Re: Seeing past the appendix; the role of ultrasound in right iliac fossa pain

Sir, Re: Seeing past the appendix; the role of ultrasound in right iliac fossa pain. (Ultrasound 2014;22:104–12) I read with interest the article by White et al. Right iliac fossa pain is a common symptom presenting to emergency departments and surgical admissions units and the authors are to be congratulated for highlighting the potential ultrasound offers in interrogating the differential diagnoses. The focus of the article is on mimics of appendicitis and therefore the brevity on appendicitis appropriate, but several critical elements have been excluded. The variation of the dimensions of the normal appendix, which in the largest published study ranged from 1 to 24 cm (average 8 cm) in length,1 The maximum outer diameter of the normal appendix may be much greater than 6 mm in the presence of faecal impaction or air distension (Figure 1), and 6 mm is therefore an unreliable diagnostic threshold diameter, unless accompanied by other features of inflammation,2,3 Figure 1 High-frequency linear probe axial image of the appendix (solid arrow) and small bowel (broken arrow) in the right iliac fossa. The appendix is distended with faeces with an MOD 8.4 mm In focal appendicitis, the appendix may not be enlarged; the lesion may be missed if the organ is not imaged completely,4 Appendicoliths are often present in the normal appendix.5