Don't get numbed by all the names - useful revision of pain terminology
Anaesthesia:an induced state of temporary loss of sensation and/or awareness for surgery OR a complete loss of normal sensation to an affected body part.
Dysesthesia:an abnormal unpleasant sensation/feeling in a body part e.g. burning, acid under the skin, electric shocks, wetness. Can be spontaneous/un-evoked or evoked e.g. clothing touching skin
Hypoesthesia:an abnormal decreased sense of touch i.e. the feeling of numbness to the affected body area.
Hyperesthesia:an abnormal increased sense of touch to the affected body area.. A non-threatening/non-painful stimulus causes pain e.g. you get pain from a breeze. It includes both allodynia and hyperalgesia.
Paraesthesia: an abnormal non-painful skin sensation i.e. pins and needles, tingling, dead leg/arm, limb “falling asleep”
Hyperalgesia: A mildly threatening/painful stimulus produces high levels of pain/an exaggerated response e.g. insect bite or pin prick
Allodynia: a non-threatening/non-painful stimulus causes pain when applied to the affected body area. Occurs in central sensitisation.There are different types of allodynia:
Thermal allodynia – pain from normally mild skin temperatures (hot or cold)in the affected area
Movement allodynia - pain triggered by normal movement of joints or muscles
Mechanical allodynia aka tactile allodynia
Static mechanical allodynia – pain in response to light touch/pressure
Dynamic mechanical allodynia – pain in response to stroking lightly
Sensitisation: Increased sensitivity in a body area e.g. knee
The nerves (sensory) in the area of the affected body part (e.g. knee) change = peripheral sensitisation
The pathways in the brain change = central sensitisation
Peripheral sensitisation: increased sensitivity in the affected body part e.g. knee. There are sensory nerves around the knee. They pick up information related to stimuli (touch, pressure, temperature, texture, shape, vibration, stretch, threat/danger, chemicals). These sensory nerves respond more intensely to naturally occurring stimuli i.e. less is needed to make the nerves send a message to the spinal cord and brain. Additionally, the response from the low message is more intense/stronger/louder.
Central sensitisation: increased sensitivity in the brain.
The pathways in the brain continue to go off and send messages to the historically affected body part e.g. knee, independently of what is going on in the knee. Similar to a song on repeat, you continue to internally generate and hear the same tune over and over again, despite what song is actually being played on your phone/radio.
A threatening/painful stimulus causes explosive radiating delayed onset of pain when applied to an affect body region. wMay occur with allodynia, hyperalgesia, hyperesthesia, dysesthesia. Unable to local and identify the stimulus.