Urinary tract Calculi

Question 1

what is urolithiasis?

Answer 1

the formation of stones anywhere in the urinary tract

• kidney (most)
• ureter
• bladder

Question 2

what is renal colic?

Answer 2

an acute, severe loin pain caused when a urinary stone:

• moves from the kidney
• obstructs the flow or urine through the ureter

Question 3

What is hydronephrosis?

Answer 3

swelling of the renal pelvis and calyces in the kidney due to obstruction of the urinary tract causing back pressure into the kidneys

Question 4

What is idiopathic hydronephrosis?

Answer 4

narrowing of the pelviureteric junction

Question 5

Give 4 causes of obstruction within the lumen of the ureter:

Answer 5

1) calculus (stone)
2) blood clot
3) sloughed papilla
4) tumour of the renal pelvis, ureter or bladder

Question 6

What is the renal papilla?

Answer 6

the tip of the renal pyramid where the collecting ducts drip urine into the minor calyx

Question 7

Give 3 causes of sloughed papilla:

Answer 7

1) diabetes
2) analgesia misuse
3) sickle cell disease

Question 8

Give 2 causes of renal obstruction from within the wall:

Answer 8

1) pelviureteric neuromuscular dysfunction
2) ureteric strictures
+ lots of congenital wall abnormalities

Question 9

Give 5 external causes of renal obstruction:

Answer 9

1) tumours
2) diverticulitis
3) aortic aneurysm
4) retroperitoneal fibrosis
5) benign prostatic hypertrophy

Question 10

Give 7 clinical features of urinary tract obstruction:

Answer 10

1) loin pain (often worsened by increased fluid intake)
2) anuria
3) terminal dribbling
4) sense of incomplete bladder emptying
5) hesitancy
6) dysuria
7) infection symptoms (malaise, fever, septicaemia)

Question 11

Give 3 abdominal examination findings that support diagnosis of urinary tract obstruction:

Answer 11

1) loin tenderness
2) enlarged hydronephrotic kidney (palpable)
3) enlarged bladder

Question 12

Give 2 examinations used to assess prostatic obstruction and pelvic malignancy in urinary tract obstruction:

Answer 12

1) genitalia exam
2) rectum exam

Question 13

Name 6 investigations of urinary tract obstruction:

Answer 13

1) urinalysis (for haematuria)
2) midstream sample of urine (infection)
3) U+Es
4) ultrasound
5) X-ray (for stones)
6) CT scan (high sensitivity)

Question 14

What is pyelography?

Answer 14

imaging of the kidneys

Question 15

True or false: an obstructed and infected urinary tract is a medical emergency

Answer 15

true (delay can lead to septicaemia)

Question 16

Give three treatments for hydronephrosis:

Answer 16

1) bladder/ suprapubic catheterisation
2) percutaneous nephrostomy
3) ureteric stent

Question 17

Where is a suprapubic catheter inserted?

Answer 17

the abdominal wall above the symphysis pubis into the urinary bladder

Question 18

Give one potential complication of relief of urinary tract obstruction:

Answer 18

massive diuresis may cause severe sodium, water and potassium depletion requiring IV replacement
(occurs in a minority of cases)

Question 19

What are the most common types of kidney stones? (2)

Answer 19

1) calcium oxalate
2) calcium phosphate

Question 20

What compound is found in struvite stones?

Answer 20

magnesium ammonium phosphate

Question 21

Other than calcium stones, name three other types of nephrolithiasis:

Answer 21

1) struvite
2) uric acid
3) cystine

Question 22

True or false: kidney stones rarely reoccur

Answer 22

false (more than 50% of patients will experience a second stone within 10 years of their first)

Question 23

Describe why kidney stones form on a basic solute level:

Answer 23

solute concretions exceed saturation, particularly in dehydration

Question 24

Give two causes of calcium stone formation:

Answer 24

1) hypercalcaemia/ primary hyperparathyroidism
2) hyperoxaluria

Question 25

Give 3 causes of hyperoxaluria:

Answer 25

1) ingestion of oxalate foods such as spinach, rhubarb and tea 2) GI disease such as Crohns associated with increased colon oxalate absorption 3) inborn errors of glyoxylate metabolism

Question 26

Give the two types of inborn errors of glyoxylate metabolism:

Answer 26

1) type 1: alanine-glyoxylate aminotransferase deficiency 2) type 2: glyoxylate reductase hydroxypyruvate reductase deficiency

Question 27

Give a cause of uric acid kidney stones:

Answer 27

hyperuricaemia

Question 28

Give two causes of hyperuricaemia:

Answer 28

1) idiopathic gout 2) myeloproliferative disorders (uric acid is the endpoint of purine synthesis)

Question 29

Describe how struvite stones are formed?

Answer 29

infection by bacteria like Proteus mirabilis hydrolyse urea to form ammonium hydroxide, favouring stone formation

Question 30

Give 3 examples of primary renal disease that can cause nephrolithiasis:

Answer 30

1) polycystic disease 2) medullary sponge kidney 3) renal tubular acidosis

Question 31

What is medullary sponge kidney?

Answer 31

Congenital dysplastic cystic dilatation of the medullary pyramids due to tubular ectasia or dysplasia

Question 32

What is renal tubular acidosis?

Answer 32

decrease in either tubular H+ secretion or HCO3- reabsorption that leads to a non-anion gap metabolic acidosis

Question 33

Name 3 drugs that can cause calcium stones:

Answer 33

1) loop diuretics 2) antacids 3) glucocorticoids

Question 34

Give two drugs that can cause uric acid stones:

Answer 34

1) thiazides 2) salicylates (aspirin)

Question 35

Give two drugs that can precipitate into kidney stones:

Answer 35

1) indinavir 2) triamterene

Question 36

What is renal colic?

Answer 36

passage of the stone through the ureter.

Question 37

Give 3 ways renal colic can be managed:

Answer 37

1) analgesia 2) increased hydration 3) if the stone is more than 1cm, radiological or urological intervention may be needed e.g. extracorporeal shock wave therapy

Question 38

What is nephrocalcinosis?

Answer 38

A condition of calcium deposits within the renal parenchyma

Question 39

What is obstructive megaureter?

Answer 39

a childhood condition, only becoming evident in adult life where the ureter becomes wider due to the presence of a region of defective peristalsis at the lower end of the ureter

Question 40

Is obstructive megaureter more common in males or females?

Answer 40

males

Question 41

Give 3 symptoms of obstructive megaureter:

Answer 41

1) UTIs 2) flank pain 3) haematuria

Question 42

What is retroperitoneal fibrosis?

Answer 42

inflammatory fibrotic tissue encasing the aorta and ureters, compressing the ureter

Question 43

Is retroperitoneal fibrosis more common in males or females?

Answer 43

Males (x3)

Question 44

Give 4 presentations associated with retroperitoneal fibrosis:

Answer 44

1) lower back pain 2) weight loss 3) testicular pain 4) haematuria

Question 45

Give 3 lab findings that support diagnosis of retroperitoneal fibrosis:

Answer 45

1) anaemia 2) raised CRP 3) low GFR

Question 46

What imaging technique is used to view the peri-aortic mass seen in retroperitoneal fibrosis?

Answer 46

contrast-enhanced CT

Question 47

Give 3 management techniques for retroperitoneal fibrosis:

Answer 47

1) stenting of the ureters 2) corticosteroids 3) biopsy for underlying cause

Question 48

what is the most common type of urinary tract stone?

Answer 48

CALCIUM STONES - specifically calcium oxalate stones - mainly linked to hypercalciuria

Question 49

are calcium phosphate stones associated with low or high urine pH?

Answer 49

high - linked to renal tubular acidosis

Question 50

are uric acid stones associated with low or high urine pH?

Answer 50

low <5.5 - caused by diseases resulting in excessive breakdown of tissue

Question 51

what causes struvite stones?

Answer 51

UTI - bacteria hydrolyses urea into ammonium > high urine pH >7.2

Question 52

what minerals form struvite stones?

Answer 52

- magnesium - ammonium - phosphate

Question 53

what causes cystine stones?

Answer 53

a genetic disorder > cystinuria

Question 54

what are the risk factors of developing urinary tract stones?

Answer 54

- obesity - dehydration - diets rich in oxalate (fruits, nuts and cocoa), urate, sodium and animal protein - FH - anatomical abnormalities in urinary tract - medical conditions eg hyperparathyroidism, renal tubular acidosis, myeloproliferative disorders and chronic diarrhoea - drugs - previous urinary tract stone

Question 55

what are the investigations for urinary tract stones?

Answer 55

- urinalysis - urine MC+S - vital signs - FBC, U+Es, calcium and uric acid - non contrast CT = gold standard

Question 56

what investigation should be used for imagine urinary tract stones in pregnant women and children?

Answer 56

ultrasound

Question 57

what surgery is used for urinary tract stones <2cm?

Answer 57

- extracorporeal shockwave lithotripsy (ESWL) - ureteroscopy (middle/distal ureteric stones and pregnant)

Question 58

what surgery is used for urinary tract stones >2cm?

Answer 58

- percutaneous nephrolithotomy - open stone surgery (severe or above fails)

Question 59

what are the complications of urinary tarts calculi?

Answer 59

- OBSTRUCTION OF URINARY FLOW > kidney damage or pyelonephrititis - renal carcinoma - CKD - rupture