SONOGRAPHY OF THE APPENDIX Harry H. Holdorf PhD, MPA, RDMS (Ab, Ob, BR), RVT, LRT(AS)

Understand the main drivers promoting sonography of the appendix objectives 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”

BACKGROUND 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%

LEGAL 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

LEGAL 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%

MONETARY 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

MONETARY 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 important With 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

RADIATION 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

RADIATION 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

ANATOMY Vermiform appendix comes from Latin and means “worm-shaped” Blind-ended tube at the end of the cecum Average length is 10cm and measures between 3-6mm in diameter

ANATOMY Layers of the appendix Mucosal lining with a collapsed lumen Submucosa Muscular wall Serosa

Although the neck of appendix is fairly consistent, approximately 2 Although 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.

LOCATION IS VARIABLE Intraperitoneal 95% Retroperitoneal 5% Behind the Cecum 65% In the pelvis 30%

Location McBurney’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.

LOCATION McBurney’s Point

Although the base of the appendix is usually around McBurney’s point, the tip can be anywhere in the right lower quadrant.

LOCATION

CAUSES 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%

Lymphoid 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

Progression 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

Progression 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

CAUSES OF APPENDICITIS Lymphoid hyperplasia predominately occurs within the mucosal and submucosal areas Mucosa Submucosa

CAUSES 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

CAUSES OF APPENDICITIS The serosal surface may also become thicker and more hypoechoic Mucosa Submucosa

Normal appendix Inflamed appendix Two images of the appendix. Note that in the inflamed appendix the mucosal and sub mucosal layers are thickened .

CLINICAL 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

REALITY When 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…

Physicians 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

Overcome 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

Be 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

Be 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 At times, it can take at least 10 to 15 minutes of careful scanning just to find a portion of the 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.

Be organized Use a high-frequency, linear transducer (10 MHz or higher). A lower frequency may be needed for large patients. Start with graded compression over the area of maximum tenderness, as determined by the patient. 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.

Be organized Begin at the hepatic flexure and slowly move down toward the cecum 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

Be 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

Be 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

Be 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.

Be CAREFUL

Be CAREFUL Mesenteric adenitis can also mimic appendicitis .

Be 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.

Be CAREFUL Appendicolith

Be 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.

Be CAREFUL A ruptured or perforated appendix can measure with a normal diameter Notice the surrounding fluid with internal echoes

I wish they were all this easy!

I wish they were all this easy!

NORMAL APPENDIX Will measure 6mm or less in AP diameter Must be blind-ending Will be partially compressible Will not have any peristalsis Be careful not to push too hard as this may limit peristalsis

MEASURE CORRECTLY Because a normal appendix is not usually perfectly round, make sure that you measure AP (anterior posterior) and not transversely Wrong Correct

The following slides contain images of normal appendices

NORMAL APPENDIX measuring 5.2mm

NORMAL APPENDIX

NORMAL APPENDIX

NORMAL APPENDIX

NORMAL APPENDIX measuring 2.9mm This is a transverse image of a normal appendix measuring 2.9mm.

NORMAL APPENDIX measuring 3 NORMAL APPENDIX measuring 3.0mm that is seen just posterior to normal peristalsing small bowel

NORMAL APPENDIX

NORMAL APPENDIX

NORMAL APPENDIX

NORMAL APPENDIX

NORMAL APPENDIX

NORMAL APPENDIX

A mildly prominent appendix that was interpreted as normal at 5.9mm.

NORMAL APPENDIX

NORMAL APPENDIX Arrow= Rt ovary

NORMAL APPENDIX

NORMAL APPENDIX

NORMAL APPENDIX

NORMAL APPENDIX

NORMAL APPENDIX

The following slides contain images of abnormal appendices

ABNORMAL APPENDIX with an Appendicolith

ABNORMAL APPENDIX Mild or early stage of Appendicitis

ABNORMAL APPENDIX

ABNORMAL APPENDIX

ABNORMAL APPENDIX

ABNORMAL APPENDIX

ABNORMAL APPENDIX

ABNORMAL APPENDIX

ABNORMAL APPENDIX Perforated-why the lumen appears to be compressed

ABNORMAL APPENDIX

ABNORMAL APPENDIX with the presence of hyperemia

ABNORMAL APPENDIX

ABNORMAL APPENDIX-inflammation with swollen adjacent fat

MAKE SURE THAT YOU EVALUATE THE ENTIRE APPENDIX Appendicitis can be confined to only one segment of the appendix This occurs in approximately 20% of all patients Can be in either the proximal or distal end More common in the distal end If you find a normal segment of the appendix and stop your evaluation there, you may miss a focal appendicitis

Next Slide The 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.

SUMMARY 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

SUMMARY The anatomy of the appendix, causes of appendicitis and the typical progression of appendicitis What a normal and abnormal appendix looks like with sonography There are a few potential pitfalls that we need to keep in mind We need to overcome our fear, be persistent and be organized in our examination of the appendix Finally, we have learned a suggested protocol in performing sonography of the appendix

The End Thank you for your time and attention. We hope you have enjoyed this presentation Ultrasound of the Appendix.