Evaluation of pt with urolithiasis

Naveed Mahar
Resident Urology
JPMC, Karachi

 Detailed history

 Examination

 Metabolic evaluation

 Radiological investigations

HISTORY
 Demographic biodata
 Life style
 Occupation
 Diet/fluid intake
 Drug history
 Systemic disease
 Family history
 History of bowel surgery

OCCUPATION
 Sedentary occupations predispose to stones more
than manual work

 Low activity levels predispose to bone
demineralization and hypercalciuria.

 Physical activity agitate urine and dislodge crystal
aggregates

DIET
 Water intake
 Low fluid intake (<1200 ml/day) predisposes to stone
formation
 A less energy-dense diet may decrease the incidence of
stones.
 Vegetarians have decreased incidence of urinary stones
 High sodium intake is associated with increased urinary
 Sodium
 Calcium
 PH
 Decreased urinary citrate

CLIMATE
 Summer is the season of urinary stones and
dehydration is the key factor
 Concentrated urine has a lower ph, encouraging
cystine and uric acid stone formation
 Exposure to sunlight may also increase endogenous
vitamin D production, leading to hypercalciuria.

FAMILY HISTORY
 Incidence increases with positive family history
 Familial diseases like
 Cystinuria
 An auto-somal recessive disorder of transmembrane cystine
absorption
 RTA
 Type 1 or distal RTA: the distal tubule is unable to secret H+
 Urinary ph(>5.5)

 Low urinary citrate

 Hypercalciuria

 Type 2 or proximal RTA: failure of bicarbonate resorption in the
proximal tubule.
 Type 3: a variant of type 1 RTA
 Type 4 : is seen in diabetic nephropathy and interstitial renal disease.

PAST HISTORY
 Bowel resection
 Inflammatory bowel disease
 Systemic diseases i-e
- Gout
- Hyperparathyroidism
- Sarcoidosis

DRUG HISTORY
 The antihypertensive(triamterene) is associated with
urinary calculi
 Long-term use of antacids containing silica leads to
silicate stones.
 Protease inhibitors in immunocompromised patients
are associated with radiolucent calculi.
 Corticosteroids (increase enteric absorption of
calcium, leading to hypercalciuria)
 Chemotherapeutic agents (breakdown products of
malignant cells leads to hyperuricemia)

PHYSICAL EXAMINATION
 Pt frequently changes posture to find pain relief
 Renal colic is associted with tachycardia, sweating,and nausea
 Costovertebral angle tenderness may be apparent.
 An abdominal mass may be palpable in patients with hydronephrosis
 A thorough abdominal examination to exclude other causes of
abdominal pain.
 Abdominal tumors,
 Abdominal aortic aneurysms
 Herniated lumbar disks
 Pregnancy
 Bladder palpation as urinary retention may present with pain similar
to renal colic.
 Incarcerated inguinal hernias
 Epididymorchitis
 A rectal examination helps exclude other pathologic conditions.

METABOLIC EVALUATION
 Depends on the stone type(composition)
 Stone type is analyzed by
 Polarizing microscopy
 X-ray diffraction
 Infrared spectroscopy
 If stone is not retrieved
 Radiological appearance radiolucecy/opacity
 Metabolic evaluation

METABOLIC EVALUATION…
 Urine pH
 pH <6 in a patient with radiolucent stones suggests the
presence of uric acid stones.
 pH consistently >5.5 suggests distal RTA (~70% calcium
phosphate stones)
 Evaluation for cystinuria
 Cyanide-nitroprusside colorimetric test (cystine spot test)
 Measurement of 24-hour urinary cystine (>250 mg is
diagnostic)
 Evaluation for RTA
 If fasting morning urine ph >5.5, the patient is labeled to
have distal RTA.

COMPOSITION & PREVELENCE OF RENAL STONES

PH VALUES AND PREDISPOSITION TO STONE TYPE

RADIOLOGIC INVESTIGATIONS
1. X-ray KUB

2. Ultrasonography

3. Intravenous pyelography

4. Computed tomography

5. Magnetic resonance imaging

PLAIN X-RAY KUB
 Not useful if stones are
 Radiolucent
 Smaller than 4mm
 Lies over the sacrum or other bony structure.
 Bowel gases can obscure its efficacy.
 Can not differentiate between
 Stones
 Calcified lymph nodes
 Phleboliths
 Sensitivity for diagnosis of stones is 50–70%

US KUB

 Usually done to compliment x-ray KUB

 Its sensitivity for detecting renal calculi is ~95%

 Very sensitive for the diagnosis of obstruction and
can detect radiolucent stones missed on KUB
 Its non invasive

 May miss small stones and ureteral stones

 Particularly important in pregnant pt

INTRAVENOUS PYELOGRAPHY

 Useful for patients with suspected indinavir stones
 Requires trained technician
 Its an invasive procedure predisposing pts to highly
allergic IV contrasts
 Its very prolonged procedure takes hours
 Require proper pt preparation
 Not good investigative modality in acute renal colic

IVP
Films and “phases” of IVP
 Plain film:
 This is used to look for calcification overlying the region of
the kidneys, ureters, and bladder.
 Nephrogram phase:
 Film taken immediately following iv contrast
 The nephrogram is produced by filtered contrast within
the lumen of the proximal convoluted tubule
 Pyelogram phase:
 Much denser than the nephrogram phase.
 As concentrated contrast accumulates in plvicalycel
system

COMPUTED TOMOGRAPHY
 Has greater specificity (95%) and sensitivity (97%) for
diagnosing ureteric - stones
 Noncontrast spiral CT scans are now the imaging modality of
choice
Advantages:
 It is rapid
 No need for experienced radiologic technician
 No need for intravenous contrast.
 Uric acid stones are also visualized
Disadvantage:
 Distal ureteral calculi can be confused with phleboliths.
 These images do not give anatomic details as seen on an IVP
(for example, a bifid collecting system)

MAGNETIC RESONANCE IMAGING

 MRI is a poor study to document urinary stone disease.

 Clue towards obstruction by diagnosing
hydronephrosis

Evaluation of pt with urolithiasis

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