Week 5 - H - Imaging in renal and urological disorders Flashcards
What is the usual cause of renal colic?
This would be a ureteric calculus
What other things can stimulate renal colic?
Pyelonephritis or gynaelogical disease can stimulate renal colic
If the patient has renal colic and a good history has been taken suggesting ureteric calculi, what is the next step and what are you looking for?
Carry out urinalysis looking for any haematuria which is often associated with ureteric calculi
What investigations are carried out in renal colic?
Offer urgent (within 24 hours of presentation) low-dose non-contrast CT to adults with suspected renal colic. If a woman is pregnant, offer ultrasound instead of CT. * Offer urgent (within 24 hours of presentation) ultrasound as first-line imaging for children and young people with suspected renal colic. * If there is still uncertainty about the diagnosis of renal colic after ultrasound for children and young people, consider low-dose non-contrast CT.
What investigation is carried out if thinking pyelonephritis or gynaeolocial disease?
Ultrasound to exclude ureteric obstruction - pyelonephritis if gynaecological disease is likely do US instead, to visualise uterine, ovarian and uterine tubal pathology
If the patinet is pregnant, what should be done to avoid radiation exposure to the foetus and mother?
use US and/or MRI to avoid radiation exposure to foetus
What stones show up on KUBxray? Which do not? Which drug is known to cause renal stones?
Calcium stones show as they are dense and radioopaque pure uric acid, indinavir-induced, and cystine calculi are relatively radiolucent on plain radiography. the antiviral indanivir causes renal stones
What is usually the first imaging test to image renal stones? What is the gold standard for renal stones?
Offer urgent (within 24 hours of presentation) low-dose non-contrast CT to adults with suspected renal colic. If a woman is pregnant, offer ultrasound instead of CT. * Offer urgent (within 24 hours of presentation) ultrasound as first-line imaging for children and young people with suspected renal colic. * If there is still uncertainty about the diagnosis of renal colic after ultrasound for children and young people, consider low-dose non-contrast CT.
What is the normal ureteric course?
The ureters descend inferiorly over the psoas major muscles, they cross the common iliac artery bifurcation before entering the pelvis through the pelvic brim, and then pass inferomedially into the posteriolateral apsect of the bladder
Knowledge of normal ureteric course makes it easier to spot ureteric calculi. Where are renal calculi usually located?
They can be located at the pelviureteric junction (PUJ) The pelvic brim (where the ureter passes over the bifurcation of the common iliac artery - there is a small change in direction to posteriomedially) and At the vesicoureteric junction (VUJ)
Most calculi will pass as the calculi usually has to be 6mm or more to have difficulty passing The KUBxray lacks specificty as it is hard to differentiate from other causes of calcification small local, usually rounded, calcification within a vein. What are these?
Phleboliths - When located in the pelvis they are sometimes difficult to differentiate from kidney stones in the ureters on X-ray.
Non-contrast enhanced CT (‘CT stone search’) is now the definitive test to confirm a symptomatic ureteric calculus When should the CT scan be avoided?
CT gives a high radiation dose, so should be avoided in pregnancy and if possible, non-pregnant young females, when US and/or MRI may be used to give similar information Also avoid CT in renal impairment
Most calculi pass spontaneously If you want to check the progress of a stone only seen on CT previously what would you do?
Use a CT again To check progress, use the simplest test that showed the calculus at presentation, as shown in the series opposite
Macroscopic haematuria may arise from the kidneys, ureters or bladder What are some causes of macroscopic haematuria?
Calculi, tumour, infection, glomerulonephritis, BPH the list goes on
If a patient over 50 presents with macroscopic haematuria, what investigation is carried out?
CT urography (CTU) examines the kidneys, collecting systems and ureters Cystoscopy examines the bladder and urethra
There are two steps in CT urography (they both look for different things) What is step 1?
Step 1 - pre contrast scan to detect for renal calculi being the cause Administration of IV contrast which is concentrated and excreted by kidneys over 15 minutes Top up dose so the renal parenchyma can be viewed
In step 2 of CT urography, the whole of the kidneys, collecting system and ureters can be viewed What is looked for in the second stage?
Any renal parenchymal tuours (RCC usually) and any urothelial tumours in the collecting ducts and ureters
When identifying a tumour it is important to look to see if the tumour is confined to the kidney What is T1 and T2 renal cell carcinoma?
T1 - tumour has not spread through renal capsule T2 - tumour has not spread through renal deep fascia (gerota’s fascia)
If the renal cell carcinoma is within T1 and 2, what is the treatment?
Carry out nephrectomy or partial nephrectomy
Under 50 years age, the incidence of urothelial tumours of kidney or ureter is very low, so routine CTU which imparts a double radiation dose is unjustified when there is macroscopic haematuria What is done instead?
US of kidneys to detect calculi and renal parenchymal tumours Cystoscopy to look for occasional bladder TCC, bladder calculi, other bladder tumours or evidence of urethritis/prostatitis Renal cancers less common in patients under 50 so CT urography is not as commonly carried out
CT is typically used to assess mass size density (fat, fluid, soft tissue, calcified) uniformity (is density all the same or variable) internal morphology (presence of nodules, septa) If the tumour contains fat on CT, what is it likely to be?
Angiomyolipoma - they can bleed due to the vessel part of the benign tumour
What is usually done if the mass is less than 3 cm in size?
It is recognised that renal masses smaller than 3cm very rarely metastasize, whatever their appearance, so these are often followed up rather than operated upon
What is often sufficient when diagnosing a simple renal cyst?
Ultrasound - Can see the benign cyst on CT here - best seen in nephrographic phase
What are the four stages of robson staging of renal cell carcinoma?
Stage 1 -tumour confined to renal capsule Stage 2 - tumour confined to gerota’s fascia Stage 3 - tumour involement of regional lymph nodes and/or renal vein and cava Stage IV - adjacent organs or distant metastases
What can be seen here?
invading the inferior vena cava (robson stage 3)
What is hydronephrosis?
It is the dilatation of the renal pelvis
