Case studies · Surgery · 27 October 2026

Acute appendicitis case study

The case

Patient: A 22‑year‑old male university student, previously healthy, presents to the emergency department.

Presenting complaint: Abdominal pain for 48 hours.

History of present illness:

• Onset: Sudden, periumbilical pain that began 2 days ago while studying.
• Progression: Pain migrated to the right lower quadrant (RLQ) over the next 6 hours and has become constant and worsening.
• Associated symptoms: Nausea (no vomiting), low‑grade fever (recorded at home 37.8 °C), loss of appetite. No change in bowel habit, no dysuria, no urinary frequency.
• Aggravating factors: Movement, coughing, and lying supine.
• Relieving factors: Temporary relief when lying in the fetal position.

Past medical history: Unremarkable. No previous abdominal surgeries.

Medications: None.

Allergies: No known drug allergies.

Social history: Non‑smoker, occasional alcohol, no illicit drug use. Lives in a hostel, eats regular meals.

Family history: No hereditary diseases.

Examination:

Initial investigations:

Provisional diagnosis: Acute appendicitis (likely uncomplicated).

Questions

1. What is the most likely diagnosis and which clinical and investigational findings support it?
2. According to the latest guidelines, what are the recommended imaging modalities for suspected acute appendicitis in a young adult, and why was ultrasound chosen first in this case?
3. Outline the current (2023‑2024) management algorithm for uncomplicated acute appendicitis, including operative and non‑operative options.
4. What are the potential intra‑operative and post‑operative complications of an appendectomy, and how can they be prevented or recognized early?
5. If the patient’s condition deteriorates (e.g., develops peritonitis), how does the management plan change, and what additional investigations become essential?

Answers

1. Diagnosis and supporting findings

Diagnosis: Acute appendicitis (uncomplicated).

Why the diagnosis fits:

The combination of typical history, physical signs, laboratory inflammation, and sonographic evidence makes acute appendicitis the most probable diagnosis.

2. Recommended imaging modalities and rationale for ultrasound

Guidelines referenced:

• World Society of Emergency Surgery (WSES) 2020 consensus on diagnosis of acute appendicitis.
• American College of Radiology (ACR) Appropriateness Criteria 2022.
• NICE guideline NG125 (2021) for acute abdominal pain.

Imaging hierarchy for a young adult (≤40 years) with suspected appendicitis:

Why ultrasound was chosen first:

1. Age & body habitus: 22‑year‑old male, likely slim, providing good acoustic windows.
2. Radiation safety: Avoids unnecessary ionising exposure in a young patient.
3. Speed & accessibility: Can be performed at bedside, facilitating rapid decision‑making.
4. Guideline recommendation: Both WSES and NICE advise US as the first‑line imaging in children and young adults when expertise is available.

If US were inconclusive (e.g., due to obesity or atypical anatomy), a contrast‑enhanced CT would be the next step per the same guidelines.

3. Management algorithm for uncomplicated acute appendicitis (2023‑2024)

Step 1 – Resuscitation & baseline care

• Nil per os (NPO).
• Intravenous (IV) crystalloid 20 mL/kg isotonic saline if dehydrated.
• Analgesia: IV paracetamol 1 g; consider low‑dose opioid (e.g., morphine 2–4 mg) if pain severe.
• Antiemetics (ondansetron 4 mg IV) if nausea persists.

Step 2 – Decision on operative vs. non‑operative treatment

Step 3 – Operative management

• Laparoscopic appendectomy (3‑port technique).
• Prophylactic antibiotics: Cefazolin 2 g IV (or cefuroxime 1.5 g) administered within 60 min before incision; add metronidazole 500 mg IV if perforation suspected.
• Intra‑operative assessment: Look for gangrene, perforation, abscess.

Step 4 – Post‑operative care

• Early ambulation (within 6 h).
• Oral intake as tolerated (clear fluids → regular diet).
• Analgesia: Paracetamol ± NSAID (ibuprofen 400 mg PO q6h).
• Discharge criteria: Afebrile ≥24 h, tolerating oral intake, pain controlled with oral meds, ambulating.
• Follow‑up: Surgical clinic in 7‑10 days; advise to return for worsening pain, fever, vomiting.

Step 5 – Non‑operative pathway

• Admit for IV antibiotics for 24‑48 h, monitor vitals, pain, labs.
• If clinical improvement (pain ↓, afebrile, WBC normalising), switch to oral antibiotics and discharge.
• Educate patient on signs of failure (increasing pain, fever, vomiting) and arrange early review.

Evidence base: Meta‑analyses up to 2023 show comparable success rates (≈85‑90 %) for antibiotics alone in selected patients, but higher recurrence (≈20 % within 1 year) versus surgical cure. Hence surgery remains first‑line in most guidelines.

4. Intra‑operative and post‑operative complications

Prompt recognition relies on regular vital sign checks, pain assessment, wound inspection, and laboratory trends (WBC, CRP).

5. Management when the patient deteriorates (suspected perforation/peritonitis)

Clinical red flags: Persistent fever >38.5 °C, worsening abdominal pain despite analgesia, rigid abdomen, tachycardia >120 bpm, hypotension, leukocytosis >15 × 10⁹/L, rising lactate.

Re‑assessment steps:

1. Repeat focused examination – look for generalized peritonitis.
2. Laboratory panel: CBC, CRP, serum lactate, electrolytes, renal function, blood cultures.
3. Imaging: Contrast‑enhanced CT abdomen/pelvis (if not already done) to identify perforation, abscess, phlegmon, or free fluid.

Management changes:

• Broad‑spectrum IV antibiotics immediately (e.g., piperacillin‑tazobactam 4.5 g q6h or meropenem 1 g q8h) covering Gram‑negative, anaerobic, and aerobic organisms.
• Fluid resuscitation: Crystalloid bolus 30 mL/kg, then titrate to maintain MAP >65 mm Hg.
• Urgent surgical intervention: Open or laparoscopic appendectomy with peritoneal lavage; if extensive contamination, consider a staged approach (damage‑control surgery) with temporary abdominal closure.
• Post‑operative intensive care if septic shock develops: vasopressors, organ support, serial lactate monitoring.

Additional investigations:

• Serum lactate (baseline and 2‑hour trend) to gauge tissue hypoperfusion.
• Arterial blood gas for acid‑base status.
• Chest X‑ray (to rule out diaphragmatic irritation or free air under diaphragm).

Guidelines (Surviving Sepsis Campaign 2021, WSES 2020) emphasize early source control (appendectomy) within 6 hours of diagnosis in perforated appendicitis to reduce morbidity and mortality.

Key learning points

• Classic migration of pain from periumbilical region to RLQ, together with Rovsing’s, psoas, and rebound signs, strongly suggests acute appendicitis.
• Graded‑compression ultrasound is the first‑line imaging in young, non‑obese patients; a non‑compressible tubular structure >6 mm is diagnostic.
• Laparoscopic appendectomy remains the gold‑standard treatment for uncomplicated appendicitis, offering lower wound infection rates and faster recovery.
• Antibiotic‑only management is an acceptable alternative in selected patients, but carries a higher recurrence risk and requires close follow‑up.
• Early recognition of perforation or peritonitis (clinical deterioration, rising lactate, CT evidence) mandates broad‑spectrum antibiotics, aggressive fluid resuscitation, and urgent surgery.
• Common complications include intra‑abdominal abscess, wound infection, and postoperative ileus; prevention hinges on meticulous surgical technique and early mobilization.
• Post‑operative discharge criteria: afebrile ≥24 h, tolerating oral intake, pain controlled with oral analgesics, and ambulating independently.
• Adherence to current guidelines (WSES 2020, ACS 2022, NICE NG125 2021) ensures evidence‑based, patient‑centred care.

Practice MCQs

1. A 24‑year‑old woman presents with 12 h of RLQ pain, fever 38.5 °C, and a WBC of 13 × 10⁹/L. Ultrasound is inconclusive due to bowel gas. Which is the most appropriate next imaging step?

A. Repeat ultrasound after 6 h
B. Contrast‑enhanced CT abdomen/pelvis
C. MRI abdomen without contrast
D. No further imaging – proceed to surgery

Answer: B — In a young adult with inconclusive ultrasound, CT offers the highest sensitivity and specificity for appendicitis and can detect perforation or alternative diagnoses.

2. Which of the following laboratory findings is least specific for acute appendicitis?

A. Neutrophilic leukocytosis
B. Elevated C‑reactive protein (CRP)
C. Serum amylase elevation
D. Mild hyponatremia

Answer: C — Serum amylase elevation is more associated with pancreatitis; it is not a specific marker for appendicitis, whereas leukocytosis and CRP are inflammatory markers commonly raised in appendicitis.

3. According to the 2022 ACS guidelines, the recommended prophylactic antibiotic regimen for an uncomplicated laparoscopic appendectomy in a patient without penicillin allergy is:

A. Cefazolin 2 g IV pre‑incision only
B. Cefazolin 2 g IV pre‑incision + metronidazole 500 mg IV intra‑operatively
C. Piperacillin‑tazobactam 4.5 g IV pre‑incision only
D. No antibiotics are required for uncomplicated cases

Answer: A — For uncomplicated appendicitis, a single dose of cefazolin 2 g IV administered within 60 minutes before incision is sufficient prophylaxis per ACS 2022. Metronid

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