Nephrology Book

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Postrenal FailureAka: Postrenal Azotemia, Hydronephrosis, Urinary Tract Obstruction

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  1. Epidemiology
    1. Accounts for 1-10% of Acute Renal Failure cases
    2. More common in elderly
  2. Pathophysiology
    1. Urinary tract obstruction
    2. Results in renal pelvis dilatation
    3. Progressive decrease in Renal Function
      1. Increased intratubular pressure
      2. Decreased capillary filtration pressure
  3. Etiologies
    1. Intrarenal (distal tubules)
      1. Multiple Myeloma protein
      2. Uric Acid crystals
        1. Hyperuricemia
        2. Gout
      3. Methotrexate
      4. Acyclovir
    2. Extra-Ureteral Obstruction
      1. Prostate Cancer
      2. Bladder Cancer
      3. Cervical Cancer
      4. Retroperitoneal fibrosis
      5. Accidental ureteral ligation during pelvic surgery
    3. Ureteral Obstruction (Bilateral in Renal Failure)
      1. Nephrolithiasis
      2. Thrombosis
      3. Pyogenic debris or sloughed papillae
      4. Edema from retrograde pyelography
    4. Bladder neck obstruction
      1. Benign Prostatic Hypertrophy (BPH)
      2. Prostate Cancer
      3. Bladder Cancer
      4. Autonomic Neuropathy
      5. Ganglionic blocking medication
    5. Urethral Obstruction
      1. Urethral valves
      2. Urethral stricture
  4. Symptoms
    1. Abdomen or Groin Pain (colic-type attacks)
  5. Signs
    1. Mass at flank, suprapubic, or central abdomen
    2. Abdominal exam
    3. Pelvic exam
    4. Rectal exam
    5. Anuria (Indicates obstruction in 90% cases)
  6. Labs
    1. See Renal Function
    2. Urine Sediment
      1. Normal sediment
      2. Hematuria
      3. Pyuria
      4. Crystals
  7. Diagnostic Testing
    1. Post-void residual >100 ml
      1. Indicates Bladder outlet obstruction
    2. Ultrasound or Intravenous Pyelogram
      1. Dilated ureters or renal pelvis
    3. Abdominal CT or Abdominal MRI
    4. Percutaneous nephrostomy drainage trial
  8. Management
    1. Exclude reversible causes rapidly
    2. Renal Function recovery reflects obstruction duration
  9. References
    1. Anderson (8/15/1993) Hospital Practice, p. 61-75

Hydronephrosis (C0020295)

Definition (MSH)Abnormal enlargement or swelling of a KIDNEY due to dilation of the KIDNEY CALICES and the KIDNEY PELVIS. It is often associated with obstruction of the URETER or chronic kidney diseases that prevents normal drainage of urine into the URINARY BLADDER.
Definition (CSP)distention of the pelvis and calices of the kidney with urine, as a result of obstruction of the ureter, with accompanying atrophy of the parenchyma of the organ.
Definition (NCI)Abnormal enlargement of a kidney, which may be caused by blockage of the ureter (such as by a kidney stone) or chronic kidney disease that prevents urine from draining into the bladder.
ConceptsDisease or Syndrome (T047)
ICD9591
EnglishHydronephroses, Hydronephrosis
Spanishhidronefrosis
CreditsDerived from the NIH UMLS (Unified Medical Language System)



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