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Adrenaline Systemic Absorption Symptoms — FRCA Final MCQ

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ModerateRegional AnaesthesiaAdrenaline Systemic Absorption SymptomsFRCA Final

A 35-year-old man (ASA I) undergoes excision of a lipoma under local anaesthesia. He develops anxiety, tremor, tachycardia, and light-headedness. The surgeon has infiltrated 30 mL of 1% lidocaine with adrenaline 1:200000. What is the most likely cause?

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Correct answer: D — Systemic absorption of adrenaline causing sympathomimetic effects

The symptoms (anxiety, tremor, tachycardia, lightheadedness) are most consistent with systemic absorption of adrenaline from the local anaesthetic solution. Adrenaline 1:200000 = 5 mcg/mL; 30 mL = 150 mcg adrenaline absorbed systemically. This can cause palpitations, tachycardia, tremor, and anxiety. The total lidocaine dose (300 mg) is within the safe limit with adrenaline (7 mg/kg = 490 mg for a 70 kg man). True LAST would present with perioral tingling, metallic taste, and visual disturbance first. Reassurance and monitoring are appropriate management.

Reference: BNF – 2025 – Local anaesthetic and adrenaline; RCOA – 2023 – Local anaesthetic pharmacology