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27 Cards in this Set
- Front
- Back
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Nephrolithiasis: Signs and symptoms |
The classic presentation for a patient with acute renal colic is the sudden onset of severe pain originating in the flank and radiating inferiorly and anteriorly; at least 50% of patients will also have nausea and vomiting. Patients with urinary calculi may report pain, infection, or hematuria. Patients with small, nonobstructing stones or those with staghorn calculi may be asymptomatic or experience moderate and easily controlled symptoms.
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Presentation: stones obstructing ureteropelvic junction |
Mild to severe deep flank pain without radiation to the groin; irritative voiding symptoms (eg, frequency, dysuria); suprapubic pain, urinary frequency/urgency, dysuria, stranguria, bowel symptoms |
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Presentation:Stones within ureter |
Abrupt, severe, colicky pain in the flank and ipsilateral lower abdomen; radiation to testicles or vulvar area; intense nausea with or without vomiting |
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Presentation:Upper ureteral stones |
Radiate to flank or lumbar areas |
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Presentation:Midureteral calculi |
Radiate anteriorly and caudally |
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Presentation:Distal ureteral stones |
Radiate into groin or testicle (men) or labia majora (women)
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Presentation: Stones passed into bladder
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Mostly asymptomatic; rarely, positional urinary retention
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Nephrolithiasis: Examination findings |
-Dramatic costovertebral angle tenderness; pain can move to upper/lower abdominal quadrant with migration of ureteral stone
-Generally unremarkable abdominal evaluation: Possibly hypoactive bowel sounds; usually absence of peritoneal signs; possibly painful testicles but normal-appearing -Constant body positional movements (eg, writhing, pacing) -Tachycardia -Hypertension -Microscopic hematuria |
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Nephrolithiasis: Initial tests |
-Urinary sediment/dipstick test: To demonstrate blood cells, with a test for bacteriuria (nitrite) and urine culture in case of a positive reaction
-Serum creatinine level: To measure renal function |
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Nephrolithiasis: other useful tests |
-CBC with differential in febrile patients
-Serum electrolyte assessment in vomiting patients (eg, sodium, potassium, calcium, PTH, phosphorus) -Serum and urinary pH level: May provide insight regarding patient’s renal function and type of calculus (eg, calcium oxalate, uric acid, cystine), respectively -Microscopic urinalysis -24-Hour urine profile |
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Nephrolithiasis: Imaging Studies |
-Noncontrast abdominopelvic CT scan: The imaging modality of choice for assessment of urinary tract disease, especially acute renal colic
-Renal ultrasonography: To determine presence of a renal stone and the presence of hydronephrosis or ureteral dilation; used alone or in combination with plain abdominal radiography -Plain abdominal radiograph (flat plate or KUB): To assess total stone burden, as well as size, shape, composition, location of urinary calculi; often used in conjunction with renal ultrasonography or CT scanning -IVP (urography) (historically, the criterion standard): For clear visualization of entire urinary system, identification of specific problematic stone among many pelvic calcifications, demonstration of affected and contralateral kidney function -Plain renal tomography: For monitoring a difficult-to-observe stone after therapy, clarifying stones not clearly detected or identified with other studies, finding small renal calculi, and determining number of renal calculi present before instituting a stone-prevention program -Retrograde pyelography: Most precise imaging method for determining the anatomy of the ureter and renal pelvis; for making definitive diagnosis of any ureteral calculus -Nuclear renal scanning: To objectively measure differential renal function, especially in a dilated system for which the degree of obstruction is in question; reasonable study in pregnant patients, in whom radiation exposure must be limited |
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Nephrolithiasis: Supportive management |
-IV hydration
-Nonnarcotic analgesics (eg, APAP) -PO/IV narcotic analgesics (eg, codeine, butorphanol, morphine sulfate, oxycodone/APAP, hydrocodone/APAP, meperidine, nalbuphine) -NSAIDS -Uricosuric agents (eg, allopurinol) -Antiemetics (eg, metoclopramide) -Antidiuretics (eg, DDAVP) -Antibiotics (eg, ampicillin, gentamicin, ticarcillin/clavulanic acid, ciprofloxacin, levofloxacin, ofloxacin) -Alkalinizing agents (eg, potassium citrate, sodium bicarbonate): For uric acid and cysteine calculi -Corticosteroids (eg, prednisone, prednisolone) -Calcium channel blockers (eg, nifedipine) -Alpha blockers (eg, tamsulosin, terazosin) |
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Nephrolithiasis: Surgical Options |
Stones that are 7 mm and larger are unlikely to pass spontaneously and require some type of surgical procedure, such as the following:
-Stent placement -Percutaneous nephrostomy -Extracorporeal shockwave lithotripsy (ESWL) -Ureteroscopy -Percutaneous nephrostolithotomy -Open nephrostomy -Anatrophic nephrolithotomy |
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Nephrolithiasis: Extracorporeal Shockwave Lithotripsy |
The efficacy of ESWL lies in its ability to pulverize calculi in vivo into smaller fragments, which the body can then expulse spontaneously. Shockwaves are generated and then focused onto a point within the body. The shockwaves propagate through the body with negligible dissipation of energy (and therefore damage) owing to the minimal difference in density of the soft tissues. At the stone-fluid interface, the relatively large difference in density, coupled with the concentration of multiple shockwaves in a small area, produces a large dissipation of energy. Via various mechanisms, this energy is then able to overcome the tensile strength of the calculi, leading to fragmentation. Repetition of this process eventually leads to pulverization of the calculi into small fragments (ideally < 1 mm) that the body can pass spontaneously and painlessly.
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Stone Types |
Calcium stones 75% Struvite (magnesium ammonium phosphate) stones 15% Uric acid stones 6% Cystine stones 2% |
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Calcium stones: Associated disorders |
Hyperparathyroidism - Treated surgically or with orthophosphates if the patient is not a surgical candidate
Increased gut absorption of calcium - The most common identifiable cause of hypercalciuria, treated with calcium binders or thiazides plus potassium citrate Renal calcium leak - Treated with thiazide diuretics Renal phosphate leak - Treated with oral phosphate supplements Hyperuricosuria - Treated with allopurinol, low purine diet, or alkalinizing agents such as potassium citrate Hyperoxaluria - Treated with dietary oxalate restriction, oxalate binders, vitamin B-6, or orthophosphates Hypocitraturia - Treated with potassium citrate Hypomagnesuria - Treated with magnesium supplements |
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Struvite stones: Associated organisms |
associated with chronic urinary tract infection (UTI) with gram-negative, urease-positive organisms that split urea into ammonia, which then combines with phosphate and magnesium to crystalize into a calculus.
Usual organisms include: -Proteus, -Pseudomonas -Klebsiella |
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Uric acid stones: aetiology |
These are associated with urine pH less than 5.5, high purine intake (eg, organ meats, legumes, fish, meat extracts, gravies), or malignancy (ie, rapid cell turnover). Approximately 25% of patients with uric acid stone have gout.
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Uric acid stones: management |
Serum and 24-hour urine sample should be sent for creatinine and uric acid determination. If serum or urinary uric acid is elevated, the patient may be treated with allopurinol 300 mg daily. Patients with normal serum or urinary uric acid are best managed by alkali therapy alone.
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Cystine stones: aetiology |
They arise because of an intrinsic metabolic defect resulting in failure of renal tubular reabsorption of cystine, ornithine, lysine, and arginine. Urine becomes supersaturated with cystine, with resultant crystal deposition.
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Cystine stones: Management |
Treated with a low-methionine diet (unpleasant), binders such as penicillamine or a-mercaptopropionylglycine, large urinary volumes, or alkalinizing agents. A 24-hour quantitative urinary cystine determination helps to titrate the dose of drug therapy to achieve a urinary cystine concentration of less than 300 mg/L.
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Drug-Induced stones |
Indinavir
Atazanavir Guaifenesin Triamterene Silicate (overuse of antacids containing magnesium silicate) Sulfa drugs, including sulfasalazine, sulfadiazine, acetylsulfamethoxazole, acetylsulfasoxazole, and acetylsulfaguanidine |
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Nephrolithiasis: Prognosis |
Approximately 80-85% of stones pass spontaneously. Approximately 20% of patients require hospital admission because of unrelenting pain, inability to retain enteral fluids, proximal UTI, or inability to pass the stone.
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Nephrolithiasis: Complications |
Pyelonephritis, pyonephrosis, and urosepsis
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Nephrolithiasis: Recurrences |
The usually quoted recurrence rate for urinary calculi is 50% within 5 years and 70% or higher within 10 years, although a large, prospective study published in 1999 suggested that the recurrence rate may be somewhat lower at 25-30% over a 7.5-year period.
Recurrence rates after an initial episode of ureterolithiasis have also been reported to be 14%, 35%, and 52% at 1, 5, and 10 years, respectively. Metabolic evaluation and treatment are indicated for patients at greater risk for recurrence, including those who present with multiple stones, who have a personal or family history of previous stone formation, who present with stones at a younger age, or who have residual stones after treatment. |
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Nephrolithiasis: Long term follow up |
According to estimates, merely increasing fluid intake and regularly visiting a physician who advises increased fluids and dietary moderation can cut the stone recurrence rate by 60%.
In contrast, optimal use of metabolic testing with proper evaluation and compliance with therapy can completely eliminate new stones in many patients and significantly reduces new stone formation in most patients. |
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Nephrolithiasis: Patient Education |
A patient who tends to develop stones should be counseled to seek immediate medical attention if he or she experiences flank or abdominal pain or notes visible blood in the urine.
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