This document provides an outline for a presentation on the pathology and management of urolithiasis (urinary tract stones). It covers the epidemiology, pathophysiology, anatomy, and typical workup and treatment approaches. The most common stone types are calcium, urate, struvite, and cystine stones. Evaluation involves imaging like CT, ultrasound, or IVU to identify stones and rule out complications. Treatment depends on stone size and location, but may involve conservative management, medical expulsive therapy, or surgical intervention if conservative measures fail. The goal is to relieve pain, pass stones spontaneously if possible, and prevent future stone formation through lifestyle and medical management.

1. Presentation
on
Pathology and Management of Urolithiasis
By
Dr Ahmed Yakubu

2. OUTLINE:
Introduction
Pathophysiology
Management
- History
- Examination
- Investigation
- Treatment
Prevention
Conclusion
Bibliography

3. INTRODUCTION
Urolithiasis is the occurence of stones (calculi) in the urinary tract.
Urolithiasis affects all geographcal, cultural, and racial groups.
The lifetime risk of occurrence of urolithiasis is generally higher in hot
climates and also reflects dietary habits in different regions which is
also reflective higher incidence of specific kinds of stones in diferent
regions.

4. Types:
4 Most Commonly Encountered calculi:
i. Calcium Stones
ii. Urate stones
iii. Magnesium ammonium phosphate stones (struvite)
iv. Cystine stones

5. Epidemiology
A study done in South-eastern (Enugu) state of Nigeria by I. A. Meka et al. showed that
bladder stones constituted the majority of renal stones encountered in their tertiary center
(A two-center study) 58%, mean age 37.3 (9.5years) and M:F = 5.3:1
A 5-year review done in the south-western (Lagos) state tertiary hospital by Olufunmilade
Omisanjon et al. showed that bladder stones constituted the majority of renal stones
48.7%, mean age 49.13 (16.27 years) and M:F = 1.8:1
Generally significant proportion of statistics globally shows higher incidence in dry/hot
regions or regions with scarcity of water, Male > Females and commoner in young age
group.

6. Anatomy
Retroperitoneally:
- Kidneys and its vessels
- Proximal ureter
Dimensions: 12 x 6 x 3cm
Average renal pelvis: <5mls
Dermatome of pain fibres: T12 - L1

7. Avascular Plane of Brodel

8. - 25cm
- Diameter 3mm with 3
constricted areas as illustrate
- Lies anterior and slightly medial
to tips of the transverse
processes from L2 to L5
- Enters pelvis opposite the
sacroiliac joints
- Runs forward and medially at the
level of the ischial spine

9. Male: 15 to 20cm
Membranous part: least
distensible and narrowest
Female: 4cm

10. PATHOPHYSIOLOGY
Calcium Stones
1. Hyperoxaluria
- Primary hyperoxaluria:
AGT enzyme: converts glyoxylate into glycine
Deficiency of GH/HPR: converts glyoxylate into glycolate
Lactate dehydrogenase: converts accumulated glyoxylate into oxalate

11. PATHOPHYSIOLOGY
- Secondary Hyperoxaluria
Enteric Hyperoxaluria: GI related conditions such as celiac disease,
crohns disease, pancreatitis, biliary diseases, low dietary calcium or
short bowel syndrome; gastric bypass.
Dietary Hyperoxaluria: (24% - 53%) Leafy green (especially spinach and
rhubarb), chocolate, cocoa, black tea, nuts, peanut butter , or starfruit,
may increase serum, urine oxalate levels.

12. PATHOPHYSIOLOGY
2. Hypercalciuria:
Defined by urinary calcium in excess of 250mg in females; 300mg/day
in males or 4mg/kg/day
Defective Calcium Handling:
- Transcelluar Route: Apical entry via TRP calcium channel and L-type
calcium channel; Intracellular buffering + shuttling via Calbindin;
basolateral transport via PMCA and NCX1.
- Paracellular Route: Paracellular claudin protein; NKCC2/ROMK
channel; NHE3; CaSR.

13. PATHOPHYSIOLOGY
*With excessive GI absorption and/or defective renal reabsorption
hypercalciuria ensues thus absorptive hypercalciuria or renal leak
hypercalciuria occurs.
- Renal phosphate leak hypercalciuria: Defective NPT2a
- Resorptive Hypercalciuria: Hyperparathyroidism

14. PATHOPHYSIOLOGY
Hyperuricaemia/Hyperuricaemia:
In acidic media with pH <5.5 nearly 100% of uric acid is in the
undissociated form.
Precipitating factors
- Low urinary pH:
Primary gout, Dehydration, Familial, IBD, Obesity, DM, Metabolic
syndrome
- Elevated urinary uric acid:
High purine-rich diet, myeloproliferative Dxs, In-born errors of
metabolism (HGPT deficiency, PRPS superactivity, G6PD deficiency),
and medications.

15. PATHOPHYSIOLOGY
Cystinuria:
rBAT and b0,+AT cystine transporter are defective due to SLC3A1 and
SLC7A9 genetic mutation
Magnesium ammonium phosphate calculi:
Urea splitting organisms result in the generation of ammonium,
bicarbonate and carbonate. In alkaline media the dissociation potential
of struvite salts reduces.

16. PATHOPHYSIOLOGY
The Balance!
Metastable supersaturated state vs unstable saturated state of urine
Simple crystalluria vs crystal aggregation (epitactic induction of
crystallization)

17. PATHOPHYSIOLOGY
Inhibitors
- Inorganic pyrophosphate (calcium phosphate)
- Diphosphonates (calcium oxalate)
- Urinary citrate and magnesium
- Glycosaminoglycans; urinary prothromin fragment 1; osteopontin; Tamm horsfall protein
Promoters:
- High urinary calcium, oxalate, sodium and uric acid
- Low urine volume
- Stasis/urinary tract obstruction

18. PATHOPHYSIOLOGY
The pain - Nerve endings and chemoreptors in the submucosa tract
- Stretching and irritation of tract
- Acute dilatation
- Reflex Spasm
- Migration of calculi
- Reactive inflammationwith (edema formation)
- Proximal hyperperistalsis
?Infection

19. PATHOPHYSIOLOGY
Most acute pain subside after 24hrs and further in following weeks in
the absence of infection or stone movement:
- Ureteral hyperperistalsis diminishes
- Renal blood flow diminishes
- Decline in urine production
- autoregulatory/reflex retrograde pyelovenous and pyelolymphatic
drainage
- Reduction in proximal hydrostatic pressure and pain
- ?Pericalculous leakage

20. MANAGMENT -
History:
Complain:
*Pain
Hematuria
Irritative/obstructive urinary tract symtoms (LUTS)
Features of urosepsis
Features renal decompensation

21. History
Pain character and associations
- Pelvo-calyceal calculi
- Proximal ureteral calsuli
- Mid ureteral
- Distal ureteral
- Bladder stones

22. Differential Diagnosis
Left: Pancreatitis
PUD
Diverticulitis
Right:
Cholecystitis
Appendicitis
Biliary colic
Papillary necrosis
Pyelonepritis
Acute scrotum
Cystitis
Renal cell carcinoma
Prostatic diseases
Renovascular disorders
*Abdominal aortic aneurysm

23. Conditions associated with increased risk of urolithiasis:
- Intestinal resection
- Hyperparathyroidism
- Spinal cord injury
- Hyperthyroidism
- Renal tubular acidosis
- Jejunoileal bypass
- Crohn’s disease
- Malabsorptive conditions
- Sarcoidosis

24. Medications associated with stone formation
- Acetazolamide
- Sulphonamides
- Triamterene
- Indinavir

25. Complications:
- Intractable pain
- UTI/Urosepsis
- Calculous Hydronephrosis
- Calculous pyonephrosis
- Renal failure (Long standing obstruction)
- Squamous cell carcinoma
- Perinephric abscess
- Perforation + extravasation

26. Examination
- Diaphoretic
- Restless
- Costovertebral tenderness
- Tender testicles but not pathologic
- Vitals: Tachycardia + Elevated BP
- Fever IN THE SETTING OF URINARY INFECTION

27. Investigations:
Non-contrast Abdominopelvic CT

28. KUB Radiograph
Radioopaque: 85% of upper
urinary tract calculi
- Calcium stones
- Struvite stone
Relatively radiolucent:
- Uric acid stones
- Indinavir stones
- ?Cystine stones

29. Differetials of calcifications on KUB Radiograph:
- Gall stones
- Costal cartilage calcifications
- Calcified adrenals
- Phlebolith
- Fecolith
- Calcified lymph nodes

30. Ultrasonography
- Low sensitivity for ureteral stones
- Recommended as first line in pregnancy
- Pediatric cases
- May be utilized in follow-up monitoring of calculi migration
- Can reveal obstructions

31. Intravenous Urography
- Outines the urinary tract
- Reveals anatomical anomalies
- Gives an idea of renal fuction
- Useful in extensive extrarenal calfications
- Reveal non-opaque calculi
Draw backs:
- Nephrotoxicity
- Allergy
- TAT
- False negatives

32. Anatomical abnormalities associated with stone formation
- Medullary stone kidney
- Horseshoe kidney
- Pelvo-ureteral junction obstruction
- Caliceal diverticulum
- Caliceal cyst
- Ureterocele
- Ureteral stricture
- Vesico-ureteral reflux

33. - Urinalysis:
Leukocytes
Nitrite
pH
Haemoglobin
SG
Urobilinogen/Bilirubin
Glucose
Protein

34. FBC + Differentials
E/U/Cr; Ca2+, PO4
-3 and Albumin
Urine microscopic
Urine culture & sensitivity testing

35. 24 Hour Urine Profiling:
Objective indications:
- Initial presentation with multiple calculi
- Urolithiasis with renal failure
- Solitary kidney
- family history of urolithiasis
- More than one case of urolithiasis in a year
- Bilateral calculi
Commonest findings: Hypercalciuria, hyperoxaluria, hyperuricosuria, hypocitraturia and
low urinary volume

36. 24hour Urine Analysis
Volume: 2500mls/day;
Urine creatinine: 18 to 24mg/kg for male
15mg to 20mg/kg for female.
pH 5.7 to 6.3
Hypercalciuria: >300mg/24 hour in men
>250mg/24 hour in women
Hyperuricosuria: >800mg/24hour in men
>750mg/24 hour in women
Hypocitraturia: <320mg/24 hour (1.67mmol/24hour)
Hyperoxaluria: >40mg/24hour
*Other parameters routinely included are urinary potassium, sodium and magnesium levels.

37. Treatment:
Emergency Care:
- Excruciating Pain!!!
- Adequate analgesic: Stat dose of opoids, subsequent doses for
breakthrough pain; NSAIDs maintenance.
- Antiemetic
- Hydration
- Investigate: ?Position ?size ?number ?complications ?comorbid
conditions

38. Non-operative Treatment
Conservative therapy - Active MET:
Out-patient care in the post-acute phase
Favourable factors:
Lower ureteric stones
<10mm (<5mm)
Reasonable pain control
Normal kidney function
Sterile urine
A preferred approach in pregnancy and pediatrics

39. Active MET
Enhances chance of spontaneous passage
Reduces surgically related complications
General Interventions:
- Enhanced fluid intake with output goal of >2.5/day
- Reasonable analgesia
- Alpha RBs
- CCB: nifedipine
- Avoid prolong period of recumbencys
- Restricted sodium/protein intake
- Enhanced intake of citrate rich meals
- Magnesium supplements

40. Active MET continues
Hyperoxaluria:
General interventions
No calcium restriction
Hypercalciuria:
General interventions
Thiazide diuretics
Cystine calculi:
General interventions
Chelating agents: MPG/D-
pencillamine
Urate calculi:
General interventions
Allopurinol
Alkalinization of urine (Likewise in
cystine calculi)

41. Active MET continues
Follow up: 14days
- Regular image monitoring
- Monitoring of renal function
- Monitoring of sterility of urine
- Use of urinary strainer at all times
- Report if worsening of symptoms/onset of warning symptoms

42. Active MET continues
Contraindications to conservative management:
- Occupation: Pilot
- Deteriorating renal function
- UTI
- Intractable pain
- Ureteral obstruction in solitary kidney/transplated kidney

43. Extracoporeal Shockwave Wave Lithotripsy
A system utilized to fragment renal calculi via generation and focusing
of shock waves using a lithotripzer guided by a localization device.
4 Components:
- Energy source (electromagnetic, electrohydraulic and piezoelectric)
- Focusing device
- Coupling medium
- Localization system via fluoroscopy/ultrasonography

44. Features favouring use ESWL:
<3mm
Solitary calculi
Location: upper/mid pole calculi & proximal ureter
Calcium stones
Normal anatomy
*May be used as adjuvats to PCNL/URS

45. Unfavourable conditions:
Extreme of ages
Morbid obesity
Lower pole calculi
Obstruction
*The reverse of favourable conditions

46. Contraindications:
- Patient with pacemakers/defibrilators implants
- Pregnancy
- Cytine stones
- Calcium oxalate calculi >2.5cm/Struvite >5cm
- Starghorn calculi
- Calcified aortic aneurysm within 5cm of focus
- Renal artery aneurysm
- Urosepsis

47. Complications:
Ureteric stricture
Incomplete stone fragmentation and obstruction
Urosepsis
Arrythmias
perirenal hematoma
pancreatitis

48. Operative Management
Stenting and Percutaneous Nephrostomy:
*Obstructions and/or Infections
- Persistent pain
- Pyonephrosis
- Anuria
- Solitary kidney prior to ESWL
- Infected hydronephrosis

49. Percutaneous Nephrolithotomy
- Failed ESWL
- Cystine calculi
- Patient with pacemakers or
defibrilators implants
- Calculi with abnormal anatomy
- Lower pole calculi<10mm
*Absolutely contraindication:
Coagulopathy
- Calculi >2cm
- Renal artery aneurysm
- Proximate calcified aortic
aneurysm
- Renal pelvic calculi/proximal
ureteral calculi

50. Uretero-renoscopy + Lithotripsy
- Most suited for calculi >1.5cm
- Cystine calculi
- Upper pole calculi
- Lower pole calculi <10mm
- Combined Renal + ureteric calculi

51. Pyelolithotomy:
- Surgical removal of calculi in the pelvi-calyceal complex
Nephrolithotomy:
- Surgical removal of calculi deep in the renal parenchyma
Indications:
- Failed or unavaibility of ESWL/PCNL/URS+Lithotripser
- Co-existing pathology necessitating approach
*Necessary in less than 3% cases of urolithiasis
*Lateral approach/Dorsal lumbotomy

52. Nephrectomy:
Non-functional/poorly kidney(s)
- GFR <15ml/min/1.73m2
- <10 to 15% Functional capacity
Ureterolithotomy:
- Removal of calculi via an incision through the ureter
- Fading out of practice

53. Bladder calculi:
Transurethral cytolitholapaxy
Percutaneous suprapubic cytolitholapaxy
Open suprapubic cystotomy
*Contraindicated only in unstable or near-terminal asymptomatic
patients
*ESWL - not so effective in bladder calculi cases

54. PREVENTION
- High fluid intake
- Restricted dietray salt intake
- Caution with diet high in purine
- Increase citrus fruit intake

55. CONCLUSION
The understanding of the pathogenesis of urolithiasis is a growing area
in urology that delves deeper with each unveiling understanding of the
process.
Its mangement spans from non-operative active MET and ESWL
interventions to temporizing measures such as stenting/percutaneous
nephrostomy to corrective minimally invasive interventions.

56. BIBLIOGRAPHY
- MedScape - Nephrolithiasis by Chirag N Dave
- A comprehensive approach to long cases in surger - approach to
patient with gross hematuria, urinary calculi by Emeka Kesieme
- 2007 guidelines for management of ureteral calculi by EAU/AUA
Neprolithiasis guideline panel
- Inhibitors and promoters of stone formation by Herbert Fleisch
- Textbook of Medical biochemistry for medical students by DM
Vasudevan
- Last’s anatomy - regional and applied, part 11 by Chummy S.
Simmatamby