What causes the pain associated with a stone in the ureter?
|A||Obstruction of urine flow with distention of the renal capsule|
|B||Irritation of the ureteral mucosa by the stone|
|C||Excessive ureteral peristalsis in response to the obstructing stone|
|D||Irritation of the intramural ureter|
a. It is mentioned in the manual that the pain is usually caused by acute distention of the renal capsule, usually from inflammation or obstruction.
b. The obstruction will lead to distension of the renal capsule (stretching) and cause the pain.
c. Pain of inflammation has a constant nature, whereas, pain due to obstruction fluctuates in intensity.
d. Colicky pain due to ureteric stone occurs because of hyperperistalsis in the proximal part of the ureter above the obstruction.
e. Afferents from the ureter travel in the segments T-11, 12 and L-1, 2.
f. Depending upon the level of obstruction, the pain may be referred to the loin (lumbar) region and shifts antero-inferiorly to groin (inguinal region) as the stone advances in the ureter.
g. This referred pain may also be felt in the anterior thigh or external genitalia along the distribution of genitofemoral nerve (L1 and 2).