REVIEW ARTICLE
IMAGING AS AN AID TO THE DIAGNOSIS OF ACUTE APPENDICITIS
Lionel I Wijesuriya FRCS (Eng), Associate Professor, Department of Surgery, International Medical University, Seremban, Malaysia
Address for correspondence: Associate Professor Dr Wijesuriya LI , International Medical University, Clinical School, Jalan Rasah, 70300 Seremban, Negeri Sembilan, Malaysia. Tel: 06-7677798, Fax: 06-7677709, Email: lionelwijesuriya@hotmail.comConflict of interest: none
Acute appendicitis has been known as a disease entity for well over a century but a confident diagnosis before surgery in all patients suspected of the condition is still not possible. Timely diagnosis is essential to minimise morbidity due to possible perforation of the inflamed organ in the event treatment is delayed; so much so that surgeons often preferred to operate at the slightest suspicion of the diagnosis in the past. This resulted in the removal of many normal appendixes. When the diagnosis of appendicitis is clear from the history and clinical examination, then no further investigation is necessary and prompt surgical treatment is appropriate. Where there is doubt about the diagnosis however it is advisable to resort to imaging studies such as abdominal ultrasound or computed tomography to clear such suspicions before subjecting the patient to an appendicectomy. These studies would also help avoid delays in surgery in deserving patients.
Key words: Appendicitis, diagnosis, computed tomography, ultrasound
INTRODUCTION
Acute appendicitis, as we know it today, was first diagnosed in 1886.1 Although it is by far the most common acute abdominal emergency that requires surgical treatment,2 a confident diagnosis of acute appendicitis before operation in all patients is still beyond reach. Since family physicians may have first contact with at least some of these patients it is imperative that they are familiar with the clinical features as well as the initial steps in making the diagnosis.
Diagnostic difficulty is particularly common in children3 in whom the symptoms and signs may often be somewhat nonspecific. The fact that the position of the appendix is also more abdominal rather than pelvic in children makes certain physical signs, particularly the point of maximum tenderness, different. Diagnostic problems are also common in the elderly of both genders as well as in women of reproductive age. Since the most common extra-uterine emergency that requires surgery during pregnancy is also acute appendicitis4 it is even more important to arrive at the correct diagnosis in this group of patients.
Accurate and timely diagnosis of the condition is essential in all groups of patients to minimise morbidity as only prompt surgical treatment would ensure reduction of the risk of perforation of the appendix. This is because there is a significant rise in mortality from less than 1% in non-perforated cases to 5% or more when perforation does occur.5 Largely because of this, surgeons over the years preferred to perform appendicectomy at the slightest suspicion of acute appendicitis rather than to ‘sit on’ such patients and risk the grave consequences associated with perforation of the organ. Even half a century ago, the typical advice to surgeons in training used to be “If the diagnosis of appendicitis is in doubt, take the appendix out”.6 Take the appendix out they did, often in the middle of the night!
This policy however resulted in many normal appendixes being removed and the rather embarrassing non-therapeutic appendicectomy rates sometimes as high as 50 per cent.7 Clearly, this position have to improve.
CLINICAL DIAGNOSIS
The diagnosis of acute appendicitis has always been clinical, based on the patient's history and the findings on physical examination but unfortunately there is such wide variation in the clinical presentation of the disease that diagnostic errors are committed worldwide; too frequently for comfort.8 The few studies reported from Malaysia also reveal that there is room for improvement in our diagnostic accuracy.9,10 In a retrospective Malaysian study of the pathology of 1000 consecutive appendicectomy specimens, where the pre-operative diagnosis was acute appendicitis, up to 22.5% of appendixes removed did not have acute inflammation.11 A diagnostic delay may of course result in a higher perforation rate too, as detected at the time of surgery.9,12
