Colic is a form of pain, characterised by intense episodes that start and stop abruptly. It occurs when a muscular tube contracts against an obstruction from within the lumen.
The frequency of the fluctuations in pain can help us determine the anatomical location of the obstruction.
- Renal: The smooth-muscle layer in the distal one third of the ureters contracts at a frequency of 3 per minute.
- Thus, renal colic is characterised by extreme loin pain with frequent fluctuations in intensity.
- Biliary: Neither the cystic duct nor the common bile duct has peristaltic motility however, the post-prandial gall bladder will contract at a frequency of 3 per hour.
- Thus, biliary colic is characterised by intense, spasmodic pain every 10-20 minutes until a steady state of dull, aching pain in the upper right quadrant after approximately one hour.
- Gastrointestinal: Perstalsis in the gut varies along its length (stomach 3/min, duodenum 12/min, ileum 9/min) but contractions last a few minutes per 10-20cm segment.
- Thus, bowel colic tends to be cramping in nature and lasts 2-3 minutes. This is a true colic as there is no pain between episodes.