Studying appendicitis prevalent in Nepal

1. Case presentation
Acute Appendicitis

2. • 22 years male
• h/o pain in lower right iliac fossa
• Tenderness and rebound tenderness present

4. • A blind ending, tubular, aperistaltic, non-compressible, hypoechoic
tubular structure with wall to wall diameter of approx. 11.2mm
noted in right iliac fossa.

8. Appendix - Anatomy
• The appendix arises from the posteromedial surface of the caecum,
approximately 2-3 cm inferiorly to the ileocaecal valve, where the taena
coli converge. It is a blind diverticulum, which is variable in length from 2-
20 cm. The appendix lies on its own mesentery, the mesoappendix.
• The tip of the appendix can
have a variable position within
• the abdominal cavity :
• -retro-caecal (65-70%)
• -pelvic (25-30%)
• -pre- or post-ileal (5%)

9. Acute appendicitis
• Acute appendicitis is the most common cause of acute
abdominal pain requiring surgery
• Acute appendicitis is typically a disease of children and young adults
with a peak incidence in the 2nd to 3rd decades of life
• pathogenesis of acute appendicitis is thought to relate
to obstruction of its orifice

10. Appendicitis is typically caused by
obstruction of the appendiceal lumen,
with resultant build up of fluid,
secondary infection, venous
congestion, ischaemia and necrosis.
Obstruction may be caused by:
-lymphoid hyperplasia (~60%)
-appendicolith (~33%)
-foreign bodies (~4%)
-Crohn disease or other rare causes,
e.g. stricture, tumour, parasite

11. Imaging in Appendicitis
• In older clinical literature before routine cross-sectional imaging was
available, laparotomy resulted in removal of normal, noninflamed
appendices in 16% to 47% of cases (mean, 26%)
• Also, perforation occurred in up to 35% of cases.

12. Plain X ray abdomen
• The presence of calcified fecoliths
(appendicoliths) is the single most important sign of
appendicitis seen plain x ray abdomen
• Generalized paralytic ileus may occur in cases of perforated appendicitis
but pneumoperitoneum is rare.

13. Ultrasound
Findings supportive of the diagnosis of appendicitis include :
• -Aperistaltic, noncompressible, dilated appendix ( >6 mm outer
diameter)
• -Appendicolith
• -Distinct appendiceal wall layers
• -Echogenic prominent pericaecal fat
• -Periappendiceal fluid collection
• -Target appearance (axial section)

15. Puylaert’s technique of Graded compression
• Allows normal and gas filled loops of gut to be displaced from the
field of view or compressed between the layers of musculature of the
anterior and posterior abdominal wall.
• patient is able to provide input as to the point of maximal tenderness,
which is often useful in focusing the examination in the correct area
• When a patient can self localize the site of maximal tenderness, there
is a significant sonographic finding at this site in 94% of cases

16. Other maneuver
• Turning the patient into the left lateral decubitus position maybe
helpful in visualizing the retrocecal appendix.
• Transducers with a variable short focal zone and a frequency
of 5–9 MHz have been recommended.

17. • Sonographic studies of normal individuals show that up to 23% of
normal patients have appendicular sizes >6 mm

18. • early acute appendicitis-catarrhal stage-five layers can
be identified
1) A central, thin hyperechoic line representing the collapsed
lumen and mucosal lining
2) Hypoechoic layer (2–3 mm) representing the edematous
lamina propria and muscularis mucosa
3) Hyperechoic sub mucosa ( 2–3 mm)
4) Hypoechoic muscular layer (2–3 mm)
5) Outer most thin hyperechoic line representing the serosa

20. • In the later suppurative stages, the lumen of the appendix
gets distended with pus/fluid and there may be an
increase in the thickness of the submucosa and muscular
layer in the range of 3–6 mm.
• Appendicoliths are seen as bright, echogenic foci with
clean distal acoustic shadowing.

21. • Inflammatory change in the adjacent fat appears bright and
noncompressible and is a sonographic clue to the presence of
appendicitis in doubtful cases.
• Enlarged mesenteric lymph nodes may be identified.

22. • An asymmetric thickening of the appendiceal wall with
a focal/circumferential lack of visualization of the echogenic
submucosa indicates perforation of the inflamed appendix.
• An appendiceal mass is seen as a complex paracecal
mass of mixed echogenicity and thickened paracecal fat.

23. • In cases of appendicitis, the presence of hyperaemia in the
appendiceal wall and adjacent mesoappendix is a sensitive indicator
of inflammation and can be well demonstrated on colour Doppler.

24. • The contribution of Doppler US is most evident in cases of equivocal
grey scale US examination in which it is uncertain as to whether the
imaged appendix is inflamed or normal.

25. pitfalls
• The most important cause for a false negative result is overlooking
of the appendix.
• Other causes are obesity and a retrocecal position of the appendix
• Peritonism may prevent graded compression in patients with
perforation, or the dilated, air filled loops of adynamic ileus can hide
the appendix from view.

26. • The appendix may be relatively thickened in cases of
perforated peptic ulcer or sigmoid diverticulitis and a false
positive diagnosis is possible.
• In some cases the terminal
ileum may be misinterpreted as the inflamed appendix

27. CT
• The most commonly used CT technique for studying the appendix is a scan
of the entire abdomen and pelvis after both oral and IV administration of
contrast material
• Disadvantage of this technique is the time taken for the
oral contrast to reach the cecum, which is essential for best
results.
• CT is highly sensitive (94-98%) and specific (up to 97%) for the diagnosis of
acute appendicitis and allows for alternative causes of abdominal pain to
also be diagnosed.

28. • Periappendiceal inflammation, including stranding of the adjacent fat
and thickening of the lateroconal fascia or mesoappendix.
• -Extraluminal fluid
• -Inflammatory phlegmon
• -Abscess formation
• -Appendicolith may also be identified

29. • In the absence of secondary changes, a luminal diameter of 9 mm
has been advocated as the threshold size for appendicitis.
• Linear fat stranding, local fascial thickening and subtle
clouding of the mesentery are characteristic
findings of periappendiceal inflammation in nonperforated
appendicitis

30. Caecal bar sign
• The caecal bar sign is a secondary sign in acute appendicitis. It refers
to the appearance of inflammatory soft tissue at the base of the
appendix, separating the appendix from the contrast-filled caecum.

31. Arrowhead sign
• The arrowhead sign refers to the focal caecal thickening centered on
the appendiceal orifice, seen as a secondary sign in acute
appendicitis. The contrast material in the cecal lumen assumes an
arrowhead configuration, pointing at the appendix.
• The arrowhead sign is applicable only when enteric contrast distends
the caecum.

32. MRI
• Magnetic resonance imaging (MRI) is not routinely advocated in cases
of suspected appendicitis, it can be useful in cases where sonography
is equivocal and CT is not possible or contraindicated such as
pregnant women
• On MRI acute appendicitis is best seen in T2W sequences
in the axial and coronal planes.

33. • T2W images are superior to T1W images because of better
visualization of the bright signal intensity of inflammatory change
associated with acute appendicitis
• On T2W imaging, the thickened appendiceal wall is seen
as a slightly hyperintense ring with a markedly hyperintense
centre representing intraluminal fluid

35. • The cutoff threshold of the appendix is the same as for CT.
• Periappendiceal inflammation gives a marked hyperintense signal.
• Appendicoliths are difficult to demonstrate on MRI as they are seen
as intraluminal structures without signal intensity on all sequences.

36. Complication of acute appendicitis

37. Complication- perforation
• If appendicitis is allowed to progress, portions of the appendiceal
wall eventually become ischemic or necrotic and the appendix
perforates.
• CT findings—extraluminal air, extraluminal appendicolith, abscess,
and a defect in the enhancing appendiceal wall—allows excellent
sensitivity (95%) and specificity (95%) for perforation in patients with
known appendicitis who underwent preoperative CT. In that study,
the individual finding with highest sensitivity was a mural
enhancement defect (64%).

38. 32-year-old man with acute appendicitis. Unenhanced CT shows appendicolith (arrowhead), periappendiceal fat
stranding (black arrows), lateral conal fascia thickening (white arrow), and periappendiceal fluid. Perforation was
confirmed on surgery

39. Abscess formation
• Abscess is the most frequent complication of perforation. The
abscess remains localized if periappendiceal fibrinous adhesions
develop before rupture. CT shows a loculated, rim- enhancing fluid
collection that may have mass effect on adjacent bowel loops. If the
abscess is large (> 4 cm), percutaneous drainage followed by delayed
appendectomy is the preferred treatment .

40. 47-year-old man with periappendiceal abscess. Helical CT after IV contrast injection shows periappendiceal
abscess extending into psoas muscle (arrowheads).