Loin (flank) pain
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...