Emergency Medicine

ALLERGIC OR IMMUNOLOGICAL CONDITIONS

General Medical Emergencies 111

Angioedema

DIAGNOSIS

1 This is an urticarial reaction involving the deep tissues of the face, eyelids,
lips, tongue and occasionally the larynx, often without pruritus.

2 The causes are as for urticaria, especially ACE inhibitors, aspirin or a bee
sting.

3 It may cause facial, lip and tongue swelling, progressing to laryngeal oedema
with hoarseness, dysphagia, dysphonia and stridor.

4 Attach a cardiac monitor and pulse oximeter to the patient.

5 A rare autosomal dominant hereditary form is due to C1 esterase inhibitor
deficiency. A family history of attacks without urticaria, often following
minor trauma, and recurrent abdominal pain are suggestive.

MANAGEMENT

1 Commence high-dose oxygen aiming for an oxygen saturation above 94%.

2 Give 1 in 1000 adrenaline (epinephrine) 0.3–0.5 mg (0.3–0.5 mL) i.m. into
the upper outer thigh, repeated as necessary.

3 Call the senior ED doctor urgently and prepare for intubation, if airway
obstruction persists.
(i) Give 1 in 1000 adrenaline (epinephrine) 2–4 mg (2–4 mL)
nebulized, repeated as necessary.
(ii) Change to 1 in 10 000 or 1 in 100 000 adrenaline (epinephrine)
0.75–1.5 g/kg i.v., i.e. 50–100 g or 0.5–1.0 mL of 1 in 10 000
or 5–10 mL of 1 in 100 000 adrenaline (epinephrine) slowly over
5 min i.v., if rapid deterioration occurs with imminent airway
obstruction. The ECG must be monitored.

4 Give H 1 and H 2 blockers and steroids, only after cardiorespiratory stability
has been achieved.
(i) Promethazine 12.5–25 mg i.v. slowly plus ranitidine 50 mg i.v.
(ii) Hydrocortisone 200 mg i.v.

5 Hereditary angioedema responds poorly to adrenaline (epinephrine). Give
urgent C1 esterase inhibitor i.v. or fresh frozen plasma.

6 Admit the patient when stable for 6–8 h observation, as late deterioration
may occur in up to 5% (k nown as biphasic anaphyla xis).

7 Then discharge home on prednisolone 50 mg once daily, loratadine 10 mg
once daily plus ranitidine 150 mg b.d., all orally for 3 days.
(i) Inform the GP by fax or letter.
(ii) Refer all significant or recurrent attacks to the allergy clinic,
especially if the cause is unavoidable or unknown.