Hematuria / Stones - Russ Flashcards
What is the most common screening test for blood and protein in the urine?
Urine Dipstick
When do false negative results occur with urine dipstick testing?
- Presence of formalin
- High urinary concentration of ascorbic acid
When do false positive results occur with urine dipstick testing?
- Alkaline urine (pH > 9.0)
- Contamination with oxidizing agents used to clean the perineum
How many RBCs per high power field is considered hematuria in adults? Children?
- Adults = 2 RBC/HPF
- Children = 5 RBC/HPF
What are the four most common causes of hematuria?
- Transient unexplained
- UTI
- Stones
- Cancer (bladder, kidney, prostate)
What are some less frequent causes of hematuria?
- Exercise
- Trauma
- Endometriosis
- cyclic hematuria
- Sickle Cell Disease
- Polycystic Kidney Disease
- Glomerular Disease
What are some risk factors for urinary tract MALIGNANCY?
- Age >35
- Smoking history
- Occupational exposure to chemicals
- History of:
- gross hematuria
- chronic cystitis
- pelvic irradiation
- exposure to cyclophosphamide
- obesity
- HTN
- analgesic abuse
- chronic indwelling foreign body
- Alcohol may be protective!
What three presentations could look like hematuria but is not hematuria because the urine supernatant is red after spinning a urine sample and the urine dipstick is negative for heme?
- Porphyria
- Phenazopyridine
- like Azo
- Beets
- due to red pigment = betalaine
What are some historical clues to the diagnosis of hematuria?
- Concurrent pyuria and dysuria
- pyuria = pus in urine
- dysuria = painful/difficult urination
- Recent URI
- Family Hx of renal failure
- Unilateral flank pain with radiation to the groin
- Symptoms of hesitancy and dribbling
- Vigorous exercise/trauma
How can you tell if the hematuria is glomerular vs. extraglomerular bleeding?
- Glomerular
- red cell casts
- proteinuria
- dysmorphic appearing red cells
- smokey brown or “coca cola” color
- Extraglomerular
- clots
What is 50% of unexplained hematuria due to?
underlying glomerular disease
Is microscopic hematuria in children worrisome?
NO
- Fairly common, transient
- 3-4% have positive dipstick for blood
- 6-15 yoa
- 1% have positive dipstick for blood after second UA
What are the most common causes of persistent microscopic hematuria in children?
- Glomerulopathies:
- IgA nephropathy
- Alport’s syndrome (Hereditary nephritis)
- Thin basement membrane disease (Familial hematuria)
- Post-infectious glomerulonephritis
- Hypercalciuria
- urine calcium/creat >2
- Nutcracker syndrome
- left renal vein compression by the aorta and superior mesenteric artery
How should you evaluate microscopic hematuria in children?
- Asymptomatic & isolated (no protein):
- benign
- just observe
- Asymptomatic with proteinuria:
- quantitate protein with a 1st void morning specimen for urine total protein/creatinine ratio
- normal <0.3
- measure serum creatinine
- consider nephrology referral if either are abnormal
- quantitate protein with a 1st void morning specimen for urine total protein/creatinine ratio
What are some causes of symptomatic hematuria in children?
- Glomerular diseases
- Interstitial/tubular diseases
- Lower UTI
- Nephrolithiasis
- Tumor
- Vascular disease
- Gross hematuria:
- UTI
- Trauma
- Irritation of meatus or perineum
What percentage of men will develop a symptomatic stone by age 70?
12%
What percentage of women will develop a symptomatic stone by age 70?
5%
Who is more likely to get a kidney stone:
Young vs. older?
Men vs. women?
White vs. Black?
- Older: rate of urolithiasis increases with age
- Men > women
- Whites > blacks
What are the four types of stones?
-
Calcium = 80% of stones
- ***Oxalate = most common
- Phosphate
- Uric acid
- Struvite
- Cystine
What are common symptoms of urolithiasis?
- Flank pain
- Abdominal pain
- Testicle/Labial pain
- waxing & waning pain
- Gross/microscopic hematuria
- Possible N/V, dysuria, urgency
What are the treatment options for urolithiasis?
- Pain medications
- Hydration
- Alpha blocker (tamsulosin) = relax ureters
- Calcium channel blocker (nifedipine) = relax ureters
- Ureteroscopy
- Extracorporeal shock wave lithotripsy
- Endoscopic lithotripsy
- Pyelolithotomy
- flank incision
- Percutaneous nephrolithotomy
- with scope using guidewire
What kind of stones have urine sediment showing both dumbbell-shaped, envelope-shaped, and needle-shaped crystals?
Calcium oxalate
What are the risk factors for calcium stone formation?
- Increased calcium excretion = hypercalciuria
- Increased uric acid excretion = hyperuricosuria
- uric acid forms center of stone and calcium oxalate forms around
- Reduced citrate excretion = hypocitraturia
- Low urine volume
- Increased oxalate excretion
What are three possible types of Idiopathic Hypercalciuria that predispose individuals to calcium stones?
- Absorptive hypercalciuria
- autosomal dominant trait
- increased absorption of calcium in GI → increased calcium excretion
- elevated Calcitriol levels
- Fasting (resorptive) hypercalciuria
- bone loss
- Renal hypercalciuria
- renal leak
- abnormal calcium reabsorption in the proximal tubule
What are five possible etiologies for Hypocitraturia that may predispose individuals to getting calcium stones?
- Chronic diarrhea
- Renal tubular acidosis
- Ureteral diversion
- High protein diet
- more acid that needs excretion
- Topiramate
- migraine medicine
***Any disease that causes metabolic acidosis!
What can Hyperoxaluria be attributed to in the context of calcium oxalate stones?
- Diet - 10%
- Glycine metabolism - 40%
- Ascorbic acid metabolism - 40%
- Increased oxalate absorption
- low calcium diet
- absorptive hypercalciuria
- enteric hyperoxaluria (malabsorption of fatty acids and bile salts)
- Overproduction of oxalate = Primary hyperoxaluria
- RARE
What are three medical problems associatd with calcium stone formation?
- Primary hyperparathyroidism
- Medullary sponge kidney
- abnormality in renal papilla → more susceptible to injury → crystals latch onto damaged tissue
- Distal renal tubular acidosis
What is the appropriate metabolic work-up for diagnosing why calcium stones are forming?
- Plasma [Ca2+]
- Parathyroid hormone
- Electrolytes
- rule out metabolic acidosis
- Serum uric acid
- 24 hour urine collection
- volume
- Ca2+, Uric Acid, Citrate, Oxalate, Creatinine, pH, Na+, PO4
What dietary recommendations are appropriate for a patient with calcium stones?
- Fluid
- drink 2L+ of water per day
- Restrict salt intake
- Lower protein intake
- protein increases citrate excretion
- Continue Calcium intake!
- don’t decrease dairy products → will make calcium stones worse
- Restrict Oxalate
- if calcium oxalate stones
What medicinal treatments are appropriate for calcium stones?
- Thiazide diuretics
- Potassium citrate or Bicarbonate
- Orthophosphate
- Allopurinol/Febuxostat
- decreases uric acid production and excretion
- Calcium carbonate
- take TUMS with meals
What type of stones are non-opaque (radiolucent) on plain films, comprise 5-10% of stones in the US & Europe, but are 40% of stones in hot/arid climates?
Uric acid urolithiasis
(Hot/arid climates → low urine volume & acidic urine pH)
How are uric acid stones diagnosed?
- Analyze stone material recovered
- Indirectly by demonstrating increased urine uric acid excretion
What is the treatment for uric acid urolithiasis?
- Fluids: drink >2 L per day
- increase urine output
- Alkalinization of urine
- Allopurinol/Febuxostat
What type of stones produce “coffin lid” crystals in urine sediment and only form in alkaline urine?
Struvite Stones
(Magnesium ammonium phosphate)
What urine pathology are struvite stones most associated with?
- UTI due to Proteus/Klebsiella (most commonly)
- urease producing organism
- Increased ammonia production
- Increased urine pH
- decreases solubility of phosphate
- urease producing organism
What is the treatment for Struvite Stones?
- Chronic administration of antibiotics
- Acetohexemic acid
- urease inhibitor
- ESWL/percutaneous nephrolithotomy
- most effective treatment
What kind of stone produces hexagonal crystals in urine sediment?
Cystine Stones
What is cystinuria?
- Impairment of cystine transport leading to decreased proximal tubular re-absorption and increased cystine excretion
- autosomal recessive trait
How is Cystinuria characterized?
- The amount of cystine excreted by the parents
- parents usually = asymptomatic heterozygotes
How are cystine stones diagnosed?
- Family Hx
- Hexagonal cystine crystals on urinalysis
- Measure cystine excretion
What is the medical treatment for cystine stones?
- High fluid intake: >3 L/day
- Alkalinization of urine: pH >7.0
- Restrict dietary Na+
- Drugs that attach to cystine → increase solubility
- Penicillamine
- Tiopronin
- Captopril
What are procedural treatments for cystine stones?
- Irrigation of renal pelvis via catheter with penicillamine or acetylcystine
- RESISTANT to ESWL
- very soft stones
- Percutaneous nephrolithotomy / ultrasonic lithotripsy
- CURE = renal transplant
When is medical treatment indicated for the first kidney stone?
- Only in patients with metabolically active stone disease
- formation of new stones
- enlargement of old stones
- passage of gravel
- multiple stones at presentation
What is the risk of having a symptomatic 2nd stone?
- 1 year = 15%
- 5 years = 35-40%
- 10 years = 50%
- Men > Women
What is the recommended evaluation for the first kidney stone?
- Limited evaluation:
- dietary history
- plasma calcium x2
- consider CT scan with IV contrast
- looking for medullary sponge kidney
Increase fluid intake → 2+L/day
How do asymptomatic stones typically resolve?
- 50% required procedure
- 50% passed stone spontaneously
***Need to balance the risk of symptoms vs. the risk of morbidity from ESWL
What are common complications of ESWL?
- Treatment of <2 cm stones can lead to a 2-3% increased incidence of obstruction
- Reversibly damages blood vessels and tubules
- New onset HTN (8%)
- presumably due to renin release form focal areas of renal ischemia
- Impairment in renal function
- due to scar formation
- Residual calculi
- (particularly with struvite stones)
Does a complaint of red urine equate to blood in the urine?
NO
- Could be caused by:
- Beets
- Porphyria
- Azo
Does painless hematuria help narrow the DDx?
Yes
points towards malignancy
Does kidney function help in the DDx?
Yes
can differentiat between obstruction or glomerulonephropathies
