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Case of the Month

January 2011

Patient Data: Male patient 14 years old

Clinical Info: Pain in the right lower abdomen. Slightly raised infection parameters

There is a normal terminal ileum. The appendix is not in its most common position

A normal looking appendix could be found in a retrocecal position

Longitudinal image of the normal looking appendix in a retrocecal position. There is some air in the lumen. No signs of inflammation

CT scan of the same patient shows a normal appendix in a retrocecal position

Two days later the patient was examined again because of persistent pain in the right lower abdomen and raised infection parameters. Longitudinal image of the right kidney with a small amount of perirenal fluid. The appendix could be found in its retrocecal position again without signs of inflammation

Transverse image of the right kidney with perirenal effusion

There was also a small effusion at the undersurface of the right liver lobe. What was not noticed was a small round structure next to this effusion

The folowing day the ultrasound examination was repeated because the CRP had increased to 300. There is an increase of the effusion below the liver with tiny air bubbles. There is still a tiny amount of perirenal fluid

Again there is a rounded structure next to the effusion

The rounded structure was an inflamed tip of a very long retrocecal appendix. The largest part of the appendix still remained normal

36812-3830338_20101208_SMALL-_PARTS-__0001.AVI.SWF videoclip of the appendix in transverse direction

36813-3830338_20101208_SMALL-_PARTS-__0002.AVI.SWF Videoclip of the same patient in longitudinal direction.

36819-Mijn_Film.wmv.SWF A CT scan confirmed the findings. The patient was operated and an appendectomy was performed.

The following case shows that the diagnosis of a focal appendicitis of the tip is not always easy. This is a longitudinal image of an appendix of a 10 year old girl with suspicion of an appendicitis. The tip is slightly thickened

Detail of the tip of the appendix with vascularity

Transverse image of the tip with color doppler. The diameter is nearly 6 mm. which is just within normal limits, however it is more rounded and not compressible

Transverse image of the proximal appendix which is oval and measures 4,3 mm. The patient was operated because we found the ultrasound findings a bit suspicious for a moderate focal appendicitis. At operation a mildly thickened tip of the appendix was found just like the ultrasound examination, however without signs of inflammation. Because of the ultrasound findings an appendectomy was performed. The pathologist however found a normal appendix without signs of an inflammation

In the first case only the proximal part of the appendix was visualized in the first examinations. The inflamed tip was initially missed leading to a small perirenal effusion and an effusion at the lowerpole of the liver. A retrocecal appendix can be difficult to examine with ultrasound becuse of overlying bowel gas. When it is very long, a focal abnormality can easily be missed.
The second case illustrates that a focal thickening of the appendix doesn't always mean that there is an appendicitis. Although the rounded shape of the tip and the vasculatity were suspicious for inflammation, in this case it was still fysiological. The diameter was still within normal limits and there were no secundary signs of inflammation

For more examples of appendicitis see

Optimizing US examination to detect the normal and abnormal appendix in children.
Peletti AB, Baldisserotto M.
Pediatr Radiol. 2006 Nov;36(11):1171-6.

US features of the normal appendix and surrounding area in children.
Wiersma F, Srámek A, Holscher HC.
Radiology. 2005 Jun;235(3):1018-22.

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