Calculus Dx Flashcards
Risks factors of calculus
Increased weight and body mass index
Increased socioeconomic status
Obesity in women
Metabolic syndrome (acid calculi due to low urinary pH)
2 phenomenon important for crystal formation in urine
Supersaturation of urine with stones
Presence of urinary inhibitors - nephrocalcin, uropontin, citrate, magnesium , tamm-horsfall
What is the noncrystalline component of stones made of
Mucoprotein s
Proteins
Carbohydrates
Urinary inhibitors
Most important determinant of acid stone formation
Low urinary pH
Stones formed in low pH
Calcium oxalate stones
Uric acid stones
Type of urine in infection stones
Alkaline urine
Type of bacteria in infection stone
Urease producing bacteria
Name of stones formed in infection stones
Triple phosphate stones
What happens when urine is above Ksp (solubility product )
Normally no formation of crystals due to inhibitors of crystal formation
What happens when urine concentration of calcium and oxalate is very high above Kf ( formation product)
Inhibitors become ineffective and crystals form
When do you say that urine is metastable
When urine is between solubility product and formation product
Steps of crystal formation
Nucleation - crystal formation on epithelial , foreign bodies, other crystals surfaces
Aggregation - crystal nuclei form into clumps
Location of calcium absorption
Small intestine
Hormone responsible for conversion of 25-dihydroxyvitamin D3 to 1,25(OH)2D3
Parathyroid hormone
Hormone responsible for proximal tubular reabsorption of calcium and renal phosphate excretion n
PTH
Factors influencing intestinal oxalate absorption
Luminal calcium
Magnesium
Oxalate degrading bacteria
Biochemistry of absorptive hypercalciuria
Normal serum calcium
Normal or suppressed PTH
Normal fasting urinary calcium
Elevated urinary calcium
Biochemistry of renal hypercalciuria
Impaired renal calcium reabsorption
PTH hypersecretion
Increased fasting hypercalciuria
Dx causing resorptive hypercalciuria
Primary hyperparathyroidism
Indications for metabolic stone evaluation
Recurrent stone formers
Strong family hx
Intestinal dx specially if chronic diarrhea
Pathologic skeletal fractures
Osteoporosis
Hx Urinary trat infection with calculi
Hx of gout
Infirm health
Solitary kidney
Anatomical abnormalities
Renal insuffiency
Hx taking in stones
Predisposing conditions
Medications (calcium, vitamin C, vitamin D, acetazolamide , steroids)
Diet excess
inadequate fluid intake
Excessive fluid loss
Metabolic Investigations
Metabolic panel - sodium, potassium, chloride, carbon dioxide , blood urea nitrogen , creatinine
Calcium
Parathyroid hormone
Uric acid levels
Urine investigations
Urinalysis - pH<7.5 (infection lithiasis) , pH<5.5 ( uric acid lithiasis)
Sediment for crystalluria
Urine culture
Urea splitting organisms for infection
Qualitative cystine
Radiography findings
Radioopaque stones in calcium oxalate , calcium phosphate , magnesium, ammonium phosphate , cystine
Radioluscent stones in urine acid, xanthine, triamterene
Stone analysis
Conservative medical management
Drink - 3000ml / day to maintain urine output abode 2500ml/day
Medical expulsion therapy when stone <5mm
Low animal protein intake
High fruits and vegetables diet
Restriction of dietary sodium
CHO restriction
Calcium supplement
Decrease oxalate diet
Avoid large doses of vitamin c
Medications used in medical expulsion therapy
Tamsulosin
NSAIDs
Phytothérapie
Potassium citrate
Does dietary calcium restriction decrease stone formation
No actually increase it
How can dietary calcium help decrease stone
By binding intestinal oxalate and decrease its absorption
Medications that form stone
Inidnavir
Ephedrine
Triamterene
Magnesium trisilicate antacids
Sulfamethoxazole-trimethoprim
Medications that provoke stone formation
Carbonic anhydrase inhibitors
Topirimate
Furosemide
Vitamin c excess
Vitamin d excess
Laxatives
Surgical management of stones in kidney
Endoscopy with percutaneous nephrolithotomy or uteroscopy+laser fragmentation
Laparoscopic nephrolithotomy
Open surgery
Extracorporeal shockwave lithotripsy
Surgical management of stones in bladder
Endoscopic cystolitholapaxy/
Open cystolithotomy
Surgical management of stones in ureters
Uteroscopy+laser, ballistic or ultrasonic lithotripsy
Open ureterolithotomy
PCNL
Surgical management of stones in urethra
Endoscopic extraction
Open urethrolithotomy
Age group with highest incidence of renal stone in developed countries
Young men
Predisposing factors for kidney stones
Low urine volumes: high ambient temperatures, low fluid intake
Diet: high protein, high sodium, low calcium
High sodium excretion
High oxalate excretion
High urate excretion
Low citrate excretion
Hypercalcaemia
Ileal disease or resection (increases oxalate absorption and urinary
excretion)
Renal tubular acidosis type I
Familial hypercalciuria
Medullary sponge kidney
Cystinuria
Renal tubular acidosis type I (distal) • Primary hyperoxaluria
People at risk of bladder stone in developing countries
Children
Are renal or bladder stone more common in the developed countries b
Renal stone
Clinical features
Asymptomatic
Pain
Hematuria
Acute loin pain radiating to anterior abdomen + hematuria + restlessness ->renal or ureteric colic
Pallor
Sweating
Vomiting
What disease is indicated by ureteric colic
Obstruction of ureter by calculus or tumor or renal papilla
Investigations
Plain abdominal x ray for calcium stone
Non contrast CTKUB gold standard
US in unstable patient, young women with undersirable exposition. To radiation
Blood test - calcium, phosphate, uric acid , urea and electrolytes , bicarbonate , parathyroid
Urine - dipstick for proteins, blood, glucose, amino acids
24h urine
Stone for composition
Treatment
Immédiat -> analgesics , antiemetics
ATBS if surgery
Uteroscopy and stone fragmentation
extracorporeal shock wave lithotripsy
Nephrtomy or stent
