Kidney Stones Pales

Question 1

Types of stones based on composition

Answer 1

Calcium stones (80%)

• -Calcium oxalate
• -Calcium phosphate

Uric acid stones (5-10%)

Struvite (Mag/Ammonium/phosphate) stones (10-15%)

Cystine stones (less than 1%)

Question 2

Etiology of stones

Answer 2

Process of crystallization

• Too much solute
• Too little solvent (water)
• “Other” physical conditions (stasis, ph)

Question 3

Calcium stones risk factors

Answer 3

Hypercalciuria:

• Higher salt in the diet
• Higher non-dairy animal protein diet
• High Sucrose content in the diet
• Hyperparathyroidism
• Hypercalciuric Hypocalcemia

Hyperoxaluria

• Increased intake in high oxalate-containing food
• Decreased in oral calcium intake

Hypocitraturia

High urine pH
- RTA type I

Low urine volume

Question 4

Uric acid stones

risk factors

Answer 4

Hyperuricemia/hyperuricuria

• Gout
• Polycythemia Vera
• Tumor lysis syndrome

Low urine pH
- obesity, type 2 diabetes mellitus, and high non-dairy animal protein intake

Question 5

Struvite stones risk factors

Answer 5

Chronic UTI with urease producing bacteria (Proteus or Klebsiella)

Question 6

Cystine stones risk factors

Answer 6

Cystinuria (autosomal recessive disorder)

Question 7

Clinical Manifestations of stones

Answer 7

Asymptomatic during formation
Renal colic when stone moves through and/or obstructs one of the ureters
Micro- or macro-hematuria
Sometimes associated with UTI
- Fever/leukocytosis/pyuria/sepsis

Question 8

Renal colic

Answer 8

Sudden
Acute
Severe
Non-remitting with positional changes
Abdominal or back pain
Unilateral

Question 9

Differential Diagnosis

Answer 9

Acute cholecystitis 
Acute appendicitis 
Acute cystitis/pyelonephritis
Acute diverticulitis 
Muscular or skeletal pain
Herpes zoster
Duodenal ulcer 
Abdominal aortic aneurysm 
Ureteral obstruction by materials other than a stone
Pelvic Inflammatory Disease

Question 10

Diagnosis made by?

Answer 10

Usually based on clinical presentation
Urine: RBC, WBC, crystals
Leukocytosis, ARF
Imaging
- Plain film: May show Calcium stones
- IVP—used less frequently now
- CT-renal protocol—gold standard (no contrast!)
- US—may show intrarenal stones and/or hydronephrosis. Not sensitive for ureteral stones

Question 11

Treatment of acute attacks

Answer 11

Medical Therapy

• Pain control
• Nausea control
• Propulsive therapy
• –Calcium channel blockers
• –Alfa-blockers

Surgical Therapy

• Ureteroscopy with stone removal and stent placement
• Percutaneous nephrostomy

Question 12

Treatment after acute attack

Answer 12

ECWL (lithotripsy) if large stones

Nephrostomy (temporary measure to relieve the kidney)

Question 13

Prevention of Recurrences

Answer 13

Analyze the stone
Collect the information about dietary preferences and fluid intake
Serum Ca, Phosphorus, uric acid
If Ca is elevated, do hypercalcemia work-up
PTH, Vit D level, Protein electrophoresis
24 urine collection for Ca, urate, oxalate, citrate

Increase fluid Intake

Question 14

Dietary Modification

Calcium Stones:

Answer 14

Adequate dietary Calcium intake

• From food, not from supplements
• Not too much, not too little
• Likely binds oxalate and prevents its absorption

Restriction of nondairy animal protein (e.g., meat, chicken, seafood)

Avoidance of spinach (the highest oxalate-containing food).

Reducing sodium intake to less than 3g/day

• It will decrease concurrent urinary excretion of calcium
• Decreasing sucrose intake, which may increase urinary calcium excretion

Increasing potassium-rich foods.

Question 15

Prevention of Recurrences: Uric acid stones

Answer 15

Increasing urine pH by

• Reducing the intake of animal proteins
• Increasing the intake of alkali-rich foods (fruits and vegetables)
• Oral bicarbonate

Question 16

Prevention of Recurrences: Medications

Answer 16

Thiazides
- Increase calcium reabsorption and decreases urine Calcium

Allopurinol
- Decreases uric acid in the serum and urine

Potassium Citrate

Magnesium
- Forms soluble complexes with oxalate in the bowel or urine.