SA Medical - General Medicine And Imaging of Disease

Pain Sensation: fast and Slow Pain Classification Fast Pain Slow Pain All pain receptors are free nerve endings Three types of Stimuli Pain receptors are activated by mechanical, thermal and chemical stimuli Mechanical and thermal stimuli - fast pain Chemical stimuli - slow pain No adaptation, progressively greater as the pain stimulus  continues, this is called hyperalgesia Two separate pathways of Pain transmission A-delta fibers fast - 6 to 30m/s - Mechanical and thermal stimuli C-Fibers slow - 0.5 to 2m/s  neospinothalamic tract - A-delta fibers paleospinothalamic tract - C-fibers The neospinothalamic tract is used in pain localisation Activity in the paleospinothalamic system may impart unpleasant perception of pain. paleospinothalamic pathway Brain and Spinal Cord: Internal Pain Suppression system The periaqueductal gray  the periadueductal gray of the midbrain and the rostral pons receives input from the ascending pain pathways in addition to...

This can present suddenly as severe pain in the flank reaching a peak within minutes or hours ( acute loin pain ).  Alternatively, it may have a slower course of onset (chronic loin pain), developing over weeks or months.  Loin pain is frequently presumed to be urological in origin on the simplistic basis that the kidneys are located in the loins. However, other organs are located in this region, pathology within which may be the source of the pain, and pain arising from extra-abdominal organs may radiate to the loins (referred pain). So, when faced with a patient with loin pain think laterally the list of differential diagnoses is long! The speed of onset of loin pain gives some, though not an absolute, indication of the cause of urological loin pain. Acute loin pain is more likely to be due to something obstructing the ureter, such as a stone. Loin pain of more chronic onset suggests disease within the kidney or renal pelvis. Acute loin pain The most common ca...