Urinary Tract Metabolic Disease - Module 4

Stones in the urinary system (general term referring to a stone anywhere in the renal system)

Define urolithiasis

Stones in the renal collecting system

Define nephrolithiasis

Calyces, pelvis, ureter, or bladder

Where would a stone be located in the case of nephrolithiasis

Calcifications in the renal parenchyma

Define nephrocalcinosis

Cortex or medulla of the kidney

Where would the stone be located in the case of nephrocalcinosis

Very common

Is nephrolithiasis common or rare

Age

An increased incidence of nephrolithiasis has been seen with:

Caucasian males

What type of patients more commonly are affected by nephrolithiasis

Don't really know why they form but there are certain things that can increase your risk

Do we know the etiology of nephrolithiasis

Hereditary, limited water intake (chronic dehydration), diets high in animal protein, urinary stasis

What are some risk factors for nephrolithiasis

12%

What % of the population will have urinary stones at some point in their lifetime

True

T/F: stones can move through the collecting system

UPJ, at iliac vessels, UVJ

What are the 3 location of natural narrowing in the

Uretopelvic junction, located where the ureter attaches to the kidney pelvis

What does UPJ stand for and where is it located

When the ureters cross over the iliac vessels they are narrowed a little bit

Why does the ureter narrow at the iliac vessels

Ureterovesicular junctions, is where the ureter connects to the bladder

What does the UVJ stand for and where is it located

UVJ

Where is the most narrowest portion of the ureter

80%

What % of stones get stuck at the UVJ

<5mm

What size of stones typically are able to be passed unassisted

80%

What % of stones <8mm can be pass without assistance

>5mm

What size of stones more commonly require intervention to be passed/get ride of

UPJ

What is 1

Ureters crossing over the iliac vessels

What is 2

UVJ

What is 3

Often asymptomatic

What is the usually presentation of nephrolithiasis

Hematuria and flank pain

What are some other symptoms of nephronlithiasis

If the stone is just sitting in the calyces and not moving will probably not cause much problems but once it starts going down the ureter and get stuck is when it usually causes pain

Describe the the location of a kidney stone may affect the symptoms

Microscopic or gross/frank

What are the 2 types of hematuria that may be seen with nephrolithiasis

Visualized in urine (the urine is visually red/brown)

What does gross or frank hematuria mean

Only can see the blood under the microscope (wont be able visually see a colour change)

What is microscopic hematuria

Echogenic focus or foci with posterior shadowing

Describe the sonographic appearance of nephrolithiasis

Nephrolithiasis

What does this image show

Nephrolithiasis

What does this image show

Number, size, location, and complications

What are the 4 main pieces of info that you should try to answer when you find nephrolithiasis

To determine if the stone can pass or if the patient will need intervention

Why is it important to determine the size of the stone

Assess where the urine is backed up, it will back up proximally to the level of the stone

How can you determine the location of the stone if the stone is not well visualized

Hydronephrosis or small/absent urine jet in the bladder

What are some supporting findings/complications of nephrolithiasis

Twinkle artifact

What is an artifact that a stone may produce

When a stone is located in the sinus region, it is hard to determine if it is a stone bc it will blend into the hyperechoic sinus. You can use colour or power Doppler to look for a twinkly artifact a stone will give off

Explain how you can use the twinkling artifact to your advantage when suspicious of a stone in the sinus region

Stone difficult to identify in the sinus region

What does this image show

Stone now identified with the twinkle artifact

What does this image show

Colour reverberation

What is the twinkling artifact

Colour or power Doppler

What mode do you have to use in order to be able to see the twinkling artifact

Staghorn calculi

What does this image show

Calcifications filling all or most of the renal collection system/calyces

What is staghorn calculi

Staghorn calculi

What does this image show

X-ray of staghorn calculi

What does this image show

Twinkle artifact from staghorn calculi

What does this image show

Staghorn calculi

What does this image show

Intrarenal gas, renal artery calcifications, calcified sloughed papilla, calcified tumours, ureteric stent

What are some false positives for nephrolithiasis (things we may mistake for a stone in the collecting system)

Bacteria in the collecting system may be gas production and appear as an echogenic focus with dirty shadowing

Explain how intrarenal gas can be mistaken for stones in the renal collecting system and what causes it to

Small vessels of our renal arteries can calcify as we age, and may look echogenic and mimic a stone (i dont think it would really have shadowing tho)

Describe when renal artery calcifications occur and how the can be mistaken for nephrolithiasis

Apex of the pyramids

Papilla=

In some disease processes, the pyramids becomes calcified and sloughed off. Since they are calcified they will look like echogenic foci

What is calcified slough papilla and how can they mimic nephrolithiasis

When someone has a stone in their ureter, the ureter can become very inflammed. This can cause the wall of the ureter to stick together and even scar togethe. They will often put a stent in to keep the ureter wall away from each other while they are healing

Describe when a ureteric stent would be used

The stent may be bright and shadow so can mimic a stone

Why may a ureteric stent be confused for nephrolithiasis

Try to follow the dilated tube (ureter) until you find an echogenic focus or the end of the dilation

What is a tip to help you determine the location of a stone in the ureter

Very hard to follow the ureters at all their length bc of bowel gas

Why is it sometimes hard to identify the location of a stone in the ureter

Posterior aspect at the trigone of bladder

Where do the ureters connect into the bladder

Want to determine if the stone is completely or just partially obstructing an ureter

Why do you ALWAYS want to asses a urine jet when you find a stone in the ureter

Urethral jet

What does this image show

One

How many bladder calculi does a patient usually have

Asymptomatic

What is the usually symptoms of bladder calculi

Hematuria and pain

What are some over possible s/s of bladder calculi

Stone formed in the kidney and went down the ureter into the bladder OR a stone that formed in the bladder itself (due to urinary stasis)

What are the 2 possible causes of bladder calculi

Mobility

What feature of a bladder calculi do you need to confirm

Bc if it doesn't move it may be more concerning for a calcified mass

Why should you try as hard as you can to get the bladder calculi to move

Depending portion of the bladder (gravity dependent)

Where would a bladder calculi be located

Dilation of the renal collection system

What is hydronephrosis

True

T/F: hydronephrosis may be asymptomatic and an incidental finding

Obstructive and non obstructive

What are the two types/causes of hydronephrosis

Renal atrophy

What can hydronephrosis lead to eventually if it is left untreated for a long amount of time

Intrinsic or extrinsic obstruction of urine flow

Define obstructive hydro

Something obstructing urine physically in the collecting system

What would intrinsic obstructive hydro be

Something of the outside of the collecting system putting pressure on the system

What would extrinsic obstructive hydro be

Masses, enlarged lymph nodes, etc

What are some examples of extrinsic obstructive causes of hydro

Ureteral jets (is it fully or partially obstructive?)

What else should you assess if you identify obstructive hydro

The treatment/how fast we need to treat the patient (if fully obstructive may be more emergent)

Why do you need to determine if an obstruction in the collecting system is fully obstructive

Reflux, infection, polyuria

What are some examples of non obstructive causes of hydro

Pt is producing excessive amounts of urine

What is polyuria

DM can cause this, the patient will produce so much urine so quikcly that they can't empty it out fast enough and it will back up into the kidneys (therefore causing hydronephrosis)

Explain an example of polyuria leading to hydronephrosis

Grade 1/mild, grade 2/moderate, grade 3/severe

What are the 3 classifications of hydro

Sonographic appearance

How is the severe of hydronephrosis classified

Slight separation (splaying) of sinus echoes (just in the mid sinus region)

Describe the appearance of grade 1 hydro

2mm

The sinus echoes must be separated at least ______ to be considered grade 1 hydro

Pt is probably just hydrated, doesn't really mean anything

What does it mean if the sinus echoes are separated by less than 2 mm

Grade 1 hydro

What does this image show

Grade 1 hydro

What does this image show

Separation of entire central sinus and club calyces

Describe the appearance of grade 2 hydro

Pelvis, minor and major calyceal system

What is dilated in the case of grade 2 hydro

Rounded like the slubs in a deck of cards (can see an outline of the calyceal system)

Describe the appearance of clubbed calyces

Grade 2 hydro

What does this image show

Grade 2 hydro

What does this image show

Cortical thinning, extensive enlargement of renal sinus and calyces, loss of individual calyx definition

Describe the appearance of grade 3 hydro

How collecting system is blown out and very dilated that it starts pushing on the cortex bc not enough room in the kidney

Why do we see cortical thinning with grade 3 hydro

Loss of the clubbed shape of the calyces, they start to loose their normal shape because so dilated

Describe the appearance of the calyces in grade 3 hydro

Grade 3 hydro

What does this image show

Grade 3 hydro

What does this image show

Look for dilated ureter, then locate lvl of obstruction/cause of hydro, then go to the bladder and look for jets

Describe the next three steps you should take when you find hydronephrosis

Over distended bladder, extra-renal pelvis, multiple parapelvic cysts, AV malformation

What are some false positives for hydronephrosis