APIMC243889243 - CME/CMLE - Urinary Crystals-APIMC243889243

APIMC243889243 - Educational Activity

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This educational commentary by Koy Kubala discusses urinary crystals, or crystalluria, emphasizing their types, identification, causes, and treatment. Crystalluria can be pathological or non-pathological; identification of crystal types through microscopy and urine pH measurement helps differentiate normal from abnormal crystals. Normal crystals, such as calcium oxalate (monohydrate and dihydrate), uric acid, and amorphous crystals, are commonly found in acidic, neutral, or alkaline urine. Abnormal crystals include cystine, cholesterol, tyrosine, leucine, bilirubin, sulfonamides, radiographic dye, and ampicillin, often related to metabolic disorders, inherited conditions, or medication effects.<br /><br />A urine sample should be analyzed within 2 hours at room temperature to avoid artifact crystal formation from refrigeration. Brightfield and polarized microscopy (at 40x) help identify crystals based on shape, color, and birefringence (light refractive properties). For example, calcium oxalate monohydrate crystals are dumbbell-shaped and colorless with positive birefringence, while uric acid crystals are yellow-brown and rhombic. Abnormal crystals have distinctive morphologies and can often be linked to specific patient histories, such as medication use or metabolic disease.<br /><br />Non-pathological causes of crystalluria include diet (high in oxalate and purines), dehydration, and urinary tract infections (UTIs), where struvite crystals are common. Pathological causes include genetic disorders like cystinuria and tyrosinemia, metabolic abnormalities, chemical exposures (e.g., ethylene glycol poisoning causing calcium oxalate monohydrate crystals), and medication-induced crystalluria leading to nephropathy.<br /><br />Prevention focuses on adequate hydration, dietary modification (reducing salts, calcium, oxalate-rich foods), and managing underlying diseases. Treatment for kidney or bladder stones caused by crystalluria may involve pain management, hydration, medications to dissolve or facilitate stone passage (e.g., allopurinol, thiazide diuretics, citrate salts, alpha-blockers), or invasive procedures like lithotripsy and ureteroscopy depending on stone size and location.<br /><br />In conclusion, identifying urinary crystal types is critical for proper diagnosis and management, requiring comprehensive analysis of urine pH, microscopy features, and clinical context.

Keywords

crystalluria

urinary crystals

calcium oxalate

uric acid crystals

microscopy identification

urine pH

pathological crystals

non-pathological crystals

kidney stones treatment

metabolic disorders