Crystals & Casts - Key Notes

Name	Shape	Urine pH	Seen in cases of:	Breeds predisposed:
Struvite (Magnesium ammonium phosphate or triple phosphate)	Orthohombric (coffin-lid)	Alkaline	Staphylococcal infection	Miniature Schnauzer. The most common crystal in cats
Calcium carbonate	Spheroids	Alkaline	Only seen in horses, rabbits, guinea pigs & goats	N/A
Calcium phosphate	Amorphous or thin long prisms (may aggregate as rosettes or needles)	Alkaline or neutral	May form in conjunction with calcium oxalate or in association with infection induced struvite crystalluria	N/A
Calcium oxalate dihydrate	Envelopes or octahedral	Acidic or neutral, but may form in alkaline urine	May arise from ethylene glycol (anti-freeze) poisoning	N/A
Calcium oxalate monohydrate	Spindles, hemp seed or dumbbells	Acidic or neutral, but may form in alkaline urine	May arise from ethylene glycol (anti-freeze) poisoning	N/A
Cystine	Hexagonal	Acidic or neutral, occasionally alkaline	Poss inherited defect of the renal tubules or associated with the metabolic disorder cystinuria	Bassett hound, Bull mastiff, Dachshund, Pekinese
Leucine	Spheroids with radial & concentric laminations	Only Acidic	May occur as a result of acute hepatic damage	N/A
Bilirubin	Needles or granules (red-brown)	Only acidic	Indicative of an abnormality in bilirubin metabolism	N/A
Ammonium urate	Spherulites, thorn apples	All	Seen in dogs with portal vascular abnormalities	Dalmatian, Bulldog, Yorkshire terrier

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