Urology: renal colic and stones

Question 1

What is renal colic?

Answer 1

a presenting complaint associated with kidney stones.

Renal colic- unilateral loin to groin pain
Colicky- fluctuating in severity as the stone settles

Question 2

What is the most common renal stone composition?

Answer 2

Calcium- calcium oxalate

Question 3

What are struvite stones associated with?

Answer 3

Infection

Question 4

What are the symptoms of renal stones?

Answer 4

Restless movement
Haematuria
Nausea and vomiting
Reduced urine output
Symptoms of sepsis if there is an infection

Question 5

What non imaging investigations would you do for a patient presenting with renal colic?

Answer 5

Bedside:
* Urinalysis to detect blood and assist in stone identification for further follow-up. Urinalysis frequently reveals haematuria, although a negative result doesn’t exclude renal colic.
* Urine MC+S as there may be a co-existing infection/precipitant.
* Observations to look for any signs of sepsis which may indicate an infected obstruction, which is a urological emergency.

Blood tests:

• Full Blood Count to detect any inflammatory response hinting at an infected system.
• Urea and Electrolytes to assess any impairment in renal function.
• Calcium & Uric acid to identify underlying metabolic conditions predisposing to stone formation.

Question 6

What is the gold standard imaging for kidney stones?

Answer 6

Non- contrast CT scan KUB

Question 7

A 46 male patient comes in with intense pain in the left lower loin, he has not passed urine 8 hours, and has vomited 4 times, what are your differentials?

Answer 7

Ruptured AAA, appendicitis, kidney stone, AKI due to obstruction?

Question 8

Define renal colic

Answer 8

Unilateral loin to groin pain that is excruciating.

Question 9

If a pt has “colicky” pain due to renal stones, what does this mean?

Answer 9

Pain fluctuates in severity as the stone moves and settles.

Question 10

Where do renal stones most commonly get stuck?

Answer 10

Vesico-ureteric junction

Question 11

Name the most common type of renal stone?

Answer 11

Calcium oxalate.

Question 12

What are risk factors for getting calcium oxalate renal stones?

Answer 12

Hypercalcaemia, low urine output

Question 13

Name three types of renal stones?

Answer 13

Calcium oxalate, calcium phosphate, uric acid, struvite, cystine.

Question 14

Where can renal stones be found in the urinary system?

Answer 14

Pelvi-ureteric junction, crossing the pelvic brim and vesicoureteric junction.

Question 15

How do renal stones present?

Answer 15

Pt moving restlessly due to pain. Haematuria. N&V, reduced urine output, Sx of sepsis if infected.

Question 16

Name 2 differentials for renal stones presentation

Answer 16

Ectopic pregnancy, pyelonephritis, ruptured AAA, biliary pathology, appendicitis.

Question 17

Name a complication of renal stones

Answer 17

Obstruction —> lead to AKI. Infection can result with obstructive pyelonephritis.

Question 18

What investigations would you do for suspected renal stones?

Answer 18

Urine dip - helps exclude infection, and may show haematuria. Blood tests - FBC, U+Es, calcium levels, eGFR. Abdo XR. Non contrast CT KUB. US if pregnant

Question 19

What is the gold standard for suspected renal stones?

Answer 19

Non-contrast CT scan KUB within 24hours.!!

Question 20

What initial management may be part of your plan after confirming a pt with renal stones?

Answer 20

1) Pt is dehydrated - may need fluid resuscitation. 2) Analgesia - IM or rectal diclofenac (or IV para if NSAIDs not tolerated). 3)Anti-emetic if nauseas/vomiting. 4) Abx if infection or septic signs. 5) Tamsulosin may help pass stone. 6) If stone is in lower ureter or <5mm, may pass.

Question 21

What surgical management would you think about for renal stones?

Answer 21

Extracorporeal shock wave lithotripsy if smaller than 2mm.
Percutaneous nephrolithotomy.
Ureteroscopy and laser lithotripsy.
Stent insertion or nephrostomy.

Question 22

What advice would you give a patient about recurrent renal stones?

Answer 22

They can happen! Need to: 1) increase oral intake - add fresh lemon, avoid carbonated drinks, reduce salt, maintain normal Ca2+ intake.

Question 23

A patient has calcium oxalate stones. What would you tell them to avoid in their diet?

Answer 23

Oxalate rich foods - spinach, beetroot, nuts, rhubarb, black tea.

Question 24

A pt has uric acid stones. What should they avoid in their diet?

Answer 24

Kidney, liver, anchovies, spinach, sardines.

Question 25

Analgesia for renal colic as per guidelines?

Answer 25

IM diclofenac

Question 26

RF for renal colic

Answer 26

Non-modifiable:
- Previous stone disease. The risk of developing a second stone is 30-40% over 5 years.
- Anatomical abnormalities of the collecting system
- Family history
- Underlying medical conditions. These include:
Hyperparathyroidism
Renal tubular acidosis
Myeloproliferative disorders
All chronic diarrhoeal conditions

Modifiable:
- Obesity
- Dehydration
- Diet

Question 27

Blood test investigations for renal colic?

Answer 27

FBC - for inflammation and infection
CRP - inflammation
U+Es - impaired renal function which needs management
Calcium and uric acid - ID any underlying metabolic condition which is causing stone formation

Question 28

Bedside investigations for renal colic?

Answer 28

Urinalysis - will likely show the presence of blood in the urine, and may help with stone identification and subsequent follow up in stone clinic.

Question 29

Radiological investigations for renal colic?

Answer 29

Non-contrast helical CT KUB
XR - useful for planning management if CT confirms stone. XR is also needed for ESWL (extracorporeal shockwave lithotripsy)

Question 30

Infection and organism most commonly linked to struvite calculi in renal colic?

Answer 30

Recurrent UTIs with Proteus spp.