Urinary Tract Calculi Flashcards
What are urinary tract calculi? (2 things)
- Stones formed anywhere in UT
- Caused by precipitations of solutes in urine
What are some general risk factors for urinary tract calculi? (3 things)
- Male
- FHx
- Dehydration (increases concentration of urine solutes)
What medical conditions increase the risk of urinary tract calculi? (5 things)
- UTI
- Gout (high uric acid)
- Hyperparathyroidism (high Ca)
4 HTN - DM
What features of a diet increase the risk of urinary tract calculi? (3 things)
- High Na = reduces Na + Ca reabs @ PCT = hypercalciuria
- High Ca
- High oxalate
What medications increase the risk of urinary tract calculi?
Loop diuretics = X Ca reabs @ DCT
What foods increase oxalate? (5 things)
- Chocolate
- Tea
- Rhubarbs
- Strawberries
- Nuts
What causes Calcium oxalate stones?
Metabolic / idiopathic
What causes Calcium phosphate stones?
Metabolic / idiopathic
What causes Magnesium Ammonium Phosphate stones?
UTI
What causes Urate stones?
Hyperuricaemia
What causes Cystine phosphate stones?
Renal tubular defects
What are the most common sites for stones to lodge? (3 things)
- Pelviureteric junction (renal pelvis + ureter)
- Pelvic brim (ureteral crossing of iliac vessels)
- Vesicoureteric junction (urinary bladder + ureter)
When can urinary tract calculi be asymptomatic? (2 things)
- Small stones
- Stones @ renal pelvis / bladder
What are the clinical features of urinary tract calculi? (6 things)
- Fever (inf / pyelonephritis)
- N+V
- Abd pain (colicky, unilateral) (bc ureteric obst)
- Costophrenic Angle Tenderness
- Haematuria
- Inability to lie still (differentiates from peritonitis)
What is Costovertebral Angle tenderness?
Where does the Abd pain in Urinary Tract Calculi radiate to? (2 things)
- Groin
- Testes / labia majora
What are other differentials that present similarly to urinary tract calculi? (4 things)
- Acute appendicitis
- Biliary colic
- Diverticulitis
- Testicular torsion
How do you differentiate Acute Appendicitis from Urinary Tract Calculi?
UTC = causes FLANK pain
How do you differentiate Biliary Colic from Urinary Tract Calculi?
UTC pain NOT related to eating
How do you differentiate Diverticulitis from Urinary Tract Calculi?
UTC NO bloody stools
How do you differentiate Testicular Torsion from Urinary Tract Calculi?
UTC = causes FLANK pain
What lab tests should be done for Urinary Tract Calculi? (5 things)
- Urine dip (haematuria / infection)
- FBC (raised WCC in infection)
- CRP (raised in infection)
- U&Es
- renal function
- urate + calcium levels (to find stone type)
- stone in urine –> retrieve + analyse to find type - Urine culture (if infection present)
What is the Gold standard imaging for Urinary Tract Calculi?
Non-contrast CT of KUB (kidneys ureters and bladder)
Why is non-contrast CT of KUB the Gold standard imaging for UTC? (2 things)
- 99% stones visible
- Excludes acute abdomen differentials (e.g ruptured AAA)
What are the disadvantages of AXR for UTC?
Not all stones are radio-opaque
When can a US be done for UTC?
To assess for hydronephrosis (kidney swelling)
What is the disadvantage of US for UTC?
Detects renal stones but NOT ureteric stones
How should all patients with UTC be managed initially? (3 things)
- IV fluid resus
- Analgesia
- Abx if infection (piperacillin / tazobactam / gentamicin)
After initial management of a UTC patient what does the next management depend on?
Size of stones
How should a patient with a stone smaller than 5mm be managed?
Just observe (stone will pass by itself)
How should a patient with a 5-10mm stone be managed?
- alpha-blockers (tamsulosin)
- Calcium channel blockers (nifedipine)
How do alpha-blockers and Calcium channel blockers help patients with UTC? (2 things)
How?
- Promote stone expulsion
- Reduce analgesia req
By dilating + relaxing ureters
How should a patient with a 10-20mm stone be managed? (2 things)
- ESWL (extracorporal shock wave lithotripsy)
- Ureteroscopy
How does ESWL help a patient with UTC?
US shock waves shatter stone
What are the contraindications for ESWL in UTC patients?
Obese patients because poor penetration of US waves
What are the side fx of ESWL used in UTC? (3 things)
- Renal injury
- Increased BP
- DM
How should a patient with a 20+ mm stone be managed? (2 things)
Percutaneous nephrolithotomy (key whole surgery to remove stone)
How should a patient with a Calcium stone be managed? (3 things)
- Low sodium diet = increases Na + Ca reabs @ PCT
- Thiazide diuretics = increases Ca reabs @ DCT
- Citrate (dissolves Calcium oxalate crystals)
How should a patient with a Magnesium Ammonium Phosphate stone be managed?
Abx (bc caused by UTI)
How should a patient with a Urate stone be managed? (2 things)
- Potassium citrate = alkalises urine = dissolves crystals
- Allopurinol = reduces uric acid prod
How should a patient with a Cystine stone be managed?
Tiopronin / Penicillamine = chelates crystals
What are the complications of UTC? (3 things)
- Hydronephrosis (swollen kidney)
- Acute Pyelonephritis
- Post-renal AKI
What is Acute Pyelonephritis? (2 things)
- Bac overgrowth caused by stone obstructing UT
- Renal pelvis inflamm
(complication of UTC)
How does Acute Pyelonephritis present? (4 things)
- Fever
- Frequency
- Urgency
- Dysuria
What is hydronephrosis? (2 things)
- Proximal accum of urine caused by stone obstructing UT
- Renal pelvis + calyx dilation (visible in US)
(complication of UTC)
