5- Micro-examination: Crystals Flashcards
kidney stone disease is called
nephrolithiasis
stones that are in the ureter is called
ureterolithiasis
urinary bladder stones which form or have passed into the bladder is called
cystolithiasis
seeing crystals under microscope do not guarantee that they result from:
urolithiasis
Crystal precipitation after micturition is most commonly due:
changes in urinary temperature
changes in urinary pH
Crystals are usually not found in
freshly voided urine
Normal Urinary Crystals
Normal acidic crystals
Normal alkaline crystals
Abnormal Urinary Crystals
Metabolic origin
Iatrogenic origin
Abnormal crystals usually seen in acidic urine
Urinary Crystals-formation factors
In vivo (body) factors:
- Solute concentration
- Kidney filtration rate
- Urine pH
- Diet
- Excretion of:
diagnostic and therapeutic agents
Urinary Crystals-formation factors
In vitro factors:
- Temperature (solubility decreases with low temperature)
- Evaporation (increases solute concentration)
- Urine pH (changes with standing and bacterial overgrowth)
Normal Urinary Crystals MOST are clinically _____
insignificant
clinically significant crystals are present in
freshly voided urine
or
metabolic disorders
urinary calculi aka
urolithiasis
Metabolic disorders may produce crystals
- Cystine (inherited metabolic disease)
- Leucine
- Tyrosine
- Cholesterol
Latrogenic disorders-high doses of some drugs that froms crystals?
- Salicilates (Aspirin)
- Sulfonamides
- Ascorbic Acid (vitamin C)
Polarized light is used for the identification of
crystals and other anisotropic
crystals that polarize the light are said to be?
optically active
Birefringence is used for
differential diagnosis between various crystals
Negative birefringence: (Y-B)
in polarizing filter with red compensator filter, the crystals are yellow when aligned
parallel
Negative birefringence: (Y-B)
but crystals turn blue when aligned
across the direction of polarization
Positive birefringence:(B-Y)
crystals are blue when aligned
parallel to the slow axis of the red compensator
Positive birefringence:(B-Y)
but they turn yellow when aligned
across the direction of polarization
Birefringence - VS +
(picture)
Uric Acid crystals size and shape
can vary in both size and shape
Uric Acid is Pathologic only when seen in
freshly voided urine
Urate crystals are common in patients with
urate urolithiasis
or
acute urate nephropathy
A high uric acid level in the urine may be due to
- gout (monosodium urate)
- high-purine diet (red meats, seafood, fish, spinach, mushrooms, dried peas)
- Lesch-Nyhan syndrome
- cancer metastases
- rhabdomyolysis (breakdown of muscle fibers)
- myeloproliferative disorders (e.g. multiple myeloma, leukemias)
define Lesch-Nyhan syndrome
when the body is not able to process purine due to lack an enzyme
Low uric acid levels in the urine may be due to
- inability of kidney to get rid of uric acid well, which can lead to gout with kidney damage
- chronic glomerulonephritis
- lead poisoning
- long-term (chronic) alcohol use
- a diet low in purines
what colour will uric acid crystals look under polarizes light?
various colours
Viewing uric acid with red compensation filter demonstrates
negative birefringence (yellow to blue color)
Amorphous urates often seen in:
acidic urine
especially after refrigeration
Amorphous urates appear as aggregates of finely granular material without
any defining shape at the light microscopic
Amorphous urates will re-solubilize when
heated at 60° C
does Amorphous Urates has any clinical interpretation?
No
Monosodium Urate vs Calcium pyrophosphate
Calcium oxalate crystals may occur as either
di-hydrate (bi-hydrate)
or
mono-hydrate calcium oxalate
Calcium Oxalate can be seen in
- individuals with high dietary oxalate ingestion
- patients with urolithiasis
- patients with acute renal failure
Calcium Oxalate in patients with acute renal failure due to
ethylene glycol (antifreeze) intoxication
what form of Calcium Oxalate found in acute renal failure?
monohydrate calcium oxalate
75% of all urinary tract stones consists of
oxalates or combination with calcium phosphate
Common calcium oxalate appearance
bi-hydrate
colorless
bi-pyramids
Crystals Commonly Found in Alkaline Urine
- Triple Phosphates
- Calcium Carbonates
- Ammonium biurate
Triple phosphate crystals are frequently seen in
patients with UTI caused by urea-splitting bacteria, such as Proteus or Klebsiella species
Calcium carbonate crystals are normally found in urine, in _____ pH
alkalinic
Calcium carbonate appearance
small
colorless granules
dumbbells
A unique feature of calcium carbonate is
crystals bubbling with hydrochloric acid or acetic acid
Ammonium Biurate shape
Yellow–brown spherical bodies
with long, irregular spicules
“thorn apple”
Cystine occur in the sediment of patients with
Cystinuria
Define Cystinuria
genetic defect in renal cystine transport
Cystine crystals indicate an abnormality in metabolism of
the amino acid cystine
Cystine crystals are the most frequent cause of kidney stones in
children or young patients
cystine stones can fill renal collecting system, resulting in formation of
staghorn calculi
Define Staghorn calculi
branched stones that occupy a large portion of the renal pelvis and branch into several or all of the calices
Cystine crystals vs Uric acid under light
Cystine crystals do not polarize light
Uric acid crystals are multicolored when polarized
Cystine crystals vs Uric acid crystals solubility in ammonia?
Cysitine is soluble
Uric acid is not
Tyrosine Is found in patients with
severe liver disorders
The presence of tyrosine crystals is usually accompanied by
bilirubin
and
leucine crystals
describe Tyrosine
Colorless to yellow-brown single needles.
also as sheaves or rosettes, needles in bundles.
Describe Leucine shape and color
yellow-brown spheroids
concentric rings around the outer edge
radial striations in the center
leucine crystals is often accompanied by
bilirubin
and
tyrosine crystals
Leucine can indicate which disease
Maple Syrup Disease
Cholesterol can be present in cases of
glomerulonephritis associated with Nephrotic Syndrome
describe the shape and color of Cholesterol
colorless
large
flat
rectangular plate with one or more corners notched
Bilirubin Crystals color and shape
Yellow-brown needles or granules
Bilirubin crystals are seen in patients with
hepatic disorders
Bilirubin Crystals are present in urine is called
(name the condition)
bilirubinuria
Confusing Artifacts includes
- Starch
- Talc
- Glass fragments
Confusing Artifacts: Starch
Polarize light into Maltese cross but without the:
outer edge resembling “crushed diamonds”
Confusing Artifacts: Talc and Glass Fragments
(Picture)
