Kidney stones- renal calculi- urinary stones

Renal stones or Kidney stones:
(This article is meant for both the layperson and those new to the science and art of sonography).
Most urinary stones or calculi as they are called in medical parlance, originate in the kidneys. Some are also known to form in the urinary bladder due to stasis of urine or collection of urine within the urinary bladder. Kidney stones in the urinary system pass from the kidney (renal calculi) to the ureter and thence, down to the urinary bladder.
One of the simplest and most inexpensive methods of diagnosing renal stones (kidney stones) is ultrasound imaging.
The symptoms of kidney stone include- passage of blood in the urine, or hematuria or pain in the side of the abdomen, along the flanks. Pain is usually the first symptom and may be the only sign of kidney stone. However, I have come across many patients who have absolutely no symptoms at all and kidney stone disease may be found only incidentally during an ultrasound scan. With phosphate stones in the kidney, the stone or kidney calculus may actually reach a very large size over a period of time (many years) and yet the patient may be unaware of the disease.
  Here are some ultrasound images of kidney stones:

Case 1: Left kidney stone- in the renal pelvis:

The urinary bladder in this lady appears normal as are the uterus and adenxae (ovaries).

The above ultrasound images show a large stone in the left kidney. The right kidney appears normal. The renal stone/ calculus is within the central part of the kidney called the renal pelvis, within which the urine from the kidney enters or collects. From here the urine passes to the ureter or muscular tube from the renal pelvis to the urinary bladder. The kidney stone here measures 1.8 cms., and has not produced any significant obstruction to the passage of urine to the left ureter below- this despite the large size of the left renal calculus. We can say this because there is no hydronephrosis of the left kidney. We shall discuss this term in detail below:

Case-2: Kidney stone causing moderate hydronephrosis of the left kidney

This patient shows a typical kidney stone location called PUJ calculus or stone located at the pelvi-ureteric junction, in the left kidney. The PUJ or UPJ is the junction between the renal pelvis and the ureter and is pretty narrow. The large kidney stone (shown above) is unable to pass down into the left ureter, and has become stuck at the narrow junction causing partial flow of urine downwards through this bottle-neck.

This has resulted in back pressure due to collection of urine within the collecting system of the left kidney causing the left kidney to "balloon up". This condition is called hydronephrosis and we can see this change in the obstructed left kidney above. If not treated quickly (meaning within a few months), this kidney could pass to a stage of severe hydronephrosis and ultimately become non functional or result in what is called renal failure.
Case-3: Hydronephrosis due to left PUJ calculus:

This is yet another case of left PUJ/ UPJ calculus with a relatively small kidney stone stuck at the narrow left uretero-pelvic junction with resulting left kidney swelling or hydronephrosis.(Note :-) kidney stones shown here are from 3 different patients and there is no evidence that the left kidney has a greater chance of being affected by stone disease).

The above ultrasound video clip shows the left PUJ stone in a better perspective with the resultant left hydronephrosis.
From the above ultrasound case studies of kidney stones, it is obvious that small stones can produce more trouble for the patient if located in a critical location, and that the size of the kidney stone alone is not the only factor that causes symptoms and clinical complaints and complications.
In case 1 above despite the large size of the kidney stone, its location above the narrow bottle neck called the pelvi-ureteric junction, has resulted in absence of any hydroneprhosis in the affected left kidney.
In cases 2 and 3, there is significant ballooning of the kidney as a result of the kidney stone being located at the PUJ (the bottle neck). In case -3 the kidney stone is less than half the size of the stone seen in case-1.

Case-4: Right mid ureteric calculus with right hydronephrosis:

This patient shows  moderately severe hydronephrosis of the right kidney. This is seen as collection of urine (dark space within the right kidney- image on left side). However there is no stone visualized in this ultrasound image. The left kidney appears normal (image on right half of the picture above).

We tried to trace the dilated (distended) right ureter (called hydroureter) downwards and this is what we found. There is a stone (ureteric calculus) in middle third of the right ureter, and it is pretty large (at 1.7 cms.). Tracing stones in the ureter can be a very cumbersome task and much of this depends on displacing gas distended bowel away from the front of the ureter. This is done by gently pressure with the ultrasound probe. This ureteral stone originated in the right kidney and has managed to pass down the right renal pelvis and right PUJ down to the middle of the ureter. This patient has experienced severe pain (called ureteric colic) as the stone irritates the soft muscle of the ureter. The next task for the stone is to negotiate the next major bottle neck in its passage downwards- the right VUJ (vesico-ureteric junction). This is the narrowest point in the urinary tract and is the point of entry of the ureter into the urinary bladder. We shall next see what happens when a stone gets impacted at the VUJ (vesico-ureteric junction).

Have a look at the ultrasound video clip of this case:

Case-5: Right vesico-ureteric Junction calculus:
The next destination that the kidney stone has to reach on its way out in the urinary system is the urinary bladder. But unfortunately for the patient, things are not so easy, and the narrow bottle-neck called the vesico-ureteric junction (VUJ) being the narrowest point in the urinary tract, most stones lodge here for some time before being expelled into the urinary bladder.
This is one such case-

This young adult male shows a small stone impacted in the right VUJ (ultrasound image of urinary bladder above). At 5 mm. size this urinary stone has transited successfully all the way from the right kidney, down the right ureter, and has almost made it to the bladder! But it has not quite made it. The stone is stuck in this narrow point, despite its small size. What is its effect on the right kidney? See the ultrasound image below:

 

Even a stone as small as 5 mm. is able to wreak havoc on the right kidney, which shows moderate hydronephrosis with right hydroureter. The left kidney appears relatively normal in this ultrasound image of the kidneys.

Case-6: Left VUJ calculus:

 

This is another patient with severe left flank pain. The ultrasound image of the urinary bladder above shows a suspicious looking areas in the left VUJ (vesico-ureteric junction). Most probably this is a stone in the left VUJ.

 

When in doubt, I switch on the color Doppler ultrasound button, and the result was a little twinkling (the blue color- arrow)  around the left VUJ. This is a clear sign of a stone here.

When we examined the left kidney, this is what we saw (ultrasound image of left kidney- below):

There is clear evidence of left hydronephrosis in this image above. The final diagnosis was- left VUJ calculus with resultant left hydronephrosis.

Final destination- the Urinary bladder:
Case-7: bladder sediments and debris:

 

What this image shows is transrectal ultrasound imaging (TRUS) study of the prostate (the triangular soft tissue structure in upper part of image). But what is even more striking is the particulate matter within the urinary bladder below (this is an upside down ultrasound image of the bladder). This is common finding in elderly male patients with urinary tract infection- the debris (particles) within the bladder being a sign of that.

Have a look at the TRUS ultrasound video clip of this patient:

The motion of the particles within the urinary bladder can be fully appreciated in this ultrasound video clip. particulate matter of this type can often result in colloid gel like matter forming the nidus (precursor) for stone formation in the urinary bladder. Thus elderly male patients with chronic difficulty in urination can sometimes develop urinary bladder stones. See: http://www.ultrasound-images.com/urinary-bladder/#Large%20urinary%20bladder%20calculus

Case-8: Urinary bladder stones:
As said earlier there are various causes for the formation of bladder stones. Chronic obstructive conditions in the lower urinary tract such as patients with benign prostatic hypertrophy can often develop urinary bladder stones.
These ultrasound images are of an elderly male with benign prostatic enlargement. There is a stone of 1.5 cms. seen in the urinary bladder in both transabdominal and transrectal ultrasound images (see below).

Transabdominal ultrasound image of stone in urinary bladder (arrow). Also seen is a Foley catheter bulb within the bladder.

Transrectal ultrasound image showing urinary bladder stone (above)....arrow.
Shown below is the TRUS ultrasound video clip of the bladder stone: