Renal Colic - Kidney stones Flashcards
Renal stones can be referred to as …
Renal caliculi
Urolithiasis
Nephrolithiasis
Kidney Stones
What are kidney stones
hard stones that sit in the renal pelvis where the urine collects before travelling down to the ureters
Stones form in collecting ducts
Most common site that stones would get stuck
Vesico - ureteric junction
Two key complications of stones
Obstruction- leading to AKI
Infection- with obstructive pyelonephritis
Most common type of kidney stone and its subgrouops
CALCIUM BASED STONES
Calcium oxalate - 80-85
Calcium Phosphate
major risk factors for stones
Hypercalcaemia
Low urine output
Dehydration
Other types of kidney stones
Uric acid- not visible on x ray
Struvite- produced by bacteria
Cystine- associated with cystinuria
What is a staghorn calculus
where the stone forms in the shape of the renal pelvis,
The body sits in the renal pelvis with horns extending into the renal calyces.
Presentation of stones
- RENAL COLIC
- unilateral loin to groin pain ‘ patient cant lie still’
- Colicky as the stone moves and settles
-Luts
-Haematuria - dysuria
- fever
Other signs and symptoms of kidney stones
Haematuria
Nausea or vomiting
Reduced urine output
Symptoms of sepsis, if infection is present
Investigations for renal colic
- Urine dipstick- will show haematuria
- Blood tests - elevated wbc may indicate infection
- Abdo x ray- can show calcium based stones
- Non contrast CT of kidneys, ureters and bladder within 24 hrs
- 1st line KUB XRAY
- GS: Non-Contrast Computerized Tomography Scan of the kidneys, ureter, and bladder
Presentation of hypercalcaemia ?
“renal stones, painful bones, abdominal groans and psychiatric moans”.
The three main causes of hypercalcaemia
calcium supplementation, hyperparathyroidism and cancer
Management of Kidney stones
NSAID’s
Antiemetics for N AND V
Antibiotics if infection
Tamsulosin to aid in spontaneous passage of stones
What are the surgical interventions for kidney stones ?
Extracorporeal shock wave lithotripsy : generates shock waves and directs them at the stone under x ray guidance
Dietary recommendations for calcium and uric acid stones
Calcium- reduce intake of oxalate- rich , spinach, beetroot, nuts, rhubarb
Uric acid stones - reduce intake of purine rich foods, kidney, liver anchioves sardines and spinach
Pathophysiology of kidney stones
Excess solute in CD– Supersaturated urine – favors crystallisation- causes kidney damage
Common Obstruction sites
Pelvic URETERIC JUNCTION
Pelvic brim
Vesoureteric junction
RF for stones
Chronic Dehydration
Polycystic kidney disease
HyperPTH
UTI’s
How is urine formed
Glomerular filtration - blood is filtered here, blood is filtered in such a way that all the constituents of the plasma reach the bowmans capsule
Reabsorption- via active and passive transport
Differential diagnoses of renal colic
- ruptured abdominal aortic aneurysm
- appendicitis
- ectopic pregnancy
- ovarian cysts
- bowel obstruction
What would urea and electrolytes show for renal colic
Raised creatinine suggesting AKI
What is the treatment of stones < 5mm in the lower ureter
90-95% pass spontaneously , increase fluid
Treatment for other kidney stones
Symptomatic relief - hyrdation, NSAIDs (IV Diclofenac for extreme pain)
Decrease sodium and protein intake
Mechanism of stone formation
Nucleation theory
What is the nucleation theory?
suggest that stones form from crystals in supersaturated urine
As Concentration product of ions (e.g. Ca and Oxalate) go up it reaches Ksp the solubility point and goes up from there to Kfp - formation point
History taking pneumonic
SOCRATES
What does socrates stand for
S = site
O = onset
C = character
R = radiation
A = associated features
T = timing
E = exacerbating / relieving factors
S = severity
Pros and cons Non-contrast Computerised Tomography – Kidneys, Ureter, Bladder
Very rapid (one breath hold)
99+% sensitive for stones Specificity ~90%
No contrast (allergies, renal function)
Other pathology/organs
But:
No functional info
Radiation (18/12 background, ~3.3mSv)
Guide to interpreting NCCT
1) Count the kidneys
2) Condition of kidneys:
Perinephric tissues
Cortical thickness
Hydronephrosis +/- hydroureter
Stones
3) Other pathology?
What can large kidney stones do?
- Larger stones occlude calyces and/or Pelvi-ureteric junction
- Can acutely obstruct – renal or ureteric colic
- Chronic renal damage (esp. if infection stone)
-abscess
-fistulae
-XPN (xanthogranulomatous pyelonephritis)
