Tubulointerstitial Flashcards
Most common stone type
calcium oxalate
Next common stone types in order
- calcium phosphate,
- uric acid,
- struvite and
- cystine
Increasing prevalence of stone is due to
Westernization of lifestyle habits
Economic impact in stone formation affects
workiing age
Urine is what kind of solution
Supersaturated
calcium oxalate stones grow on calcium phosphate at the tip of the renal papilla
Randall’s plaque
may be the initiating event of calcium phosphate formation
Tubular plugs of calcium phosphate
Risk Fators: Diet
- high animal protein ,
- high oxalate,
- high sodium,
- high sucrose
- high fructose
- low calcium
- high potassium
- Vit C supplements
Risk Fators: Diet
Results
- Higher intake of animal protein -
- Higher Na and sucrose -
- Higher K intake -
° Vitamin C supplements -
- Higher intake of animal protein - increased calcium nd UA excretion, decreased urinary citrate excretion
- Higher Na and sucrose - increase Ca excretion
- Higher K intake - decreases Ca excretion, increase urinary citrate
- Vitamin C supplements - increased risk of calcium oxalate stones in MEN (high urinary oxalate levels) - AVOID
Risk Factors: Fluids and Beverages
- Risk increases as urine volume decreases (risk doubles if <1L/day)
- Fluid intake - main determinant or urine volume
- Sugar sweetened beverages - increases risk
Associated with reduced risk of Nephrolithiasis
- Coffee,
- tea,
- beer,
- wine and
- orange juice
NEPHROLITHIASIS
RISK FACTORS - NON DIETARY
- Age, race, body size and environment
- Weight gain increases risk
- Environmental and occupational
+ Hot environment
+ Lack of ready access to water or bathroom
NEPHROLITHIASIS
URINARY RISK FACTORS
- URINE VOLUME
+ Readily modifiable - URINE CALCIUM
+ Increased excretion increases risk calcium oxalate and phosphate stones - URINE OXALATE
+ Increased risk - URINE CITRATE
+ Natural inhibitor
+ metabolic acidosis decreases its excretion - URINE URIC ACID
+ Excess purine congumption and genetic conditions with overproduction of uric acid - URINE pH
+ Uric acid <5.5
+ Calcium phosphate >6.5
2 most common presentations of Nephrolithiasis
- renal colic
- painless gross hematuria
Urine sediments found
- WBC,
- RBC,
- crystals
no need to wait for other tests to start treatment if this is done
Urinalysis
Diagnosis confirmed of NEPHROLITHIASIS by
helical CT non-contrast
Goal in NEPHROLITHIASIS
maintain euvolemia
Drugs that increase rate of spontaneous stone passage
Alpha blockers
Uro intervention postponed unless with ___, low probability of stone passage (___ or with anatomic abnormality) or ___
- UTI
- > 6mm
- intractable pain
Least invasive method for NEPHROLITHIASIS
ESWL
More than half of 1st timers will have recurrence within
10 years
Test used for NEPHROLITHIASIS
- Electrolytes , crea, calcium and uric acid
- PTH with vitamin D: when high calcium
- U/A with sediments, sutures
- 24 hour urine collection - cornerstone on which therapeutic recommendations are made
- Stone analysis (uric acid low Hounsfield unison CT)
- Gold Standard - helical CT without contrast
NEPHROLITHIASIS
PREVENTION OF NEW STONE FORMATION
- Depends on the stone type and results of the metabolic evaluation
- Modification of urine composition
- Urine volume should at least be 2L/day
- HOW MUCH MORE THEY NEED TO DRINK
