Renal Stones + Pyelonephritis Flashcards
What is the other name for renal tract stones?
Urolithiasis
What are the different types of renal tract stones?
Calcium (80%): - calcium oxalate - calcium phosphate - mixed Struvite (magnesium ammonium phosphate) Urate Cystine
What type of stones classically cause ‘stag horn calculi’?
Struvite
Which stones are radiolucent (can’t be seen on xray)?
Urate stones
What causes the development of urate stones?
High levels of purine in the blood
- e.g. from diet (red meats)
- or haematological disorders e.g. myeloproliferative disease
What causes the development of cystine stones?
Familial disorders affecting cystine metabolism - hypocystinuria
What are the three main locations when renal tract stones are found?
Natural narrowed points:
- pelviureteric junction (PUJ)
- where iliac vessels cross the ureter in the pelvis
- vesicoureteric junction (VUJ)
What are the clinical features of a renal tract stone?
Asymptomatic if non obstructing Ureteric stone: - pain --> ureteric colic - sudden onset, 'loin to groin' - associated nausea + vomiting - haematuria in 90% - fever, rigors if associated infection
How should suspected urolithiasis be investigated?
Urinalysis +/- culture Bloods: - FBC + CRP - U&Es - urate + calcium levels Imaging
Which imaging is gold standard for urolithiasis?
Non-contrast CT KUB
USS is useful to look for hydronephrosis in cases of known stone disease
What is the initial management of urolithiasis?
Often dehydrated so ensure adequate fluid intake
ANALGESIA - opiates + rectal NSAIDs (diclofenac)
Majority of stones pass spontaneously, especially if in lower ureter or < 5mm
If signs of infection –> IV antibiotics + urgent urology referral
What is the criteria for inpatient admission for urolithiasis?
Post obstructive AKI
Uncontrolled pain from simple analgesia
Evidence of infection
Large stones (>5mm)
Which methods are used to temporarily relieve obstruction in urolithiasis if there is nephropathy or infection?
Stent insertion:
- into ureter via cystoscopy
or Nephrostomy:
- tube directly into renal pelvis to relieve the obstruction proximally
What are the options for definitive management of renal/ureteric stones which do not pass spontaneously?
Extracorporeal shock wave lithotripsy (ESWL)
Percutaneous nephrolithotomy (PCNL)
Flexible uretero-renoscopy (URS)
What is extracorporeal shock wave lithotripsy (ESWL) and when is it used/contraindicated?
Targeted sonic waves to break up stone
Used for small stones (<2cm)
CI: pregnancy or stone positioned over bony landmark e.g. pelvis
What is percutaneous nephrolithotomy (PCNL) and when is it used?
Used of renal stones only –> best method for large renal stones including staghorn calculi
Percutaneous access to kidney, nephroscope passed into renal pelvis + stones fragmented using lithotripsy
What is flexible uretero-renoscopy (URS)?
Scope passed retrograde up into ureter + stones fragmented through laser lithotripsy
What are the main complications of urolithiasis?
Infection
Post-renal AKI
Recurrent renal stones –> renal scarring and loss of kidney function
What causes bladder stones?
Urine stasis –>chronic urinary retention
Infection –> schistosomiasis
Passed ureteric stones
What are the clinical features of pyelonephritis?
Classical triad:
- fever
- unilateral loin pain
- nausea + vomiting
May be symptoms of lower UTI + haematuria
Costovertebral angle tenderness
How should suspected pyelonephritis be investigated?
Urinalysis + culture
Beta-HCG
Routine bloods
If evidence of obstruction:
- renal USS (infected obstruction is urological emergency)
- then non-contrast CT KUB
How is pyelonephritis managed?
If uncomplicated - antibiotics in the community
If systemically unwell -
- ABCDE
- IV fluids + empirical antibiotics
- analgesia + anti-emetics
What are the complications of pyelonephritis?
Severe sepsis Renal scarring --> CKD Pyonephrosis (infected obstructed kidney) Preterm labour in pregnant women Chronic pyelonephritis --> CKD Emphysematous pyelonephritis
What is emphysematous pyelonephritis?
Rare, sever pyelonephritis caused by gas forming bacteria –> high mortality
Most commonly seen in diabetics
CT –> gas within and around the kidney
