Why CMG / Cystoscopy?

What is CMG Cystoscopy?

CMG is the short form of Cystometrogram which in plain English means Bladder Pressure Studies. It is also called Urodynamic Studies. The regular Urodynamic Studies are carried out at only very few centers with sophisticated machines. Two tubes are passed into the urinary bladder one to fill the bladder and the other to measure the pressure inside the bladder. The sophisticated machines have a balloon in the rectum and computers subtract the pressures from this from the pressures recorded in the bladder. The pressure patterns give a lot of information. Cystoscopy is having a look inside the urinary bladder through normal urinary passage.

Why is CMG Cystoscopy necessary?

CMG Cystoscopy can give a lot of information regarding the various conditions that affect the lower urinary tract. Roughly about one third of the nerves from the lower part of the spinal cord go to the bladder and its control. In addition to the commonly not well evaluated neurological problems other problems that cause bladder out flow obstruction could be evaluated by this study. The study gives objective evidence and treatment could be based on these evidence rather than suspicions.

What are the indications for CMG Cystoscopy?

Anyone with LUTS or Lower Urinary Tract Symptoms needs an evaluation with CMG Cystoscopy. Those with Bladder outflow obstruction for instance due to enlargement of the prostate gland CMG cystoscopy is necessary to plan the type of treatment whether it should be surgical or medical. It also helps in assessing the progress of disease especially those with nuerovesical dysfunction who are treated with medicines. The study is also helpful in evaluation of the complications and progress of the disease.

What are the Lower Urinary Tract Symptoms or LUTS?

The following symptoms are present with Lower Urinary tract disease. The causes are also given along with the description of the symptoms.

  • Poor Urinary Stream: This is one of the common symptoms. Usually the bladder has to generate pressures of 40 cm of water in women and 60 cm of water in men to overcome the resistance of the sphincter that controls leak from the bladder to pass urine. If there is any obstruction and the resistance is high the urinary stream would be poor. If the urinary bladder is not able to generate sufficient pressure then again the flow would be poor and again if there is lack of coordination between the bladder muscles and the sphincter the flow would be poor.
  • Hesitancy: This is an early symptom of obstruction. When full the bladder sends information to the brain which instructs to initiate passing urine when conditions are optimal [like urinal being available and free and there is privacy etc]. It takes a while to start passing urine once the brain gives the instruction as bladder needs time to generate the require pressure. It would take longer time with obstruction.

pie chart 1115-666

  • Incomplete voiding: This happens when the bladder muscles are not able to sustain contractions to completely empty the bladder at one go. It might be due to obstruction or lack of coordination due to nuerovesical dysfunction. This leaves residual urine in the bladder and this urine always has some bacteria and the usual doubling time of bacteria is about 20 minutes. Hence with each time at the start the number of bacteria are higher and eventually a time will come when there is significant urinary tract infection.
  • Intermittency: This is probably an earlier stage of incomplete voiding. Here the voiding is completed although with difficulty and the force of passing urine varies and it takes a long time to pass urine.
  • Increased frequency of voiding: This is one of the most common symptoms. This could be due to a variety of causes. As mentioned earlier if the bladder is unable to empty completely it in effect has a lower capacity. If there is any infection or irritation in the bladder or urinary passage it causes passing of smaller amounts of urine frequently. If the actually capacity of the bladder is small due to TB or some other condition it again leads to frequent voiding. It helps the doctor if you maintain a frequency – volume chart. The time and amount of urine passed is recorded over a 24 hour period.
  • Nocturia: This is the name given for increased night time frequency. The increase in day time frequency could be psychological and could be due to a variety of reasons. However of one has to wake up to pass urine at night it means significant increase in frequency.
  • Dysuria: This is the name given for burning pain while passing urine. Infection is a common cause for this. However irritation by stones could also be a cause.

table 1 - dr g

  • Hematuria: This means blood in the Urine that could either be macroscopic or visible to the naked eye or microscopic when it is detected in urine examination. Infection, stones, bladder cancers etc can cause this.
  • Loin pain and lower abdominal pain: Sometimes with poor sensations bladder distention is felt only as a vague lower abdominal pain. Anything that causes a thick bladder wall could also present as lower abdominal pain. Stones in the ureter can present as loin pain and so can some abnormalities of the uretero- vesical junction.
  • Urgency: This refers to inability to hold urine for a long time and desire to go to pass urine as quickly as possible once the sensation of having urine in the bladder appears.
  • Incontinence: This occurs with severe urgency when a few drops or more urine leaks out before going to the toilet when there is urgency. Sometimes with nuerovesical dysfunction the patient might not be aware of the leak earlier and notices only when clothes are wet.
  • Stress incontinence: This occurs in women when the bladder is lax and goes away from the pubic bones affecting the angulations of the bladder and urethra. Any strain like coughing, laughing, etc. would result in leak of urine.

Stress incontinence

  • Inability to pass urine: This could be either intermittent or total and either painful or painless depending on the cause. A small stone in the urinary bladder can intermittently block the passage. Prostate enlargement leads to painful retention of urine while nuerovesical dysfunction can lead to painless retention of urine.

CMG and cystoscopy would help to evaluate the causes of all the symptoms mentioned above.

What does the normal study look like?

The findings in CMG would be as follows:
Usually, the resting pressure is about 10 cm of water. When the volume is less, it can be lower, and reaches about 10 cm of water when the bladder is at about 100 ml. From 100 ml to about 350 ml or more, the bladder pressure hardly changes. There is a slight increase in pressure when the sensation of voiding starts and a little more increase in pressure gives urgency. While voiding, the maximum voiding pressure is about 40 cm for women and 60 cm for men. People feel that there is some urine in the bladder when the volume is about 150 ml, and they have the normal sensation of desiring to pass urine at about 350 ml. The post-void residue is typically less than 30 ml.

What do the Urologists look for?

The Urologists are looking at some of the following during the CMG:

  1. High Voiding Pressures: The normal maximum voiding pressure for men is about 60 cm of water, and for women, it is about 40 cm of water. With obstruction, especially due to benign prostatic hypertrophy, the voiding pressures go up. When the maximum voiding pressure goes up above 90 cm of water, then the chance of having acute painful retention is high, and hence they are generally advised surgical treatment, while patients with voiding pressures from 60 to 90 would benefit by medical treatment.
  2. Poor Sensations: Conditions like diabetic cystopathy affect the sensations of the bladder. Those affected are not aware of the bladder sensations of fullness or urgency, and the bladder can fill to a great extent. Sometimes, there might even be overflow incontinence, especially in women.
  3. Poor Compliance: When there is thickening of the bladder wall, the elasticity of bladder is not present. There is a linear increase in bladder pressure with any increase in volume. In other words, from about 100 ml to 350 or 400 ml, the bladder pressure increases when the volume in the bladder increases. Cystitis or inflammation of the bladder causes poor compliance of the bladder. Cystitis could be due to infection, autoimmune disease or tuberculosis.
  4. Unstable or Uninhibited Contractions: Control of the bladder functions uses as much as one third of the spinal cord nerves. The detrusor muscle of the bladder should contract only while passing urine. If the bladder muscle contracts during the filling phase, it is called unstable or uninhibited contractions. Neurovesical dysfunction or impairment of the neurological function of the bladder causes the unstable contractions, which causes urgency and sometimes incontinence.
  5. Increased Post-Void Residue: When there is any obstruction to the outflow, the bladder muscles cannot sustain contractions for a long time to completely empty the bladder, and the post-void residue increases. Neurovesical dysfunction could also lead to increased post-void residue.

It looks as though all the people with lower urinary tract disease require CMG and Cystoscopy and that the machines and procedure look expensive. Is there a less expensive alternative?

We have devised a low-cost method of CMG cystoscopy that offers almost all the necessary information as the sophisticated machines. The difference is that it involves intelligent observation and the good news is that it is available at the doorsteps of the patients during the diagnostic camps of SEESHA and Surgical Services Initiative.

IV Tube - Dr G

An ordinary IV tube is used as a manometer to measure the pressures. Although the combined abdominal and bladder pressures are measured corrections are possible and variations in abdominal pressures are observed and not taken into account.

What does cystoscopy diagnose?

Cystoscopy or looking inside the urinary bladder with the telescope gives lot of valuable information like the following:

  • It helps to detect things like infection, narrowing or strictures, stones, valves, injuries, etc. in the urethra or the passage to the urinary bladder.
  • It can help to find out about the prostate, the opening of the ejaculatory ducts, etc.
  • In the bladder it can help to find out infection, stones, tumours, diverticulum, foreign bodies, etc.
  • It can also help to identify abnormalities in the uretero – vesical junction like reflux and ureterocele and also to find out which side blood is coming from if there is bleeding.

Would you advise CMG Cystoscopy for all patients with Lower Urinary symptoms?

Yes it is advisable for proper and complete evaluation of any lower urinary tract symptoms.

Why doesn’t everyone order these studies?

Although all the doctors would love to do these investigation as mentioned earlier due to the high cost the expensive machines are not available at all the centers. They are also very expensive at the centers where they are available.

Where are these low-cost Urodynamic studies available?

The low cost CMG Cystoscopy or Urodynamic study is available at the SEESHA Karunya community hospital at Karunya at the SEESHA surgical camps at Bethesda Hospital Aizawl, Sielmat Christian Hospital at Churachandpur at Manipur, Family Health Hospital at Dimapur and the other places where the Bethesda Hospital Aizawl conducts diagnostic camps.

gnanaraj Dr. J. Gnanaraj MS, MCh [Urology], FICS, FARSI, FIAGES is a urologist and laparoscopic surgeon trained at CMC Vellore. He has been appointed as a Professor in the Electronics and Instrumentation Engineering Department of Karunya University and is the Director of Medical Services of the charitable organization SEESHA. He has a special interest in rural surgery and has trained many surgeons in remote rural areas while working in the mission hospitals in rural India. He has helped 21 rural hospitals start minimally invasive surgeries. He has more than 150 publications in national and international journals, most of which are related to modifications necessary for rural surgical practice. He received the Barker Memorial award from the Tropical Doctor for the work regarding surgical camps in rural areas. He is also the recipient of the Innovations award of Emmanuel Hospital Association for health insurance programs in remote areas and the Antia Finseth innovation award for Single incision Gas less laparoscopic surgeries. During the past year, he has been training surgeons in innovative gas less single incision laparoscopic surgeries.

Image: Left Levator ani from within. Source/Author: Henry Gray, before 1858. Access the original Image information here: https://commons.wikimedia.org/wiki/File:Gray404.png

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