Urogenital Flashcards
What is renal colic?
Pain due to renal calculi (kidney stones)
What are renal calculi/kidney stones also known as?
Nephrolithiasis
Describe the epidemiology of nephrolithiasis
- 10% lifetime risk
- More common in men (2:1)
- Higher prevalence in Middle East
What are 6 causes of nephrolithiasis?
- Urinary (dehydration)
- Infection (proteus, Klebsiella, Pseudomonas)
- Hypercalciuria
- Hyperoxaluria
- Uric acid stones
- Cystine stone
What are 6 risk factors for nephrolithiasis?
- Chronic dehydration
- Obesity
- High protein/salt diet
- Recurrent UTIs
- Hyperparathyroidism
- Congenital abnormalities
Describe the pathophysiology of nephrolithiasis (nucleation theory)
- Urine is composed of water (solvent) and particles (solute)
- When solute becomes too concentrated –> supersaturated –> solute precipitates and forms crystals
- Occurs due to an increase in solute or decrease in solvent
What commonly occurs in nephrolithiasis?
Stones cause obstructions leading to hydronephrosis (one/both kidneys become stretched/swollen due to the build-up of urine inside)
What are the 3 most common blockage sites in nephrolithiasis?
- Pelviureteric junction (PUJ) - most common
- Pelvic brim
- Vesicoureteric junction (VUJ)
What 7 things commonly make up the components of kidney stones/renal calculi?
- Calcium oxalate (forms in acidic urine)
- Calcium phosphate (forms in alkaline urine)
- Calcium carbonate
- Struvite (ammonium phosphate)
- Uric acid
- Cystine
- Drug precipitants
What is the main symptom of nephrolithiasis?
Renal colic:
- Severe unilateral abdominal pain
- Starts in loin and radiates to ipsilateral groin/testicle/labia
- Classically onset and early in the morning
What are 4 other symptoms of nephrolithiasis?
- Restlessness
- Nausea and vomiting
- Haematuria (blood in urine)
- Dysuria (painful urination)
What are 4 investigations for nephrolithiasis?
- Non contrast CT KUB (GOLD STANDARD)
- Ultrasound KUB in pregnancy
- Dipstick (haematuria, leucocytes, nitrites)
- Bloods (FBC, CRP, U&Es)
What is the treatment for nephrolithiasis?
- Small enough stones (<5mm) pass on their own
- ESWL (extracorporeal shock wave lithotripsy - breaks stones into smaller fragments using shockwaves)
- Ureteroscopy PCNL (percutaneous nephrolithotomy - nephroscope used to remove stone)
- Symptomatic relief (NSAIDs/opioids)
- Decrease sodium/protein intake
- Increased citrus fruit
- Rehydration/adequate fluid intake
What are 3 complications of nephrolithiasis?
- Recurrence is common
- Irreversible renal damage
- Long term blockage can cause sepsis
What is acute kidney injury (AKI)?
Rapid deterioration of renal function
Describe the epidemiology of AKI
- 15% of adults admitted to hospital develop AKI
- More common in the elderly
What are 8 risk factors of AKI?
- HTN
- Volume depletion
- CKD
- Diabetes
- Cirrhosis
- Nephrotoxic medications
- Cancer
- Trauma
Describe the pathophysiology of pre-renal AKI
Decreased volume = decreased perfusion = decreased GFR and decreased creatinine clearance
What are 2 pre-renal causes of AKI?
- Low blood volume (bleeding/dehydration/shock/D&V)
- Low effective circulating volume (cirrhosis/congestive HF)
Describe the pathophysiology of glomerular intra-renal AKI
Barrier damage and protein leakage = decreased oncotic pressure = decreased GFR
What is a cause of glomerular intra-renal AKI?
Glomerulonephritis
Describe the pathophysiology of tubular intra-renal AKI
Complex blood supply –> cells infarct –> break away –> plug tubules –> decreased hydrostatic pressure = decreased GFR
What are 3 causes of tubular intra-renal AKI?
Necrosis:
1. Prolonged ischaemia
2. Infection
3. Nephrotoxins
Describe the pathophysiology of interstitial intra-renal AKI
Inflammation and immune cells = damage