Transcript Az Kidney Disease Hypertension Phoenix

Stop…let Me A-”cyst” You
A Case Study about Cystinuria
by Amy Albright
Patient History
• 57 year old woman with history of renal
problems
• Patient hospitalized upon urgent referral
from doctor’s office
• Urinalysis was performed
Urinalysis Results
Test
Patient Result
Color
Yellow
Clarity
Cloudy
Glucose
neg
Bilirubin
neg
Ketones
neg
Sp. Gravity
1.021
Blood
2+
pH
7.5
Protein
1+
Urobilinogen 1.0
Nitrite
neg
Leuk. Esterase 3+
RBC
11-24
WBC
51-100
Epithelials
57
Hyaline cysts 1
Bacteria
1+
Crystals
cystine 1+
Reference Range
(negative)
(negative)
(negative)
(1.005-1.030)
(negative)
(5.0-8.0)
(negative)
(0.2-1.0)
(negative)
(negative)
(0-3)
(0-5)
(none)
(<10)
(negative)
(negative)
Past Patient History
• Diagnosed with cystinuria as a child
• Left side nephrectomy as a child secondary
to damage by cystine stones
• Recurrent kidney stones in the remaining
right kidney
• Nephrostomy tube placed into
remaining kidney
Questions to be Considered:
1.) How does the patient’s current renal problems
relate to the cystine crystals found?
2.) What laboratory tests are performed to confirm
the presence of cystine crystals in the urine?
3.) What are the long term effects of cystine crystal
formation?
4.) Are there treatments available for patients with
cystinuria?
Pathogenesis of Cystinuria
• Autosomal recessive disorder
• Involves a defect in the renal transport of cystine
by the tubules
• Defect results in lack of cystine reabsorbtion of
the kidney
• Homozygous patients usually the only ones to
present with problems
• Heterozygotes have a milder form of cystinuria
(cystine crystals found in urine during analysis but don’t usually form
stones)
Solubility within the Kidney
• Normal excretion of amino acids such as cystine
into the urine is about 100 mg/day
• Heterozygous excrete around 100-300 mg/day
• Homozygous excrete around 500-1000 mg/day
• Solubility limit is around 300-400 mg/day
• Stones composed of cystine form when the
concentration of cystine exceeds the normal
solubility levels and the excess cannot go into
solution (cystine crystals favor the existing free
cystine and will compound it to form the stone)
Cystine Confirmation
• Initially found during a microscopic urinalysis
– crystals are found in neutral to acidic pH and are flat
hexagonal shapes
• Confirmation test for cystine once crystals are
found microscopically is a cyanide-nitroprusside
test
– involves mixing the urine with sodium cyanide and
then sodium nitroprusside which will chemically react
to produce a red-purple color indicative of presence of
cystine crystals in the urine
Positive Nitroprusside
Reaction:
Left side: Negative control
Right side: Positive for cystine
Long Term Effects of
Cystinuria
• Recurrent stone formation as seen with this
patient
• Possible nephrectomy due to renal failure
• Pain associated with stone formation and
passage
Treatments
• Focus is on management
• Relief of symptoms (pain medications)
• Prevention of further stones (drinking large
amounts of water to dilute the urine)
Treatments - continued…..
• Watching diet ( avoiding methionine rich foods)
• Alkanization of the urine (use of sodium
bicarbonate or sodium citrate to more readily
dissolve the cystine)
• Lithotripsy (non-invasive, shock waves to break
up the stone to where it can be passed)
• Invasive procedures for stone removal
Summary
• 57 year old women with presence of cystine
crystals in the urine
• Confirmatory nitroprusside test was positive
for cystine
• History revealed many renal problems
associated with cystinuria
• Treatments are unpredictable
Credits
This case study was
prepared by
Amy Albright, MT(ASCP)
while she was a
Medical Technology
student in
the 2004 MT Class at
William Beaumont
Hospital, Royal Oak, MI.