Peds Radiology Case - Appendicitis

Question 1

Describe the pathological changes of acute appendicitis.

Answer 1

Inflamed appendix
Lumen filled with neutrophils
Ulcerated mucosa
Inflamed visceral and parietal peritoneum

Question 2

Appendiceal inflammation is associated with obstruction in 50-80% of cases due to what?

Answer 2

Fecalith, tumor, or ball of worms (oxyuriasis vermicularis)

Question 3

Potential complications of acute appendicitis?

Answer 3

Perforation (most serious)
Pylephlebitis with thrombosis of the portal vein
Liver abscess

Question 4

What imaging procedures are useful in the evaluation of a patient suspected to have appendicitis?

Answer 4

CT scan
U/S
Plain abdominal radiograph

Question 5

Role of CT in evaluating appendicitis?

Answer 5

Most ideal imaging procedure for diagnosing appendicitis and its complications; enables differentiation of diffuse periappendiceal inflammation from an abscess but also detects many diseases on the differential of acute appendicitis

Spiral CT - useful when not quite sure of diagnosis from H&P
Appendiceal CT - highest sensitivity and specificity

Question 6

Role of U/S in evaluating appendicitis?

Answer 6

Can be limited by gas in bowel
Useful in pregnant women with abdominal pain or young children when there is clinical doubt
Reliable and sensitive for the detection of appendicoliths and the demonstration of an abnormally distended or thick-walled appendix

Question 7

Role of plain film radiograph in evaluating appendicitis?

Answer 7

Low sensitivity

Conventional abdominal radiography along with contrast-enema radiography no longer has a role

Question 8

Is imaging required in all suspected cases of appendicitis?

Answer 8

When the surgeon is confident of the diagnosis, he or she may opt to take the patient to the OR without the need for imaging

Despite the number of algorithms and diagnostic tests available, 20% of patients with appendicitis are misdiagnosed. Also, 15-40% of all operations performed for suspected appendicitis turn out to have normal appendices

Question 9

Sensitivity and specificity of spiral CT in diagnosing appendicitis?

Answer 9

Sensitivity: 90-100%
Specificity: 91-99%
PPV: 95-97%
Accuracy: 94-100%

Question 10

What limits the accuracy of U/S in diagnosing appendicitis?

Answer 10

Associated bowel gas
Operator dependent

75-90% sensitivity
86-100% specificity
89-93% PPV

Question 11

Radiological findings of appendicitis in plain abdominal radiographs?

Answer 11

No specific signs, but you may see:

Ileus
Appendicoliths
Sentinel loop (dilated adjacent ileum)
Evidence for perforation or abscess
Widening and blurring of peritoneal fat line
RLQ haze due to fluid, edema, and mass
Mass indenting the cecum

Question 12

Radiological findings of appendicitis on abdomen CT?

Answer 12

Ileus (dilated bowel loops)
Appendix >6 mm in diamter
Appendicolith
Failure of the appendix to fill with oral contrast
Enhancement of appendiceal wall with IV contrast medium
Periappendiceal inflammation/inflammatory infiltration of fat
Free fluid in cul de sac
Abscess (inflammatory phelgmon mass, air pockets, contrast enhancement), extraluminal gas from perforation, pericecal lymphadenopathy , cecal wall thickening

Question 13

How does acute appendicitis appear on abdominal CT?

Answer 13

Dilated appendix + dilated loops of bowel

Question 14

Most sensitive sign of appendicitis on U/S? Other findings?

Answer 14

Non-compressible appendix with a diameter of 7 mm or greater

Appendicolith, thickened appendiceal wall, abscess, fluid around appendix