Background

Hereditary angioedema (HAE) is a rare genetic disease caused by a deficiency of C1 esterase inhibitor (C1-INH). Mutations in SERPING1 gene can cause low C1-INH levels (type 1) or a non-functioning C1-INH protein (type 2), ultimately leading to bradykinin accumulation and consequent vasodilatation and vascular oedema. HAE is characterized by recurrent episodes of angioedema of the skin, gastrointestinal tract, and respiratory tract. Flares can be triggered by trauma, infection, cold and emotional stress, among others. Laryngeal oedema with upper airway obstruction and shock are anaesthesiologist’s main concerns.

Case Report

54-year-old male, ASA III (type 2 HAE, rheumatoid arthritis, myocardial infarction 19 years ago) proposed for urgent reconstructive left hand surgery after a knife accident.

He was regularly medicated with danazol, etanercept, methotrexate and folic acid. No predictors of difficult airway found. 1000U of plasma-derived C1-INH concentrate were administered prophylactically two hours before surgery. Two additional doses were kept ready in the OR.

We successfully performed an ultrasound-guided axillary brachial plexus block with ropivacaine 0,75% and lidocaine 2% (total volume of 30 mL). Active warming and sedation with midazolam and fentanyl were achieved. A difficult airway trolley was kept available throughout the procedure. Surgery lasted one hour and was uneventful. The patient was then transferred to the PACU. No flares occurred, and he was discharged home one day later.

Discussion

HAE perioperative management challenges even the most experienced anaesthesiologist.

Preoperatively, even in urgent cases, short-term flare prophylaxis should be performed with C1-INH concentrate. Potential triggers should be avoided during the perioperative period. When HAE patients present with trauma, perioperative flare risk is theoretically higher than in patients proposed for elective surgery.

Intraoperatively, general anaesthesia and endotracheal intubation should be avoided, although difficult airway equipment should be available. Regional anaesthesia should be preferred when suitable. Sedation helps on emotional stress management. Anaesthetic drugs are safe. Adrenaline, corticosteroids and antihistamines are ineffective in angioedema episodes.

Learning points

Anaesthetic management in HAE patients includes identifying triggers for angioedema episodes, minimizing airway manipulation and administering prophylactic therapy with C1-INH.

06 / Brachial plexus block for urgent surgery in Hereditary Angioedema