Nephrolithiasis: Difference between revisions

From IDWiki
m (Aidan moved page Renal calculi to Renal calculus without leaving a redirect)
No edit summary
 
(One intermediate revision by the same user not shown)
Line 1: Line 1:
−
== Epidemiology ==
 +
== Background ==
   
  +
* Also known as kidney stones or renal stones
 
* 10% lifetime prevalence in men, 5% in women
  
* 10% lifetime prevalence in men, 5% in women
   
−
== Pathophysiology ==
 +
=== Stone Types ===
  +
{| class="wikitable"
  +
!Stone
  +
!%
  +
!Composition
  +
!Risk Factors
  +
|-
  +
|Calcium oxalate
  +
|75%
  +
|calcium oxalate monohydrate, or calcium oxalate dihydrate
  +
|usually in acidic urine; [[hyperparathyroidism]], [[hypercalciuria]], [[hyperoxaluria]], [[hypomagnesemia]], and [[hypocitraturia]]
  +
|-
  +
|Calcium phosphate
  +
|10%
  +
|calcium phosphate, including apatite and brushite
  +
|usually in alkaline urine; [[hyperparathyroidism]], [[renal tubular acidosis]]
  +
|-
  +
|Uric acid
  +
|10%
  +
|uric acid
  +
|only in acidic urine, pH <5.5; associated with purine-rich food intake (fish, legumes, meat), gout, and cancer
  +
|-
  +
|Struvite
  +
|<10%
  +
|calcium, ammonium, and magnesium phosphate
  +
|usually in alkaline urine; caused by gram-negative urease-producing bacteria, including [[Pseudomonas]], [[Proteus]], and [[Klebsiella]] (but not [[Escherichia coli]])
  +
|-
  +
|Cystine
  +
|<5%
  +
|cystine
  +
|from intrinsic metabolic defect that lead to decreased reabsorption of cystine, lysine, ornithine, and arginine in the renal tubules
  +
|}
   
  +
=== Pathophysiology ===
  +
* Varies by stone type
 
* Low urine output/poor oral intake
  
* Low urine output/poor oral intake
 
* Increased uric acid, which precipitates in low pH
  
* Increased uric acid, which precipitates in low pH
Line 21: Line 55:
 
* [[Urinary tract infection]] caused by [[urease-positive]] bacteria, leading to [[struvite stones]]
  
* [[Urinary tract infection]] caused by [[urease-positive]] bacteria, leading to [[struvite stones]]
 
* Urinary stasis, e.g. in polycystic kidney disease, medullary sponge kidney
  
* Urinary stasis, e.g. in polycystic kidney disease, medullary sponge kidney
−
* Medications, especially HIV medications
 +
* Medications, including [[atazanavir]] and other HIV medications, [[guiafenesin]], [[indinavir]], [[sulfonamides]], and [[triamterene]]
  +
  +
== Clinical Manifestations ==
  +
  +
* Common cause of hematuria and abdominal, flank, or groin pain
   
 
== Investigations ==
  
== Investigations ==

Latest revision as of 15:43, 19 August 2024

Background

  • Also known as kidney stones or renal stones
  • 10% lifetime prevalence in men, 5% in women

Stone Types

Stone % Composition Risk Factors
Calcium oxalate 75% calcium oxalate monohydrate, or calcium oxalate dihydrate usually in acidic urine; hyperparathyroidism, hypercalciuria, hyperoxaluria, hypomagnesemia, and hypocitraturia
Calcium phosphate 10% calcium phosphate, including apatite and brushite usually in alkaline urine; hyperparathyroidism, renal tubular acidosis
Uric acid 10% uric acid only in acidic urine, pH <5.5; associated with purine-rich food intake (fish, legumes, meat), gout, and cancer
Struvite <10% calcium, ammonium, and magnesium phosphate usually in alkaline urine; caused by gram-negative urease-producing bacteria, including Pseudomonas, Proteus, and Klebsiella (but not Escherichia coli)
Cystine <5% cystine from intrinsic metabolic defect that lead to decreased reabsorption of cystine, lysine, ornithine, and arginine in the renal tubules

Pathophysiology

  • Varies by stone type
  • Low urine output/poor oral intake
  • Increased uric acid, which precipitates in low pH
  • Low pH, which precipitates animal protein
  • Hypercalciuria
    • Genetic (familial)
    • Hypercalcemia: hyperparathyroidism, vitamin D
  • Increased oxalate
    • Genetic
    • Diet: nuts, greens, chocolate, etc.
    • IBD: fatty acids bind to calcium in gut, allowing oxalate absorbtion
    • Malabsorption
    • Vitamin C
  • Decreased citrate (i.e. 3 bicarbs), e.g. from RTA
  • Increased phosphate, e.g. from carbonated beverages, which precipitates in high pH
  • Urinary tract infection caused by urease-positive bacteria, leading to struvite stones
  • Urinary stasis, e.g. in polycystic kidney disease, medullary sponge kidney
  • Medications, including atazanavir and other HIV medications, guiafenesin, indinavir, sulfonamides, and triamterene

Clinical Manifestations

  • Common cause of hematuria and abdominal, flank, or groin pain

Investigations

  • Dietary assessment
  • Electrolytes (especially for K and HCO3), calcium profile, PTH, urinalysis, urine microscopy
  • 24h urine collection, sent for
    • volume
    • creatinine, CrCl
    • Na, K, urea
    • calcium
    • oxalate
    • uric acid
    • phosphate
    • spot test for cystine
    • citrate and magnesium in a separate collection

Management

  • Imaging
  • Stone diet
    • Maintain urine output 2L/d
    • Low salt
    • Normal calcium
    • Increased fruit and vegetables
    • Moderate meat and alcohol
  • Potassium citrate 20mEq BID, to increased citrate and pH of the urine
  • Hydrochlorothiazide, to decrease urine calcium
  • Allopurinol, to decrease urine urate
Retrieved from "https://idwiki.org/index.php?title=Nephrolithiasis&oldid=10586"
Powered by MediaWiki
Powered by Semantic MediaWiki