A multitude of changes in the peripheral nervous system, spinal cord, brainstem, and brain may contribute to abnormal pain processing. Hyperalgesia is a condition where a person develops an increased sensitivity to pain. The word hyperalgesia means an increased response to a painful stimulus. Allodynia definition, causes, diagnosis, treatment. When a person becomes more sensitive to pain as a result of. Allodynia definition is pain resulting from a stimulus such as a light touch of the skin which would not normally provoke pain. Multimodal pharmacologic and nonpharmacologic interventions were used to reduce pain and allodynia, and complementary analgesic therapies, such as ea and anticonvulsants, were needed to reduce pain, allodynia and hyperalgesia in a cat with neuropathic pain after major trauma and postherniorrhaphy. In allodynia, the stimulus mode and the response mode differ, unlike the situation with hyperalgesia.
The application of heatinactivated hsv1 induced no allodynia, hyperalgesia and skin lesion. Mechanical allodynia other pain is a painful sensation caused by innocuous stimuli like light touch. If you want to understand allodynia and fibromyalgia, t ry to imagine a world where the gentle touch of a loved ones hand causes excruciating pain. The condition is characterized by a paradoxical response whereby a patient receiving opioids for the treatment of pain could actually become more sensitive to certain painful stimuli. Allodynia and hyperalgesia are classified according to the. Hyperalgesia and allodynia are frequent symptoms of disease and may be useful adaptations to protect vulnerable tissues. Opioidinduced hyperalgesia oih is defined as a state of nociceptive sensitization caused by exposure to opioids. Models and mechanisms of hyperalgesia and allodynia citeseerx.
Allodynia is when pain is experienced despite there being no obvious cause for pain. Opioid induced hyperalgesiaexploring myth and reality duration. Pdf the aim of this book is to present a variety of 1 a general view to the phenomena of allodynia and hyperalgesia in pain sensation. Most pain can be classified according to its three components.
Opioidinduced hyperalgesia oih and allodynia oia are abnormal pain states that result. Considerable progress has been made in developing clinically relevant animal models for identifying the most significant underlying mechanisms. Unlike inflammatory hyperalgesia that has a protective role, allodynia has no obvious. Subscribe to americas largest dictionary and get thousands more definitions and advanced searchad free. The main difference between allodynia and hyperalgesia condition is the nature of initial stimulant. Jul 05, 2008 two of the most commonly used terms in the pain research and medicine world are hyperalgesia and allodynia. In this world, putting on a tshirt, dropping an ice cube on your arm, or a friendly tickle can lead to discomfort or extreme pain. Aug 23, 2017 hyperalgesia is an enhanced pain response.
Allodynia article about allodynia by the free dictionary. Allodynia and hyperalgesia are concomitant features of burn injury in humans and is seen both at the site of burn and at areas in close proximity to the injury. Cold hyperalgesia is present in the spared nerve injury model animals, manifesting as a reduced latency of withdrawal response threshold at temperatures that elicit cold pain in naive rats. It is thought to be related to a range of nerve conditions and does not relate to an oversensitivity to pain.
Both may, however, also emerge as diseases in their own right. Mar 27, 2017 allodynia is an unusual symptom that can result from several nerverelated conditions. Allodynia is a condition where pain is caused by a stimulus that does not normally elicit pain. Hyperalgesia and allodynia are frequent symptoms of disease and may be. Scalp and muscle tenderness have been recognized in migraine, and 6080% of migraine patients have cutaneous allodynia during an acute attack 8. Hyperalgesia definition of hyperalgesia by the free dictionary. Induction and expression of hyperalgesia and allodynia are context sensitive. Tactile allodynia and formalin hyperalgesia in streptozotoci.
Allodynia definition of allodynia by the free dictionary. Lastly, with a proper schematic diagram, i will try to conclude the video. Alfentanil, but not amitriptyline, reduces pain, hyperalgesia. His pains began in 1981 with a motor vehicle accident. It is particularly noticeable in conditions in which visceral pain occurs intermittently e. Thermal and mechanical hyperalgesia the journal of pain. Hyperalgesia and allodynia are frequent symptoms of disease and may be useful adaptations to. In this video, i will go through what is meant by hyperalgesia and allodynia and their key difference. The peripheral, spinal, and supraspinal elements that are essential for hyperalgesia and allodynia are listed in section v. Neuronal and nonneuronal cell populations have been identified that are indispensable for the induction andor the expression of hyperalgesia and allodynia as summarized in section v. Methods to assess hyperalgesia or allodynia 711 iii. Hyperalgesia medical definition merriamwebster medical. Multimodal analgesia for treatment of allodynia and.
What may not hurt most people can cause significant pain in an individual with hyperalgesia. Allodynia and hyperalgesia are common and bothersome symptoms in patients with pain due to a disease or injury of the nervous system. A more sustained noxious stimulus may result in more diffuse pain and generation of increased pain perception from a painful stimulus hyperalgesia and pain from a stimulus previously perceived as innocuous allodynia. When youre experiencing it, you feel pain from stimuli that dont normally cause pain. Cannabinoid receptor type 1 antagonist, am251, attenuates. Models and mechanisms of hyperalgesia and allodynia. For example, bad sunburn can cause temporary allodynia, and touching sunburned skin, or running cold or warm water over sunburned skin can be very painful. Cutaneous allodynia is the perception of pain when a nonnoxious stimulus is applied to normal skin 7. Hyperalgesia is increased pain from a stimulus that normally. The peripheral mechanism of hyperalgesia is considered to be the result of nociceptor.
Opole, md, phd, is a boardcertified internist and a current teaching professor of medicine at the university of kansas. In1985 he broke an ankle and in 2000 he developed chronic inflammatory demyelinating polyneuropathy. The withdrawal threshold for cold allodynia is 15c in both the spared nerve injury and spinal nerve ligation models of neuropathic pain. Ref models and mechanisms of hyperalgesia and allodynia. General conditions that influence induction of hyperalgesia or allodynia. Models and mechanisms of hyperalgesia and allodynia ju. In addition, what appears to be opioid tolerance can be caused by opioidinduced hyperalgesia lowering the baseline pain level, thus masking the drugs analgesic effects. Hyperalgesia of a somatic area that is referred from diseased or inflamed viscera is a common clinical observation. With other cutaneous modalities, hyperesthesia is the term which corresponds to hyperalgesia, and as with hyperalgesia, the quality is not altered. Spontaneous pain hyperalgesia and allodynia disproportionate to the inciting event complex regional pain syndrometype i. Allodynia is different from hyperalgesia, which is an exaggerated response.
This pain type is frequently associated with fibromyalgia, 1. Allodynia and hyperalgesia became apparent in the hind paw on the inoculated side on day 5 and persisted until at least day 8. Pdf nociceptive signals are generated by peripheral sensory organs called nociceptors, which are endings of smalldiameter nerve fibers. Adrienne dellwo is an experienced journalist who was diagnosed with fibromyalgia and has written extensively on the topic. Reorganization of sensory processing in cortical areas may also be longlasting 8, 518, 519, 532. Other conditions associated with allodynia include neuropathy, postherpetic neuralgia shingles. Allodynia pain due to a stimulus that does not usually provoke pain and hyperalgesia increased pain from a stimulus that usually provokes pain are prominent symptoms in patients with neuropathic pain. Allodynia is a rare type of pain, generally on the skin, thats caused by something that wouldnt normally cause pain. Opioid induced hyperalgesia oih is a phenomenon observed in the patients treated with opioids, demonstrating an increased sensitivity to painful stimulus velayudhan et al. Pdf models and mechanisms of hyperalgesia and allodynia. John not his real name is a 51yearold chronic pain patient that i have been seeing since 2003. Opioid induced hyperalgesia exploring myth and reality duration. Allodynia and hyperalgesia induced by herpes simplex virus t. In my quest for knowledge i stubbled upon this free article on hyperesthesia and allodynia.
Whereas in allodynia, a nonpainful stimulant such as rubbing your arm with a cotton bud will cause you to experience the painful condition. Detection of cold pain, cold allodynia and cold hyperalgesia. Hler center for brain research, medical university of vienna, vienna, austria i. Allodynia definition at, a free online dictionary with pronunciation, synonyms and translation. Hsv1 dna was detected in the dorsal root ganglia from days 2 to 8 postinoculation, with a peak effect on day 5.
Tactile allodynia and hyperalgesia heiferly i have a disease called postural orthostatic tachycardia syndrome pots, a type of dysfunction of the autonomic nervous system, which can go handinhand with fibromyalgia symptoms. Allodynia and fibromyalgia types, treatments and my experience. Tactile allodynia and hyperalgesia pain management medhelp. Acute noxious stimuli result in welllocalized pain. Allodynia is pain due to a stimulus that does not normally elicit pain. In opioidinduced hyperalgesia, sensitization of pronociceptive mechanisms occurs, resulting in a decrease in the pain threshold, or allodynia. Both are seen in various peripheral neuropathies and central pain disorders, and affect 1550% of patients with neuropathic pain. To access free multiple choice questions on this topic, click here. Allodynia is also not hyperalgesia, which is a pain stimulus more painful than usual. Allodynia is a sensory phenomenon in which a normally nonnoxious stimulus is perceived as painful, and hyperalgesia refers to an increase response to a noxious stimuli.