What is appendicitis and how does it present?

Acute appendicitis is inflammation of the vermiform appendix, usually caused by obstruction of its lumen — by a faecolith (a hardened stool pellet), lymphoid tissue swelling after a viral illness, or occasionally a tumour. The classical presentation is a dull central abdominal pain around the umbilicus that shifts over several hours to a sharp, localised pain in the right iliac fossa, with loss of appetite, nausea, low-grade fever and tenderness at McBurney's point. However, this classical pattern occurs in only about half of patients — appendicitis presents atypically in young children, the elderly, pregnant women, and when the appendix lies in a retrocaecal or pelvic position. It is the most common abdominal surgical emergency worldwide, with a lifetime risk of approximately 7-8%.

Can appendicitis be treated with antibiotics instead of surgery?

Sometimes — this is now a legitimate option for selected patients. The CODA trial (NEJM 2020, 1,552 patients) found antibiotics non-inferior to appendicectomy at 30 days for uncomplicated appendicitis. However, patients need honest counselling on the trade-off: approximately 30% of antibiotic-treated patients had undergone appendicectomy within 90 days, and approximately 40% by four years. Crucially, the presence of an appendicolith (a stone in the appendix, visible on CT) substantially increases the failure rate and favours upfront surgery. Antibiotics-first is therefore reasonable for uncomplicated appendicitis without an appendicolith, particularly in patients who wish to avoid or defer an operation — but it is a shared decision, not a default, and it is not appropriate for perforated or complicated appendicitis.

Why is appendicitis harder to diagnose in some patients?

Because both the anatomy and the physiology vary. In pregnancy, the enlarging uterus displaces the appendix upward and laterally, so pain may be in the right upper quadrant, and the physiological nausea and mild leukocytosis of pregnancy obscure the picture. In the elderly, inflammatory responses are blunted — fever and white cell count may be normal despite advanced gangrenous appendicitis, and perforation rates at presentation are high. In young children, the history is limited, the appendiceal wall is thin, and the omentum is underdeveloped and cannot wall off a perforation — leading to perforation rates over 80% in under-5s. In women of reproductive age, the gynaecological differential (ectopic pregnancy, ovarian torsion, ruptured cyst, PID) is wide, and a pregnancy test is mandatory in every case.

What happens if appendicitis is not treated?

Untreated appendicitis progresses through mucosal ischaemia to gangrene and then perforation — typically over about 36-72 hours from symptom onset, though this is highly variable and much faster in small children. After perforation, one of two things happens. Either the omentum and adjacent bowel wall off the inflammation, producing an appendiceal mass or localised abscess — which can often be managed non-operatively at first with antibiotics and, if needed, percutaneous drainage. Or the perforation is not contained, producing generalised peritonitis with sepsis — a life-threatening emergency requiring urgent surgery. Late complications of perforation include intra-abdominal abscess, adhesive small bowel obstruction, portal pyaemia, and — in women — tubal damage and subsequent subfertility.

Is a tumour ever found in the appendix?

Yes — in approximately 1% of appendicectomy specimens, which is why every appendix removed must be sent for histopathological examination. The commonest is a neuroendocrine tumour (carcinoid), usually a small incidental finding at the appendix tip; tumours under 1cm require no further treatment, whereas those over 2cm or with mesoappendiceal invasion require a right hemicolectomy. Other findings include appendiceal adenocarcinoma, goblet cell adenocarcinoma, and low-grade appendiceal mucinous neoplasm (LAMN), which can seed the peritoneum and cause pseudomyxoma peritonei if it perforates. Practical implication: in patients over 40 presenting with appendicitis — particularly with an appendiceal mass, or after successful non-operative management — further investigation (colonoscopy and cross-sectional imaging) should be considered to exclude an underlying caecal or appendiceal tumour.

How does GMJ News cover appendicitis?

GMJ News covers pathogenesis and time course to perforation, the CODA trial and antibiotics-first as a shared-decision option, the appendicolith as a failure predictor, Alvarado and AIR scoring, clinical signs (McBurney, Rovsing, psoas, obturator), imaging strategy by age and sex, appendicitis in pregnancy and fetal loss rates, paediatric perforation rates, laparoscopic vs open appendicectomy, negative appendicectomy and the gynaecological differential, appendiceal mass management, and appendiceal neoplasms. Directly relevant to PHIG's emergency surgery and essential surgical care programme.

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Appendicitis

GMJ News knowledge hub · last reviewed August 2026 · Georgian Medical Journal

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Acute appendicitis — inflammation of the vermiform appendix, usually from luminal obstruction by a faecolith, lymphoid hyperplasia or (rarely) tumour — is the most common surgical emergency worldwide, with a lifetime risk of approximately 7-8% and peak incidence in the second and third decades of life (WHO). The most significant recent development is the emergence of a genuine non-operative alternative: the CODA trial (NEJM 2020) demonstrated that antibiotics were non-inferior to appendicectomy at 30 days for uncomplicated appendicitis, though approximately 40% of antibiotic-treated patients had undergone appendicectomy by four years and the presence of an appendicolith substantially increased failure — establishing antibiotics-first as a legitimate shared-decision option rather than a replacement for surgery, while perforated appendicitis, diagnostic uncertainty in women of reproductive age, and the elderly (in whom appendiceal malignancy must be considered) continue to require operative management.

Key messages

The most common surgical emergency worldwide — lifetime risk 7-8%

Acute appendicitis is the commonest abdominal surgical emergency globally, with a lifetime risk of approximately 7-8% and peak incidence in the second and third decades. Pathogenesis: luminal obstruction (faecolith, lymphoid hyperplasia following viral illness, and — importantly in patients over 40 — tumour) → mucus accumulation → raised intraluminal pressure → venous congestion → bacterial invasion → mucosal ischaemia → transmural inflammation → gangrene → perforation. The classical time course from onset to perforation is approximately 36-72 hours, but is highly variable and much faster in young children.

CODA trial — antibiotics-first is a legitimate option, not a replacement

The CODA trial (NEJM 2020, 1,552 patients) found antibiotics non-inferior to appendicectomy at 30 days for uncomplicated appendicitis, using a general health status measure. However: approximately 30% of antibiotic-treated patients underwent appendicectomy within 90 days, rising to approximately 40% by four years; and the presence of an APPENDICOLITH substantially increased failure (approximately 41% appendicectomy by 30 days). Antibiotics-first is therefore a legitimate shared-decision option for selected patients with uncomplicated appendicitis without an appendicolith — but patients must be counselled that the appendix remains and a substantial minority will need surgery later.

Classical migratory pain is present in only about half of patients

The textbook sequence — periumbilical visceral pain (T10 referred, from midgut appendiceal distension) migrating to the right iliac fossa as parietal peritoneum becomes involved, with anorexia, nausea and low-grade fever — is present in only approximately 50-60% of cases. Atypical presentations are the rule in: retrocaecal appendix (flank or back pain, less abdominal tenderness, positive psoas sign); pelvic appendix (suprapubic pain, diarrhoea, urinary frequency, tenderness only on rectal examination); pregnancy (the appendix is displaced upward and laterally by the gravid uterus); the elderly (minimal signs, normal inflammatory markers, high perforation rate at presentation); and young children.

Imaging strategy is age- and sex-dependent

Adult men: clinical assessment plus scoring often suffices; CT where diagnosis is uncertain. Women of reproductive age: the differential (ectopic pregnancy, ovarian torsion, ruptured cyst, PID, tubo-ovarian abscess) is wide and the historical negative appendicectomy rate was as high as 20-40% — pregnancy test is mandatory, and ultrasound is first-line, with MRI or CT as needed. Children: ultrasound FIRST to avoid ionising radiation, with MRI second-line; CT only if these are non-diagnostic and the clinical need is high. Pregnancy: ultrasound first, then MRI (no ionising radiation; high accuracy) — appendicitis is the most common non-obstetric surgical emergency in pregnancy and perforation substantially increases fetal loss.

Appendiceal tumours — always send the specimen, and reconsider in over-40s

Neoplasms are found in approximately 1% of appendicectomy specimens: neuroendocrine tumours (the commonest — usually incidental, tip location, <1cm requires no further treatment; >2cm or mesoappendiceal invasion requires right hemicolectomy); appendiceal adenocarcinoma; low-grade appendiceal mucinous neoplasm (LAMN — which can cause pseudomyxoma peritonei if it perforates, so must never be treated casually); and goblet cell adenocarcinoma. Clinical implications: every appendicectomy specimen must go to histopathology; and in patients over 40 presenting with appendicitis — particularly with an appendiceal mass, or after non-operative management — interval colonoscopy and/or imaging should be considered to exclude a caecal or appendiceal tumour causing obstruction.

Appendiceal mass and abscess — conservative first, then reassess

A patient presenting late (typically 5+ days) with a palpable right iliac fossa mass has usually walled off the inflammation with omentum and adjacent bowel. Management: initial non-operative treatment (IV antibiotics, with percutaneous drainage if there is a drainable abscess >3-4cm) is preferred to immediate appendicectomy, which in this setting is technically difficult and carries higher morbidity including the risk of requiring ileocaecal resection. Interval appendicectomy is no longer routine — but interval investigation IS important in adults, especially over 40, because caecal carcinoma and Crohn's disease both present exactly this way.

Key statistics

7-8%

lifetime risk of acute appendicitis — the commonest abdominal surgical emergency

WSES/WHO

CODA 2020

antibiotics non-inferior to appendicectomy at 30 days for uncomplicated appendicitis (NEJM)

NEJM 2020

~40%

of antibiotic-treated patients had undergone appendicectomy by 4 years (CODA follow-up)

JAMA Surg/NEJM

Appendicolith

substantially increases antibiotic failure — favours upfront appendicectomy

CODA/NEJM 2020

~50-60%

of patients have the classical migratory pain — atypical presentation is common

WSES

~1%

of appendicectomy specimens contain a neoplasm — always send for histology

WSES/ESMO

Appendicitis — diagnostic imaging strategy by patient group (WSES/ACR)

Source: WSES/ACR. Ultrasound and MRI are preferred in children and pregnancy to avoid ionising radiation.

Glossary of key terms

Alvarado score and AIR score
Clinical scoringAlvarado score (MANTRELS, max 10): Migration of pain to RIF (1); Anorexia (1); Nausea/vomiting (1); Tenderness in RIF (2); Rebound tenderness (1); Elevated temperature ≥37.3°C (1); Leukocytosis >10×10⁹/L (2); Shift to the left/neutrophilia >75% (1). Score ≤4: appendicitis unlikely — consider discharge or alternative diagnosis. 5-6: equivocal — imaging. ≥7: high probability — surgical assessment. The Appendicitis Inflammatory Response (AIR) score adds CRP and performs better than Alvarado in several validation studies, particularly in women and children. Scores are decision AIDS to stratify who needs imaging or admission — they do not replace clinical assessment and should never be used alone to exclude appendicitis in a patient who looks unwell.

Clinical signs in appendicitis
ExaminationMcBurney's point: maximal tenderness one third of the distance from the right anterior superior iliac spine to the umbilicus. Rovsing's sign: palpation of the LEFT iliac fossa elicits pain in the RIGHT iliac fossa. Psoas sign: pain on passive extension of the right hip — suggests a retrocaecal appendix lying on the psoas muscle. Obturator sign: pain on internal rotation of the flexed right hip — suggests a pelvic appendix adjacent to the obturator internus. Rebound tenderness and percussion tenderness: indicate peritoneal irritation (percussion tenderness is kinder and equally informative). Guarding and rigidity: perforation with peritonitis. None of these signs is sufficiently sensitive or specific alone; their value is cumulative.

Laparoscopic vs open appendicectomy
Surgery/CochraneLaparoscopic appendicectomy is now the standard approach in most settings. Cochrane evidence: lower wound infection rates, less postoperative pain, shorter hospital stay and faster return to normal activity compared with open appendicectomy — at the cost of a higher rate of intra-abdominal abscess in some analyses (particularly in perforated appendicitis) and longer operative time. It offers a clear diagnostic advantage in women of reproductive age (full pelvic inspection) and in obese patients. Open appendicectomy (Lanz or gridiron incision) remains entirely appropriate where laparoscopy is unavailable, in haemodynamic instability, or in extensive adhesions — an important consideration for resource-limited settings.

Appendicitis in pregnancy
Obstetrics/SurgeryAppendicitis is the most common non-obstetric surgical emergency in pregnancy (approximately 1 in 1,500 pregnancies). Diagnosis is difficult: the appendix is displaced superiorly and laterally by the gravid uterus (pain may be right upper quadrant in the third trimester); nausea, vomiting and mild leukocytosis are physiological in pregnancy; and peritoneal signs are blunted by the interposed uterus. Imaging: ultrasound first; MRI second (no ionising radiation, high accuracy) — CT avoided where possible but not absolutely contraindicated if essential. Key principle: the risk of NEGATIVE appendicectomy is far lower than the risk of PERFORATION — perforated appendicitis carries fetal loss rates of approximately 20-35% compared with approximately 2-5% for uncomplicated appendicitis. Delay to avoid surgery is the greater danger.

Negative appendicectomy and the diagnostic differential
SurgeryNegative appendicectomy (a normal appendix removed) historically occurred in 15-30% of cases, and remains highest in women of reproductive age. Increased use of CT and ultrasound has reduced this to approximately 5-10% in well-resourced settings. Key differentials to consider before operating: gynaecological (ectopic pregnancy — always do a pregnancy test; ovarian torsion; ruptured ovarian cyst; PID; tubo-ovarian abscess; mittelschmerz); gastrointestinal (mesenteric adenitis — especially in children after viral illness; Crohn's ileitis; Meckel's diverticulitis; caecal diverticulitis; infectious ileocolitis — Yersinia, Campylobacter); urological (ureteric colic; UTI/pyelonephritis; testicular torsion referring to the abdomen — always examine the scrotum in boys and men); and medical mimics (diabetic ketoacidosis, lower lobe pneumonia in children).

Paediatric appendicitis
Paediatrics/SurgeryChildren present the greatest diagnostic difficulty and the highest perforation rates — approximately 30% overall, and over 80% in children under 5 — because history is limited, examination is difficult, and progression is faster (thinner appendiceal wall, less developed omentum to wall off perforation). Presentation may be dominated by vomiting, diarrhoea or lethargy, and is frequently mistaken for gastroenteritis — a diagnosis that should be made with great caution in a child with abdominal pain preceding vomiting (in gastroenteritis, vomiting usually precedes pain). Scoring: Paediatric Appendicitis Score (PAS) or the Alvarado score. Imaging: ultrasound first-line; MRI where available; CT reserved for non-diagnostic cases given cumulative lifetime radiation risk in children.

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