The syndrome is not necessarily linked to the damage done by the injury rather a disruption of the interaction between the central and the peripheral nervous system. Trauma causes inflammation, redness, and swelling with a reduction in function. CRPS is still a medical mystery, a review suggests.
Ketamine For Complex Regional Pain Syndrome
According to a meta-analysis, ketamine infusion can provide 3 months of relief in the complex regional pain syndrome. Ketamine infusion is considered to be one of many treatment therapies for CRPS, a study suggests.
Another review found that ketamine infusions can help relieve symptoms of complex regional pain syndrome. The disease causes periods of increased exacerbations of symptoms, also known as flare-ups. A 2020 case report declares that ketamine (when used as an anesthetic) is effective in alleviating pain from CRPS.
Even the topical application of ketamine can be a beneficial step in the management of CRPS. According to a 2018 study published in the International Journal of Pharmaceutical Compounding, ketamine showed promising results in relieving reflex sympathetic dystrophy (RSD). A comprehensive review also promotes the use of ketamine in CRPS.
A 2018 study revealed that ketamine provides exceptional pain-killing effects in CRPS patients by modulating the balance between receptors responsible for pain (GABA receptors). GABA receptors are present on the nerve cells and they slow the activation of nerves. Ketamine plays a role in reducing the excitation of pain signals in the brain.
As per a systematic review and meta-analysis, chronic pain that arises due to CRPS can be managed very effectively with the use of ketamine infusions.
CRPS may be triggered after a percutaneous coronary intervention, also known as cardiac stenting. Cardiac surgeons are recommended to be cautious when performing the procedure. According to a case study, ketamine is a promising agent in the therapeutic management of type 2 CRPS due to percutaneous coronary intervention.
Sub-anesthetic doses of ketamine can provide good analgesia for patients suffering from chronic pain. According to a study published in 2019, ketamine infusions can also provide effective pain relief in refractory patients of CRPS who do not respond well to opioids.
If you suffer from Chronic Regional Pain Syndrome, please call (310) 928-6863 to schedule a free consulation to see whether you’re a good candidate for Ketamine Infusions!
Migraines
A Migraine is a type of headache that has multiple associated effects. It can last for hours or even days. It is most often associated with photosensitivity (sensitivity to light) and symptoms of nausea and vomiting.
According to research, cervical nerves and neuropeptides are recognized to play a role in the development of migraine symptoms. It is difficult to find an effective form of treatment for severe headaches or migraines.
Types Of Migraine Headache
There are different types of migraine:
Classic Migraine
Migraine with an associated aura is known as classic migraine. Auras are characterized by sensory disturbances felt with the onset of headache. There is a wide variety of auras which include symptoms of:
- Changes in vision
- Zigzag lines floating across the field of vision
- Blind spots are also known as scotomas
- Flashes of light
- Tingling in hand and/or face
Common Migraine
This type lacks the presence of an associated aura. The symptoms of common migraine are similar to classic migraine (minus the aura) and the treatment for both types is the same.
Based on the origin, there are further classifications of the disease:
- Menstrual migraine during periods in women
- A vestibular migraine that is associated with balance problems and nausea, vomiting
- Abdominal migraine characterized by abdominal pain and headache
- Acephalic migraine where the only aura is present and headache is absent
Signs And Symptoms
In most cases, there are different stages of migraine i.e. prodrome, aura, attack, and postdrome.
Prodrome
Prodrome symptoms include:
- Photosensitivity
- Mood changes
- Bloating
- Constipation or diarrhea
Aura
These nervous systems start slowly but may last for an hour. 60% of migraine patients experience auras while some only experience the attack.
Auras include:
- Hallucinations (seeing flashes of light and mobile wavy lines, etc.)
- Inability to speak
- Alterations in basic senses (smell, taste, and touch)
- Tunnel vision or even temporary blindness
Attack
80% of migraine patients report pain, described as a dull to severe throbbing headache, along with a feeling of fainting. Patients have reported that the condition worsens with physical activity.
Postdrome
These symptoms may last up to a day after the migraine subsides:
- Fatigue
- Muscle weakness, stiffness, and tenderness
- Residual migraine headache
Ketamine For Migraines
Migraine patients rush to the emergency department for the relief of headaches. There are several medications used to manage migraines including NSAIDs, prochlorperazine, and antihistamines, etc. However, evidence suggests that ketamine can play a key role in relieving symptoms of migraines.
Research suggests that subanesthetic doses of ketamine infusions can help treat chronic migraines and new daily persistent headaches when all other forms of aggressive treatment has failed. Spreading depolarization in the cortex of the brain is responsible for the development of migraines. Studies suggest that ketamine administration successfully halts depolarization in the brain and brings immediate relief to symptoms.
As of recently, THINK (Treatment of Headache with Intranasal Ketamine) therapy for migraine is becoming a popular form of treatment. Though the results of this therapy are not as superior as IV metoclopramide, the method of administration is much less difficult. Another 2019 study promotes the presence of ketamine in the emergency department and the use of THINK therapy for both migraines and severe headaches.
A 2020 review found that even intranasal ketamine can bring about overall pain relief in the body as well as a reduction in migraine symptoms. Therefore, intranasal ketamine can be employed as an effective treatment for chronic migraine headaches.
In a review of glutamate receptor modulators, it was found that glutamate receptor antagonists like ketamine can play a role in relieving migraine symptoms. Ketamine infusion therapy can be used to treat episodic migraines accompanied with or without aura along with treatments including triptans, prochlorperazine, and ketamine, a study suggests.
Ketamine For Headaches
In addition to migraines, there are different types of headaches such as cluster headaches, tension headaches, and hypnic headache. Luckily, ketamine has shown to be effective in managing a variety of headaches.
Targeting the overactive NMDA receptor is a potential curative step in the management of chronic cluster headaches. According to randomized controlled trials, ketamine can successfully subside cluster headaches.
It was found in a retrospective analysis that ketamine is effective in providing short-term pain relief in patients with refractory headaches. According to a randomized clinical trial intravenous administration of ketamine was linked to alleviation of headaches.
If you suffer from migraines or severe headaches, please call (310) 928-6863 to schedule a free consulation to see whether you’re a good candidate for Ketamine Infusions!
Neuropathic Pain
Neuropathic pain is an evident type of chronic pain that is the result of injury to the nerves or the somatosensory system. Nerve disease or injury to the nerves can trigger this type of pain.
The exacerbations of this pain are unpredictable as you can experience a flare-up at any point in time.
Causes Of Neuropathic Pain
Neuropathic pain occur as the result of many different issues, some of which are discussed below:
Underlying Diseases
Infirmities such as multiple sclerosis, trigeminal neuralgia, and multiple myeloma can lead to the development of neuropathic pain. It is reported that 30% of neuropathic cases are seen in patients with diabetes. This is due to alterations in the nervous system known as diabetic neuropathy. Therefore, chronic diabetes is identified as a causative agent for nerve pain. Trigeminal neuralgia is a condition where neuropathic pain is felt on one side of the face i.e. unilateral nerve pain.
Chronic alcoholism is also recognized as a cause of neuropathic pain along with diabetes, a study suggests.
Trauma And Injury To Nerves
Disc herniation or spondylitis can impinge or compress the spinal cord leading to pain. The condition may arise after a fall, trauma, or injury. Similarly, injuries to the nerves in the hips and thigh region can lead to the development of sciatic nerve inflammation (sciatica) and eventually sciatic nerve pain.
Infectious Conditions
It is a rare chance that infection can lead to neuropathic pain but still there is a possibility. Postherpetic neuralgia is a condition of nerve pain that develops after herpes infection. Similarly, shingles can trigger nerve pain following the course of the affected nerve. Syphilis infection can also be a cause of nerve pain.
Limb Issues
Phantom limb syndrome is a condition where abnormal, painful sensations are felt inside the amputated limb. It has been reported that almost 80 to 100% of limb amputees suffer from this issue. Facial nerve issues have been found to also contribute to these problems.
Ketamine For Neuropathic Pain
As per studies, pain relief is achieved with the use of intravenous ketamine. Ketamine therapy is rapidly gaining popularity in the management of nerve pain. According to a study, intravenous ketamine infusion can prove to be a promising therapy in the treatment of neuropathic pain.
In another analysis of patients suffering from neuropathic pain, it was found that ketamine effectively imparts sufficient analgesia. A total of 30 participants were a part of the study that had refractory neuropathic pain. 50% of the patients showed solid improvements in symptoms.
According to a randomized controlled trial, a combination of magnesium and ketamine provided neuropathic pain relief at 5 weeks of administration. Ketamine infusions showed 20% improvement while the magnesium and ketamine combo showed 35% improvement.
In a comparative study on the effect of methadone and ketamine, it was found that ketamine has a superior impact on treating neuropathic pain than methadone or methadone/ketamine combination. Another 2020 study reveals that ketamine usage prevents chronification of pain and also reduces central sensitization.
As per another randomized controlled trial, magnesium sulfate and ketamine combination can aid in neuropathic pain reductions.
How Ketamine Alleviates Neuropathic Pain?
This sort of pain is the result of dysregulation of the peripheral and the central nervous system. Abruptions in neurotransmitters are involved in the occurrence of pain. These disruptions lead to the spontaneous firing of neurons, thus producing pain.
There is also an activation of the excitatory NMDA receptors. The blockade of the NMDA receptors by glutamate receptor antagonists, like Ketamine, prevents central sensitization of the neurons and brings pain relief, a study suggests.
If you suffer from neuropathic pain, please call (310) 928-6863 to schedule a free consulation to see whether you’re a good candidate for Ketamine Infusions!
Summary
Ketamine is famous for its analgesic effect when given in sub-anesthetic doses. The drug is an N-methyl-D-aspartate receptor antagonist that inactivates the overactive receptors. This property promotes the use of ketamine for the management of chronic pain.
Chronic pain may be classified as nociceptive and neuropathic pain. Chronic pain arising from surgery, cancer, arthritis, or an injury can be treated well with intravenous ketamine infusions.
Similarly, refractory migraine and cluster headaches can be treated with small doses of ketamine. In modern times Treatment of Headaches with Intranasal Ketamine (THINK) therapy is becoming popular.
Complex regional pain syndrome is a form of chronic pain that is also difficult to manage. Ketamine infusions are potent in providing pain relief in these cases too. The drug seems to have superb therapeutic effects on neurogenic pain too.
Ketamine is commonly known for its use as a sub-anesthetic to achieve analgesia, but recent studies have also warranted its use as a prophylactic that can achieve both analgesic and anti-depressant properties.
If you are interested in learning if Ketamine Infusions are right for you, please call (310) 928-6863 to schedule your free consultation!
