Harry H Holdorf PhD MPA RDMS Ab Ob BR RVT LRTAS objectives Understand the main drivers promoting sonography of the appendix Provide a better understanding of the anatomy of the appendix and how appendicitis occurs ID: 909166
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Slide1
SONOGRAPHY OF THEAPPENDIX
Harry H. Holdorf
PhD, MPA, RDMS (Ab, Ob, BR), RVT, LRT(AS)
Slide2objectives
Understand the main drivers promoting sonography of the appendix
Provide a better understanding of the anatomy of the appendix and how appendicitis occurs
Assist the sonographer in developing a protocol or “plan of attack”
Slide3BACKGROUND
Each year, in the United States 250,000 cases of appendicitis are reported, representing 1 million patient-days
Considering appendectomy carries a 4-15% complication rate, there are increased costs as well as increased hospital stays
In order to minimize the risk of complications, the surgeon must make an accurate diagnosis as soon as possible
The mortality rate for acute appendicitis is currently 0.2-0.8%
The mortality rate for children is between 0.1-1%
The mortality rate for adults older than 70 is above 20%
Slide4LEGAL RISK
In children less than 3 years old, the rate of appendiceal perforation is
80-100%
In children 10 to 17 years old, the rate of appendiceal perforation is less than 10-20%
Delay in diagnosis increases the perforation rate
Increase in perforation rate will increase the mortality and morbidity rate
A quick and accurate diagnosis is invaluable information for the surgeon
Slide5LEGAL RISK
The overall complication rate of appendectomy depends on the status of the appendix at the time that the appendix is removed
If the appendix is
not ruptured, the overall complication rate is only about 3%
If the appendix has ruptured
, the complication rises to almost 59%
Slide6MONETARY RISK
Timely diagnosis reduces the complication rate, thereby reducing:
Costs associated with complications
Costs associated with longer hospital stays
If diagnosis can be made with sonography instead of CT, there are huge global healthcare cost savings
Slide7MONETARY RISK
Today we find ourselves in an environment of healthcare reform. Although we do not know all the specifics yet, we
do
know that the cost of diagnosing any disease process has become very importantWith sonography, we find ourselves in a very advantageous position
Due to our relatively low cost and because there are no adverse side effects, sonography will increasingly become the modality of choice
Slide8RADIATION RISK
It has been estimated that approximately 62 million CT scans are performed per year, including at least
4 million per year for children
The growth of CT use in children has been primarily due to the decrease in time it takes to perform a scan, now less than 1 second.
The major growth area, in children, has been presurgical evaluation of appendicitis
Slide9RADIATION RISK
Most of the quantitative data that we have regarding radiation-induced cancer comes from survivors of the Atomic bombs dropped in Japan in 1945
The mean dose of radiation was about 40 mSv, which is approximately equal to a typical CT involving two or three scans in an adult.
Children are at greater risk than adults due to these two facts:
They are much more radiosensitive than adults
They have more remaining years of life in order to potentially develop a radiation-induced cancer
Slide10ANATOMY
Blind-ended tube at the end of the cecum
Average length is 10cm and measures between 3-6mm in diameter
Vermiform appendix comes from Latin and means “worm-shaped”
Slide11ANATOMY
Layers of the appendix
Mucosal lining with a collapsed lumen
Mucosa
Submucosa
Muscular wall
Serosa
Slide12Although the neck of appendix is fairly consistent, approximately 2.0cm below the cecal valve, the tip location can be variable. It could be introperitoneal 95% of the time, it could be retroperitoneal 5% of the time, it could be behind the cecum 65% of the time,
and it could also be in the pelvis approximately 30% of the time.
Slide13LOCATION IS VARIABLE
Intraperitoneal 95%
Retroperitoneal 5%
Behind the Cecum 65%
In the pelvis 30%
Slide14LocationMcBurney’s point is the name given to the point over the right side of the abdomen that is approximately one-third of the way between the anterior superior iliac spine and the umbilicus. This point is roughly the location of the base of the appendix where it is attached to the cecum.
Slide15LOCATION
McBurney’s Point
Slide16Although the base of the appendix is usually around McBurney’s point, the tip can be anywhere in the right lower quadrant.
Slide17LOCATION
Slide18CAUSES OF APPENDICITIS
Appendicitis results from obstruction of the lumen of the appendix
Obstruction may be caused from:
Lymphoid hyperplasia 60%
Fecalith or fecal stasis 35%
Foreign body 4%
Tumor 1%
Slide19Lymphoid Hyperplasia
Only a few submucosal lymphoid follicles are noted at birth
These follicles enlarge, peaking between 12-20 years old
These same follicles decrease in size after peaking at age 12-20
This correlates well with the incidence of appendicitis
This form of obstruction is mostly observed in children and is known as catarrhal appendicitis
Slide20Progression
Following obstruction, there is an increase in the production of mucous which leads to an increase in pressure
Following increased pressure and stasis from obstruction, there is an overgrowth of bacteria
Mucous then turns into pus which increases the luminal pressure even more
This leads to distension of the appendix and visceral pain which is usually located in the epigastric or periumbilical area
As the luminal pressure increases, obstruction of the lymphatic system occurs causing edema of the appendix
Slide21Progression
This stage is called acute or focal appendicitis
The overlying parietal peritoneum becomes irritated, and the pain now becomes localized to the RLQ
This progression is the classic migration of pain that is often seen in patients with appendicitis
Slide22CAUSES OF APPENDICITIS
Lymphoid hyperplasia predominately occurs within the mucosal and submucosal areas
Mucosa
Submucosa
Slide23CAUSES OF APPENDICITIS
you can typically see these areas becoming more prominent and darker on sonography
Lymphoid hyperplasia predominately occurs within the mucosal and submucosal areas
Mucosa
Submucosa
Slide24CAUSES OF APPENDICITIS
The serosal surface may also become thicker and more hypoechoic
Mucosa
Submucosa
Slide25Normal appendix Inflamed appendix
Two images of the appendix. Note that in the inflamed appendix the mucosal and sub mucosal layers are thickened
Slide26CLINICAL PRESENTATION
Patient experiences anorexia, and then vague periumbilical pain
Over the next several hours pain usually migrates to Right Lower Quadrant
Nausea and Vomiting, if present, will follow the pain
Diarrhea may occur
Fever, if present, is low grade
Appendix commonly ruptures 24-48 hours after onset of symptoms
Slide27When a Technologist mentions to the physician that we should be evaluating the appendix with sonography instead of CT, this is the look that they usually get…
REALITY
Slide28Slide29Physicians and technologists: Overcome your fear!!
“I can never find the appendix”
“If I can’t find it, they always do a CT”
“Just tell them to do a CT instead, and that will just save a step”
You have to be willing to accept the challenge and try to find the appendix
With newer equipment and newer transducer technology, it is becoming a lot easier to image the appendix
Slide30Overcome your fear
If you are willing to accept the challenge and begin the process of improving your proficiency in finding the appendix with sonography, you can:
Help reduce radiation exposure, especially in the pediatric population
Become more proficient and begin to separate yourself and/or your practice from your peers
Slide31Be persistent
After failing to find the appendix in your first several attempts, it becomes easy to just quit trying
Becoming proficient in sonography of the appendix is a process and you shouldn’t be discouraged
Don’t fall into the trap of taking just a couple of images of the Right Lower Quadrant (RLQ) to show that you at least looked
Slide32Be persistent
It’s easy to say that “if it’s positive and I’m going to find it, I should find it right away”
Sonography of the appendix is not only about finding a case of appendicitis, but also about trying to find a normal appendix
If you are able to find the entire length of the appendix and it’s normal, you have statistically ruled-out appendicitis and changed the course of medical management for that patient.
At times, it can take at least 10 to 15 minutes of careful scanning just to find a portion of the appendix
Slide33Be organized
Use a high-frequency, linear transducer (10 MHz or higher). A lower frequency may be needed for large patients.
If the appendix is not identified in that location, a careful, systemic approach should be initiated.
Begin by placing the transducer in a transverse position and apply deep graded compression, which will help to displace the gas and bring the bowel closer to the transducer.
Start with graded compression over the area of maximum tenderness, as determined by the patient.
Slide34Be organized
Continue in a slow, methodical fashion making sure that the whole RLQ area is evaluated until, hopefully, the appendix is identified
The appendix is not always identifiable due to bowel gas or body habitus
Begin at the hepatic flexure and slowly move down toward the cecum
Slide35Be organized
Make sure that you also look for secondary signs of a possible appendicitis which could include:
Free fluid in the right lower quadrant
Changes with echogenic inflammatory periappendiceal fat
Enlarged mesenteric lymph nodes
Presence of positive rebound tenderness
Slide36Be organized
This is a suggested addition to your protocol:
If you find the appendix and it is positive for appendicitis, you are done
If you find the appendix and it is normal, or if you can’t find the appendix
Take a quick look at the right kidney to make sure there is no hydronephrosis and normal flow from the right ureter. This may save the patient from having a CT trying to diagnosis a possible appendicitis, just to diagnosis a right ureteral stone
If the patient is a female, take a quick look at the right ovary to make sure that the ovary is not the cause for the pain
Slide37Be CAREFUL
This is a case of a 3 year old girl where sonography was not able to see the appendix, but also missed and area of very abnormal echogenic fat. This area was seen in retrospect, the next day. Because this area was not noticed during the exam, a CT was ordered, which then diagnosed appendicitis.
Slide38Be CAREFUL
Slide39Be CAREFUL
Mesenteric adenitis can also mimic appendicitis
Slide40Be CAREFUL
The presence of an appendicolith may be present in the normal or abnormal appendix. If one is seen in a normal appendix in a pediatric patient, make sure that it is noted as this patient may be a candidate for elective appendectomy. This is not necessarily so in the adult patient.
Slide41Be CAREFUL
Appendicolith
Slide42Be CAREFUL
Make sure that if you see air outside of the appendix you will always mention it, as this is a possible sign of appendiceal perforation.
Slide43Be CAREFUL
A ruptured or perforated appendix can measure with a normal diameter
Notice the surrounding fluid with internal echoes
Slide44I wish they were all this easy!
Slide45I wish they were all this easy!
Slide46NORMAL APPENDIX
Will measure 6mm or less in AP diameter
Must be blind-ending
Will be partially compressibleWill not have any peristalsis
Be careful not to push too hard as this may limit peristalsis
Slide47MEASURE CORRECTLY
Because a normal appendix is not usually perfectly round, make sure that you measure AP (anterior posterior) and not transversely
Correct
Wrong
Slide48The following slides contain images of normal appendices
Slide49NORMAL APPENDIX measuring 5.2mm
Slide50NORMAL APPENDIX
Slide51NORMAL APPENDIX
Slide52NORMAL APPENDIX
Slide53NORMAL APPENDIX measuring 2.9mm
Slide54NORMAL APPENDIX measuring 3.0mm that is seen just posterior to normal peristalsing small bowel
Slide55NORMAL APPENDIX
Slide56NORMAL APPENDIX
Slide57NORMAL APPENDIX
Slide58NORMAL APPENDIX
Slide59NORMAL APPENDIX
Slide60NORMAL APPENDIX
Slide61A mildly prominent appendix that was interpreted as normal at 5.9mm.
Slide62NORMAL APPENDIX
Slide63NORMAL APPENDIX
Arrow= Rt ovary
Slide64NORMAL APPENDIX
Slide65NORMAL APPENDIX
Slide66NORMAL APPENDIX
Slide67NORMAL APPENDIX
Slide68NORMAL APPENDIX
Slide69The following slides contain images of abnormal appendices
Slide70ABNORMAL APPENDIX with an Appendicolith
Slide71ABNORMAL APPENDIX
Mild or early stage of Appendicitis
Slide72ABNORMAL APPENDIX
Slide73ABNORMAL APPENDIX
Slide74ABNORMAL APPENDIX
Slide75ABNORMAL APPENDIX
Slide76ABNORMAL APPENDIX
Slide77ABNORMAL APPENDIX
Slide78ABNORMAL APPENDIX
Perforated-why the lumen appears to be compressed
Slide79ABNORMAL APPENDIX
Slide80ABNORMAL APPENDIX with
the presence of hyperemia
Slide81ABNORMAL APPENDIX
Slide82ABNORMAL APPENDIX-inflammation with swollen adjacent fat
Slide83MAKE SURE THAT YOU EVALUATE THE ENTIRE APPENDIX
Appendicitis can be confined to only one segment of the appendix
If you find a normal segment of the appendix and stop your evaluation there, you may miss a focal appendicitis
This occurs in approximately 20% of all patients
Can be in either the proximal or distal end
More common in the distal end
Slide84Next SlideThe appendix in this patient was tortuous and was able to image a normal section of the appendix as well as an inflamed section.
The first section of the appendix appears totally normal.
The second portion of the appendix appears to be inflamed.
Slide85Slide86SUMMARY
We have learned:
Some of the main drivers promoting sonography of the appendix, such as
Legal Risks that require a quick, accurate diagnosis for the physician or surgeon
Monetary, or financial Risks showing that sonography has a definite advantage over other modalities, such as CT
Radiation Risks showing that there are serious radiation concerns, particularly for the pediatric population
Slide87SUMMARY
The anatomy of the appendix, causes of appendicitis and the typical progression of appendicitis
We need to overcome our fear, be persistent and be organized in our examination of the appendix
What a normal and abnormal appendix looks like with sonography
There are a few potential pitfalls that we need to keep in mind
Finally, we have learned a suggested protocol in performing sonography of the appendix
Slide88The End