Chronic Pain

What Is Chronic Pain?

The onset of pain is a symptom of illness or injury in the part of the body that is experiencing the pain. The sudden onset of pain is called acute pain. Acute pain gets a person's attention and prompts him or her to take action to prevent further worsening of the condition causing the pain. This could be a simple action such as the reflex that makes a person jerk their hand off a hot stove, or it could be more complex such as cooling, resting, or elevating an injured ankle. Moreover, the pain could prompt the person to see a doctor. Chronic pain is pain that persists over time (6 months or longer) and typically results from long-standing (chronic) medical conditions or damage to the body.

Pain interrupts our work, our recreation, and our relationships with our families. Comfort, that is, not being in pain, is one of the goals if a person becomes sick, and treatment by a health care professional for an illness associated with chronic pain is another goal.

Once the cause of the pain is found and proper treatment is started, the pain may serve the useful function of keeping the affected individual at rest so that the injury or illness can heal. But if the pain is from an illness that is incurable and will never heal, the pain loses its usefulness and becomes harmful. This type of pain keeps a person from normal activity, and inactivity decreases strength.

Common sources of chronic pain include injuries, headaches, backaches, joint pains due to an arthritis condition, sinus pain, tendinitis, or overuse injuries such as carpal tunnel syndrome. Chronic pain is also a feature of many types of advanced cancers.A number of symptoms can accompany chronic pain and can even arise as a direct result of the pain. These can include insomnia or poor quality sleep, irritability, depression and mood changes, anxiety, fatigue, and loss of interest in daily activities. Pain can trigger muscle spasms that can lead to soreness or stiffness.

  • Why pain can become worse: There is a "wind-up phenomenon" that causes untreated pain to get worse. Nerve fibers transmitting the painful impulses to the brain become "trained" to deliver pain signals better. Just like muscles become stronger for sports with training, the nerves become more effective at sending pain signals to the brain. The intensity of the signals increases over and above what is needed to get the affected person's attention. To make matters even worse, the brain becomes more sensitive to the pain. So the pain feels much worse even though the injury or illness is not worsening. At this point, pain may be termed chronic pain. And it is no longer helpful as a signal of illness.
  • The goal in treating pain: When a doctor is consulted, the goal for both patient and the doctor is to no longer have chronic pain. The patient wants the cause of their pain to be found and cured so that he or she can resume normal life without needing medication or further visits to health care professionals.
  • Treating lifelong pain: Unfortunately, many illnesses do not have known cures. The treatment of illnesses such as diabetes and high blood pressure is often lifelong. In these chronic illnesses, as in the treatment of chronic pain, the person's goal is to live as normally as possible. Sometimes medication is needed for the rest of a person's life in order to achieve that goal.
  • A sensible view of addiction: Chronic pain is no different from diabetes or high blood pressure. If a person needs to be on pain medicine for the rest of his or her life, they should not be said to be "addicted" to pain medicine any more than a person with diabetes who needs to be on insulin for the rest of his or her life should be said to be "addicted" to insulin.
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General Somatic Pain (pain from the outer body)

  • Pains from the skin and muscles are easily localized by the brain because these pains are common. People have experienced general somatic pain since childhood when the person has fallen or been hit by a person or an object. Normally, somatic pain resolves in a few days.
  • Some people develop pain that never goes away. Fibromyalgia and chronic back pain can be in this category.
  • General somatic pain is often treated with nonsteroidal anti-inflammatory drugs (NSAIDs) such as ibuprofen (Motrin) or naproxen (Naprosyn) or with acetaminophen (Tylenol). Sometimes, opioids may be needed.

Visceral Pain (pain from the internal organs)

Pain originating in the internal organs is more difficult for a person to pinpoint. The connections from pain sensors in the internal organs to the brain are less sophisticated than the nerve connections from the skin and muscles. So, for example, gallbladder problems can cause right shoulder pain. Pain from acid indigestion or constipation is an example of visceral pain that is common and easy to recognize. These pains are easily treated and improve quickly either on their own or with treatment using nonprescription medicines.

Bone Pain

  • Pain in the bones from a bruise or a fracture is temporary. Pain from bone cancer, osteoporosis (softening of the bones that often appears in older people), osteomyelitis (an infection in a bone), or arthritis (inflammation of the joints) can last a long time.
  • Bone pain is gnawing and throbbing and may require long-term pain treatment. Bone pain from Paget's disease of bone can be treated with with bisphosphonates, such as alendronate (Fosamax). Sometimes, the NSAIDs (such as ibuprofen) are used. Sometimes opioids are needed.

Muscle Spasm (Muscle Cramps)

  • Muscle spasm, such as charley horse or cramp, can cause severe pain especially in the back. Pain medication alone may not be able to resolve the pain. Muscle relaxants such as cyclobenzaprine (Flexeril) or baclofen (Lioresal) may be needed to relax the muscles.

Chronic Pain Definition

Chronic pain: Pain (an unpleasant sense of discomfort) that persists or progresses over a long period of time. In contrast to acute pain that arises suddenly in response to a specific injury and is usually treatable, chronic pain persists over time and is often resistant to medical treatments.

Chronic pain may be related to a number of different medical conditions including (but not limited to) diabetes, arthritis, migraine, fibromyalgia, cancer, shingles, sciatica, and previous trauma or injury. Chronic pain may worsen in response to environmental and/or psychological factors.

There are a variety of treatment options for people with chronic pain. The goal of pain management is to provide symptom relief and improve an individual's level of functioning in daily activities. A number of types of medications have been used in the management of chronic pain, including acetaminophen, ibuprofen, aspirin, COX-2 inhibitors, antimigraine medications, sedatives, opioids, and antidepressants. Nonmedicinal treatments for chronic pain can include exercise, physical therapy, counseling, electrical stimulation, biofeedback, acupuncture, hypnosis, chiropractic medicine, and other treatments.

SOURCE:
MedTerms.com. Chronic pain.

Peripheral Neuropathy (pain arising in the nerves leading from the head, face, trunk, or extremities to the spinal cord)

  • In a sense, all pain comes from nerves because nerves transmit painful impulses to the brain. But some painful impulses do not arise from the nerve endings that normally sense injury or illness. Some painful impulses come from irritation to the nerve along its length instead of at the nerve ending.
  • Sciatica, for example, is caused by pinching of the sciatic nerve, which goes from the leg to the spine. The pinching often takes place near the lower part of the spine, but the pain is perceived as coming from the nerve endings in the leg because the sciatic nerve usually transmits feelings from the leg.
  • Other examples of illnesses that cause peripheral neuropathy or "nerve pain" are ruptured discs in the spine, which pinch nerves, cancers that grow into nerves and cause irritation, or infections, such as shingles, which can cause irritation to nerves.
  • Common diseases that often cause peripheral neuropathy are diabetes and AIDS.
  • Nerve pain can feel like a painful "pins and needles" sensation. This kind of nerve pain can be treated with tricyclic antidepressants. Other, more severe nerve pain can be described as a sharp, stabbing, electric feeling. Anticonvulsants (medicines that treat seizures) can be used for this kind of nerve pain.
  • Some nerve pain is due to loss of a limb. The arm or leg that has been amputated feels like it's still present, and hurts severely. This kind of nerve pain, called deafferentation, or "phantom limb pain," can be treated with clonidine (Catapres) (a blood pressure medicine that also relieves nerve pain).
  • Herpes zoster (shingles) causes an infection of the nerve endings and of the skin near the nerve endings. Local application of capsaicin (Zostrix), an over-the-counter pain medication in the form of an ointment, is sometimes helpful for this. In addition, opioids may be needed.
  • Pregabalin (Lyrica) is a drug that is used for the treatment of postherpetic neuralgia and diabetic peripheral neuropathy, while duloxetine (Cymbalta) has been approved for use in the treatment of diabetic peripheral neuropathy.

Circulatory Problems

  • Poor circulation is often a cause of chronic pain. Poor circulation is usually caused by tobacco use, diabetes, or various autoimmune diseases (diseases where the body makes antibodies that fight against itself) such as lupus or rheumatoid arthritis.
  • Partial blockage of arteries by fatty deposits called plaques (arteriosclerosis) is also a common cause of poor circulation. The reason for the pain of poor circulation is that the part of the body that does not get good blood circulation becomes short of oxygen and nourishment. The lack of oxygen and nutrition causes damage to that part of the body, and the damage causes pain.
  • Pain from poor circulation may be treated by surgery to bypass the clogged arteries with artificial arteries in order to improve the blood circulation. Sometimes this is not possible, and blood thinners or opioids may be needed to control the pain.
  • Another common cause of poor circulation is reflex sympathetic dystrophy (RSD), also known as complex regional pain syndrome (CRPS). This is a problem of both circulation and nerve transmission because painful nerve transmissions cause the blood vessels to become narrower. The narrowing prevents enough oxygen and nourishment from getting to the part of the body that is affected. RSD can sometimes be treated with a surgical sympathectomy, an operation to stop the nerve impulses from causing a narrowing of the blood vessels. Often, non-opioid medication, either with or without surgery, is needed. Sometimes opioids are needed.
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Headache Pain

  • Headaches can be caused by many illnesses. There are several types of headaches, including migraine, tension, and cluster headaches. Headaches can also result from sinusitis, trigeminal neuralgia, giant cell arteritis, or brain tumors. The treatment of the various kinds of headaches varies depending on the kind of headache and the severity of the pain. Often, non-opioid medicines are used. But, in some cases, opioid therapy is needed.
  • Migraines are often on one side of the head. They can be associated with nausea and vomiting, photophobia (light hurting the eyes), phonophobia (sound hurting the ears), and scintillating scotomata (parallel lines that vibrate at the edges of objects, especially at the borders between light and dark places). Sometimes these auras appear before the headache starts and alerts the person that a migraine is coming. Migraine pain can vary in intensity from mild to severe. There are many specific medications for migraine. Sumatriptan (Imitrex) is particularly useful for some, but not all, migraine sufferers.
  • Cluster headaches come in groups, sometimes several times a day, lasting for days to weeks. Many cluster headaches are severely painful. Oxygen therapy may be helpful for some cluster headaches.
  • Sinusitis can cause facial pain and is frequently worse in the morning. Sinus pain may respond to antibiotic treatment along with decongestants. Sometimes sinus surgery is needed.
  • Trigeminal neuralgia is actually a peripheral neuropathy (nerve pain) that is severe. It occurs on one side of the head and face and has a "trigger point," usually on the side of the face, which causes intense pain if it is touched. Anticonvulsants (antiseizure medicine) are often helpful for this type of pain, and muscle relaxants drugs are also sometimes used.

Measuring Chronic Pain

The World Health Organization has a "pain ladder" that characterizes cancer pain according to three levels. The levels are mild pain, moderate pain, and severe pain. These general principles can be applied to all types of chronic pain.

  • Mild pain: Mild pain is self-limited. It goes away either with no therapy at all or with the use of nonprescription medication such as acetaminophen (Tylenol), aspirin, or other nonsteroidal anti-inflammatory drugs (NSAIDs). There are a variety of NSAIDs (examples are Motrin, Advil, and Aleve). Some are available without a prescription. Patients can try different types to find the one that works best for them.
  • Moderate pain: Moderate pain is worse than mild pain. It interferes with function. The person may be unable to ignore the pain and it interferes with the activities of daily life, but it goes away after a while and doesn't come back after it has been treated. Moderate pain may need stronger medications than acetaminophen or nonprescription NSAIDs. Most NSAIDs, including ibuprofen (Motrin), have been found to be as effective at relieving pain as codeine. A health care professional can work with the patient to find the type of NSAID, either prescription or nonprescription, that works best for the patient.
  • Severe pain: Severe pain is defined as pain that interferes with some or all of the activities of daily living. The person may be confined to bed or chair rest because of the severity of the pain. Often, it doesn't go away, and treatment needs to be continuous for days, weeks, months, or years. For severe pain, the World Health Organization recommends strong opioids, such as morphine, oxycodone, hydrocodone, hydromorphone, methadone, or fentanyl, as well as other medications (called adjuvant therapies) as needed for the particular kind of pain. A number of adjuvant therapies are described in the previous section.
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Chronic Pain Management: Medications

Most medications have a maximum dose. Usually, the maximum dose is one that you cannot exceed without suffering harm to the patient. In the case of most pain medications, taking more than the maximum dose will not increase the pain relief but may cause toxic side effects such as stomach ulcers, kidney damage, liver damage, chemical imbalance in the bloodstream, or death.

Strong opioid medications are slightly different in this regard, and this is fortunate for people who suffer from severe pain. With strong opioids, the dose depends on the amount of pain. These medications should not mixed with acetaminophen or other non-opioid drugs when used to treat chronic pain. People with intense pain can take very high doses of opioids without experiencing side effects. Some people with intense pain receive such high doses that the same dose would be fatal if taken by someone who was not suffering from pain. In the pain patient, that same high dose can control the pain and still allow the person to be wide awake enough to do his or her activities of daily living.

Long-acting opioid: The best way to treat chronic, severe pain is by keeping it under control all the time. The doctor can do this by using a long-acting opioid to keep the pain under control and a short-acting opioid to deal with those few times during the day when the pain breaks through. So, if a patient is on morphine, he would receive a slow-release tablet that would keep the pain under control most of the time, and a short-acting tablet or liquid for those times when the pain breaks through.

Some opioids are not recommended for chronic pain.

  • Demerol (meperidine), which is used often for acute pain after surgery, is a poor drug for chronic pain. It is not absorbed well when taken by mouth, and it causes dysphoria (feeling truly lousy) and seizures if used for more than a few days.
  • Talwin (pentazocine) is also not appropriate for chronic pain, because it has a ceiling effect. There is a maximum dose, after which raising the dose gives no further pain relief. It also causes withdrawal symptoms when given to someone who is also taking another opioid.
  • The opioid/acetaminophen or opioid/NSAID combination drugs are acceptable for short-term use, but acetaminophen is poisonous to the kidneys and liver when used for a long time or in high doses. Many NSAIDs are toxic to the kidneys and stomach when taken for a long time or in high doses.

Complications of Opioids

Nausea and vomiting: These are common side effects at the beginning of opioid therapy. If they are a problem, they can be controlled with nonprescription medication for nausea such as meclizine (Bonine, Dramamine), or diphenhydramine (Benadryl), or, in some cases, by prescription medication such as prochlorperazine (Compazine) or haloperidol (Haldol). The nausea and vomiting usually stop within a few days, and then the antiemetic (antinausea and vomiting) medication can be stopped.

Dizziness: Dizziness and sleepiness are common when you take opioids. That is why it is recommended that patients not drive, drink alcohol, or operate machinery while taking opioids. People who have chronic pain often develop tolerance for this side effect of opioids, and often can do all the normal activities of daily living while on opioid therapy.

Constipation: Opioids always cause this problem, and constipation continues to be a problem for as long as the patient takes opioids. Constipation can become a serious problem if the patient does not keep it under control. The stool can become totally blocked off (fecal impaction) to the point at which manual disimpaction must be performed. Stool softening medications such as docusate can help prevent or relieve constipation.

Addiction: Hospice patients worry about becoming addicted to opioids. With hospice, however, it is rarely an issue. People with chronic pain also worry about addiction, but it turns out that for most adults, if they do not already have a substance (alcohol or drug) abuse problem, addiction is not much of an issue even when opioids are used on a long-term basis.

  • A study was done in which 12,000 nonaddicted people who needed opioids were followed up to see if they had become addicted. Four out of 12,000 showed addictive behavior (less than one tenth of 1%).
  • Generally, the only people who develop addictive behavior after being given opioids, had an addiction problem before the opioids were given for pain. Most people take opioids until the pain goes away. Then they stop taking them because they do not want to feel dizzy or drowsy. Once the pain goes away, the toxic side effects of dizziness and drowsiness come back.
  • Anyone who takes any medication just to "get high" is already showing addictive behavior and needs to stop taking addictive substances, including opioids, other addictive drugs, and alcohol, immediately.
  • Some people with actual painful illnesses are addicted to mind-altering substances. They get prescriptions because of their actual illnesses. Normally, the dose of opioids is arrived at by the patient telling the doctor how they are doing with the pain and by participating in their activities of daily living. A chronic pain patient who is not addicted to medication will tell the doctor the truth about his or her ability to function and do what needs to be done in daily life.
  • Addicts will lie about performing activities of daily living. The addict will claim that the pain is so severe that they need a higher dose until they get to a dose that causes them to sleep most of the time. Then, they will tell the doctor that they are doing fine and are able to do all the activities that they need to do.
  • Selling narcotic pain medicine to others is a federal crime.
  • Family members should discuss their concern with a health care professional if they suspect the patient may be addicted to pain medication. When an addicted person actually has a painful syndrome, the doctor, with the help of the family, may have to decide what the dose of medication should be, without reference to the dose the pain patient thinks would be best. Sometimes, in severely addicted people, the opioids should not be used at all. Some addicted people can be treated with opioids if necessary as long as they cooperate carefully with the treatment plan.

Respiratory depression: The most dangerous complication of opioid therapy is respiratory depression. A lot of people know that some drug addicts have been known to get pure heroin or fentanyl, and then die with the needle still in their arm because they fell asleep and didn't breathe. That happens because of a huge overdose in a patient who is not in pain. Pain is a potent stimulator of the respiratory center in the brain. So if a person has pain, and the doctor increases the dose of opioids carefully until the pain is controlled, and then stops raising the dosage, the patient will not get respiratory depression.

Fortunately for people with pain, large doses of opioids can safely be used if they are necessary to combat severe chronic pain.

Living With Chronic Pain

It is not always possible to completely get rid of chronic pain. The patient's goal may be simply becoming able to perform more normal activities of daily living than before.

  • The doctor may ask the patient to rate the pain on a scale from 1 to 10.
  • It is also helpful to report whether it is possible to go to work, go shopping, exercise, sleep, or have sexual intercourse.
  • Sometimes, the only measure of effectiveness of treatment is that a patient can do certain things that were not possible before the treatment started. This is what the doctor needs to know in order to make decisions about the patient's treatment.
  • If nothing else works for the patient's pain and the doctor is unwilling to use opioids to control the pain, consider asking for a referral to a pain specialist or a pain clinic.
Reviewed on 11/21/2017

Medically reviewed by Joseph Carcione, DO; American board of Psychiatry and Neurology

REFERENCES:

The American Chronic Pain Association.

World Health Organization. WHO's pain ladder.

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