Urinary crystals

Question 1

Which crystals are pathological (all acidic urine)

which crystals are due to drugs?

Answer 1

cystine, leucine, tryosine, cholesterol, billirubin

sulfa, acyclovir, indinavir

Question 2

Which are non pathological acidic urine crystals?

Answer 2

uric acid-product of purine metabolism not necessarily associated with gout if seen in urine
* Form when the urine pH is < 5.5
* Appear with a variety of shapes (rosettes, four sided flat plates, wedges)
* May be seen in patients with leukaemia who are undergoing chemotherapy

amorphous urates (yellow to brown- precipitate pink after centrifugation),

calcium oxalate (dihydrate form is oxahetral in shape- found in urine based on diet Increased presence following ethylene glycol intoxication),
monohydrate form is dumb bell shaped - harder to break (for kidney stone)= supersaturated w ca oxalate

hippuric acid.
rare in urine Colourless or yellow-brown
- Elongated prisms or plates that often clump together
- Some can be very thin like needles

Question 3

Pathological crystals (acidic urine)

1. Abnormal, Rare but indicate liver disease or hereditary AA metabolic disorders
   - Often accompany bilirubin in urine
   - May be seen with tyrosine crystals in the same sample
   * Yellow-brown spheroids with concentric rings around the outer edge (BF)
   - Centre area contains radial striations
   * Pseudo-maltese cross under polarised light
2. Abnormal in urine
   - Severe liver disease or
   - Defect in amino acid metabolism
   - Often accompany bilirubin in urine
   - May be seen with leucine crystals in the same sample
   * Fine colourless/yellow-brown needles/rosettes/sheaves- look like hay
3. Abnormal in urine
   * Defect in amino acid metabolism (inherited cystinuria)
   Poor reabsorption of cystine AND ornithine, lysine, arginine in the proximal tubules
   * Thin, colourless hexagonal plates
   * Most frequent cause of renal calculi in children
4. Abnormal in urine
   * Associated with nephrotic syndrome
   - Kidney damage (renal capillaries)
   - Proteinuria and hypoalbuminaemia
   - Elevated blood lipids - Oedema
   * Clear flat plates with notched corners
   * May also see oval fat bodies, fatty casts and fat droplets

Answer 3

1. Leucine crystals
2. Tyrosine crystals
3. Cystine crystals
4. cholesterol crystals

Question 4

What are the non pathological crystals in alkaline urine?

1. (like amorph urates but sediment is white, in alkaline urine greater than 6.5)
2. Normal in urine but may be associated with calculi formation
   * Large, flat plates/wedges that may appear in rosettes
   - Single prisms are usually blunt on one end and pointed on the other
3. Composed of magnesium, ammonium and phosphate
   - Coffin lid appearance (freshly formed crystals have a fern leaf cross)
   * Alkalinisation of urine with ammonia
   - Usually found in long standing specimens due to the breakdown of urea
   by bacteria in the sample
   OR
   - The breakdown of ammonia associated with UTI (usually caused by Proteus sp. or Providencia, Morganella, Klebsiella)
   - Untreated UTI can lead to the development of renal calculi
4. Appear as variable sized spherical bodies with radial striations
   * Smaller examples may be round, ovoid or have dumbbell shapes
   * Not pathological
5. Spherical bodies with irregular protrusions resembling “thorny-apples” that are usually brown/yellow
   Not pathological – usually indicate an old or poorly preserved specimen – suggest recollection

Answer 4

1.Amorphous phosphates
2. calcium phosphate,
3. triple phosphate crystals
4. calcium carbonate,
5. ammonium biurate

Question 5

What other elements can you see in urine microscopy?

Answer 5

Trichomonas vaginalis, Schistosoma haematobium
-Associated with a high incidence of bladder cancer
Trypanosoma cruzi (unusual), spermatozoa, fibres, Pediculosis pubis- public louse