Goubaa Mohamed MD Djerba Tunisia

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This 18-year-old male presented with colicky left flank pain. A ureteral stone and hydronephrosis were found, and a ureteral stent was placed. abdominal and endorectal Ultrasound was performed to evaluate the position of the stone and the degree of hydronephrosis. (scans and video). Ce Patient âgé de 18 ans s'est présenté pour une colique néphrétique gauche. Une dilatation pyelo-calicielle et urétérale ont été retrouvé et la lithiase a été identifié. L'échographie abdominale et endorectale comme ici est performante pour la localisation de la lithiase et pour évaluer l'hydronéphrose (cliché et video).


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Video (div x) 534 K (large format)
Video 88 K
Ureteral stones with partial ureteral obstruction and twinkle artifact Lithiase du méat urétéral avec obstruction partielle et artefact de clignotement


Ureteropelvic junction calculi

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The renal collecting system forms part of the echogenic central echo complex and is frequently not identifiable as a separate structure. Slight collecting system dilatation is a common normal finding during a diuresis or when the bladder is quite full. In these cases the dilatation resolves when the bladder is emptied. Hydronephrosis is simply a dilatation of the renal collecting system. Hydronephrosis is seen as anechoic fluid in the renal collecting system and pelvis separating the central sinus echoes. Dilated calyces lose their sharp angular margins and become blunted. When the hydronephrosis is marked, the entire collecting system is outlined as a series of connecter fluid-filled channels.
Calculi, or stones, can form anywhere within the urinary tract. Most stones original within the kidney (nephrolithiasis).

Clinical :
The clinical presentation varies depending on the size or location of the stone or whether the stone is being passed. Calculi located in the kidney or proximal portion of the ureter may cause either no pain or dull flank pain, whereas lower back pain radiating down the pelvis may be caused by a stone in the distal ureter or bladder. Severe, sharp pain (renal colic) is usually caused by the passage of a stone down the urinary tract. Other clinical symptoms may include nausea, vomiting, fever, chills, and, depending on the presence of obstruction, oliguria. The laboratory findings may consist of hematuria, white blood cells, and bacteria.
A staghorn calculus is a stone that fills the renal pelvis and extends into the infundibulum and calyces, causing dilation of the calyces. Stones can cause obstruction of the renal collecting System, or they may pass into the ureter and obstruct it, causing a hydroureter. The three most common sites of obstruction are the ureteropelvic junction (UPJ), the point at which the ureter crosses over the pelvic brim, or the location at which the ureter enters into the urinary bladder. Stones may also pass into the urinary bladder or, in rare cases, obstruct the urethra.

Sonography :
The ultrasound diagnosis of urinary calculi is based on the demonstration of a highly echogenic focus that produces an acoustic shadow. Relatively small stones can be detected, especially if there is hydronephrosis. The surrounding fluid media "urine" helps in their visualization. The presence of posterior acoustic shadowing varies according to the size and composition of the stone. Very small stones may not have posterior acoustic shadowing. Patients with urinary tract calculi may have a color Doppler artifact. The artifact is called a "twinkle artifact", which is imaged as a rapidly changing color posterior to the stone with a cornet tail (scan 7).
A calculus in the kidney may cause obstructive hydronephrosis. Stones that pass into the ureter may obstruct it. Absence of a unilateral ureteral jet may occur with complete ureteral obstruction. A partial ureteral obstruction may cause absence of a ureteral jet or decreased blood flow, which has a pattern that resembles a burning candle (candle sign) (scan 8). Sonographic documentation of a ureteral stone is difficult to obtain because of the small size of the calculi, posterior location of the ureter, lack of fluid surrounding the stone, and adjacent bowel gas.
Bladder stones appear as high intensity echoes within the bladder, have an associated acoustic shadow. The color Doppler examination is of minor importance in the evaluation of patients with stone disease. The stone need not be calcified to be detected by ultrasound. Unless embedded in the bladder wall, the calculi shift to the dependent portion of the bladder with change in patient position.

Differential :
The stones can be extremely difficult to identify when there is no hydronephrosis. There are other normal structures in the renal pelvis that may cause a focal area of bright echogenicity although they will not cause distal sonic shadowing. This includes focal areas of hyperechoic renal hilar fat and blood vessels. Ultrasound evaluation for renal stones can be extremely helpful in patients with an unexplained filling defect on an intravenous urogram. The differential diagnosis of non-calcified stone, tumor, and blood clot can be difficult radiographically. A non-calcified stone, such as a uric acid stone, will still cause a bright echo reflection and distal sonic shadowing. Blood clots and epithelial tumors, on the other hand, will be less hyperechoic and will not cause distal sonic shadowing.