Appendicitis
Definition
Acute appendicitis is defined as an inflammation of the inner lining of the vermiform appendix that spreads to its other parts (1). It is the most common surgical emergency worldwide, and timely diagnosis and intervention are crucial to prevent complications.
Epidemiology
In Malaysia, acute appendicitis is the most frequent cause for emergency general surgery admissions. A study from a Malaysian general hospital indicated that the incidence of complicated (perforated or gangrenous) appendicitis was 15% (2). Data from a 2020 study in Pahang during the Movement Control Order (MCO) found a mean patient age of 29 years, with a slight female predominance (51%) (2). Specific national prevalence data from a comprehensive health survey is not readily available and should be interpreted with caution. A much older study from University Hospital, Kuala Lumpur, noted that appendicitis constituted 34% of all general surgical emergency operations at that time (3). Globally, the lifetime risk of appendicitis is approximately 7-8%, with a peak incidence in the second and third decades of life (4).
Pathophysiology
The primary cause of acute appendicitis is the obstruction of the appendiceal lumen. This obstruction can be due to a hardened piece of stool (fecalith), swollen lymphoid tissue (often following a viral infection), intestinal parasites, or, rarely, a tumour (5). Once obstructed, mucus produced by the appendix cannot drain, leading to increased intraluminal pressure. This pressure compromises blood flow, leading to ischemia of the appendiceal wall. Bacteria, which are normally present in the gut, then invade the ischemic wall, causing inflammation, suppuration, and potentially progressing to gangrene and perforation if left untreated (5, 6).
Classification
Acute appendicitis is broadly classified into two clinically significant categories:
Uncomplicated Appendicitis: This involves an inflamed, phlegmonous, or suppurative appendix without evidence of gangrene, perforation, or abscess formation (1).
Complicated Appendicitis: This includes gangrenous or perforated appendicitis, the presence of a localized collection of pus (appendiceal abscess), or generalized peritonitis (1). This classification is crucial as it guides the intensity and duration of treatment, particularly antibiotic therapy.
Clinical Presentation
The classic presentation of appendicitis involves migratory abdominal pain that begins in the periumbilical region and later localizes to the right iliac fossa (RIF).
Diagnostic Clues: The Alvarado score is a widely used clinical scoring system that incorporates symptoms, signs, and laboratory findings to stratify the risk of appendicitis (7). A score of 7 or more is highly predictive of appendicitis.
Common Symptoms (>50%):
Right iliac fossa (RIF) pain (migratory in ~50-60%) (6)
Anorexia (loss of appetite)
Nausea and vomiting (vomiting typically follows the onset of pain) (6)
Less Common Symptoms (10-50%):
Low-grade fever (~38.0°C)
Diarrhoea or constipation
Malaise
⚠️ Red Flag Signs & Symptoms:
High-grade fever (>38.5°C)
Signs of peritonism (rebound tenderness, guarding, rigidity)
Tachycardia and hypotension (suggesting sepsis or perforation)
A palpable mass in the RIF
Complications
Complications arise primarily from a delay in treatment, leading to perforation.
Perforation: This can lead to the spread of infection within the abdominal cavity.
Appendiceal Abscess: A localized collection of pus forms around the perforated appendix.
Generalized Peritonitis: Widespread inflammation of the abdominal lining, a life-threatening condition.
Sepsis: Systemic infection which can lead to organ failure.
Wound Infection: The most common postoperative complication.
Prognosis
For uncomplicated appendicitis treated with appendicectomy, the prognosis is excellent, with mortality rates well below 1% (4). The prognosis for complicated appendicitis is more guarded. Perforation increases the morbidity rate significantly and mortality can be as high as 5% in older patients or those with significant comorbidities (4, 6).
Differential Diagnosis
[Gastroenteritis]: This is a key differential, especially in younger patients, due to the presence of nausea, vomiting, and sometimes abdominal pain. However, in gastroenteritis, diarrhoea is often more prominent, and the pain is typically diffuse and cramping, rather than localizing to the RIF. The absence of localized tenderness makes appendicitis less likely (6).
[Mesenteric Adenitis]: Inflammation of the mesenteric lymph nodes can closely mimic appendicitis, particularly in children and young adults, often following an upper respiratory tract infection. The pain can be in the RIF, but it is often less localized, and generalized lymphadenopathy may be present. An ultrasound can be useful to visualize enlarged lymph nodes and a normal-sized appendix (8).
[Ectopic Pregnancy/Pelvic Inflammatory Disease (PID)]: In female patients of reproductive age, these are critical differentials. The presence of lower abdominal pain, adnexal tenderness on pelvic examination, and a history of menstrual irregularities should raise suspicion. A urine pregnancy test (UPT) is mandatory in this demographic to rule out a ruptured ectopic pregnancy, which is a surgical emergency. PID is often associated with vaginal discharge and cervical motion tenderness (4, 6).
Investigations
Immediate & Bedside Tests
Urine Pregnancy Test (UPT): Mandatory for all female patients of childbearing age to rule out an ectopic pregnancy, which can present with similar symptoms (6).
Urinalysis: Essential to rule out a urinary tract infection, which can cause lower abdominal pain and fever. However, mild pyuria or hematuria can occur in appendicitis due to irritation of the ureter or bladder (4).
Diagnostic Workup
First-Line Investigations:
Full Blood Count (FBC): Crucial to detect leukocytosis (an elevated white blood cell count), particularly neutrophilia, which supports the diagnosis of an acute bacterial infection (7).
C-Reactive Protein (CRP): A non-specific inflammatory marker that is almost always elevated in appendicitis; a normal CRP after 12 hours of symptoms makes appendicitis unlikely (4).
Abdominal Ultrasound: Often the first-line imaging modality, especially in children and pregnant women, to avoid radiation. It helps to visualize an inflamed, non-compressible appendix with a diameter >6mm and can identify other pathologies (8).
Gold Standard:
Contrast-enhanced Computed Tomography (CT) of the Abdomen and Pelvis: The most accurate imaging modality for diagnosing appendicitis, with a sensitivity and specificity of over 95% (9). It is essential in clinically equivocal cases to confirm the diagnosis, identify complications like abscesses or perforation, and guide management.
Management
Management Principles
The management of acute appendicitis is centred on early diagnosis, adequate resuscitation, prompt surgical removal of the appendix, and appropriate antibiotic therapy (4).
Acute Stabilisation (The First Hour)
Airway/Breathing: Ensure the patient has a patent airway. Administer supplemental oxygen if there are signs of respiratory distress or sepsis to maintain SpO2 >94%, which is vital to prevent tissue hypoxia (4).
Circulation: Secure intravenous (IV) access, preferably with two large-bore cannulas. For patients with signs of dehydration or sepsis, administer a stat fluid bolus of IV Normal Saline or Hartmann's solution at 20mL/kg to restore intravascular volume and improve tissue perfusion (10).
Disability/Exposure: Keep the patient nil by mouth (NBM) in anticipation of surgery. Provide adequate analgesia, such as IV paracetamol or a cautious dose of an opioid like morphine, to alleviate pain, which also reduces physiological stress.
Definitive Therapy
The definitive treatment for acute appendicitis is an appendicectomy. The choice between laparoscopic and open surgery depends on local expertise and patient factors (4, 9).
Antibiotic Therapy (as per Malaysian National Antibiotic Guideline 2019):
Uncomplicated Appendicitis: For patients undergoing appendectomy, prophylactic antibiotics should be given. If a non-operative approach is considered, the recommended regimen is IV Amoxicillin/clavulanate 1.2g q8h OR IV Ampicillin/sulbactam 1.5-3g q6h. An alternative is IV Cefuroxime 1.5g q8h PLUS IV Metronidazole 500mg q8h. This antibiotic cover targets common gut flora like E. coli and anaerobes to prevent postoperative infection and treat the ongoing inflammation (10).
Complicated Appendicitis (with Sepsis): Broader coverage is required. The first-line recommendation is IV Piperacillin/tazobactam 4.5g q6-8h. This provides robust coverage against gram-negative and anaerobic bacteria to control the intra-abdominal infection and prevent systemic complications (10).
Supportive & Symptomatic Care
Analgesia: Regular intravenous or oral analgesia to ensure patient comfort.
Antiemetics: Administer as needed for nausea and vomiting (e.g., IV Metoclopramide 10mg).
Thromboprophylaxis: For patients with prolonged immobility, consider subcutaneous heparin to prevent deep vein thrombosis.
Key Nursing & Monitoring Instructions
Strict hourly monitoring of vital signs (BP, heart rate, respiratory rate, SpO2, temperature).
Maintain an accurate input/output chart, especially for patients on IV fluids.
Inform the medical officer immediately if systolic BP drops below 100 mmHg, heart rate rises above 120/min, or urine output is <0.5mL/kg/hr.
Monitor for increasing abdominal pain or distension, which may indicate worsening peritonitis.
Long-Term Plan & Patient Education
Post-appendicectomy, most patients recover fully. Educate the patient and family on wound care and to look for signs of infection (redness, swelling, discharge, increasing pain). Advise a gradual return to normal activities over 2-4 weeks, depending on whether an open or laparoscopic procedure was performed (4).
When to Escalate
Call Your Senior (MO/Specialist) if:
The patient shows signs of hemodynamic instability (tachycardia, hypotension) unresponsive to an initial fluid bolus.
There is clinical deterioration with worsening abdominal signs (e.g., development of generalized rigidity).
The diagnosis remains uncertain despite initial investigations.
The patient is at the extremes of age (very young or elderly) or is pregnant, as these groups have a higher risk of complications.
Referral Criteria:
All patients with suspected or confirmed acute appendicitis require an urgent referral to the General Surgery team for assessment and management.
References
Clinical Practice Guidelines - Acute Appendicitis. (n.d.). Retrieved from Scribd. https://www.scribd.com/document/238638397/Clinical-Practice-Guidelines-Acute-Appendicitis (Note: While this document aligns with general practice, its official MOH source is unverified).
Chong, H. Y., et al. (2021). Effect of the Movement Control Order on the Incidence of Complicated Appendicitis During the COVID-19 Pandemic: A Cross-Sectional Study. Malaysian Journal of Medical Sciences, 28(6), 113–122. https://pmc.ncbi.nlm.nih.gov/articles/PMC8793977/
Lee, H. Y., Jayalakshmi, P., & Syed Naori, S. H. (1993). Acute Appendicitis ~ The University Hospital Experience. Medical Journal of Malaysia, 48(1). https://www.e-mjm.org/1993/v48n1/Acute_Appendicitis.pdf
Gorter, R. R., Eker, H. H., Gorter-Stam, M. A., Abis, G. S. A., Acharya, A., Ankersmit, M., van den Berg, A., van den Boezem, P. B., Bökkerink, W. J. X., Boll, D., van den Broek, W. T., Bruin, S. C. A., van Dam, D. A., Defoort, B., Deijen, C. L., van Dijk, S. T., Drupsteen, J., van Duren, B. H. M., Dwars, B. J., … van Westreenen, H. L. (2016). Diagnosis and management of acute appendicitis. EAES consensus development conference 2015. Surgical Endoscopy, 30(11), 4668–4690. https://doi.org/10.1007/s00464-016-5245-7
Bhangu, A., Søreide, K., Di Saverio, S., Assarsson, J. H., & Drake, F. T. (2015). Acute appendicitis: modern understanding of pathogenesis, diagnosis, and management. The Lancet, 386(10000), 1278–1287. https://doi.org/10.1016/S0140-6736(15)00275-7
Wagner, M., Tubre, D. J., & Asensio, J. A. (2024). Evolution and Current Trends in the Management of Acute Appendicitis. Surgical Clinics of North America, 104(3), 399–413.
Alvarado, A. (1986). A practical score for the early diagnosis of acute appendicitis. Annals of emergency medicine, 15(5), 557-564.
Trout, A. T., Towbin, A. J., & D’Souza, S. (2021). Imaging of pediatric appendicitis. Pediatric Radiology, 51(12), 2247-2263.
Di Saverio, S., Podda, M., De Simone, B., Ceresoli, M., Augustin, G., Gori, A., Boermeester, M., Sartelli, M., Coccolini, F., Tarasconi, A., de’ Angelis, N., Weber, D. G., Tolonen, M., Birindelli, A., Biffl, W., Moore, E. E., Kelly, M., Soreide, K., Kashuk, J., … Catena, F. (2020). Diagnosis and treatment of acute appendicitis: 2020 update of the WSES Jerusalem guidelines. World Journal of Emergency Surgery, 15(1), 27. https://doi.org/10.1186/s13017-020-00306-3
Ministry of Health Malaysia. (2019). National Antimicrobial Guideline 2019 (3rd Edition). Pharmaceutical Services Programme. Retrieved from https://jknpenang.moh.gov.my/hbm/images/hbm/antimicrb_guideline_2022.pdf
