Renal: Renal Colic Flashcards

1
Q

What is renal colic?

A

Describes an intense wave-like pain related to the passage of ureteric stones.

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2
Q

Are renal stones more common in males or females?

A

Males 3x

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3
Q

When do renal stones cause pain?

A

Renal calculi do not ordinarily cause pain when they remain in the kidney. However, when those kidney stones drop into the ureters, it can be excruciating.

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4
Q

What are the 2 key complications of renal stones?

A

1) Obstruction: leading to AKI

2) Infection: with obstructive pyelonephritis

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5
Q

How can obstruction of a ureter be fatal?

A

The stasis of urine in a blocked kidney can lead to superimposed infection, which can cause rapid-onset sepsis.

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6
Q

What are the 3 anatomical points that renal calculi often obstruct the ureters?

A

1) Pelvic ureteric junction (PUJ): the junction between the renal pelvis and ureter

2) Pelvic brim: where the ureter crosses above the common iliac vessels into the pelvis

3) Vesicoureteric junction (VUJ): the junction between the ureter and bladder

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7
Q

What causes the colicky pain in ureteric calculi?

A

This is from reflex spasms of the ureter as the stone passes through.

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8
Q

Anatomically, what nerve does the ureter lie close to?

A

Genitofemoral nerve (a branch of the lumbar plexus)

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9
Q

What referred pain may be seen in renal stones in men?

A

Referred testicular pain (hence the characteristic description of ‘loin to groin’ pain) –> due to the ureter lying close to the genitofemoral nerve.

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10
Q

Broad risk factors for the formation of kidney stones?

A

1) Dehydration

2) Previous stones or FH

3) Metabolic conditions (e.g. cystinuria, primary hyperparathyroidism, gout etc.)

4) Medications including diuretics, antiretrovirals and antacids predispose to stone formation

5) Obesity

6) Bowel conditions (e.g. inflammatory bowel disease)

7) Idiopathic (most stones)

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11
Q

What are the 5 different types of kidney stones?

A

1) Calcium oxalate

2) Calcium phosphate

Note - calcium stones may be mixed (oxalate & phosphate).

3) Uric acid

4) Struvite

5) Cystine

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12
Q

What is the most common type of kidney stone?

A

Calcium oxalate

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13
Q

What is the major risk factor for calcium oxalate stones?

A

Hypercalciuria

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14
Q

Causes of hypercalciuria?

A

Note - any cause of hypercalcemia is likely to result in secondary hypercalciuria.

1) Hyperthyroidism
2) Renal tubular acidosis
3) Sarcoidosis
4) Vitamin D intoxication
5) Glucocorticoid excess
6) Paget disease
7) Paraneoplastic syndromes e.g. lung squamous cell carcinoma

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15
Q

Hyperoxaluria can increase the risk of calcium oxalate stones.

What is hyperoxaluria? Causes?

A

A state of disordered metabolism characterised by an increased urinary excretion of oxalate.

Causes:
- genetic defect
- eating too many foods high in oxalate e.g. green leafy veg, soy etc

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16
Q

What foods are high in oxalate?

A

Green leafy veg, soy, almonds, potatoes etc

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17
Q

Why is hypocitraturia a risk factor for calcium oxalate stones?

A

Because citrate forms complexes with calcium, making it more soluble.

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18
Q

Appearance of calcium oxalate stones on xray?

A

Radio-opaque (though less than calcium phosphate stones)

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19
Q

What is the key risk factor for cystine stones?

A

Cystinuria –> Inherited recessive disorder of transmembrane cystine transport leading to decreased absorption of cystine from intestine and renal tubule.

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20
Q

Appearance of cystine stones on xray?

A

Relatively radiodense because they contain sulphur

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21
Q

What is uric acid a product of?

A

Purine metabolism

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22
Q

Risk factors for uric acid stones?

A

1) low urinary pH

2) high protein diet

3) loss of fluid due to chronic diarrhea or malabsorption
4) diabetes or metabolic syndrome

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23
Q

Appearance of uric acid stones on xray?

A

Not visible on xray - radiolucent.

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24
Q

Risk factors for calcium phosphate stones?

A

1) May occur in renal tubular acidosis –> high urinary pH increases supersaturation of urine with calcium and phosphate

2) Renal tubular acidosis types 1 and 3 increase risk of stone formation (types 2 and 4 do not)

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25
Q

Appearance of calcium phosphate stones on xray?

A

Radio-opaque

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26
Q

What are struvite stones formed from?

A

Magnesium, ammonium and phosphate

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27
Q

What do struvite stones occur as a result of?

A

Urease producing bacteria

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28
Q

What are struvite stones associated with?

A

Chronic infections

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29
Q

What is typical urine pH?

A

individual variation from pH 5-7

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30
Q

How does eating affect urine pH? Why?

A

Post prandially the pH falls as purine metabolism will produce uric acid.

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31
Q

When a renal stone is not available for analysis, what may help to determine which stone was present?

A

Urine pH

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32
Q

Describe typical urine acidity in calcium phosphate stones

A

Normal- alkaline (pH >5.5)

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33
Q

Describe typical urine acidity in calcium oxalate stones

A

Variable (typically around 6)

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34
Q

Describe typical urine acidity in uric acid stones

A

Acidic (5.5.)

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35
Q

Describe typical urine acidity in struvate stones

A

Alkaline (>7.2)

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36
Q

Describe typical urine acidity in cystine stones

A

Normal (around 6.5)

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37
Q

Clinical features of renal colic?

A

Symptoms:
- sudden onset, severe unilateral loin-groin pain (‘worse than childbirth’)
- nausea & vomiting
- pain on urination (dysuria)
- systemic symptoms (e.g. fever): suggests an infected, obstructed system
- hypercalcaemia symptoms

Signs:
- typically unremarkable abdominal examination.
- severe, unilateral flank pain on palpation can indicate an infected urinary system.
- haematuria
- reduced urine output

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38
Q

Describe the pain in renal colid

A

Typically severe, intermittent, sharp ‘colic’ pain.

The patient often is restless/moving around.

Pain will wake patients up from sleep.

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39
Q

How long can episodes of colicky pain last in renal colic?

A

Can vary substantially in their duration, from seconds to hours. For patients with an infected, obstructed system, the pain can be constant.

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40
Q

Important areas to cover in history in renal colic?

A

1) PMH:
- previous stones
- metabolic conditions (cystinuria, primary hyperparathyroidism, gout etc)

2) DH:
- diuretics
- antiretrovirals
- antacids

3) FH

4) SH:
- smoking (a risk factor for stone formation)
- fluid intake
- occupation (heavy machinery operators or pilots will not be able to work until the stone is treated)

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41
Q

Which medications may increase the risk of renal stones?

A

1) aspirin

2) antacids

3) diuretics

4) antiretrovirals

5) Abx e.g. ciprofloxacin

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42
Q

Which diuretics are most associated with renal stones?

A

Loop diuretics

43
Q

How can loop diuretics predispose to renal stones?

A

Increase calcium excretion

44
Q

What exam is indicated in suspected renal colic?

A

Abdo exam:
a) to exclude complications (e.g. infected obstructed system

b) to exclude differential diagnoses (e.g. a ruptured abdominal aortic aneurism).

45
Q

What are some differentials for renal colic (i.e. severe unilateral abdominal or flank pain)?

A

1) Ruptured AAA (most important!)

2) Ectopic pregnancy

3) Ovarian torsion

4) Tubuloovarian abscess

5) Testicular torsion

Right-sided pain:

6) Biliary colic

7) Cholecystitis

8) Cholangitis

9) Portal vein thrombosis

10) Appendicitis

11) Ascending colon diverticulitis

Left-sided pain:

12) Descending/sigmoid colon diverticulitis

46
Q

How may patients with a ruptured AAA present?

A

These patients may present as haemodynamically unstable, but others may have more subtle signs, such as an AKI.

47
Q

Who should a ruptured AAA always be considered in?

A

older men with risk factors (e.g. smoking)

48
Q

How may patients with an ectopic pregnancy present?

A

Abdominal +/- pelvic pain +/- vaginal bleeding. May present acutely in shock.

Always check a urinary HCG in women of reproductive age.

49
Q

How may patients with an ovarian torsion present?

A

Intermittent iliac fossa tenderness.

50
Q

How may patients with a tubuloovarian abscess present?

A

Severe constant iliac fossa tenderness which can mimic appendicitis. These patients may be systemically unwell.

51
Q

How may patients with a testicular torsion present?

A

Severe sudden onset unilateral testicular tenderness, which can radiate to the abdomen.

52
Q

Location of biliary colic pain?

A

RUQ pain

53
Q

Typical presentation of biliary colic pain?

A

Intermittent pain RUQ pain classically related to fatty food.

54
Q

Location of cholecystitis pain?

A

RUQ (spreads towards right shoulder)

55
Q

Typical presentation of cholecystitis pain?

A

Constant pain with positive Murphy’s sign (unable to take a deep breath in when palpating the right upper quadrant of the abdomen).

56
Q

What is Murphy’s sign?

A

Murphy’s sign is elicited in patients with acute cholecystitis by asking the patient to take in and hold a deep breath while palpating the right subcostal area.

If pain occurs when the inflamed gallbladder comes into contact with the examiner’s hand, Murphy’s sign is positive.

57
Q

What condition does a positive Murphy’s sign indicate?

A

Cholecystitis (inflamed gallbladder)

58
Q

Presentation of cholangitis?

A

Triad:
1) fever
2) RUQ pain
3) jaundice

59
Q

Presentation of portal vein thrombosis?

A

Severe right upper quadrant pain, often with jaundice.

60
Q

Location of pain in appendicitis?

A

Right iliac fossa (with raised inflammatory markers)

61
Q

What is there often a preceding history of in diverticulitis?

A

Constipation

62
Q

What is a staghorn calculus?

A

A staghorn calculus is where the stone forms in the shape of the renal pelvis, giving it a similar appearance to the antlers of a deer stag.

The body sits in the renal pelvis with horns extending into the renal calyces.

63
Q

What type of stone do staghorn calculi most commonly occur with?

A

Struvite

64
Q

How do recurrent upper UTIs predispose to struvite stones?

A

The bacteria can hydrolyse the urea in urine to ammonia, creating the solid struvite.

65
Q

Initial investigations in renal colic?

A

1) Urine dipstick

2) Urine culture

3) U&Es: check renal function

4) FBC/CRP: look for infection

5) Calcium/urate

6) Lactate (sepsis)

66
Q

What may a urine dipstick show in kidney stones?

A

Haematuria.

Urine dipsticks are also helpful to exclude infection.

67
Q

Does a normal urine dipstick exclude stones?

A

No

68
Q

Gold standard imaging in renal stones?

A

CT KUB (kidneys ureter bladder)

69
Q

How long after admission should suspected renal stones patients have a CT KUB?

A

Within 14 hours of admission

70
Q

What is added benefit of a CT KUB in renal stones?

A

Can measure stone density (in Hounsfield units) and demonstrate renal anatomy, which can affect management.

71
Q

When may an US be indicated over a CTKUB?

A

In young or pregnant patients.

72
Q

When may an US be helpful in renal stones?

A

1) young or pregnant patients

2) useful for demonstrating hydronephrosis

73
Q

Which renal stones do NOT show up on XR?

A

Uric acid stones (radiolucent)

74
Q

Presentation of calcium based stones on XR?

A

Radio-opaque

75
Q

What are the 3 key causes of hypercalcaemia?

A

1) calcium supplementation

2) hyperparathyroidism

3) cancer (e.g., myeloma, breast or lung cancer)

76
Q

What is the most effective analgesia for renal colic?

A

NSAIDs e.g. IM diclofenac

77
Q

Typical NSAID used in renal colic?

A

IM diclofenac

78
Q

Management of renal stones can be conservative, medical & surgical.

What does conservative management consist of?

A
  • Fluids
  • Analgesia
  • Antiemetics eg. metoclopramide, prochlorperazine or cyclizine

In the case of small stones (<5mm), a trial of waiting can be used.

79
Q

What size renal stone may indicate a ‘watching and waiting’ approach’?

A

<5mm

80
Q

When should patients be reviewed again to see if the stone passes on its own?

A

Patients should be re-reviewed in an outpatient setting in approximately four weeks to ensure that the stone has passed.

81
Q

What does medical management of renal stones involve?

A

1) medical expulsive therapy: however this is controversial

2) analgesia (NSAIDs)

82
Q

What may be used for the medical expulsion of renal stones?

A

alpha-adrenoceptor blocker (e.g. tamsulosin) for small distal ureteric stones.

83
Q

What size stones will usually pass spontaneously?

A

<5mm

84
Q

Who are surgical options reserved for in renal stones?

A

1) Irretractable pain despite good analgesia

2) AKI

3) Infected-obstructed kidney (urgent)

4) Bilateral obstructed kidneys/obstructed kidney in a patient who has a single functioning kidney (emergency)

85
Q

For patients with an infected urinary system due to renal stones, what is the 1st line of management?

A

Relieving the obstruction: stent or nephrostomy.

86
Q

How can a stent relieve obstruction in renal stones?

A

A stent is a small tube which sits in the ureter and allows the passage of urine from the kidney into the bladder.

It is inserted under general anaesthetic with the help of a rigid camera through the urethra and into the bladder.

87
Q

What is a nephrostomy?

A

A nephrostomy is a tube placed percutaneously (through the skin) straight into the kidney.

These patients will still need treatment of their stones at a later date, with a ureteroscopy (camera up the ureter) and laser fragmentation of their stones.

88
Q

For patients who do not have an infected system with renal stones, what is the 1st line management?

A

Primary stone treatment with either:
- ureteroscopy and laser stone fragmentation
- extracorporeal shock wave lithotripsy (ESWL).

89
Q

What does ESWL involve?

A

ESWL is performed while patients are awake, whereby a series of shockwaves are focused onto the area of stone burden to break them down and allow passage.

In hospitals where these are not available in the urgent setting, patients can once again be given a ureteric stent and brought back for treatment on an elective basis.

90
Q

What advice can be given to patients to prevent further renal stone formation?

A

All patients should be advised to maintain a good fluid intake of at least 2-3 litres per day.

Calcium based stones: Lemon juice can increase urinary citrate, reducing the recurrence of these.

Oxalate stones: avoidance of oxalate-rich foods can reduce the risk of forming these stones (e.g. leafy greens, soy products and potatoes)

Urate stones: avoidance of foods high rich in purines can reduce the risk of forming these stones (e.g. red meat, eggs and shellfish)

91
Q

Foods rich in purines (e.g. red meat, eggs) can increase the risk of which stones?

A

Urate stones

92
Q

Gout is associated with which type of renal stones?

A

Urate stones

93
Q

Who is ESWL contraindicated in?

A

Pregnant women

94
Q

What can be used for surgical managmenet of renal stones in pregnant women?

A

Ureteroscopy

95
Q

What surgical management is indicated for complex renal calculi and staghorn calculi?

A

Percutaneous nephrolithotomy

96
Q

Which diuretics may decrease the formation of renal stones?

A

thiazides diuretics (increase distal tubular calcium resorption which decreases urinary calcium)

97
Q

What is ESWL?

A

ESWL involves an external machine that generates shock waves and directs them at the stone under x-ray guidance. The shockwaves break the stone into smaller parts to make them easier to pass.

98
Q

What is ureteroscopy and laser lithotripsy?

A

A camera is inserted via the urethra, bladder and ureter, and the stone is identified. It is then broken up using targeted lasers, making the smaller parts easier to pass.

99
Q

What is percutaneous nephrolithotomy (PCNL)?

A

PCNL is performed in theatres under a general anaesthetic. A nephroscope (small camera on a stick) is inserted via a small incision at the patient’s back. The scope is inserted through the kidney to assess the ureter. Stones can be broken into smaller pieces and removed. A nephrostomy tube may be left in place after the procedure to help drain the kidney.

100
Q

What type of stones can lemon juice reduce the risk of?

A

Calcium based stones: citric acid binds to urinary calcium reducing the formation of stones.

101
Q

What 2 medications may be used to reduce the risk of renal stone recurrence?

A

1) thiazide diuretics (e.g. indapamide)

2) potassium citrate

102
Q

What type of renal stones may thiazide diuretics reduce the risk of?

A

in patients with calcium oxalate stones and raised urinary calcium

103
Q

What type of renal stones may potassium citrate reduce the risk of?

A

in patients with calcium oxalate stones and raised urinary calcium

104
Q
A