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Common Urological Problems

Urinary Stone Disease Evaluation

  • - General Urology - Common Urological Problems - Urinary Stone Disease
  • Jul 25, 2010
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Tags: | abdominal pain | acute abdomen | biliary stone | bowel obstruction |

D. PHYSICAL EXAMINATION
A detailed physical examination is an essential component of the evaluation of any patient suspected of having a urinary calculus. The patient presenting with acute renal colic typically is in severe pain, often attempting to find relief in multiple, frequently bizarre positions.

This fact helps differentiate patients with this condition from those with peritonitis, who are afraid to move. Systemic components of renal colic may be obvious, with tachycardia, sweating, and nausea often prominent. Costovertebral angle tenderness may be apparent. An abdominal mass may be palpable in patients with long-standing obstructive urinary calculi and severe hydronephrosis.

Fever, hypotension, and cutaneous vasodilation may be apparent in patients with urosepsis. In such instances there is an urgent need for decompression of the obstructed urinary tract,  massive intravenous fluid resuscitation,  and intravenous antibiotics.  Occasionally,  intensive-care support is needed.

Urinary Stone Disease

Urinary Stone Disease

A thorough abdominal examination should exclude other causes of abdominal pain.  Abdominal tumors, abdominal aortic aneurysms, herniated lumbar disks, and pregnancy may mimic renal colic.  Referred pain may be similar owing to common afferent neural pathways. Intestinal ileus may be associated with renal colic or other intraperitoneal or retroperitoneal processes.  Bladder palpation should be performed because urinary retention may present with pain similar to renal colic.  Incarcerated inguinal hernias, epididymitis, orchitis, and female pelvic pathologic states may mimic urinary stone disease. A rectal examination helps exclude other pathologic conditions.

E. RADIOLOGIC INVESTIGATIONS
1. Computed tomography-
Noncontrast   spiral   CT scans are now the imaging modality of choice in patients presenting with acute renal colic. It is rapid and is now less expensive than an intravenous pyelogram (IVP). It images other peritoneal and retroperitoneal structures and helps when the diagnosis is uncertain. It does not depend on an experienced radiologic technician to obtain appropriate oblique views when there is confusion with overlying bowel gas in a nonprepped abdomen. There is no need for intravenous contrast.  Distal ureteral calculi can be confused with phleboliths. These images do not give anatomic details as seen on an IVP (for example, a bifid collecting system) that may be important in planning intervention. If intravenous contrast material is used during the study,  a KUB film can give additional helpful information.  Uric acid stones are visualized no differently from calcium oxalate stones.  Matrix calculi have adequate amounts of calcium to be visualized easily by CT.

2. Intravenous pyelography-
An IVP can document simultaneously nephrolithiasis and upper-tract anatomy.

Extraosseous calcifications on radiographs may be erroneously assumed to be urinary tract calculi (Figure 16–14).

Oblique views easily differentiate gallstones from right renal calculi. Static hard-copy films can be interpreted by most clinicians.  Anecdotally,  small ureteral stones have passed spontaneously during such studies. An inadequate bowel preparation, associated ileus and swallowed air, and lack of available technicians may result in a less than ideal study when obtained during acute renal colic. A delayed, planned IVP may result in a superior study.

Acute forniceal rupture is not uncommonly associated with a highly obstructive ureteral calculus. It may result in dramatic radiographs but is of no clinical significance, and no intervention is required. The rupture may be precipitated by the osmotic diuresis of the intravenous contrast agent based solely on radiographs.

image Figure 16–14.  Scout abdominal radiograph demonstrating large extraosseous calcification that represents a uterine fibroid. This easily could be confused with a large bladder calculus.

Acute forniceal rupture is not uncommonly associated with a highly obstructive ureteral calculus. It may result in dramatic radiographs but is of no clinical significance, and no intervention is required. The rupture may be precipitated by the osmotic diuresis of the intravenous contrast agent based solely on radiographs.

3. Tomography-
Renal tomography is useful to identify calculi in the kidney when oblique views are not helpful. It visualizes the kidney in a coronal plane at a set distance from the top of the x-ray table.  This study may help identify poorly opacified calculi, especially when interfering abdominal gas or morbid obesity make KUB films suboptimal.

4. KUB films and directed ultrasonography-
A KUB film and renal ultrasound may be as effective as an IVP in establishing a diagnosis. The ultrasound examination should be directed by notation of suspicious areas seen on a KUB film; it is, however, operator-dependent. The distal ureter is easily visualized through the acoustic window of a full bladder. Edema and small calculi missed on an IVP can be appreciated with such studies.

5. Retrograde pyelography-
Retrograde pyelography occasionally is required to delineate upper-tract anatomy and localize small or radiolucent offending calculi.  Bulb ureterograms frequently leak contrast material back into the bladder, resulting in a suboptimal study. Advancing an angiographic exchange catheter with or without the aid of a guidewire 3–4 cm into the ureter is an alternative technique. Intermittent fluoroscopic images direct appropriate injection volumes and help reduce the likelihood of pyelolymphatic, pyelosinus, and pyelovenous reflux.

6. Magnetic resonance imaging-
MRI is a poor study to document urinary stone disease.

7. Nuclear scintigraphy-
Nuclear scintigraphic imaging of stones has recently been appreciated. Bisphosphonate markers can identify even small calculi that are difficult to appreciate on a conventional KUB film (Figure 16–15).

image Figure 16–15.  A: Scout abdominal radiograph demonstrating large left staghorn renal calculus. B: Nuclear scintigraphic evaluation of renal calculi. Posterior view demonstrating uptake on large left staghorn calculus after furosemide (Lasix) diuresis. Note right kidney with uptake in lower pole. C: Follow-up tomogram confirms calculus (arrow) in right lower pole missed on initial radiograph.

Differential radioactive uptake dependent on stone composition appreciated during in vitro studies cannot be appreciated on in vivo studies. Nuclear scintigraphy cannot delineate upper-tract anatomy in sufficient detail to help direct a therapeutic plan.


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Marshall L. Stoller, MD

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REFERENCES

  1. Ackermann D et al: Influence of calcium content in mineral water on chemistry and crystallization conditions in urine of calcium stone formers. Eur Urol 1988;14:305.
  2. Allie-Hamdulay S et al: Prophylactic and therapeutic properties of a sodium citrate preparation in the management of calcium oxalate urolithiasis:  Randomized,  placebo-controlled trial.  Urol Res 2005;33:116.
  3. Bilezikian JP et al:  Primary hyperparathyroidism:  New concepts in clinical,  densitometric and biochemical features.  J Intern Med 2005;257:6.
  4. Fellstrom B et al: Dietary habits in renal stone patients compared with healthy subjects. Br J Urol 1989;63:575.
  5. Gentle DL et al: Geriatric nephrolithiasis. J Urol 1997;158:2221.
  6. Heller HJ et al: Effect of dietary calcium on stone forming propensity. J Urol 2003;169:470.
  7. Langley SE, Fry CH: The influence of pH on urinary ionized [Ca2+]:

Full References  »

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