Instrumental Methods of Examination, X-rays and Radioisotopic diagnostics in Urological diseases
The Urinary system
Types of Catheters
Hello everyone! This is the second Urological Hub I am publishing in a day. Whew! As much as it is an achievement, its also a challenge, taking up the mantle just immediately after exams. Well, this hub is published to give each and everyone of us an idea of the instruments and tools used in urological analysis. Sometimes, we need to have an idea of such things so that whenever we approach the Doctor in related situations, we will can easily comprehend and blend with what the doctor is saying.
Diagnostic imaging is a dynamic recent development in medical practice with great potential for benefiting patient care. Nothing has contributed more to the improvement of existing anatomic imaging devices and the development of new ones than digital computers and their related electronics. With computers, the vast numbers of data collected in analog fashion by the basic imaging mechanics of radiography, Ultrasonography, computerized tomography (CT scanning), tomography are converted electronically into digits corresponding to the different intensities of the original bits of information. These \digits are store in the computer and can be recalled, combined, and manipulated in various ways to achieve reconverted analog images. Hard copies of selected images can be made at the time of the study, or the information can be stored permanently in digital form for subsequent retrieval and conversion to analog images.
Radiography (roentgenography) is the oldest method of urologic imaging, having been used to demonstrate radiopaque urinary calculi shortly after the discovery of X-rays by Wilhelm Roentgen in 1895. Since then, it has continued to be used for diagnosis in every branch of medicine, and it is currently the most widely available method of medical imaging. More recently and other body imaging procedures still in their very early development, eg, magnetic resonance tomography- are competing with, complementing, and in some instances, replacing long established uroradiographic tachniques.
Although bacteria are present in the distal urethra, the urinary tract is considered sterile. Therefore, any instrument entering the tract should be sterile. Instruments made of metal, rubber, and plastic may be autoclaved, but those containing optical devices must be gas-sterilized or soaked for a sufficient time in an approved solution of glutaraldehyde and then thoroughly rinsed in sterile water. The foreskin should be retracted and the glans penis washed thoroughly with cleansing solution. Th vulva must be cleansed and the labia held apart as the instrument is introduced.
Lubrication of Urethra
All transurethral maneuvers require lubrication. In women, application of lubricant to the instrument is sufficient. However, this method does not provide adequate lubrication for the entire male urethra, because the meatus tends to remove most of the lubricant as the instrument is passed. The male urethra should be lubricated by instilling at least 15 mL of a sterile, water soluble lubricant by means of a blunt, cone-tipped syringe. Oils (e.g, mineral or Olive oil) must not be used, since fatal oil emboli may result. The syringe allows introduction of the lubricant with constant, low, steady pressure, which helps overcome the normal tone of the external sphincter. This resistance may be markedly increased in apprehensive patients, leading the inexperienced instrumentalist to an erroneous diagnosis of urethral stricture.
A simple procedure such as passage of a urethral catheter may be done without anesthesia. If more complex or painful manipulations are planned, sedation or topical, regional, or general anesthesia will be necessary. Sedation may be achieved with barbiturates, tranquilizing agents, or narcotics. Topical anesthesia of the urethral mucosa may be obtained with cocaine, tetracaine, or lidocaine. In females, a cotton applicator moistened with the anesthetic may be placed in the urethra for 5 minutes. In males, these agents in liquid form are rapidly absorbed into the circulation through the posterior urethra. Contact with traumatized mucosa or injection under pressure increases the absorption. This can lead to seizures, circulatory collapse, and cardiopulmonary arrest. Dyclonine, 0.5% has been used without toxicity in males. Wherever these drugs are used as topical anesthetics for the urethra, resuscitation equipment should be available. Lidocaine as a 2% solution in carboxymethylcellulose gel provides lubrication as well as safe topical anesthesia. The drug is less readily absorbed in this form and can be used in both the male and female urethra. In females, approximately 3-5mL of the jelly is instilled into the urethra. To occlude the meatus, a cotton swab lubricated with jelly may be placed in the distal urethra or a sponge may be placed in the distal vagina. In males, 15-30mL of the jelly is instilled 5-10 minutes prior to the procedure, a penile clamp is placed at the corona; and a small amount of jelly is instilled in the distal urethra. Topical anesthesia is effective on the mucosa only and will not prevent pain from pressure or from distortion of underlying structures during manipulation. Regional or general anesthesia should be planned if more painful procedures (eg, resection or bipsy) are contemplated or if the patient is very apprehensive. The regional anesthetic must reach the third lumbar segment to provide the necessary sensory ablation during transurethral resection; thus, spinal or epidural anesthesia rather than a sacral block must be used. General anesthesia must be used when cystourethroscopy is done in pediatric patients.
Warning to Patients
Instrumentation is uncomfortable and may be painful. A forewarned, cooperative patient will be of help. Explaining the proposed maneuvers as one proceeds may reduce the patient's anxiety. The instrument must be introduced gently and advanced gradually. Gentle, sure maneuvering with adequate lubrication is essential. No movement should be rough or abrupt. Discomfort will increase as the instrument passes through the prostatic urethra, and men must be warned to anticipate some discomfort as this area is approached. Once spasm of the external sphincter develops, it may be impossible to complete the instrumentation. A very high bladder neck will cause marked angulation of the urethra that may preclude instrumentation under topical anesthesia.
Other Instrumental procedures and examinations in urology
Instrumental Methods of Examination in Urology
In most cases, a good knowledge in such instruments gives us the platform to ask constructive and intelligent questions to the medical personnel. Hence in as much as this is very good for the medical practitioner, it is also very good to the general public, and as usual, I will try and make it as simplified as possible for easy digestion. As for the Doctors and Nurses, in every urological practice, instrumental and Endoscopic methods of Examination of Urinary bladder in patients play very important role and so therefore, learning the usuage of catheters, uretherscopy and cystoscopy is very essential. Also, X-ray diagnostic has a great importance in our present medical world. Without X-ray and radioisotopic methods of diagnostic, any of urological diseases is impossible to diagnose.
Types of catheters
In general, straight rubber catheters are used for routine diagnostic catheterization. However, a coude (elbow) catheter, which is stiffer and has a curved tip, may be more readily manipulated over an enlarged prostate that has elevated the bladder neck. Uretheral catheters are: Foley, Whistle-tip, Pezzer, Malecot, Robinson, Coude.
The method of catheterization of urinary canal with plastic catheter
After proper cleansing and lubrication, the catheter can be manipulated with a sterile-gloved hand. However, it may be simpler to grasp the catheter near its tip with a sterile clamp and hold the other end of the catheter between the fourth and fifth fingers of the same hand. The catheter can then be advanced with the clamp without being touched by the unsterile hand. Begin catheterization with the penis pointed slightly drawn out.
Method of catheterization of Urinary canal with metallic catheter (in women and men)
After proper urethral lubrication, the tip of the conductor enters the urethra. The conductor is in the horizontal position over the groin. The penis is pulled out on the conductor, which is advanced down the Urethra and move simultaneously to the midline; its handle is gradually moved to the vertical position. The conductor will usually pass through the external urinary sphincter if gentle pressure is exerted on the handle at right angles to its shaft with one finger. When the conductor has passed all the way into the bladder it should be possible to rotate it freely.
These techniques are utilized in the evaluation of hematuria, chronic or recurrent urinary infection, unexplained urologic symptoms (eg, enuresis, frequency), and evaluation of congenital anomalies. They are also useful in any clinical situation in which excretory urogram have suggested pathologic change but have furnished all the information necessary for definitive diagnoses and treatment.
Filiform and followers
Filiform and followers are instruments used to dilate narrow strictures. Filiforms have woven fiber cores with a coated surface; they are very pliable and smooth. Useful sizes are 3-6F. The follower is made of metal or of woven of pliable fiber. Useful sizes are 8-30F. After lubrication jelly has been instilled into the urethra, the filiform is introduced. If it is arrested, it must be partially withdrawn, and readvanced. If this fails, one or file should be added to the first and all manipulation should be repeated.
A cystogram is a radiogram showing radiopaque outlining of the bladder cavity. Cystograms are seen as part of ordinary excretory urograms, but direct radiographic cystograms can be obtained by instilling a radipaque fluid directly into the bladder. The contrast medium is usually instilled via a transurethral catheter, but when necessary, it can be administered via percutaneous suprapubic bladder puncture. Radiograms of the filled bladder are taken using standard overhead X-ray tube equipment, or less frequently, "spot" films are taken during real-time, direct image-intensidied fluoroscopy.
Modern cystourethroscopes have a metal sheath ranging in size from 8F to 26F and interchangeable fiberoptic telescopes allowing a view from 0 to 170 degrees. The 0 to 30 degrees lenses are best for visualizing the urethra, whereas the bladder walls are best inspected with the 70 degrees lens. A retrograde (170-degrees0 lens must be used to see the vesical side of the bladder neck, particularly where prostatic tissue obstructs the view. Complete endoscopic studies are among the most precise diagnostic tests in all medicine. Any urethral lesion (e.g, Verrucae, tumors, strictures and diverticular), as well as the size and configuration of the prostate and bladder neck, are noted before the bladder is inspected. When the bladder is entered, the trigone is visualized and the size, shape, position and number of ureteral orifices noted. The bladder wall is carefully inspected for tumors, stones, diverticula, ulcers, trabeculation, hemorrhage, and edema. The normal and abnormal cystourethreoscopic findings must be specifically described.
Contraindications of cystoscopy
Cystoscopy is contraindicated in acute tract urinary infection, because trauma may exacerbate the infection and lead to sepsis. It is relatively contraindicated in the presence of severe symptoms of prostatic obstruction, since trauma may produce just enough edema of the bladder neck to cause complete urinary retention. Of course, if cystoscopy is essential, this risk must be accepted. The conditions in which cystoscopy is unnecessary are: when the volume of Urine in the bladder is more than 75ml and the environment around the bladder is transparent. A normal cystoscopic picture shows a dynamic bladder wall in which as bladder fills, small lesions will move away and may escape the examiner's field. Special care must be taken not to overdistend the bladder and to make sure that all areas have been completely inspected, often with the bladder minimally filled initially. In Adults, most of the bladder wall cannot be seen if the bladder contains more than 200-300mL of Urine.
Method of Puncture of Urinary bladder
A suprapubic catheter is useful in males when the urethra is impassable (e.g, traumatic disruption or stricture). When there is epididymitis or severe urethritis, or when prolonged bladder drainage by means of an indwelling catheter is necessary. An indwelling urethral catheter predisposes to meatitis, urethritis and epididymitis. The skin of the suprapubic area is prepared and infiltrated with a local anesthetic. If the patient is in Urinary retention, the bladder is usually readily palpated. The bladder must usually contain a minimum of 200-300mL of Urine before a suprapubic catheter can be inserted successfully. The patient may be placed in the Trendelenburg position to move the intestine upwards. A thin lumbar punctur needle is inserted above the symphisis pubica and angled toward the perineum to locate the bladder a trocar is inserted into the bladder and the suprapubic tube passed. Size 8F, 10F, and 12F suprapubic catheters are available in prepackage sets.
It is no longer considered necessary that patients should be dehydrated in preparation for urography. Indeed, dehydration is to be avoided in infants, debilitated and aged patients, and patients with diabetes mellitus renal failure, multiple myeloma, or hyperuricemic states. On the other hand, preliminary bowed cleansing is very desirable, although children under age 10 years usually need no bowel preparation for urography.
A plain film of the abdomen, frequnelty called a KUB (Kidney-Ureter-bladder) film, is the simplest uroradiologic study and the first performed in any radiographic examination of the abdomen or urinary tract. It is usually the preliminary radiogram in more extended radiologic examinations of the urinary tract, such as urography. The size of normal kidneys varies widely, not only between like individuals but also with age, sex and body stature. The long diameter of the kidney is the most widely used and most convenient radiographic measurement. The average adult kidney is about 12-14cm long, and the left kidney is ordinarily slightly longer than the right one.
X-ray contrastive stones, and their diagnostics
Identification on the plain film of calcification or calculi anywhere in the urinary tract may help to identify specific kidney diseases (eg, the calcifications occasionally seen in a Kidney cancer) or may suggest primary disease elsewhere (eg, the occasional patient with nephrocalcinosis whose underlying primary disease is hyperparathyroidism) Contrastive substances or radiographic contrast media include Liquids (almost all fo whih contain iodine), gels, solids (eg, barium preparations), and gases (most commonly air nitrous oxide and carbon dioxide). Some contrast media can only be administered by one route, which limits their usefulness for multisystem anatomic imaging.
The excretory urogram, formerly called an intravenous pyelogram, is most commonly used. Excretory urograms can demonstrate a wide variety of urinary tract lesions, are simple to perform, and are well tolerate by most patients. Ocassionally, however, retrograde urograms may be required if the excretory urogram is unsatisfactory or the patient has a history of significant adverse reaction to intravascular contrast media. The advent of excretory urography using high volumes of radiopaque contrast media and ureteral compression has decreased the need for retrograde urograms. Abdominal (ureteral) compression devices that temporarily obstruct the upper urinary tracts during excretory urograms dramatically improve the filling of renal collecting structures.
This is a moderately invasive procedure that requires cystoscopy and the placement of catheters in the urethers. A radiopaque contrast medium is introduces into the ureters or renal placement of catheters in the ureters. A radiopaque contrast medium is introduced into the ureters or renal collecting structures through the ureteral catheters and radiograms of the abdomen are then taken. The study, which is more difficult than an excretory urogram, must be performed by a urologist. Some type of local or general anesthesia must be used, and the procedure can occasionally cause later morbidity or urinary tract infection.
The use od greater than average amounts of standard contrast medium- and thus greater amounts of iodine per Kilogram of body weight- may be indicated in selected patients. The high volumes may be injected either rapidly as a bolus or more slowly as an infusion; the bolus method produces better visualization and a better urographic nephrogram than the infusion method.
This method of outlining the renal collecting structures and ureters is occasionally used when urinary tract imaging is necessary but excretory or retrograde urography has failed or is contraindicated or when there is a nephrostomy tube in place and delineation of the collecting system of the upper urinary tract is desired. The contrast medium is introduced either through nephrstomy tubes, if these are present (nephrostogram), or by direct injection into the renal collecting structures via a percutaneous puncture through the patient's back.
arteriographic study of the Kidneys is performed almost exclusively by percutaneous needle puncture and catheterization of the common femoral arteries or, much less often, the axillary arteries. Rapid serial radiograms are obstained during and after bolus injection of suitable radiopaque contrast medium into the aorta at the level of the renal arteries (aortorenal arteriogram, "flush" abdominal aortogram) or into one of the renal arteries (selective renal arteriogram).
Radioisotopic techniques provie a means of investigating the structure and function of internal organs without disturbing normal physiologic processes. Currently, 4 general types of renal readioisotopic labels are used. Classified according to the mechanisms of labeling, they are as follows;
- renal cortex labels, which are retained in the renal tubular cells,
- intravascular compartment labels;
- renal tubular function labels, which briefly lable the renal cortex as they are accumulated by renal tubular cells and then are passed into the urine and cleared from the Kidney; and
- Substances cleared solely by glomerular filtration, which allow determination of the glomerular filtration rate.
Metal (stainless steel or nickel-plated steel) sounds are used for uretral dilatation.
With the Penis stretched taut and the instrument held almost horizontally (over the groin), the tip of the sound is introduced into the lubricated urethra. When the tip reaches the bulb (at the external sphincter), the handle is brought to the vertical position, which usually enables the tip to pass through the sphincter. Moving the handle to the horizontal position (parallel to the thighs0 causes the sound to advance into the bladder. The first sound passed should be a 24F, even though the patient says he has a narrow stricture. This size has a broad tip that will not perforate a friable urethral wall and is therefore ideal for urethral exploration. if a 24F sound cannot be passed, smaller sounds can be tired. If a 20F will not pass, do not use the smaller sizes, because their tips are relatively sharp and may pierce the urethral wall. In such cases, filiforms and followers may be used.
Due to the short and relatively straight canal of the female urethra, the passage, of sounds is quite simple in women. Significant stricture is rare.
The resectoscope is a commonly used visual instrument with which transurethral resection of the prostate or of vesical carcinoma is performed. Resectoscopes remove tissue by means of the electrocauterizing retractile loop that makes multiple passes and cuts away the tissue in strips ("chips"). Hemostasis is obtained by cautery of individual blood vessels as they are visualized. Newer continuous-flow models have a double sheath that allows continuous inflow and outflow of irrigant, which provides a constantly clear view and stable bladder pressure. When the flow rate is properly set, this system allows nearly nonstop resecting, because the bladder never becomes completely distended. Due to the continuous flow allows the bladder wall to remain in a relatively stable position, this instrument is useful in resecting large bladder tumors.
Current models allow direct visualization. Simple lithotrites have metal jaws that crush small vesical calculi. Electrohydraulic and ultrasonic lithotrites trnasmit energy through special catheters place by means of the cystourethroscope; when the catheter is touched to the calculus and energy is applied, the calculus disintegrates.
Needle Biopsy of the Prostate
Various types of soft-tissue biopsy needles that remove cores of tissue from a suspicious area are available. In addition, needle aspiration to obtain specimens for cytologic examination is promising. The prostate may be approached via the perineal or transrectal route. After a local anesthetic is injected into the perieal skin, a finger in the rectum guides the tip of the needle (which is outside the rectal wall) to the suspicious area. The transrectal route does not require mucosal anesthesia but may be difficult to use in patients with tight anal sphincters. An enema given before the transrectal procedure is useful. It may be easier to biopsy small nodules via the transrectal route since the needle and the palpating finger are in direct contact. A needle biopsy may be done under general or spinal anesthesia in conjunction with cystoscopy.