Appendicitis
Pain that moves to the right iliac fossa, fever and tenderness. Pregnancy test in every woman, score it, scan when unsure, antibiotics once likely, and get the surgeon.
A 22-year-old woman has had pain around the belly button since last night that has now moved to the lower right side. She has vomited twice and does not want to eat. Temperature 37.9 °C, tender with guarding in the right iliac fossa. Her last period was 6 weeks ago.
What must you check first, and what next?
- Pregnancy testIn every woman of child-bearing age, before anything else. Positive: think ectopic.
- Is she septic or peritonitic?Rigid abdomen, high fever, low BP: sepsis care and senior now.
- Pain relief and antiemeticMorphine does not hide the diagnosis. Give it.
- Bloods and urineCBC, CRP, urea, creatinine, electrolytes, urine dipstick. Group and save.
- Nil by mouth, IV fluidsUntil the surgical plan is made.
- Score itAlvarado or AIR score. Scan if intermediate.
- Antibiotics once appendicitis is likelyAfter the surgical review or as the plan is made.
- Surgical reviewEarly.
- Generalised peritonitis or rigid abdomen
- Septic or high lactate
- Positive pregnancy test
- Sudden one-sided pelvic pain with vomiting
- Older adult with right iliac fossa mass and weight loss
- Perforated appendicitis
- Ectopic pregnancy
- Ovarian torsion
- Testicular torsion in boys
- Caecal cancer in older adults
- Ileocaecal TB or typhoid perforation
| Pregnancy test | Every woman of child-bearing age |
| Alvarado 1–4 | Low risk: consider other causes, observe |
| Alvarado 5–6 | Intermediate: ultrasound or CT, surgical review |
| Alvarado 7–10 | High: surgical review for appendicectomy |
| Antibiotics | Once likely: ceftriaxone with metronidazole (doses in the treatment section) |
Check every dose against a current drug reference and your hospital protocol.
On this page
How it presents
- Hours 0–12Vague pain around the belly button, off food, nausea
- Hours 12–24Pain moves to the right iliac fossa, sharp, worse on moving or coughing
- Hours 24–72Risk of perforation: spreading pain, high fever, rigid belly
- Classic: central pain moving to the right iliac fossa, loss of appetite, nausea or vomiting, low-grade fever.
- Signs: tenderness at McBurney's point, guarding, rebound or pain on percussion, pain in the right iliac fossa when pressing on the left (Rovsing's sign). Pain on coughing or on the car ride in.
- Atypical: children (vague, vomiting, diarrhoea), the elderly (little pain, little fever, more perforation), pregnancy (pain higher up), a pelvic appendix (urinary symptoms, diarrhoea), a retrocaecal appendix (flank or back pain).
Scoring
- Migration of pain to the right iliac fossa: 1
- Anorexia: 1
- Nausea or vomiting: 1
- Tenderness in the right iliac fossa: 2
- Rebound tenderness: 1
- Elevated temperature (37.3 °C or more): 1
- Leucocytosis (white count above 10,000/µL): 2
- Shift to the left (neutrophils above 75%): 1
1–4 low risk, 5–6 intermediate, 7–10 high risk. The AIR score (which includes CRP) is an alternative many surgeons prefer.
Mimics
| Condition | Points towards it | Test that helps |
|---|---|---|
| Ectopic pregnancy | Missed period, positive test, shoulder tip pain, shock | Pregnancy test, ultrasound |
| Ovarian torsion or cyst | Sudden one-sided pelvic pain, vomiting | Pelvic ultrasound with Doppler |
| Pelvic inflammatory disease | Discharge, bilateral pain, cervical tenderness | Examination, swabs |
| Urinary infection or stone | Burning, loin pain, blood in urine | Urine dipstick, ultrasound |
| Gastroenteritis | Diarrhoea and vomiting first, then pain, no localised tenderness | Clinical |
| Mesenteric adenitis (children) | Recent sore throat, high fever, less localised tenderness | Ultrasound |
| Ileocaecal TB | Weeks of pain, weight loss, fever, mass | CT, colonoscopy |
| Typhoid | Fever over a week; perforation causes peritonitis | Blood culture |
| Caecal cancer | Older, weight loss, anaemia, mass | CT |
| Testicular torsion (boys) | Testicular pain, high-riding testis | Examine the testes |
| Meckel's diverticulitis | Similar picture, often younger | Found at surgery |
Investigations
| Test | Why |
|---|---|
| Pregnancy test | Every woman of child-bearing age |
| CBC, CRP | Inflammation. Normal values make appendicitis less likely but do not exclude it |
| Urine dipstick | UTI or stone. A pelvic appendix can cause some white cells in the urine |
| Ultrasound | First scan, especially in children, young women and pregnancy |
| CT abdomen and pelvis | Adults when the diagnosis is unclear, older patients, suspected mass or abscess |
| Group and save | If surgery is likely |
Treatment
Resuscitation, antibiotics, urgent surgery
- Appendicectomy (usually laparoscopic)
- Antibiotics alone is an option in selected adults: surgeon's decision
- Antibiotics, drainage of an abscess
- Surgery later if needed
- Older adults: colonoscopy or CT to exclude cancer
- Observe with repeat examination
- Scan
- Repeat bloods
Common mistakes
- Not doing a pregnancy test.
- Withholding painkillers "so the surgeon can examine".
- Sending home a vague right iliac fossa pain with no plan for review.
- Missing appendicitis in the elderly because there is little fever or pain.
- Forgetting to examine the testes in boys.
- Missing ileocaecal TB in a patient with weeks of symptoms and weight loss.
Frequently asked questions
What is the Alvarado score?
A score out of 10 using migration of pain, anorexia, nausea or vomiting, right iliac fossa tenderness (2 points), rebound, fever, raised white count (2 points) and neutrophil shift. 7 or more is high risk.
Which antibiotics are used for appendicitis?
Ceftriaxone with metronidazole, or co-amoxiclav, according to local policy. After surgery they are stopped for simple appendicitis and continued for 3–5 days if perforated.
Do painkillers mask appendicitis?
No. Morphine relieves pain without reducing the accuracy of diagnosis and should not be withheld.
Test yourself
Exam-style questions on this guide, from our two question banks. Choose an answer to see why each option is right or wrong.
1. A 22-year-old woman has right iliac fossa pain and missed her last period. What is the first test?
Answer: Urine pregnancy test. In every woman of reproductive age with abdominal pain, a pregnancy test comes first. If positive, consider ectopic pregnancy.
- CT abdomen: Not before excluding pregnancy.
- Stool culture: Not relevant.
- Ultrasound abdomen: Pregnancy test first.
- Blood culture: Not first.
2. A 68-year-old has a right iliac fossa mass after 6 days of pain, treated conservatively. What must be excluded later?
Answer: Caecal cancer. An appendix mass in an older adult may hide caecal cancer. Arrange colonoscopy or CT after recovery.
- Renal colic: Unlikely.
- Meckel's diverticulum: Rare at this age.
- Ovarian torsion: Not this picture.
- Crohn's disease only: Less likely at this age.
3. A 12-year-old boy has right lower abdominal pain and vomiting. Which examination must not be missed?
Answer: Examination of the testes. Testicular torsion can present as abdominal pain in boys who are embarrassed to mention scrotal pain.
- Fundoscopy: Not relevant.
- Hip examination only: Testes first.
- Rectal examination in all: Not routine in children.
- Chest auscultation only: Not enough.
4. In late pregnancy, where may the pain and tenderness of appendicitis be felt?
Answer: Right upper quadrant. Appendicitis is the commonest non-obstetric surgical emergency in pregnancy. The gravid uterus displaces the appendix upwards and laterally, so pain may be in the right flank or right upper quadrant in the third trimester; guarding is less obvious; WCC is physiologically raised. Ultrasound then MRI; laparoscopic appendicectomy is safe in all trimesters; perforation increases fetal loss.
- Left iliac fossa: The appendix is displaced upwards on the right, not to the left iliac fossa.
- Suprapubic region: The gravid uterus pushes the appendix up, away from the suprapubic region.
- Left upper quadrant: Pain stays on the right side, displaced upward.
5. An incidental 1 cm neuroendocrine (carcinoid) tumour is found at the tip of an appendix removed for appendicitis; margins clear, no mesoappendix invasion. What further management is needed?
Answer: No further treatment. Appendiceal neuroendocrine tumours are the commonest appendix tumours, often incidental at the tip. < 1 cm with clear margins: appendicectomy is curative. > 2 cm, base involvement, mesoappendiceal invasion > 3 mm, lymphovascular invasion or high grade → right hemicolectomy. Carcinoid syndrome rare (requires liver metastases). Mucinous appendiceal neoplasm → pseudomyxoma peritonei.
- Right hemicolectomy: For > 2 cm or adverse features.
- Adjuvant chemotherapy: A small appendiceal NET with clear margins needs no chemotherapy.
- Lifelong octreotide injections: Octreotide isn’t needed after complete excision of a small carcinoid.
6. Persistence of which embryonic structure forms Meckel's diverticulum?
Answer: Vitellointestinal duct. The vitelline duct connects the midgut to the yolk sac and normally disappears by week 7. If its intestinal end persists, it forms Meckel's diverticulum on the antimesenteric border of the ileum. It may contain gastric or pancreatic tissue and bleed.
- Urachus: A patent urachus causes urine leaking from the umbilicus.
- Allantois: Becomes the urachus.
- Ductus arteriosus: Becomes the ligamentum arteriosum.
- Notochord: Becomes the nucleus pulposus.
7. What is the most common position of the appendix, and which artery supplies it?
Answer: Retrocaecal; from the ileocolic. The appendix is most often retrocaecal (about 65%), then pelvic. The appendicular artery, a branch of the ileocolic artery (from the SMA), runs in the mesoappendix; it is an end artery, so thrombosis leads to gangrene and perforation. Retrocaecal appendicitis may give psoas sign; pelvic appendicitis may give obturator sign or urinary symptoms.
- Pelvic; from the right colic: Pelvic is second; right colic does not supply it.
- Subcaecal; from the middle colic: Not correct.
- Pre-ileal; from the SMV: A vein does not supply.
- Post-ileal; from the inferior epigastric: Not correct.
References and dose sources
- WSES Jerusalem guidelines on acute appendicitis (2020)
- WSES Jerusalem guidelines (2020)
- RCS England — commissioning guide: emergency general surgery
- Paracetamol dosing: Drugs.com: Acetaminophen (paracetamol) dosage (see also our paracetamol dose page)
- Morphine dosing: Drugs.com: Morphine dosage (see also our morphine dose page)
- Ondansetron dosing: Drugs.com: Ondansetron dosage (see also our ondansetron dose page)
- Ceftriaxone dosing: Drugs.com: Ceftriaxone dosage (see also our ceftriaxone dose page)
- Metronidazole dosing: Drugs.com: Metronidazole dosage (see also our metronidazole dose page)
- Co-amoxiclav (amoxicillin with clavulanic acid) dosing: Drugs.com: Amoxicillin/clavulanate dosage (see also our co-amoxiclav (amoxicillin with clavulanic acid) dose page)
International guidance is linked where it reflects good practice. Where your hospital’s protocol differs, follow your hospital.