**3. Conclusion**

Although the diagnosis of acute appendicitis is essentially clinical, familiarisation with other causes of acute abdominal pain that can mimic appendicitis is equally important especially in females and those with the extremes of age. Here we present a plethora of gastrointestinal, urological, vascular, infectious, and gynaecological conditions that can be similar in presentation to acute appendicitis. The supplementary use of appropriate laboratory tests and radiological imaging can be pivotal where there is clinical uncertainty, not only aiding in confirming the diagnosis of appendicitis or its associated complications but also in identifying other alternative pathology. Routine blood tests that include a full blood count (FBC) and c-reactive protein (CRP) can aid in the diagnosis of acute appendicitis as evidenced by the presence of raised white cell count and CRP. Although raised inflammatory markers can raise the likelihood for clinically suspected acute appendicitis, it is non-specific and less helpful where the clinical presentation is inconclusive and other differential diagnoses are equivocal. A urinalysis also should be considered in all patients with suspected acute appendicitis as part of their workup since it is an important bedside test when assessing for potential renal or urology pathologies such as the presence of blood in urolithiasis or nitrites and leukocytes in urinary tract infection (UTI).

Special consideration is warranted for female patients presenting with abdominal pain as the presence of an underlying gynaecological pathology can potentially complicate the clinical picture and affect the diagnostic accuracy. In this special category of patients, it is particularly important to check the blood or urine samples for beta Human chorionic gonadotrophin hormone (Beta-hCG) in all female patients of childbearing age presenting to the Emergency Department with acute abdominal pain to exclude ectopic pregnancy. Ultrasound remains the first line of imaging in investigating gynaecological pathology (transvaginal ultrasound) and in the paediatric age group due to the inherent risk of radiation associated with CT imaging.

Another special consideration is given to the elderly population where the incidence of acute appendicitis is less common. In assessing elderly patients, it is of a high priority to exclude time-critical conditions such as ruptured abdominal aortic aneurysm and bowel ischemia. The current recommendation by the Royal College of Emergency Medicine in the UK is for the emergency physician to perform an ultrasound aorta in all patients who are older than 50 years presenting with acute abdominal pain to rule out abdominal aortic aneurysm (AAA). A follow up dedicated CT aortogram may be required if the patient is hemodynamically stable to confirm the diagnosis of abdominal aortic aneurysm and to evaluate for any potential leak. Bowel ischemia is another time-critical emergency where there is a compromise to the bowels blood supply. Risk factors for bowel ischemia include diabetes, hypertension, smoking, hypercholesterolemia and atrial fibrillation (AF). It is important to consider the diagnosis of bowel ischemia in all patients who are older than 50 years presenting with a sudden onset of severe abdominal pain along with a raised serum lactate level reflecting organ hypoperfusion. CT abdomen and pelvis with IV contrast or a dedicated CT angiography remains the best imaging

technique for all hemodynamically stable patients in whom bowel ischemia is suspected.

As discussed above a variety of clinical conditions can mimic acute appendicitis and familiarisation with those alternative conditions is crucial when deciding what imaging modality will best suit the patient assessment thus increasing the diagnostic accuracy and ensuring optimal care to all patients.
