Pain

In some debates regarding physician-assisted suicide or euthanasia, pain has been used as an argument to permit people who are terminally ill to end their lives.

Euthanasia (from εὐθανασία; "good death": εὖ, eu; "well" or "good" + θάνατος, thanatos; "death") is the practice of intentionally ending a life to relieve pain and suffering.

Pain is usually transitory, lasting only until the noxious stimulus is removed or the underlying damage or pathology has healed, but some painful conditions, such as rheumatoid arthritis, peripheral neuropathy, cancer and idiopathic pain, may persist for years.

It typically results in warm, swollen, and painful joints.

Allodynia is pain experienced in response to a normally painless stimulus.

Allodynia refers to central pain sensitization (increased response of neurons) following normally non-painful, often repetitive, stimulation.

Local anesthetic injections into the nerves or sensitive areas of the stump may relieve pain for days, weeks, or sometimes permanently, despite the drug wearing off in a matter of hours; and small injections of hypertonic saline into the soft tissue between vertebrae produces local pain that radiates into the phantom limb for ten minutes or so and may be followed by hours, weeks or even longer of partial or total relief from phantom pain.

A local anesthetic (LA) is a medication that causes absence of pain sensation.

Pain is usually transitory, lasting only until the noxious stimulus is removed or the underlying damage or pathology has healed, but some painful conditions, such as rheumatoid arthritis, peripheral neuropathy, cancer and idiopathic pain, may persist for years.

Pain is classed as acute (short term) or chronic (long term).

Most pain resolves once the noxious stimulus is removed and the body has healed, but it may persist despite removal of the stimulus and apparent healing of the body.

It is a prerequisite for nociception, which itself is a prerequisite for nociceptive pain.

Phantom pain is pain felt in a part of the body that has been amputated, or from which the brain no longer receives signals.

Phantom limb pain is the feeling of pain in an absent limb or a portion of a limb.

Although unpleasantness is an essential part of the IASP definition of pain, it is possible to induce a state described as intense pain devoid of unpleasantness in some patients, with morphine injection or psychosurgery.

It can be taken for both acute pain and chronic pain.

Although unpleasantness is an essential part of the IASP definition of pain, it is possible to induce a state described as intense pain devoid of unpleasantness in some patients, with morphine injection or psychosurgery.

The word suffering is sometimes used in the narrow sense of physical pain, but more often it refers to mental pain, or more often yet it refers to pain in the broad sense, i.e. to any unpleasant feeling, emotion or sensation.

Management of breakthrough pain can entail intensive use of opioids, including fentanyl.

Opioids are effective for the treatment of acute pain (such as pain following surgery).

This is usually the result of acquired damage to the nerves, such as spinal cord injury, diabetes mellitus (diabetic neuropathy), or leprosy in countries where that disease is prevalent.

In humans, disease is often used more broadly to refer to any condition that causes pain, dysfunction, distress, social problems, or death to the person afflicted, or similar problems for those in contact with the person.

Although unpleasantness is an essential part of the IASP definition of pain, it is possible to induce a state described as intense pain devoid of unpleasantness in some patients, with morphine injection or psychosurgery. The International Association for the Study of Pain's widely used definition defines pain as "an unpleasant sensory and emotional experience associated with actual or potential tissue damage, or described in terms of such damage".

The International Association for the Study of Pain (IASP) is an international learned society promoting research, education, and policies for the understanding, prevention, and treatment of pain.

A much smaller number of people are insensitive to pain due to an inborn abnormality of the nervous system, known as "congenital insensitivity to pain".

Congenital insensitivity to pain (CIP), also known as congenital analgesia, is one or more rare conditions in which a person cannot feel (and has never felt) physical pain.

This is usually the result of acquired damage to the nerves, such as spinal cord injury, diabetes mellitus (diabetic neuropathy), or leprosy in countries where that disease is prevalent.

Relatively common conditions which may be associated with diabetic neuropathy include third, fourth, or sixth cranial nerve palsy ; mononeuropathy; mononeuropathy multiplex; diabetic amyotrophy; a painful polyneuropathy; autonomic neuropathy; and thoracoabdominal neuropathy.

Most people with congenital insensitivity to pain have one of five hereditary sensory and autonomic neuropathies (which includes familial dysautonomia and congenital insensitivity to pain with anhidrosis).

Familial dysautonomia (FD), is a disorder of the autonomic nervous system which affects the development and survival of sensory, sympathetic and some parasympathetic neurons in the autonomic and sensory nervous system resulting in variable symptoms, including insensitivity to pain, inability to produce tears, poor growth and labile blood pressure (episodic hypertension and postural hypotension).

Another 20th-century theory was gate control theory, introduced by Ronald Melzack and Patrick Wall in the 1965 Science article "Pain Mechanisms: A New Theory".

The gate control theory of pain asserts that non-painful input closes the nerve "gates" to painful input, which prevents pain sensation from traveling to the central nervous system.

Another 20th-century theory was gate control theory, introduced by Ronald Melzack and Patrick Wall in the 1965 Science article "Pain Mechanisms: A New Theory".

Patrick David "Pat" Wall (25 April 1925 – 8 August 2001) was a leading British neuroscientist described as 'the world's leading expert on pain' and best known for the gate control theory of pain.

Most people with congenital insensitivity to pain have one of five hereditary sensory and autonomic neuropathies (which includes familial dysautonomia and congenital insensitivity to pain with anhidrosis).

Congenital insensitivity to pain with anhidrosis (CIPA) is a rare autosomal recessive disorder of the nervous system which prevents the feeling of pain or temperature, and prevents a person from sweating.

Pain is usually transitory, lasting only until the noxious stimulus is removed or the underlying damage or pathology has healed, but some painful conditions, such as rheumatoid arthritis, peripheral neuropathy, cancer and idiopathic pain, may persist for years.

Symptoms depend on the nerves involved, but may include pain, paresthesia (pins-and-needles), paresis (weakness), hypoesthesia (numbness), anesthesia, paralysis, wasting, and disappearance of the reflexes.

Some sensory fibers do not differentiate between noxious and non-noxious stimuli, while others, nociceptors, respond only to noxious, high intensity stimuli.

Some intense stimuli trigger reflex withdrawal, certain autonomic responses, and pain.

The second order fibers then cross the cord via the anterior white commissure and ascend in the spinothalamic tract.

The lateral spinothalamic tract conveys pain and temperature.

A very rare syndrome with isolated congenital insensitivity to pain has been linked with mutations in the SCN9A gene, which codes for a sodium channel (Na v 1.7) necessary in conducting pain nerve stimuli.

The critical role of Na v 1.7 in nociception and pain was originally shown using Cre-Lox recombination tissue specific knockout mice.

The "pain tolerance threshold" is reached when the subject acts to stop the pain.

Pain tolerance is the maximum level of pain that a person is able to tolerate.

Infants do feel pain, but lack the language needed to report it, and so communicate distress by crying.

Pain in babies, and whether babies feel pain, has been a large

This is usually the result of acquired damage to the nerves, such as spinal cord injury, diabetes mellitus (diabetic neuropathy), or leprosy in countries where that disease is prevalent.

Another complication is pain, including nociceptive pain (indication of potential or actual tissue damage) and neuropathic pain, when nerves affected by damage convey erroneous pain signals in the absence of noxious stimuli.