5.11 A) Urology Renal Colic

Front 1

What are the 3 broad categories for the causative mechanisms for renal calculi ?

Back 1

1. Supersaturation with stone-forming substances
a. Calcium
b. Phosphate
c. Oxalate
d. Cystine
e. urate
2. Decrease in urine volume
3. Lack of chemicals that inhibit stone formation
a. Magnesium
b. Citrate
c. Pyrophosphate

Front 2

What are the relative frequencies of each of the renal stone types?

Back 2

75% calcium [oxalate ; phosphate ]
10% uric acid
1% cystine
other: struvite

Front 3

Predisposing factors for stone formation ?

Back 3

1. Prolonged immobilisation
2. Strong FHx
3. Hyperparathyroidism [calcium hyperexcretion]
4. Peptic ulcer disease [ calcium hyperexcretion]
5. Small bowel disease {Crohn's / UC}
- hyperoxaluria
6. Gout [ hyperuricaemia]
7. Myeloproliferative disorders
8. Malignancy
9. Renal Tubular acidosis
10. Medications
{ calcium supplements ; acetazolamide ; Vitamins [ C /D ] }

Front 4

List the five main indications for Hospital

admission in Renal Colic.

Back 4

1. Infection
2. Deteriorating Renal function
3. Persisting pain { with parenteral opioids}
4. Stone > 5mm diameter
5. Dye extravasation

[uncommon with non contrast CT being used]

Front 5

Which is incorrect regarding renal calculi?

1. Alkaline urinary pH contributes to struvite stones
2. 75% of all stones are calcium based
3. Renal prostaglandins [ PGE2] are implicated in the pathophysiology of pain from renal calculi
4. Underlying metabolic abnormalities such as hypercalcaemia,

hyperuricaemia and hyperkalaemia can all be associated with renal

calculi

Back 5

4. hypokalaemia.

Front 6

Which is incorrect regarding renal calculi?
1. 90% stones are radio-opaque
2. CT has a sensitivity of 97% and specificity of 96%.
3. Ultrasound misses 15% of renal stones
4. 4-6 mm stones pass 50% of the time

Back 6

3. > 30%

Front 7

Management options for renal calculi?

Back 7

1. Conservative : [ analgesia and allow to pass]
2. Percutaneous nephrostomy
3. Extracorporeal shockwave lithotripsy
4. Ureteroscopic extraction
5. Open surgery [ Large or infected stones ]

Front 8

Pros of CTU in renal colic ?

Back 8

1. High sensitivity [97%] and specificity [ 96%]

2. Availability after hours
3. Accurately measures location and size of stone
4. Detects obstruction
5. Diagnoses other causes of flank pain
6. Avoids contrast

Front 9

Cons of CTU in renal colic?

Back 9

1. Radiation exposure

[ 1:500 ; 1:1000 and 1: 1400 - risk of lifetime

cancer - 20/40/60 years of age ]
2. Cost

Front 10

Pros and Cons of Ultrasound in Renal colic?

Back 10

Pros:
1. Non invasive
2. No ionising radiation exposure
3. Modality of choice in pregnancy
Cons:
1. Inaccurate measurement of stone size
2. Availability
3. Operator dependent