Nepholithiasis a.k.a Kidney Stones/ Urinary tract Calculi

Question 1

Define;

Answer 1

Crystal deposition within the urinary tract

Commonly at pelvic brim, pelvi-uteric junction and the vesicouteric junction

Question 2

What are the different types of stones?

Answer 2

Calcium oxalate - this is the most common 
o	Struvite - quite common
o	Urate - 5% 
o	Hydroxyapatite (5%)
o	Cysteine - 2%

Question 3

Aetiology:

Answer 3

Many are idiopathic. 
Metabolic:
-Hypercalcuria
-Hyperuracemia 
-Hyperparathyroidism 
-Renal tubular acidosis 
-Hypercystinuria 
-Hyperoxaluria 

Infections:

• Recurrent UTIS
• Hyperuracemia

Drugs:

• Diuretics
• Corticosteroids
• antacids
• Indinavir

Urinary tract:

• Pelvic-uteric junction obstruction
• Hydronephrosis
• Uretral stricture
• Stent
• Catheter

Question 4

Risk factors:

Answer 4

Low fluid intake

Diet - spinach, chocolate, nuts, tea are all foods high in oxalate

Vitamin D due to lots of sunlight(season)

Structural abnormalities

Question 5

Epidemiology:

Answer 5

Very common

2-3% of the population

3x more in males

20-50 years

Question 6

Symptoms:

Answer 6

• Often ASYMPTOMATIC
• SEVERE loin to groin pain – renal colic
• Nausea and vomiting
• Unable to lie still
• Urinary urgency, frequency or retention
• Haematuria

Question 7

Signs:

Answer 7

• Loin to lower abdominal tenderness – usually no tenderness on palpation
• NO signs of peritonism
• Leaking AAA is the main differential to consider in older men
• Signs of systemic sepsis if there is an obstruction and infection above the stone

Question 8

investigations:

Answer 8

• 1st: urine dipstick (for microscopic haematuria)
• Then, non-contrast CT-KUB (GOLD STANDARD)
• Then, ultrasound
• Then, U+Es to check renal function
• Note: do pregnancy test in all women of child bearing age to exclude ectopic – if pregnant, do USS instead of CT

Question 9

Management of the acute presentation:

Answer 9

o Analgesia – diclofenac 75mg IV/IM or 100mg PR If contraindicated: opioids
o Bed rest
o Fluid replacement – IV if unable to withstand PO
o Urine collection to try and retrieve any stone that has passed
o An obstructed, infected kidney is an EMERGENCY and should be treated as soon as possible to relieve the obstruction (e.g. by placing a percutaneous nephrostomy)
o Antibiotics – cefuroxime or gentamicin IV

Question 10

Management to remove stones:

Answer 10

If <5mm will usually pass with increased fluid intake

Nifedipine or alpha blockers (tamsulosin) promote expulsion and reduce analgesia requirements

Urethroscopy

Extracorporeal Shock-Wave Lithotripsy (ESWL)

Percutaneous Nephrolithotomy (PCNL) – keyhole surgery

Treat the cause

Increase fluid intake

Question 11

Complications of the stones:

Answer 11

o Infection (PYELONEPHRITIS)
o Septicaemia
o Urinary retention

Question 12

Complications of urethroscopy:

Answer 12

o Perforation

o False passage

Question 13

Complications of ESWL:

Answer 13

o Pain

o Haematuria

Question 14

Prognosis:

Answer 14

• GOOD
• However, infection of the calculus could lead to irreversible renal scarring
• Recurrence of about 50% over 5 yrs