Abscess drainage and minor procedures — branching viva

Opening question

This 6-year-old presents with a 4 cm tender, fluctuant, pointing lump on the thigh and surrounding cellulitis. Walk me through how you would assess the child before draining it, and tell me exactly what would make you refer for urgent surgical exploration rather than drain it in the treatment room. [1]

Branch 1 — anaesthesia, the weight-based dose, and the prevention of LAST

You have decided to drain it. Describe the analgesia plan, give me the weight-based maximum dose of plain lidocaine for this 22 kg child and the corresponding volume of one-percent lidocaine, and tell me how you would recognise and manage local anaesthetic systemic toxicity if it developed during infiltration. [3]

Branch 2 — the loop technique versus packing, and the indications for adjuvant antibiotics

Describe the drainage technique you would use for this 4 cm abscess, including how you decide between classical incision and drainage with packing and the loop drainage technique. Then defend your decision on adjuvant antibiotics — when are they indicated, and what would you choose? [2]

Branch 3 — the red flags of necrotising fasciitis

Suppose instead this child had presented with rapidly evolving induration, exquisite pain out of proportion to the visible skin findings, and a heart rate of 150 with cool peripheries. What has happened, what is the immediate management, and why is office drainage contraindicated? [1]

Closing — perianal abscess in a male infant

Finally, picture a 4-month-old male infant with a 1.5 cm fluctuant swelling at the anal margin. What is the most likely diagnosis, what is the natural history, and what is the role of drainage versus surgical referral? [4]