Acute Appendicitis (OSCE focused)

Candidate Instructions:You are the medical student in the Emergency Department. A 22-year-old patient presents with abdominal pain. Take a focused history and outline your most likely diagnosis, differential diagnoses, and initial management plan. You do not need to perform an examination at this station.

Key Areas to Cover ✅

• 📍 Site: Initially central/periumbilical, later localising to right iliac fossa.
• 🕒 Onset/Duration: Typically gradual over hours.
• 🔥 Character: Dull → sharp pain, worse on movement/coughing.
• 🤢 Associated Symptoms: Anorexia, nausea, vomiting, low-grade fever.
• 🚽 Bowel/Urinary: Constipation, diarrhoea, dysuria (pelvic appendix can irritate bladder).
• 📜 Risk factors: Young age, male sex, family history (weak association).

Examiner Prompts 💬

• “How would you differentiate appendicitis from other causes of RIF pain?”
• “What would be your immediate investigations?”
• “How would you manage this patient overnight?”

Differential Diagnoses 🔎

Mark Scheme (10 points) 📝

Investigations 🔬

• Bedside: Obs, urinalysis, pregnancy test (all women of childbearing age).
• Bloods: FBC (WCC/CRP), U&E, LFT, amylase, clotting, group & save.
• Imaging: Ultrasound (pelvis in females), CT abdo/pelvis if diagnostic doubt.

Management 🩺

• Resuscitation: IV access, fluids, analgesia, antiemetics.
• Nil by mouth pending surgical review.
• Antibiotics: IV broad-spectrum (e.g., co-amoxiclav or cefuroxime + metronidazole).
• Surgical: Laparoscopic appendicectomy is standard of care.
• If appendix normal at laparoscopy → look for Meckel’s diverticulum, ovarian pathology, ileitis.

Teaching Commentary 📚

This OSCE is testing your ability to identify a classic surgical emergency. Key marks come from recognising pain migration, always doing a pregnancy test in women, and suggesting IV fluids + antibiotics + urgent surgical review. Examiners reward clarity: say “This is most likely appendicitis, but in a female patient I would also urgently rule out ectopic pregnancy and ovarian torsion.” That phrase alone shows safety and scores very well.

🧑‍⚕️ Case Examples - Acute Appendicitis

• Case 1 (Typical Presentation): 🚨 A 19-year-old man presents with 24 hours of abdominal pain that began centrally and migrated to the right iliac fossa. He has nausea, low-grade fever, and guarding in the RIF. Bloods show raised WCC and CRP. Diagnosis: Classic acute appendicitis. Teaching point: Migratory pain (central → RIF) with local peritonism is highly suggestive; requires urgent appendicectomy.
• Case 2 (Perforated Appendicitis): 💥 A 30-year-old woman presents late with 4 days of abdominal pain, worsening fevers, and diffuse tenderness with rebound. She is tachycardic and hypotensive. CT abdomen shows perforated appendix with localised abscess. Diagnosis: Perforated appendicitis with peritonitis. Teaching point: Delayed presentation can lead to rupture; requires IV antibiotics, fluid resuscitation, and urgent surgery or percutaneous drainage if abscess walled off.
• Case 3 (Atypical Appendicitis in Pregnancy): 🤰 A 28-year-old woman at 22 weeks’ gestation presents with right-sided abdominal pain and nausea. The pain is more in the right upper quadrant due to upward displacement of the appendix. Ultrasound suggests appendicitis. Diagnosis: Acute appendicitis in pregnancy. Teaching point: Pregnancy alters appendix position; diagnosis can be delayed. Prompt surgical management is needed to prevent maternal and fetal complications.