Diagnosis

Urolithiasis

Etiology

Cause [cyu]

• Calcium oxalate (80%)

• Struvite stones (magnesium-ammonium-phosphate) seen in Proteus-infection (9%)

• Uric acid (9%)

• Cystine (1%)

• Indinivir

Patholphysiology [cyu]

1. Crystals supersaturate the urine due to high concentration --> crystallize forming the renal calculi

2. These crystals aggregate together and continue to enlarge with the potential to migrate into the ureter and become symptomatic

3. Obstruction --> hydronephrosis --> severe colicky pain

4. Three most common location for a stone to obstruct:

   • Ureteropelvic junction (UPJ)

   • Ureter crosses over the iliac vessels

   • Ureterovesical junction (UVJ)

Risk factors [cyu][3as]

• Poor fluid intake in a hot climate (dehydration/low diuresis)

• Red meat intake

• Oxalate intake: beans, beer, berries, chocolate, some nuts, some teas, soda, spinach, and potatoes

• High salt intake

• Increased free calcium: bony destruction, multiple myeloma, hyperparathyroidism, osteolytic lesions, sarcoidosis

• Immobilization

• Drugs: analgesics, alkalis, uricosuric agents, protease inhibitors, Atazanavir, Guaifenesin, Indinavir, Silicate, Sulfonamide, Triamterene

• GI-disease --> malabsorption: Crohns disease, ulcerative colitis, ulcer disease, Roux-en-Y gastric bypass and sleeve gastrectomy

• Other medical conditions: Kidney failure, hypertension, gout, diabetes mellitus, hyperlipidemia, obesity, endocrine, and malignancies

• Pregnancy

Complications [3as]

• Abscess

• Hydronephrosis

• Pyelonephritis

• Pyonephrosis

• Renal failure

• Urosepsis

• Ureteral calculi stricture

• Urinoma

Epidemiology

Incidence per 100.000 [ow9][d47][cym][p1e][she]

Approach

• Blood test: CBC, glucose, calcium, electrolytes (sodium, potassium, chloride, and bicarbonate), proteins (albumin and total protein), liver enzymes (ALP, ALT, and AST), bilirubin, and kidney function markers (BUN and creatinine), lactic acid, lipase, amylase, blood cultures (if febrile)

• Urine stix: hematuria, leukocyte, nitrites, WBC, urine HCG

• Abdominal x-ray

• Ultrasound abdomen

• CT abdomen

• CT pelvis

Treatment

1. Prophylaxis: [cyu][3as]

   • Oral hydration that produces approximately 2.5 L of urine per day

   • Consumption of citrate and calcium (binds oxalate in the GI tract)

2. Non-operative management: 86% will pass spontaneously [cyu]

   ≤ 2 mm: 8 days for mean passage and passage rate of 87%

   3 mm stones, 12 days for mean passage and passage rate of 76%

   4-6 mm, 22 days for mean passage and passage rate of 60%

   7 mm stone with a passage rate of 48%

   8-9 mm stone with a passage rate of 25%

   • Expectant management

   • Analgesic: NSAIDs, Opioids reserved for refractory pain

   • Nausea and vomiting: Anti-emetic medications such as ondansetron, metoclopramide, promethazine

   • Medical expulsive therapy facilitate passage of larger (5-10 mm) stones: alpha-blockers such as doxazosin and tamsulosin

3. Surgical intervention to removal the stone: obstruction, oligouria, acute renal failure, infection, solitary kidney

   • JJ-stent for rapid renal decompression

   • Extracorporeal shockwave lithotripsy (ESWL): proximal stones

   • Flexible ureteroscopy (URS): lower pole stones between 1.5 and 2 cm

   • Percutaneous nephrolithotomy (PCNL): if failed ESWL/URS or >20mm proximal stones

Differential diagnoses

Abdominal abscess, Abortion, Acute mesenteric ischemia, Acute pancreatitis, Aortic dissection, Appendicitis, Cholecystitis, Constipation, Diverticulitis, Dysmenorrhea, Gastrointestinal obstruction, Glomerulonephritis, Ovarian torsion, Pelvic inflammatory disease, Pyelonephritis, Pyonephrosis, Ruptured aortic aneurysm, Ruptured ectopic pregnancy, Urinary tract infection, Xanthogranulomatous pyelonephritis