Appendicitis and the acute abdomen — when to seek emergency care

What appendicitis is and why prompt recognition matters

Appendicitis is inflammation of the appendix vermiformis — a small finger-like pouch attached to the large bowel in the right lower abdomen. It is the most common abdominal surgical emergency in Australia, with approximately 36,000 appendicectomies performed each year and a lifetime risk of roughly 7 per cent. It occurs at all ages but peaks between ages 10 and 30.

The danger of appendicitis is progression to perforation — rupture of the appendix with leakage of faecal contents into the abdominal cavity. Perforation risk rises sharply after 24 hours of untreated symptoms and approaches 30 per cent in adults and higher in children and elderly people. Perforated appendicitis carries substantially greater morbidity, longer hospital stays, and higher surgical complication rates than uncomplicated appendicitis.

The GP role in suspected appendicitis is not to diagnose and manage the condition independently — it is to recognise the clinical pattern, assess urgency using a validated triage score, arrange urgent emergency department transfer, and provide appropriate supportive care while awaiting transfer.

A. Core clinical — the AU general-practice framework

The classic clinical presentation

The textbook sequence of appendicitis, present in approximately 50 per cent of cases:

1. Central or periumbilical abdominal pain — initial visceral pain, dull and poorly localised, often around the navel. This reflects the midgut embryological origin of the appendix and T10 visceral nerve supply.
2. Pain migrates to the right iliac fossa (right lower abdomen) over 12–24 hours as inflammation reaches the parietal peritoneum, producing localised somatic pain.
3. Anorexia — present in approximately 70 per cent; absence does not exclude appendicitis.
4. Nausea and vomiting — occurring after the pain begins. In gastroenteritis, vomiting typically precedes or accompanies the onset of pain — a useful discriminator.
5. Low-grade fever (typically 37.5–38.5°C). A high fever above 38.5°C suggests perforation, pelvic abscess, or an alternative diagnosis.
6. Constipation more often than diarrhoea (loose stool can occur with a pelvic appendix abutting the bowel).

Atypical presentations are common in children (diffuse abdominal pain, high fever), elderly people (minimal localisation, less fever, less leucocytosis), pregnant women (the gravid uterus displaces the appendix superiorly and laterally), and patients with a retrocaecal appendix position.

History

In addition to the pain history (onset, migration pattern, character — colicky versus constant; aggravating factors — movement worsens peritonitic pain, and patients with peritonism characteristically lie still and avoid movement):

• In all women of reproductive age: last menstrual period, contraception method, sexual history, and vaginal bleeding or discharge. An ectopic pregnancy must be excluded with a urine or serum beta-hCG before attributing abdominal pain to appendicitis.
• Urinary symptoms: frequency or dysuria can indicate a pelvic appendix abutting the bladder, or a coincident urinary tract infection (itself a common differential).
• Past surgical history: prior appendicectomy excludes appendicitis but stump appendicitis is a rare cause of right iliac fossa pain post-appendicectomy.
• Drug history: anticoagulants (raised bleeding risk), NSAIDs (peptic perforation differential), corticosteroids (can mask abdominal signs).

Examination

• Vital signs first. Tachycardia (heart rate above 100), hypotension, or temperature above 38.5°C indicate a sicker patient requiring urgent transfer. In a young person with tachycardia and abdominal pain, sepsis must be in the differential.
• Abdominal examination: start away from the site of maximal pain; assess for localised versus generalised tenderness; assess for guarding (voluntary muscle tensing), rigidity (involuntary), and rebound or percussion tenderness (more reliable than rebound in many patients).
• McBurney’s point: point of maximal tenderness approximately one-third of the distance from the anterior superior iliac spine to the navel on the right.
• Rovsing sign: palpation of the left lower abdomen reproduces pain in the right lower abdomen — indicates peritoneal irritation.
• Psoas sign: pain on extension of the right hip suggests a retrocaecal appendix.
• Obturator sign: pain on internal rotation of the flexed right hip suggests a pelvic appendix.
• Mandatory: urinalysis (pyuria, haematuria, ketones), and urine beta-hCG in any woman of reproductive age.

The Alvarado score — a GP triage tool

The Alvarado score is a 10-point clinical scoring system validated for stratifying appendicitis probability, originally described in 1986 and supported by the Ohle BMC Medicine 2011 systematic review:

Clinical element	Points
Migratory right iliac fossa pain	1
Anorexia	1
Nausea or vomiting	1
Tenderness in the right iliac fossa	2
Rebound tenderness	1
Elevated temperature (≥ 37.3°C)	1
Leucocytosis on FBC (WCC > 10 × 10⁹/L)	2
Left shift of white cell differential	1

Interpretation:

• 0–4: appendicitis unlikely — rule-out sensitivity approximately 99 per cent; careful observation with specific safety-netting is appropriate
• 5–6: compatible with appendicitis; CT or same-day emergency department review indicated
• 7–10: probable or very probable appendicitis — urgent transfer

Limitations: lower specificity in women due to gynaecological mimics scoring several elements; the Paediatric Appendicitis Score (PAS) or AAS (Adult Appendicitis Score) are preferred alternatives in children.

B. Evidence — imaging, surgery, and the antibiotic debate

Imaging

Abdominal ultrasound is first-line for children, pregnant women, and thin adults. Sensitivity 70–80 per cent, specificity 80–90 per cent, operator-dependent. A non-compressible, aperistaltic, blind-ending tubular structure greater than 6 mm in diameter on the right with surrounding free fluid is diagnostic. A non-visualised appendix does not exclude the diagnosis.

CT abdomen and pelvis with intravenous contrast is the adult imaging gold standard: sensitivity and specificity approximately 95 per cent, identifying or excluding appendicitis and identifying alternative diagnoses. WSES Jerusalem 2020 guidelines support CT as routine in adults with uncertain diagnosis. Radiation dose is an accepted trade-off for diagnostic accuracy. Most major Australian emergency departments now initiate CT directly from the emergency department for adult presentations.

MRI abdomen is the alternative for pregnant women in whom ultrasound is non-diagnostic — avoids radiation, high sensitivity, but less available and slower than CT.

Surgery: laparoscopic versus open appendicectomy

Laparoscopic appendicectomy is the preferred approach and now accounts for over 85 per cent of appendicectomies in Australia. Cochrane review (Sauerland 2010) demonstrates shorter hospital stay, lower surgical site infection rates, and faster return to normal activity compared with open surgery. Intra-abdominal abscess rates are marginally higher with laparoscopy in some series but overall outcomes favour the laparoscopic approach.

Antibiotic-only management: the emerging evidence

Two landmark trials have established antibiotic-only treatment as an option for selected uncomplicated appendicitis:

• CODA trial (NEJM 2020): antibiotics non-inferior to appendicectomy at 30 days for uncomplicated appendicitis in adults
• APPAC trial (JAMA 2018): approximately 70 per cent avoided surgery at one year; 30 per cent required appendicectomy within one year, rising to approximately 40 per cent by five years

Key caveats for AU practice: laparoscopic appendicectomy remains the standard of care. Antibiotic-only management is an option for carefully selected adults with uncomplicated appendicitis (no perforation, no abscess, no faecolith on CT) who prefer to avoid surgery after thorough informed discussion about the 30–40 per cent risk of ultimately requiring appendicectomy. It is not suitable for paediatric cases or when CT shows complicated appendicitis.

Analgesia does not mask the diagnosis

A common clinical myth is that giving analgesia before surgical review “masks” signs of peritonism and delays diagnosis. Manterola and colleagues (Cochrane 2011) conclusively established that opioid analgesia does not impair diagnostic accuracy and significantly reduces patient distress. Ranji and colleagues (JAMA 2006) confirmed similar findings. Withholding analgesia from a patient with suspected appendicitis is not justified. Give paracetamol, and if severity warrants, parenteral opioid analgesia titrated to pain level.

C. The acute abdomen differential — conditions that must not be missed

Suspected appendicitis is one presentation within the broader syndrome of the acute abdomen — sudden or progressive abdominal pain potentially requiring urgent surgical assessment. The following life-threatening conditions must be considered and actively excluded:

Condition	Key discriminators
Ectopic pregnancy	Reproductive-age woman, missed period, positive beta-hCG; severe unilateral pelvic pain; haemodynamic compromise → 000 immediately
Ruptured abdominal aortic aneurysm	Older male, hypertension, pulsatile mass, back pain radiating to groin, haemodynamic collapse → 000 immediately
Mesenteric ischaemia	Pain out of proportion to examination findings; atrial fibrillation or vascular disease history; elevated lactate; CT angiography required
Perforated peptic ulcer	Sudden severe epigastric pain, board-like rigidity, free air on erect chest X-ray or CT
Ovarian torsion	Severe unilateral pelvic pain, vomiting, absent Doppler flow on transvaginal ultrasound; time-critical to preserve the ovary
Bowel obstruction	Distension, vomiting, absolute constipation, colicky pain, dilated loops on plain X-ray
Ruptured ovarian cyst	Sudden mid-cycle or post-coital onset; exclude ectopic with beta-hCG first
Diverticulitis	Older adult, left iliac fossa pain, constipation history
Mesenteric adenitis	Children; preceded by upper respiratory tract infection; diffuse tenderness; resolves spontaneously
PID / tubo-ovarian abscess	Cervical excitation on pelvic examination, vaginal discharge, fever, sexual history
Myocardial infarction	Older adults with cardiac risk factors presenting with epigastric or upper abdominal pain; ECG and troponin mandatory
Testicular torsion	Young male, acute testicular pain, absent cremasteric reflex; surgical emergency — 000

D. Australian operations

What to do in general practice while awaiting transfer

If appendicitis is clinically suspected (Alvarado ≥ 5 or clear clinical picture):

1. Nil by mouth — inform the patient not to eat or drink, including water, as surgery and general anaesthesia may be imminent
2. IV access if equipment available and skill present
3. IV fluid if available and patient dehydrated — Hartmann’s solution or 0.9% sodium chloride
4. Analgesia — paracetamol 1 g IV or oral; if severe, morphine 2.5–5 mg IV or SC titrated cautiously; fentanyl 25–50 micrograms IV as an alternative
5. Anti-emetic — ondansetron 4–8 mg IV or oral-dissolving tablet
6. Document time of symptom onset, time recognised, vital signs, Alvarado score, medications, allergies, fasting status, and beta-hCG result

MBS items

• Consultations: item 23/36/44 (Level B/C/D); urgent after-hours items 19/20 or 597–600 if applicable
• ECG: item 11707 — if older patient or epigastric pain to exclude myocardial infarction
• Abdominal ultrasound: item 55036 — for children or when initiating imaging in general practice before transfer; CT is usually ordered by the emergency department directly
• Post-operative follow-up: telehealth items 91890/91891 for wound review if clinically appropriate (12-month existing-relationship rule)

Referral and transfer

• Haemodynamically unstable, or signs of peritonism: call 000; do not transport in a private vehicle
• Suspected appendicitis (Alvarado ≥ 5, or consistent clinical picture): same-day emergency department presentation; phone ahead to the receiving ED with the patient’s details, vital signs, Alvarado score, and transfer status
• Equivocal presentation (Alvarado < 5, no red flags): safety-netting card with strict return criteria; reassess within 4–6 hours or arrange same-day ED review

What to send with the patient: vital signs, Alvarado score, urinalysis result, beta-hCG result, FBC and CRP if available, current medication list, allergy status, fasting status, and time of last food and drink.

Post-appendicectomy follow-up in general practice

Wound review at two to four weeks. Histology review is mandatory — approximately 1 per cent of appendicectomy specimens contain an incidental appendiceal neoplasm (carcinoid tumour, mucinous neoplasm, or adenocarcinoma). If a neoplasm is found on histology, urgent surgical or oncology referral is required.

Return-to-activity advice: sedentary work in 1–2 weeks; heavy lifting and vigorous exercise in 4–6 weeks for laparoscopic surgery; longer for open. Mental health screen if the presentation was traumatic (unexpected surgery, complicated recovery).

E. Special populations

Children. The classic migration of pain to the right iliac fossa is present in approximately half of paediatric cases. Younger children localise pain poorly; high fever and vomiting may dominate. The Royal Children’s Hospital Melbourne pre-referral guideline recommends low threshold for ED transfer. The Paediatric Appendicitis Score (PAS) is preferred over the Alvarado score for age under 16. Perforation rates in young children are high because of delayed presentation and an underdeveloped omentum that cannot contain leaking contents. First-line imaging in children is ultrasound to minimise radiation; CT is reserved for equivocal cases.

Pregnant women. The gravid uterus displaces the appendix superiorly and towards the right flank as pregnancy progresses. Pain localisation above the right iliac fossa in the second and third trimesters is expected. Peritoneal signs may be attenuated. Ultrasound is first-line (no radiation); MRI is the alternative when ultrasound is non-diagnostic. Perforation rates are higher because of diagnostic delay and the immunomodulatory effects of pregnancy. Laparoscopic surgery is safe in pregnancy and preferred in experienced hands.

Elderly people. Atypical presentation is the rule — minimal localising signs, modest fever, less pronounced leucocytosis — while perforation rates approach 70 per cent in those over 65. Comorbidities complicate surgical management. Maintain a low threshold for CT and early specialist referral in older adults with any unexplained abdominal pain.

Aboriginal and Torres Strait Islander communities in remote areas. Distance to definitive surgical care increases the risk of delayed diagnosis and perforation. Low threshold for urgent retrieval via Royal Flying Doctor Service. Coordinate with ACCHO and RFDS transfer pathways early. Closing the Gap PBS Co-payment applies to post-operative medications.

When to escalate

Call 000 for immediate emergency ambulance if any of the following are present:

• Haemodynamic instability — heart rate above 120, low blood pressure, faintness
• Board-like abdominal rigidity (generalised peritonism)
• Visible abdominal distension with absolute constipation (bowel obstruction)
• Positive beta-hCG with pelvic pain and haemodynamic compromise (ectopic pregnancy)
• Sudden severe epigastric pain with peritonism (perforated ulcer or aortic aneurysm)
• Absent cremasteric reflex and acute testicular pain in a young male (testicular torsion)
• Acute severe unilateral pelvic pain with vomiting in a woman (ovarian torsion)

Arrange same-day emergency department transfer for:

• Alvarado ≥ 5 or clinical suspicion of appendicitis
• Severe, constant, or worsening abdominal pain not explained by reassurance
• Pregnant woman with right-sided or upper abdominal pain

What this article is and is not

This is general health information drawn from Therapeutic Guidelines (eTG), WSES Jerusalem 2020 guidelines, Royal Children’s Hospital Melbourne clinical guidelines, and peer-reviewed clinical trials. It does not constitute personal medical advice and does not establish a doctor–patient relationship. Diagnosis and treatment of suspected appendicitis and other acute abdominal emergencies must be assessed by a doctor or emergency department team.

For Australian consumer resources: HealthDirect — Appendicitis, Better Health Channel — Appendicitis, Royal Children’s Hospital Melbourne Kids Health Info — Appendicitis for paediatric information.

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Sources cited

1. Royal Australasian College of Surgeons — General surgery
2. Therapeutic Guidelines (eTG) — Acute abdomen and appendicitis
3. WSES Jerusalem guidelines — Acute appendicitis 2020
4. Royal Children’s Hospital Melbourne — Acute appendicitis pre-referral
5. Australian Medicines Handbook
6. HealthDirect — Appendicitis
7. Better Health Channel — Appendicitis
8. Alvarado A — Practical score for appendicitis (Ann Emerg Med 1986)
9. Ohle R et al. — Alvarado score systematic review (BMC Med 2011)
10. CODA trial — Antibiotics vs appendicectomy (NEJM 2020)
11. APPAC trial — Antibiotics vs appendicectomy (JAMA 2018)
12. Manterola C et al. — Analgesia in acute abdomen (Cochrane 2011)
13. Sauerland S et al. — Laparoscopic vs open appendicectomy (Cochrane 2010)