*35-year-old female with right lower quadrant pain for 3 days.
What is the most likely diagnosis?
Answer
Answer: Pelvic plastron secondary to acute appendicitis
Case Discussion:
Ultrasound images revealed acute perforated appendicitis with localized fluid collection, covering appendicular plastron.
Appendicitis is inflammation of the vermiform appendix. It is typically a disease of children and young adults with a peak incidence in the 2nd to 3rd decades of life. Appendicitis is a very common condition in general radiology practice and is one of the main reasons for abdominal surgery in young patients. CT is the most sensitive modality to detect appendicitis.
Ultrasound findings include:
aperistaltic, non-compressible, dilated appendix (>6 mm outer diameter)
appendicolith
distinct appendiceal wall layers
echogenic prominent pericaecal and periappendiceal fat
periappendiceal hyperechoic structure
periappendiceal fluid collection
target appearance (axial section)
periappendiceal reactive nodal prominence/enlargement
CT findings include:
dilated appendix with distended lumen ( >6 mm diameter)
thickened and enhancing wall
thickening of the caecal apex (up to 80%): caecal bar sign, arrowhead sign
periappendiceal inflammation, including stranding of the adjacent fat and thickening of the lateroconal fascia or mesoappendix
extraluminal fluid
inflammatory phlegmon
abscess formation
appendicolith
periappendiceal reactive nodal prominence/enlargement
non-enhancement of the mucosa representing necrosis and a precursor to perforation
Complications include:
perforation
abscess formation
generalised peritonitis
pylephlebitis
References:
1. Weissleder R, Wittenberg J, Harisinghani MG et-al. Primer of diagnostic imaging. Mosby Inc. (2007) ISBN:0323040683.
2. Callahan MJ, Rodriguez DP, Taylor GA. CT of appendicitis in children. Radiology. 2002;224 (2): 325-32.
3. Pereira JM, Sirlin CB, Pinto PS et-al. Disproportionate fat stranding: a helpful CT sign in patients with acute abdominal pain. Radiographics. 24 (3): 703-15.
4. Puylaert JB. Acute appendicitis: US evaluation using graded compression. Radiology. 1986;158 (2): 355-60.
5. Doherty GM, Way LW. Current surgical diagnosis & treatment. McGraw-Hill Medical. (2006) ISBN:007142315X.