Investigation of the urinary tract
IMAGING:
1.KUB (kidney ,ureter ,urinary bladder):
A plain radiograph of abdomen ,most urinary calculi absorb X
ray ,sought in the region of the renal shadow and along the
course of the ureter.
Stones with low calcium content and those overlying bony
structure may be difficult to see on the plain film.
So most urinary calculi are radiodense. And uric acid calculi are
typically radiolucent.
2.intrvenous urography (IVU ,excretory
urography):
It is mainstay of urological investigation ,using special organic
chemicals to which iodine atoms are attached to absorb X ray.
IVU gives excellent images of the urinary tract anatomy.
Iodine in the contrast may provoke anaphylactic
reaction.(hypersensitivity reaction in small number of patients.
Also may precipitate acute renal failure.
The technique by injection the contrast intra venously slowly,
and take a serial x- ray film , early film show nephrogrph phase,
then, show calyces and renal pelvis ,then the ureter, and
urinary bladder.
IVU is valuable to demonstrate tumors , stone within urinary
tract. Also abnormal anatomy if there is congenital anomaly
,that cannot detected by ultrasound study.
3.retrograde ureteropyelography (retrograde
ureterogram)
:
By using fine catheter pass into ureteric orifice through
cystoscopy.to visualize the anatomy of the upper urinary tract.
useful for intraluminal lesion, or in some case where there is
renal insufficiency. may carry a risk of infection and
septicaemia.
4.antigrad pyelography:
Percutaneous puncture of dilated renal collecting system ,or
through nephrostomy tube to see the anatomy of the renal
pelvis calyces and the ureter if obstruction or pathology.
5. digital subtraction arteriography
:
Imaging of renal vessels after intravenous injection of contrast
media, or intra-arterial injection through femoral artery .now is
rarely used to demonstrate tumors vasculature in renal
malignant tumors .but, use intravenous injection with CT to
see the invasion of renal vein or inferior vena cava.
6.cystography:
commonly used to asses vesico- ureteric reflux in children.
7.urethrography:
ascending uretherography to demonstrate urethral injury or
stricture, diverticula.
8.venography:
Infrequently used to diagnose renal tumor invasion.
9.ultrasonography:
Most widely used in urology ,the size of the kidney, cortex
thickness, and the presence and degree of hydronephrosios,
intra renal mass,, stones ,volume of urine in bladder, also
scrotal contents ,so it provides similar anatomical information
to IVU ,but without risk of radiation , it is safe.
10. trans -rectal ultrasound:
For prostate disease especially prostate carcinoma and to
facilitate prostate biopsy.
11.computarised tomography:
It is important to asses retroperitoneum, in renal carcinoma will
show size , site, degree of invasion, enlarge lymph node,
invasion of renal vein.
Also for staging and follow up of testicular cancer .also for
staging of bladder carcinoma .
NON contrast CT scan used routinely and important in
diagnosis of urinary calculi
.
12.magnatic resonance imaging (MRI):
Give information about the function and details of structural
images the technique depend on hydrogen atom of water
content of the tissue especially for soft tissue.
13.radioisotope scanning:
To obtain information about individual renal unite, using
diethyltriaminepentacitic acid (DTPA) used ,that labelled with
technetium 99m ,by using gamma camera can be followed
during transit through individual kidney to give dynamic
representation of the renal function.,
Useful in urinary obstruction of the kidney.
Other using dimercaptosuccinic acid (DMSA),
mercaptoacetylglycine (MAG-3), also used to asses renal
function.
Also used to asses bone metastasis in carcinoma of prostate.
14.endoscopy
:
it is visual inspection of the lower urinary tract.it is either rigid
or flexible scope , it is for
diagnostic
and
therapeutic
purpose, for diagnosis of bladder pathology also therapeutic as
resection of prostate or bladder tumor.
ANURIA:
Complete absence of urine production.
OLIGURIA
is present when less than 300 ml of urine excreted
in 24 hours with normal specific gravity
.
Diagnosis:
Check the bladder is empty, by catheterization ,or by
ultrasound of bladder.
Reduced renal blood flow or hypoxia impair renal function,
when both present danger of acute renal failure.
Renal failure divide into :
PRERENAL
RENAL
POSTRENAL(OBSTRUCTIVE)
PRERENAL:
Prerenal cause of renal failure:
*
hypovolaemia
: due to excessive loss of body fluid ,as
dehydration ,by vomiting ,diarrhea, burn, excessive sweating
*
blood lose
: due to trauma or surgery, or GIT bleeding or post
labor .
*
sepsis
: gram negative septicaemia is potent cause of
bacteraemic shock.
*
cardiogenic shock
: may due to myocardial infarction, cardiac
tamponade, pulmonary embolus. all leading to reduce cardiac
output.
*
anaesthesia
: due to hypotension.
*
hypoxia
: prolong hypoxia for any cause.
RENAL
:
Cause:
*
drugs
: as aminoglycoside, cephalosporin's, and diuretics,
prolong use of non-steroidal anti-inflammatory drugs (NSAIDs),
angiotensin-converting enzymes inhibitors.
*
poisons
.
*
contrast media
, used for IVU, especially in dehydrated
patient.
*
eclampsia
.
*
myoglobinuria
: occur after trauma and crushed muscles.
*
incompatible blood transfusion
.
*
disseminated intravascular coagulation (DIC):
following
sepsis or incompatible blood transfusion.
OBSTRUCTIVE:
Causes include:
:
1.calculi
Is the most common cause, in bilateral renal obstruction by
stone or obstruction the only single functioning kidney.
:
malignancy
2.pelvic
Ca bladder or prostate or cervix, ovary or rectum, may cause
bilateral ureter .may be palpable mass.
3.surgery:
During pelvic or retroperitoneal surgery, it is unusual lead to
damage or ligation of both ureter.
s idiopathic fibrosis.
it i
:
fibrosis
retroperitoneal
4.
to ureteric fibrosis and stenosis, may
:may lead
5.bilharizia
lead to squamous cell carcinoma.
:
6.crystalluria
Used to be associated with sulphonamide medication but it is
very rare, uric acid crystalluria can develop inpatient receiving
chemotherapy.
Clinical aspect
*catheterization of bladder should be done, if there is urine or
not .if urine present check for specific gravity ,cast,
myoglobulinuria and send for culture.
*evaluation for pre renal cause. clinical examination ,and vital
sign. Arterial oxygen concentration.
*evaluation for ureteric obstruction.by using ultrasound and
radiograph.
*drug :if it is the cause of renal impairment.
*may progress to chronic renal failure, where there is
normochromic anemia, and hypertension.
Management and treatment
:
Renal failure caused by acute tubular necrosis may pass in three
phases:
1.oliguria.
2.diuretic phase.
3.recovery
.
Oliguric phase
:
The initial management by restoration of the circulating
volume. And correction of tissue hypoxia.
Correction of hypovolemia or sepsis with inotropic support
(dopamine), to increase renal blood flow.
Diuretic may give ,mannitol(as plasma expander).
The aim is to achieve the best possible blood pressure.
If this management fail, excess fluid must be avoided .and
abnormal losses due to vomiting. Nasogastric aspiration
,diarrhea or fistula will be monitor and replaced.
A hyperkalemic acidosis is the characteristic metabolic
abnormality of the oliguric phase of renal failure. potassium is
life threatening, so medical treatment is advised. sometime
urgent dialysis is advised.
So ,shared management with nephrologist.
The diuretic phase
:
between the eighth and 10
th
day may delayed as long as 6
weeks. ,may a heavy loss of sodium and potassium can be
expected ,so, fluid and electrolyte requirement must be
carefully monitored.
Recovery phase
:
May be followed , but, some never recover, and there is
significant mortality rate.
Nutritional support:
The patient may not able to eat, so parenteral nutrition ,and
avoid circulatory overload.
Infection:
There is increased risk of infection, so should monitor carefully
by urine culture and swab, with treatment.
General nursing:
Meticulous recording fluid balance ,special care for comatose
patients, and physiotherapy for chest and extremities.
Renal support by:
Life threatening hyperkalemia is life threatening and should be
corrected at any early stage.
1.peritoneal dialysis:
By insertion of fenestrated catheter under local anaesthesia.
Using the peritoneum as a dialysis membrane .the
disadvantage, infection into the peritoneum, and slow
correcting metabolic imbalance especially hyperkalemia.
2.haemodialysis:
Lifesaving, using double lumen catheter is placed into one
major vein(subclavian, femoral..)
There is rapid correction of metabolic abnormalities, ,the
disadvantage is the using heparin that may cause problem with
surgical procedure
.
3. hemofiltration,
Like hemodialysis, but cause much less hemodynamic upset, for
acutely ill patient.
Obstructive renal failure
:
The cornerstone of treatment is
drainage
:
Urethral or suprapubic catheterization will relive obstruction
distal to obstruction.
Indwelling stent to relive ureteric obstruction can be inserted
cystoscopy or percutaneously.
*
percutaneous nephrostomy
:
Under ultra-sonographic guidance and local anaesthesia,
needle inserted to dilated pelvis of the obstructed kidney .this
will drain pus and urine .,till the renal function recover.
*
insertion of a J- stent
:
The obstructed ureter can be drained into the bladder by
insertion of pigtail or J-stent.
Can be placed under topical urethral anaesthesia using the
flexible cystoscope ,or rigid ,may left for several months, it is
prone for infection and encrustation.
*
open surgery (formal nephrostomy):
Rarely used today , through open surgery by incision through
renal pelvis.
Assis. Professor
M.R.Judi
Urologist
2018 /November
