Editing Appendicitis (section)

== '''Investigation''' ==

* '''Bloods'''
** Leucocytosis is present in      90% of cases, often with a left shift (predominance of neutrophils and      sometimes an increase in band forms)
*** Therefore 10% of cases have       a normal neutrophil count
*** Mean WCC is higher with       perforated or gangrenous appendicitis
** Mild elevation of bilirubin      is 86% specific for perforation (UTD)
** CRP <10 is 85% sensitive      at admission and nearly 100% sensitive at 48 hours after symptom onset
* '''Urine'''
** Dipstick - trace leucs are      found commonly, and presumably secondary to direct irritation of the      bladder
** Pregnancy testing mandatory      for women of childbearing age
* '''AXR''' - might see a calcified     appendicolith, but not much else (pneumoperitoneum is rare even with     perforation)
* '''USS''' 0.86/0.81 for se/sp
** Primary sign - enlarged,      immobile, and non-compressible
** Secondary signs - free      fluid, hyperaemia of adjacent bowel loops, induration of mesenteric fat,      and regional adenopathy
**
* '''CT''' with IV contrast
** Best used for equivocal      cases
** Sensitivity 76-100%
** Specificity 83-100%
** Look for an appendix >7mm      in diameter with a thickened, inflamed wall and mural enhancement/target      sign
** If the appendix is not      visualised, the absence of inflammatory findings is also quite sensitive      to exclude appendicitis
* '''MRI''' equivalent to CT
** Typically used for pregnant      patients
** No contrast necessary
** Sensitivity 97%, specificity      95%