Pathophysiology Exam 3

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Pathophysiology Exam 3
2012-11-04 16:43:43

Pathophysiology Comprehensive Exam #3
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  1. In the urinary stone disease case, what lab values were abnormal?
    • Citrate= low
    • Specific gravity= high
  2. The patient in the kidney stone disease case had what pertinent medical history issues?
    • renal stones at 35, 43, and 52 yo
    • zenker diverticulum
    • IgG immunodeficiency disorder
    • Non-Hodgkin's lymphoma
  3. Why is the patient in the kidney stone case zenker diverticulum significant?
    • prevents him from swallowing caps or tabs
    • also leads to him not drinking enough water
  4. What symptoms did the kidney stone patient have?
    • left flank pain (most common symptom)-- most likely means that he is passing the stone through the ureter
    • radio-opaque stone in left ureter
    • radio-opaque stone in inferior calyx of right kidney
  5. How are kidney stones classified?
    • by location: kidney, ureter, or bladder
    • by composition: calcium, struvite, uric acid, or cystine
  6. Has the incidence of kidney stones increased or decreased in last 10-15 years?
    • increased by 40%
    • not sure why
  7. Are kidney stones more common in males or females?
  8. Most cases of kidney stones have what type of composition (75%)?
    calcium oxalate or calcium phosphate
  9. What race is more commonly affected by kidney stones?
  10. What are the major causes of calcium kidney stones?
    • idiopathic hypercalciuria
    • hyperuricosuria
    • hyperparathyroidism
    • distal renal tubular acidosis
    • dietary, enteric, or primary hyperoxaluria
    • hypocitraturia
  11. What are the causes of uric acid kidney stones?
    • gout
    • metabolic syndrome
    • idiopathic
    • dehydration
    • Lesch-Nyhan syndrome
  12. What are the risk factors that the patient in the kidney stone case had?
    • male
    • caucasian
    • sedentary lifestyle
    • previous stones 
    • dehydration
  13. What are dietary risk factors for developing a kidney stone?
    • increased sodium and protein
    • excess oxalates or purines
    • low citrates
  14. What are metabolic acidosis risk factors associated with kidney stone development?
    • prolonged fasting
    • hypomagnesemia
    • hypokalemia
  15. Diet alterations, metabolic acidosis, genetics, and sleeping on one side are all risk factors for what?
    kidney stones
  16. What are some drugs that might induce a kidney stone?
    • triameterene
    • sulfadiazine
    • antivirals
    • antibacterials (cipro, amoxicillin, nitrofurantoin)
    • ephedrines
  17. What signs and symptoms did the kidney stone patient present with?
    • inability to remain still
    • nausea/vomiting
    • excruciating side and back pain/flank pain
  18. Which diagnostic test did kidney stone patient have done?
    spiral computed tomography (CT scan)
  19. Which type of stones are radio-opaque in imaging?
    • calcium 
    • struvite
  20. What does a radio-opaque kidney stone tell you about the stone?
    it obstructs the passage of radiant energy
  21. What color do calcium or struvite stones appear on x-ray or CT scan?
    light in color
  22. What color do uric acid or cystine stones appear on x-rays?
    black, near black
  23. What type of kidney stones are radiolucent?
    • uric acid
    • cystine
  24. What does radiolucent mean?
    permitting the passage of radiant energy
  25. What is the best method for diagnosing a kidney or ureter stone?
    CT scan (spiral computed tomography)
  26. What is the problem with the Intravenous Pyelogram (IVP)?
    • it is invasive
    • it can't be used on kidney failure patients
    • there is an allergy risk with the dyes
  27. What type of stones will a regular x-ray identify?
    • calcium 
    • not uric acid or indinavir stones
  28. Does ultrasound detect both calcium and non-calcium kidney stones?
  29. What is normal urine pH?
  30. What does persistent urinary pH below 5.5 suggest?
    uric acid or cystine stone
  31. What does persistent pH above 7.2 suggest?
    struvite or calcium phosphate stone
  32. What is a stone analysis?
    • done on recovered stones
    • identifies the components and underlying cause of the stone
  33. What is the underlying cause of a cystine stone?
    congenital cystinuria
  34. What is the underlying cause of a struvite or carbonate stone?
    UTI with urease + organism
  35. What is the underlying cause of a calcium phosphate stone?
    acidification defects
  36. What type of test is performed on recurrent kidney stone formers?
    non-restricted diet and 24 hour urine collection
  37. Where are staghorn stones located?
    major and minor calyces (deep within the kidney)
  38. Where are non-staghorn stones located?
    in the renal pelvis or sometimes in the calyces
  39. What is the order of kidney stones listed by prevalence?
    • calcium: 70-80%
    • struvite: 15%
    • uric acid: 7%
    • cystine: less than 1%
  40. How is a calcium kidney stone formed?
    • calcium increases ionic activity and saturation of crystallizing calcium salts (oxalate and phosphate)
    • calcium binds to stone inhibitors like citrate and glycosaminoglycans
    • chronic metabolic acidosis and protein load causes HYPERCALCIURIA and HYPOCITRATURIA
  41. What amount defines hypercalciuria?
    more than 200 mg of calcium excreted in the urine in 24 hours
  42. What are the 3 types of hypercalciuria?
    • Absorptive
    • Resorptive
    • Renal
  43. This type of hypercalciuria is due to increased calcium absorption in the small intestine?
  44. Which type of absorptive hypercalciuria is independent of calcium intake?
    Type I
  45. What type of absorptive hypercalciuria is diet dependent?
    Type II
  46. What type of absorptive hypercalciuria is caused by low levels of urinary phosphate resulting in increased vitamin D synthesis?
    Type III
  47. What type of hypercalciuria is due to hyperparathyroid disease, an increase in PTH, and an increase in calcium reabsorption from bones?
    Resorptive hypercalciuria
  48. What type of hypercalciuria is due to inefficient reabsorption of filtered calcium in the renal tubules?
    renal hypercalciuria
  49. What type of stones are aka infectious stones?
  50. These stones are composed of magnesium, ammonia, phosphate, and carbonate apatite?
  51. Women are at higher risk for developing which type of stones and why?
    struvite because of increased incidence of UTIs (these stones are associated with infections)
  52. In uric acid kidney stones, the concentration of _______is greater than that of ______?
    undissociated uric acid >> urate
  53. What type of stone is caused by inherited defects of renal transport and renal leakage of basic amino acids?
    cystine stone
  54. How does a kidney stone develop?
    • begins with a nidus (nucleus): in the presence of saturated urine with stone forming substances like calcium oxalate via a process called crystallization
    • increased aggregation of crystals around the nidus = stone formation
    • stone gradually increases in size on the renal tubules or in renal pelvis
  55. What contributes the formation of a crystalline nidus?
     surfaces on the renal tubules and papillae have attractive properties
  56. What are some contributine factors to retention of kidney stones?
    • urinary stasis
    • anatomical abnormalities
    • inflamed epithelium in the urinary tract
    • stone size (greater than 1 cm = almost no chance of spontaneous passage)
  57. Why is citrate important?
    • helps to solubilize precipitating agents that might cause a kidney stone
    • most abundant organic anion in human urine
    • permits base excretion without raising urine pH
    • facilitates calcium excretion in a soluble form
  58. What urine volume per day and osmolarity would contribute to forming a kidney stone?
    • < 1 liter/day
    • > 600 mOsm/kg
  59. What are some inhibitors of stone formation?
    • Tamm-Horsfall protein
    • Potassium citrate
    • Pyrophosphate
    • Magnesium
  60. What is Type I hyperoxaluria?
    • mutation/polymorphism in gene that codes for alanine-glyoxylate aminotransferases 
    • most common
  61. What is Type II hyperoxaluria?
    • inactivating mutations in genes coding for glyoxylate reductase and hydroxypyruvate reductase
    • less common
  62. What is the genetic cause of cystinuria?
    multiple inactivating mutations in genes SLC3A1 and SLC7A9
  63. How is Non-Hodgkin's Lymphoma thought to cause kidney stones?
    lymphoma = cell death = increase in DNA = increase in purines = increase in uric acid
  64. What type of lymphoma does the kidney stone patient have?
    • Diffuse Large B-Cell Lymphoma: defect in B-cell development in germinal center (IgV mutation)
    • treat with chemo and rituximab
  65. What are the complications of kidney stone formation?
    • decrease of loss of function
    • hydro ureter: complete renal obstruction, accumulation of urine, dilated ureter, increased pressure, decreased GFR, kidney injury leading to ischemia and hypoxia
    • hydro nephrosis: partial ureter obstruction, less renal impairment
    • kidney damage/scarring: due to urine retention, tissue inflammation, distended kidney for extended time
    • UTI: urinary stasis, obstruction, distention
    • Pyelonephritis: septicemia and shock
  66. What is stone reoccurrence without treatment?
    14, 35, 52%  within 1, 5, and 10 years
  67. What majority of kidney stones pass spontaneously?
  68. What size of stone did the kidney stone patient have?
    6 mm
  69. Why did kidney stone patient pass his stone in 3 hours?
    • previous stone passage = dilated ureter
    • easier to pass subsequent stones
  70. What % of stones under 5 mm pass spontaneously?
    < 5 mm
  71. Do you treat asymptomatic stones?
  72. What are the 3 invasive surgical treatments for kidney stones?
    • SWL: shock wave lithotripsy
    • PCNL: percutaneous nephrolithotomy
    • Open Operative Intervention: only use when other two fail, there is an anatomical abnormality, or the stone is too extensive
  73. The 3 surgical treatments are used only when....?
    • pain
    • infection
    • hematuria
    • stone is causing obstruction
    • stone is growing even during treatment
  74. Who is shock wave lithotripsy contraindicated for?
    • pregnant
    • infection
    • stone > 2 cm
    • cystine stone > 1 cm
  75. What are the hardest kidney stones to destroy?
  76. Who is PCNL contraindicated for?
    • pregnant
    • irreversible coagulopathy
  77. Which type of stones respond well to PCNL?
    staghorn because they are soft (even though they are usually large)
  78. What is a drug that has an off-label use for passing stones?
    Tamsulosin (Flomax)
  79. What meds can be used to prevent uric acid kidney stones?
    • allopurinol: decrease uric acid
    • citric acid, potassium citrate: increase urine pH
  80. What meds are used to prevent calcium stones (like the patient)?
    • hydrochlorithiazide: off-label, decreases renal calcium excretion
    • cellulose sodium phosphate: decreases calcium
  81. What should we do to prevent new stones?
    • increase fluid intake
    • decrease oxalate intake
    • increase exercise
    • potassium citrate supplement
  82. Why was kidney stone patient's specific gravity high?
    • dehydration
    • Zenker diverticulum
  83. How do you treat hypercalciuria?
    • Type I Absorptive-
    • Calcium chelating agent: cellulose phosphate
    • Decrease renal calcium excretion: thiazide diuretic

    • Type III Absorptive-
    • Decrease Vitamin D synthesis: orthophosphate

    • Type II Absorptive-
    • Decrease Calcium intake by 50%

    • Resorptive-
    • Manage source of Increased PTH: remove parathyroid tumor

    • Renal-
    • Thiazides