Diagnosing Diseases of the Renal System
Because many of the symptoms are similar for diseases of the renal system, differential diagnosis is required.
After blood, urine & stool tests, first line diagnostic imaging for patients presenting with symptoms suspected to be related to the kidneys would be an Ultrasound scan.
- Ultrasound uses high-frequency sound waves to create images of organs and systems within the body
- The sound waves reflect off body structures and a computer receives the reflected waves and uses them to create an image
- A renal ultrasound is mainly used in order to detect a mass, an obstruction or a stone located in the kidney
- It can also be performed to determine the size of the kidney if looking for signs of hydronephrosis
A CT scan uses x-rays to create cross-sectional pictures (slices) of the body. It takes pictures of a 3-dimensional structure, the data is then relayed to a computer which turns the information into a 2-dimensional cross-sectional image.
- A CT scan of the kidney may be performed to assess the kidneys for tumours and other lesions or obstructions such as kidney stones, abscesses, cysts and congenital anomalies
- It may be requested when another type of examination (e.g. physical examination or ultraound) is inconclusive
- CT scans of the kidney may also be used to assist in needle placement in kidney biopsies
Magnetic Resonance Imaging
MRI (Magnetic Resonance Imaging) uses magnetic field and radio waves to create detailed images. It may be done secondary to an ultrasound or CT scan to obtain a more detailed image of the anatomy.
MRI can be used for diagnosing diseases of all kinds, but within the urinary system it is used in the diagnosis of:
- Kidney disease or scarring
- Abnormalities such as cysts or tumors
- Kidney Stones
A pyelogram (or pyelography or urography) is a form of imaging of the renal pelvis and ureter which can be used for diagnosing diseases of the urinary system. Contrast medium is injected to visualise the whole urinary system under x-ray.
Pyelograms can be intravenous, antegrade or retrograde. They are not used very often, other imaging tests such as CT scans and MRIs are much more common. However, a doctor may recommend this exam if blood is present in the urine or there is pain present in the patient’s side or lower back.
Pyelograms can be used to diagnose blockages in the urinary tract caused by:
- Kidney stones
- Enlarged prostate
- Tumours in the kidney, ureters or bladder
- Scarring, either from surgery or a urinary tract infection
- Congenital problems in the urinary tract
Ureteroscopy & Cystoscopy
Ureteroscopy is an examination of the upper urinary tract, usually performed with a ureteroscope that is passed through the urethra and the bladder, and then directly into the ureter. The procedure is useful in the diagnosis and treatment of disorders such as kidney stones and urothelial carcinoma of the upper urinary tract.
Ureteroscopy can also be a method of treatment, as instruments can be passed through the scope to collect any immobilised stones.
Smaller stones in the bladder or lower ureter can be removed in one piece, while bigger ones are usually broken before removal during ureteroscopy.
Cystoscopes are larger in diameter than ureteroscopes & would usually just be used to examine the bladder. The cystoscope is passed into the bladder via the urethra.