Definition and Pathophysiology Acute appendicitis is an inflammation of the vermiform appendix, a small, tube-shaped organ attached to the caecum at the beginning of the large intestine. It is one of the most common causes of acute abdominal pain requiring urgent medical assessment. The condition usually occurs due to obstruction of the appendiceal lumen by a faecolith or lymphoid tissue enlargement. This obstruction may lead to the accumulation of secretions, bacterial overgrowth, and inflammation. In some cases, the condition may progress to reduced blood supply (ischaemia) or perforation of the appendix. Clinical Presentation Pain typically begins around the umbilicus and gradually moves to the right lower quadrant of the abdomen. Other symptoms may include loss of appetite, nausea, vomiting, and a low-grade fever. Clinical examination may reveal tenderness in the right lower quadrant, and guarding or abdominal muscle rigidity may also be present. However, symptoms can vary according to age, pregnancy, and the position of the appendix. Therefore, no single symptom or clinical sign is sufficient to confirm the diagnosis. Diagnosis The diagnosis of acute appendicitis is based on the patient’s medical history and physical examination, supported by laboratory investigations when appropriate, such as a complete blood count (CBC) and C-reactive protein (CRP). Urinalysis may be performed to exclude similar conditions, and a pregnancy test may be required when indicated. Imaging investigations include ultrasound, which is commonly used in children and pregnant patients, and computed tomography (CT), which may be used in non-pregnant adults when the diagnosis remains uncertain. Clinical scoring systems may support the diagnostic process but cannot replace specialist clinical assessment. Management and Complications Suspected acute appendicitis requires urgent surgical assessment. Appendectomy, or surgical removal of the appendix, remains a standard definitive treatment. In selected cases of uncomplicated appendicitis, antibiotic treatment without surgery may be considered after discussing its benefits, risks, the possibility of recurrence, and the potential need for surgery later. Important complications include appendiceal perforation, abscess formation, peritonitis, and sepsis. Treatment decisions depend on the patient’s condition, clinical findings, and current medical guidelines. Conclusion Acute appendicitis is a medical condition that may progress rapidly and can sometimes present with atypical symptoms. Early medical assessment is essential for accurate diagnosis and the prevention of complications. Emergency evaluation is necessary in cases of severe or worsening abdominal pain, fever, repeated vomiting, severe dizziness, or marked abdominal rigidity. References 1. Di Saverio S, et al. Diagnosis and Treatment of Acute Appendicitis: 2020 Update of the WSES Jerusalem Guidelines. World Journal of Emergency Surgery. 2020;15:27. 2. National Institute for Health and Care Excellence (NICE). Guidance and evidence related to the diagnosis and management of acute appendicitis. Educational Note: This article is intended for educational purposes only and does not replace clinical assessment or adherence to approved medical protocols. Al Mustaqbal University The First University in Iraq