Urine casts &crystals

Medicine PG poster presentation

1. by Dr.Vivekanandan
Urinary Casts
They are cylindrical aggregations of particles that form in the distal nephron, dislodge, and pass into the urine. In urinalysis they indicate kidney disease.
They form via precipitation of Tamm-Horsfall mucoprotein which is secreted by renal tubule cells.
Acellular casts Cellular casts
Hyaline casts Red cell casts
Granular casts White cell casts
Waxy casts Epithelial casts
Fatty casts

Hyaline casts :
The most common type of cast, hyaline casts are solidified Tamm-Horsfall mucoprotein
secreted from the tubular epithelial cells. Seen in fever & after strenuous exercise

Granular casts :
Granular casts can result from breakdown of cellular casts or the inclusion of aggregates of
plasma proteins or immunoglobulin light chain , indicative of chronic kidney disease


Waxy casts :
Waxy casts suggest long standing kidney disease



Fatty casts :
Formed by the breakdown of lipid-rich epithelial cells, these are hyaline casts with
fat globule inclusions,present in nephrotic syndrome, diabetic or lupus nephropathy,
acute tubular necrosis

Red blood cell casts :
The presence of red blood cells within the cast is always pathologic, and is strongly
indicative of glomerular damage. They are usually associated with nephritic syndromes.


White blood cell casts :
Indicative of inflammation or infection, pyelonephritis,acute allergic interstitial nephritis,
nephrotic syndrome, post-streptococcal acute glomerulonephritis

Epithelial casts :
This cast is formed by inclusion or adhesion of desquamated epithelial cells of the tubule lining,
seen in acute tubular necrosis and toxic ingestion, such as from mercury, diethylene glycol, or salicylate

2. by Dr.Vivekanandan
Urine Crystals
Except for the cystine crystals and a few others, the majority of crystals found in the urinary sediment are of limited clinical value. It is tempting to associate
crystals with a risk of urolithiasis, but the majority of patients with a crystalluria do not have and will not develop kidney stones. Many benign situations can
provoke crystal formation. In the majority of cases, the crystals found in urine are not present in the freshly voided specimen. Alkalization and refrigeration
are promoters of crystals formation.
Crystals in acidic urine Crystals in alkaline urine
Uric acid Ammonium magnesium phosphates
Calcium oxalate Calcium carbonate
Leucine

Cysteine

Uric acid and Urates :

Amorphous urates appear as red granules and are dissolved by heat and sodium hydroxide
but not acetic acid. Uric acid crystals vary in shape and are yellow brown in colour and are not
dissolved by heat, acetic acid or Hcl but are soluble when heated with sodium hydroxide.
Seen in disturbances of uric acid metabolism, during fever when the urine is concentrated.


Calcium Oxalate :

Commonly found in diets rich in tomatoes, spinach etc. Typically envelope shaped crystals but
occasionally dumb- bell shaped. Insoluble in strong Hcl.


Cystine :

Highly refractile, hexagonal plates.They are soluble in Hcl but insoluble in acetic acid. They are seen
in cystinosis which is an inborn error of metabolism in which cystine crystals are found in the urine,
reticuloendothelial system and eyes.



Leucine :

Slightly yellow, oily looking spheres with radial and concentric striations .They are not soluble in Hcl
or ether. They are found in liver disorders



Ammonium Magnesium Phosphates: ( Triple phosphate)

They are feathery or leaf like forms.In freshly passed urine they indicate stones in the bladder
or kidney. Dissolves in acetic acid.



Dicalcium Phosphates :

They are also seen in slightly acid or neutral urine. They are colourless prisms arranged in stars
and rosettes. They are soluble in acetic acid.


Calcium carbonate :

Amorphous granules or colourless spheres and dumb-bells which are soluble in acetic acid
with gas formation. Occurs in alkaline urine.