Renal Tract Calculi Flashcards Preview

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Flashcards in Renal Tract Calculi Deck (36)
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1

Epidemiology

2-3% of western population

More common in males and typically affect those <65 yrs

They can either form as renal stones or ureteric stones.

2

Types of calculi

Calcum oxalate (35%)

Calcium phosphate (10%)

Mixed oxalate and phosphate (35%)

Struvite stones (magnesium ammonium phosphate that are often large soft stones)

Urate stones (only radiolucent one)

Cystine stones

3

Which stone is most common cause of staghorn calculi

Struvite stones

4

Pathophysiology of urate stones

High levels of purine in the blood from either diet like red meast, haematological disorders like myeloproliferative disease.

This leads to increase of urate formation and subsequent crystallisation in the urine.

5

Pathophysiology of cystine stones.

Associated with homocystinuria

6

Location of ureteric stones.

Pelviureteric junction PUJ

Cross the pevlic brime where the iliac vessel travel across the ureter in the pelvis

Vesicoureteric junction VUJ

7

Pathophysilogy of struvite stones

Due to infection in urinary tract

 Proteus, Xanthomonas, Pseudomonas, Klebsiella, Staphylococcus, and Mycoplasma.

8

Clinical features

Pain as ureteric colic

This occurs from increased peristalsis from around the site of obstruction.

Pain is sudden onset, severe and radiation from flank to pelvis i.e. loin to groin.

Often associated with N+V

Haematuria in 90% of cases which is typically non-visible.

There might be infection and rigors, fever and lethargy.

9

Examination findings

Typically unremarkable

There might be tenderness in the affected flank

Dehydration

10

Dx

Pyelonephritis

Ruptured AAA

Biliary pathology

Bowel obstruction

Lower lobe pneumonia

MSK pain

11

Lab tests

Urine dip can show haematuria + send of urine culture as well.

Routine bloods with FBC, CRP and U&Es.

Urate and calcium levels should be assessed.

12

Imaging

Gold standard is non-contrast CT-KUB scan.

AXR is sometimes used as initial but not all stones are radio-opaque

USS can be used to assess for any hydronephrosis.

13

Initial management

Often dehydrated due to reduced oral fluid intake and or vomiting so fluid resus is required.

Majoirty will pass it spontaneously without further intervention, especially if in lower ureter or <5 mm in diameter.

Sufficient analgesia like opiate and NSAIDs per rectum is most effective

Evidence of significant infection or sepsis warrants IV abx

14

Why is tamsulosin not used anymore?

Limited benefit in ureteric stones and is no longer routinely prescribed.

15

Criteria for inpatient admission

Post-obstructive AKI

Uncontrollable pain from simple analgesic

Evidence of an infected stone

Large stones >5mm

16

Give immediate managements that are not definitive.

Stent insertion

Nephrostomy

17

Why would stent insertion or nephrostomy be done if they are not definitive managements?

Obstructive nephropathy or significant infection may warrant it.

This is where the obstruction needs to be immediately relieved to avoid renal damage.

They provide temporary relief prior to definitive management

18

Explain retrograde stent insertion.

Placement of a stent within the ureter

This is by cytoscopy.

It allows the ureter to be kept patent and temporarily relieve the obstruction.

19

Explain nephrostomy

A tube placed directly into the renal pelvis and collecting system.

This is relieving the obstruction proximally.

An anterograde stent might be put in at the same time.

20

Defintiive managements

Extracorporeal Shock Wave Lithotripsy

Percutaneous Nephrolithotomy

Flexible uretero-renoscopy

21

Explain ESWL

Targeted sonic waves breaks up the stone so it can then be passed spontaneously.

22

Indications for ESWL

Small stones <2cm and where they can be located

Performed via radiological guidance like X-ray or USS

23

Contraindications of ESWL

Pregnancy

Stone positioned over a bony landmark like pelvis

24

When is PCNL used?

In renal stones only

It is the preferred method for large renal stones like staghorn calculi.

25

Explain PCNL

Nephroscope passed into renal pelvis where then stones can then be fragmented.

This can cause pneumothorax or nerve damage

26

Explain flexible uretero-renoscopy URS

A scope is retrogradely put into the ureter

This allows the stones to be fragmented through laser lithotripsy and then the fragments are removed.

27

Complications of ureteric stones.

Infection

Post-renal AKI

Recurrency and scarring + CKD

28

Management of recurrent stone formers.

Identify what types of stones is the problem.

Advise them to stay hydrated

Have their serum urate and calcium levels checked.

29

Oxalate stone formers management

Avoid high purine foods and high oxalate foods like nuts, rhubarb and sesame

30

Calcium stone formers management

PTH levels checked to exlclude primary hyperparathyroidism

Avoid excess salt in diet