cystinuria
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Introduction
3 types of cystinuria:
- Type 1 (fully recessive or silent)
- Type 2 (high excretor)
- Type 3 (moderate excretor)
Pathology
- intestinal & renal tubular transport disorder (reduced absorption) of dibasic amino acids:
- cystine is the least soluble in normally acidic urine & tends to precipitate
- homozygotes develop urolithiasis
Genetics
- autosomal recessive
- mutation in the gene for SLC3A1 (type 1)
- mutation in the gene for SLC7A10
- mutation in the gene for SLC7A9
Clinical manifestations
Laboratory
- urinalysis
- cystine crystalluria
- positive nitroprusside test
Management
- stones can be dissolved with:
- urinary alkalinization
- high take of fluids
- maintain urine pH at 7
- chelating agents may be useful
- pyridoxine (vitamin B6) 25 mg PO QD
- potassium citrate as inhibitor of stone formation
- low protein diet
- restrict dietary sodium
More general terms
Additional terms
References
- ↑ Jump up to: 1.0 1.1 Medical Knowledge Self Assessment Program (MKSAP) 11, 17. American College of Physicians, Philadelphia 1998, 2015
- ↑ Harrison's Principles of Internal Medicine, 13th ed. Isselbacher et al (eds), McGraw-Hill Inc. NY, 1994, pg 1324
- ↑ Mayo Internal Medicine Board Review, 1998-99, Prakash UBS (ed) Lippincott-Raven, Philadelphia, 1998, pg 616