Nephrolithiasis Flashcards
What makes a stone form?
Urine becomes supersaturated w/ substances that are normally soluble. This allows crystals to form.
When do stones form?
- When the number of substances is increased in the urine (increased urine calcium)
- pH changes alter the solubility of substances
Risk factors for Nephrolithiasis
- Previous Nephrolithiasis
- Positive family history
- Prolonged immobilization
- Diet: poor fluid intake
- Diabetes
- HTN
- Gout
- Obesity
- Anatomic abnormalities
Dietary risks of Nephrolithiasis
Diets high in:
- sodium (increases urinary Ca2+)
- sucrose (increases urinary Ca2+), fructose
- vitamin C (increases urinary oxalate)
- Non dairy animal protein (not proven but thought may increase urine acidification compared to plant protein)
Diets low in:
- Calcium
- Potassium (increases urinary Ca2+)
- Fluids
Systemic diseases associated with Nephrolithiasis
- Hyperparathyroidism
- Metabolic syndrome
- Nephrocalcinosis
- Cystic Fibrosis
- Malabsorption syndromes
What is the most common type of stone?
Calcium Oxalate
Describe a calcium oxalate stone?
Envelope shapes crystals on microscopy
Describe a calcium phosphate stone
Needle shaped crystals
Describe a struvite stone
- “Triple phosphate”: magnesium ammonium phosphate
- Coffin lid shaped crystals
What are struvite stones associated with?
- Staghorn calculus formation
- Chronic urinary tract infection due to urease producing organisms: proteus, pseudomonas, providencia
Describe a cystine stone
- Hexagonal (benzene ring) shaped crystals
- Stones have a “ground-glass” appearance
- Rare
- Seen in patients with cystinuria (inherited)
Describe a uric acid stone
- rhomboid shaped crystals
Uric acid stones are seen in what kind of patients?
Seen in patients with chronically acidic urine (chronic diarrhea, gout, diabetes, obesity)
What are the signs and symptoms of Nephrolithiasis?
- Pain
- Nausea / Vomiting
- Gross hematuria (blood in urine)
Describe the pain of Nephrolithiasis
