High-yield map
Key points before the detail
- 01
The appendiceal base is found where the three taeniae coli converge.
- 02
Classic pain migrates from central abdomen to the right iliac fossa.
- 03
Imaging strategy depends on probability, age and pregnancy.
- 04
Laparoscopic appendicectomy is standard for most patients.
- 05
Antibiotics-first treatment is selective and recurrence-aware.
1. Definition and mechanism
Luminal obstruction, lymphoid hyperplasia or faecolith-related stasis can raise intraluminal pressure, impair venous/lymphatic drainage and allow bacterial invasion. Clinical course is variable, so do not use a rigid time-to-perforation model.
2. Anatomy explains atypical symptoms
| Appendix position | Clinical consequence |
|---|---|
| Pelvic | Suprapubic pain, urinary frequency or diarrhoea. |
| Retrocaecal/retrocolic | Flank or back pain, less anterior peritonism, possible psoas sign. |
| Pre-/post-ileal | Central pain, vomiting or diarrhoea. |
| Base | Posteromedial caecum where the three taeniae coli converge. |
3. Presentation and differential
- Visceral T10 pain often starts centrally then localises to the RIF when parietal peritoneum inflames.
- Anorexia, nausea and low-grade fever are common; vomiting usually follows pain.
- RIF tenderness, guarding and pain on coughing raise probability but are not individually diagnostic.
- Older, pregnant and immunosuppressed patients may have muted or atypical signs.
4. Probability and imaging
- Use scoring systems as adjuncts, not replacements for judgement.
- A non-visualised appendix on imaging is not automatically normal; interpret secondary signs and clinical probability.
| Patient group | Preferred approach |
|---|---|
| Clinically well, low probability | Consider observation/reassessment or discharge only with clear safety-netting. |
| Intermediate probability adult | Cross-sectional imaging; CT is common in non-pregnant adults. |
| Child/young person | Ultrasound first where expertise is available; MRI/justified CT if non-diagnostic. |
| Pregnancy | Ultrasound first, then MRI when non-diagnostic. |
5. Uncomplicated appendicitis
- Laparoscopic appendicectomy is the standard operative approach for most patients.
- Give pre-operative broad-spectrum antibiotics according to local policy.
- Routine postoperative antibiotics are not needed after uncomplicated disease with adequate source control.
- Identify the appendix by following the taeniae coli and send the specimen for histopathology.
6. Antibiotics-first treatment is selective
Imaging-confirmed uncomplicated appendicitis can be treated non-operatively in selected patients, but recurrence and later appendicectomy remain possible.
- Exclude diffuse peritonitis, uncontrolled sepsis, abscess and suspected tumour.
- An appendicolith increases failure/complication risk and often favours appendicectomy.
- Ensure reliable follow-up and explain recurrence/readmission risk.
7. Complicated appendicitis
| Scenario | Management principle |
|---|---|
| Free perforation/generalised peritonitis | Resuscitation and urgent operative source control. |
| Stable localised abscess/phlegmon | Antibiotics, observation and image-guided drainage when appropriate; early laparoscopy is an expert alternative. |
| Failure of conservative care | Reassess and proceed to drainage or surgery. |
| Older adult or suspicious imaging | Assess for appendiceal/caecal neoplasm after recovery. |
Active recall
Close the notes and answer these
Try each question from memory before revealing the answer. These public prompts are a small preview of the integrated retrieval system inside SurgAtlas.
01Where is the appendiceal base found?
On the posteromedial caecum where the three taeniae coli converge.
02Why does appendicitis pain migrate?
Early visceral afferent pain is poorly localised centrally; later parietal peritoneal inflammation localises pain to the RIF.
03What is the usual first imaging test in pregnancy?
Ultrasound, followed by MRI if non-diagnostic.
04What is the standard operation for most appendicitis?
Laparoscopic appendicectomy.
05What feature makes antibiotics-first management less attractive?
An appendicolith, because it is associated with higher failure/complication risk.
Sources & editorial basis
References & editorial basis
- SurgAtlas production source. General Surgery — Acute Appendicitis. Public lesson curated from the corresponding production chapter.
- WSES Jerusalem Guidelines. Diagnosis and treatment of acute appendicitis — 2025 edition published 2026, as recorded in the SurgAtlas source register.
This lesson is derived from the corresponding SurgAtlas production teaching material. Where the source makes current management or guideline claims, the public lesson uses the cited contemporary guidance. It is written for education and examination preparation, not as patient-specific clinical advice.
Editorial details
Medical Doctor (MD) · MRCS Part A · Physician · Surgical Educator
SurgAtlas is an educational resource. For patient care, verify current national guidance, local antimicrobial and transfusion policies, specialty pathways and individual patient factors.
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