The origin of the pain relates to ureteral distention.
A series of peristaltic waves along the ureter transport urine along the length of the ureter from the kidney to the bladder. As the ureteric stone obstructs the kidney, the ureter becomes distended, resulting in an exacerbation of the pain. The peristaltic waves are superimposed upon the distention, resulting in periods of exacerbation and periods of relief.
The pain is referred.
The visceral afferent (sensory) nerve fibers from the ureter pass into the spinal cord, entering the first and second lumbar segments of the spinal cord. Pain is thus referred to cutaneous regions innervated by somatic sensory nerves from the same spinal cord levels.
The patient was investigated by a CT scan.
Traditionally, a plain radiograph was used to look for the radiopaque stone (90% of renal stones are radiopaque) and this often proceeded to intravenous urography to determine precise location of renal stones. Currently, low-dose CT of the collecting system is used to visualize the renal stones and pinpoint the level of obstruction, using low radiation dose and no intravenous contrast.
An ultrasound scan may also be useful to assess for pelvicaliceal dilation and may reveal stones at the pelviureteral junction or the vesicoureteric junction. Ultrasound is also valuable for assessing other causes of obstruction (e.g., tumors at and around the ureteric orifices in the bladder) and is particularly useful in pregnant women when imaging with the use of radiation is a concern.
Usually an intravenous urogram would be carried out to enable assessment of the upper urinary tracts and precise location of the stone.
Not infrequently, CT scans of the abdomen are also obtained. These scans not only give information about the kidneys, ureters, and bladder but also show the position of the stone and other associated pathology.
If this patient’s infrascapular pain was on the right and predominantly within the right lower abdomen, appendicitis would also have to be excluded. A CT scan would enable differentiation of appendicitis and urinary colic.
A 27-year-old woman was admitted to the surgical ward with appendicitis. She underwent an appendectomy. It was noted at operation that the appendix had perforated and there was pus within the abdominal cavity. The appendix was removed and the stump tied. The abdomen was washed out with warm saline solution. The patient initially made an uneventful recovery, but by day 7 she had become unwell, with pain over her right shoulder and spiking temperatures.
This patient had developed an intraabdominal abscess.
Any operation on the bowel may involve peritoneal contamination with fecal contents and fecal flora. This may not be appreciated at the time of the operation.
Over the postoperative period an inflammatory reaction ensued and an abscess cavity developed, filling with pus. Typically, the observation chart revealed a “swinging” pyrexia (fever).
The most common sites for abscess to develop are the pelvis and the hepatorenal recess.
When a patient is in the supine position, the lowest points in the abdominal and pelvic cavities are the posterior superior aspect of the peritoneal cavity (the hepatorenal recess) and, in women, the recto-uterine pouch (pouch of Douglas).
The shoulder pain suggested that the abscess was in the hepatorenal recess and that the pain was referred from the diaphragm.
The motor and sensory innervation of the diaphragm is from nerves C3 to C5. The somatic pain sensation from the parietal peritoneum covering the undersurface of the diaphragm is carried into the spinal cord by the phrenic nerve (C3 to C5) and is interpreted by the brain as coming from skin over the shoulder—a region supplied by other somatic sensory nerves entering the same levels of the spinal cord as those from the diaphragm.
A chest radiograph demonstrated elevation of the right hemidiaphragm.