Renal Stone Disease

Front 1

Renal Stones: Epidemiology, Risk Factors, clinical presentation, differential diagnosis, Work-up

Back 1

1.Epidemiology: 10% of ppl > 60, higher in N.W. US/S.E. US/scandinavia/india/pakistan and lower in africa
2. Older age, Low fluid intake
3. Severe pain, N/V, frequency/urgency, hematuria (usually microscopic)
4. Ddx: Other causes of obstruction, pyeloneprhitis, biliary colic, bowel obstruction, pancreatitis, AAA, ectopic pregnancy, torsion/rupture, ovarian cyst, radiculitis
5. Work-up: Urinalysis (routine+microscopy), Blood tests (CBC+Cr+electrolytes), Non-contrast spiral CT scan of abdo and pelvis, KUB xray

Front 2

What are the classic locations where stones get stuck? (3)

Back 2

Uteropelvic junction
Where ureter crosses iliac vessels (debatable)
Ureterovesical junction

Front 3

Renal Stones Treatment: Medical, Emergency Surgical, Elective

Back 3

1. Medical: Analgesia (narcotics), NSAIDs, anti-emetics, antibiotics (for UTI), IV fluids (if depleted), alpha blockers (expulsion therapy)
2.Emergency surgery: Ureteric stenting, percutaneous nephrostomy
2. Elective management ureteric stones: observation (<5mm ureter, <1cm kidney+asymptomatic+non-obstructing), medical expulsive therapy, alkalinization (ureteric), shockwave lithotripsy, ureteroscopy, Percutaneous nephrolithotomy (kidney)

Front 4

What are the preferred elective treatment methods for renal stones based on size of stone? (Ureteric, Kidney)

Back 4

1.Ureteric <5mm=observation, >5mm = Medical Expulsive Therapy, Shockwave Lithotrypsy, Ureteroscopy
Kidney: <1cm+asymptomatic+non-obstructive=observation, <1.5cm=shockwave lithotripsy, 1.5-2.5cm=shockwave lithortripsy+ureteric stent, <2cm=ureteroscopy if patient prefers, >2.5cm+staghorn=percutaneous nephrolithotomy

Front 5

What are different types of renal stones? (6)

Back 5

Calcium oxalate (80%)
Uric acid (10%)
Struvite (10%)
Cystine
Matrix
Medication-stones: triamterent, indinavir

Front 6

How do you analyze a stone to determine which type it is? (3)

Back 6

Chemical analysis
X-ray defraction
Infrared spectometry

Front 7

What is involved in a full metabolic workup? (for recurrent stone formers)

Back 7

1.24hr urine culture x2: volume, pH, Cr., K+, Na+, Ca++, phosphate, uric acid, oxalate, Mg++, citrate
2. Blood work: Ca++, Po4, uric acid, creatinine, electolytes, PTH

Front 8

What causes stone formation in general? (2 categories)

Back 8

1.Excessive stone promoters: Concentrated urine, increased urine Ca++/oxalate/uric acid, urinary stasis, infection
2. Insufficient stone inhibitors: citrate (for calcium binding), magnesium (for oxalate binding), pyrophosphate, glycoprotein

Front 9

Calcium Stones: Common types, Appearance, Etiology, stone prevention

Back 9

1. Common types: Ca+oxalate>Ca+phosphate>mixed
2. Appearance: Radiopaque (xray), grey-brown-black
3. Etiololgy: Hypercalcuria (increased intestinal absorption, renal leak, resorption from bone, medullary sponge kidney, distal renal tubular acidosis), Hyperoxaluria
4. Stone prevention: Medication (hydrochlorothiazide, K+ citrate), Diet (increase fluids, reduce animal protein/Na+/oxalate/alcohol intake, do NOT reduce Ca++ intake)

Front 10

How does hypercalciuria occur? (5 mechanisms)

Back 10

1. Increased intestinal absorption: increased ingestion of Ca++ or Vit.D, idiopathic
2. Renal leak: decreased renal tubular reabsorption
3. Resorption from bone: hyperparathyroidism (primary or secondary), Immobilization, malignancy, steroids
4. Medullary sponge kidney: cystic dilation of collecting ducts causing hypercalciuria+stasis
5. Distal renal tubular acidosis: Can't excrete acid urine causing increased secretion of K+, Na+, Ca++ and PO4

Front 11

What causes hyperoxaluria?

Back 11

Increased concentration of bile salts + fatty acids reach colon which promotes oxalate absorption
Diseases: IBD, short bowel syndrome

Front 12

Struvite stones: Etiology, components, appearance, treatment

Back 12

1. Etiology: Infection with urea splitting organsisms (Proteus, Klebsiella, Pseudomonas) causes increased urine NH4/alkalinity and promotes struvite stone formation.
2.Components: Calcium, magnesium, ammonium
3.Appearance: Staghorn stone
4.Treatment: surgical removal + antibiotics for 6 wks + follow-up urine cultures

Front 13

Uric Acid Stones: Etiology, Appearance, Treatment

Back 13

1. Acid urine + high uric acid levels (gout, malignancy, drugs-ASA)
2. Appearance: Radiolucent (xray), Radiopaque (CT), Filling defect (IVP), Apparent on U/S
3. Treatment: Increase fluid intake, alkalinization, allopurinol, no high protein diet

Front 14

Cystine Stones: Etiology, Appearance, Diagnosis, Treatment

Back 14

1. Etiology: Autosomal recessive defect in tubular transport resulting in decreased resorption of Cystine, Ornithine, Lysine and Arginine (COLA)
2. Appearance: Multiple stones or staghorn, hard, yellow, "maple sugar"
3. Diagnosis: COLA in urine
4. Treatment: Increase water intake, alkalinization, decreased dietary protein, penicillamine/thiola/captopril, PCNL (renal), ureteroscopy+laser lithotripsy (ureteral)

Front 15

Bladder Stones: Etiology, appearance, Clinical Presentation, Stone types, Treatment

Back 15

1. Etiology: Stasis, foreign body
2. Appearance: large, multiple, less developed countries
3. Clinical presentation: Frequency/urgency, pain at end of urination, pyuria, hematuria, obstructive symptoms
4. Stone types: Ca++ oxalate/phosphate, Uric acid
5. Treatment: Transurethral litholapaxy, Removal of outflow obstruction (TURP, stricture dilation)

Front 16

What are indications for hospitalization or urgent intervention of renal stones? (5)

Back 16

Pain not controlled by oral analgesic
Fever and UTI
Refractory vomiting
Solitary kidney with obstruction OR bilateral obstructing stones
Severe hematuria