Urology
Seán Keenan
2022
, Urinary Tract Calculi (Nephrolithiasis)
Description
Renal stones consist of crystal aggregates. Stones form in collecting ducts and may be deposited anywhere from the
renal pelvis to the urethra, through classically at 1. Pelviureteric junction; 2. Pelvic brim; 3. Vesicouretertic junction.
Lifetime incidence is 15 % with peak age being between 20-40 YO with 3x more males being affected. 75 % of stones
are calcium oxalate, 15 % are magnesium ammonium phosphate, 5 % urate, 5 % hydroxyapatite and ~1 % brushite.
Presentation Management
- Asx: May be asymptomatic until blockage - NSAID: Diclofenac (assess CVS) used for renal colic
- Pain: Renal colic; Dependent on location (below) - Fluids: If oral fluids cannot be tolerated
- Infx: UTI; Pyelonephritis - Conservative: ↑ Fluid intake
- Urine: Haematuria; Proteinuria; Sterile Pyuria; Anuria - NB: ~90-95 % pass spontaneously if stone <5 mm
Causes - Expulsion: Nifedipine; Tamsulosin
- Oxalate: Idiopathic; Metabolic - >48 hrs: Shockwave Lithotripsy (ESWL)
- Phosphate: Idiopathic; Metabolic - SE: Renal injury; HTN; DM
- Struvite: UTI; Esp. Proteus infx - Other: Uretoscope; Percutaneous nephrolithotomy
- Urate: Hyperuricaemia Complications
- Cysteine: Renal tubular defect - Cc: Urosepsis; AKI; Kidney obstruction; Bilateral
Investigations - NB: All require urgent intervention
- Exam: Usually no tenderness Therapeutic Selection
- Bloods: U&E; FBC; CRP; - Lithotripsy: Stone burden <2 cm in aggregate
- Urinalysis: Dipstick; MSSU; Oxalate levels - Ureteroscopy: Stone burden <2 cm in pregnancy
- Imaging: Non-contrast CT - PC Nephrolithotomy: Complex/Staghorn calculi
Renal Calculi Location and Presentation of Pain
Location Pain Description
Felt in the loin between rib 12 and lateral to lumbar m.
Obstruction of Kidney Intercostal nerve irritation pain
Pain worsens on movements/pressure on trigger point
Obstruction of Mid-Ureter May mimic appendicitis/diverticulitis
Bladder irritability
Obstruction of Lower-Ureter
Pain in scrotum, penile tip or labia jora
Pelvic pain
Obstruction in Bladder or Urethra Dysuria
Strangury ± Interrupted flow
Characteristics of Renal Stones / Crystals
Type Causative Factors Appearance on X-ray
Calcium Oxalate Metabolic or Idiopathic Spiky + radio-opaque
Calcium Phosphate Metabolic or Idiopathic Smooth, may be large, radio-opaque
Struvite (NH3MgPO4) UTI (proteus infection) Large, horny, 'staghorn', radio-opaque
Urate Hyperuricaemia Smooth, brown, radiolucent
Cysteine Renal tubular defect Yellow, crystalline, semi-opaque
Seán Keenan
2022
, Urinary Tract Calculi (Nephrolithiasis)
Description
Renal stones consist of crystal aggregates. Stones form in collecting ducts and may be deposited anywhere from the
renal pelvis to the urethra, through classically at 1. Pelviureteric junction; 2. Pelvic brim; 3. Vesicouretertic junction.
Lifetime incidence is 15 % with peak age being between 20-40 YO with 3x more males being affected. 75 % of stones
are calcium oxalate, 15 % are magnesium ammonium phosphate, 5 % urate, 5 % hydroxyapatite and ~1 % brushite.
Presentation Management
- Asx: May be asymptomatic until blockage - NSAID: Diclofenac (assess CVS) used for renal colic
- Pain: Renal colic; Dependent on location (below) - Fluids: If oral fluids cannot be tolerated
- Infx: UTI; Pyelonephritis - Conservative: ↑ Fluid intake
- Urine: Haematuria; Proteinuria; Sterile Pyuria; Anuria - NB: ~90-95 % pass spontaneously if stone <5 mm
Causes - Expulsion: Nifedipine; Tamsulosin
- Oxalate: Idiopathic; Metabolic - >48 hrs: Shockwave Lithotripsy (ESWL)
- Phosphate: Idiopathic; Metabolic - SE: Renal injury; HTN; DM
- Struvite: UTI; Esp. Proteus infx - Other: Uretoscope; Percutaneous nephrolithotomy
- Urate: Hyperuricaemia Complications
- Cysteine: Renal tubular defect - Cc: Urosepsis; AKI; Kidney obstruction; Bilateral
Investigations - NB: All require urgent intervention
- Exam: Usually no tenderness Therapeutic Selection
- Bloods: U&E; FBC; CRP; - Lithotripsy: Stone burden <2 cm in aggregate
- Urinalysis: Dipstick; MSSU; Oxalate levels - Ureteroscopy: Stone burden <2 cm in pregnancy
- Imaging: Non-contrast CT - PC Nephrolithotomy: Complex/Staghorn calculi
Renal Calculi Location and Presentation of Pain
Location Pain Description
Felt in the loin between rib 12 and lateral to lumbar m.
Obstruction of Kidney Intercostal nerve irritation pain
Pain worsens on movements/pressure on trigger point
Obstruction of Mid-Ureter May mimic appendicitis/diverticulitis
Bladder irritability
Obstruction of Lower-Ureter
Pain in scrotum, penile tip or labia jora
Pelvic pain
Obstruction in Bladder or Urethra Dysuria
Strangury ± Interrupted flow
Characteristics of Renal Stones / Crystals
Type Causative Factors Appearance on X-ray
Calcium Oxalate Metabolic or Idiopathic Spiky + radio-opaque
Calcium Phosphate Metabolic or Idiopathic Smooth, may be large, radio-opaque
Struvite (NH3MgPO4) UTI (proteus infection) Large, horny, 'staghorn', radio-opaque
Urate Hyperuricaemia Smooth, brown, radiolucent
Cysteine Renal tubular defect Yellow, crystalline, semi-opaque
