Abstract Objectives: To describe the hereditary angioedema to improve awareness of this condition and reduce diagnostic delay. Data sources: Relevant articles in the MEDLINE database through PubMed. Data synthesis: Hereditary angioedema is rare and has an autosomal dominant pattern of inheritance. Its onset occurs mainly in childhood, but there is an important delay in the diagnosis. In the most frequent phenotype, there is a quantitative and/or functional deficiency in the C1esterase inhibitor protein, which regulates the activation of the complement, contact and fibrinolysis systems with greater formation of bradykinin, the main mediator of angioedema. There is a third type, the hereditary angioedema with a normal C1 inhibitor level, which is rare in children. Clinical manifestations are characterized by recurrent angioedema attacks, mainly in the extremities, abdomen and upper airways, which can progress to asphyxia and death. The main triggers are mechanical trauma, infections and stress. The diagnosis is attained by patient clinical picture and decreased serum levels of C4 and C1esterase inhibitor or its function. In hereditary angioedema with a normal C1 inhibitor, there is no change in these parameters, thus requiring a genetic study. Treatment is based on the use of attack medications and long and short-term prophylaxis. Conclusions: Hereditary angioedema is little known by pediatricians due to the significant delay in diagnosis of this condition, whose onset usually begins in childhood. The presence of recurrent angioedema that does not respond to treatment with antihistamines, corticosteroids and adrenaline should increase the diagnostic suspicion.

RESUMO As crises de angioedema são causas comuns de atendimentos nas emergências, e devido ao potencial de gravidade, é importante que os profissionais que atuam nesses serviços conheçam suas causas e abordagem. Os mecanismos envolvidos no angioedema sem urticas podem ser histaminérgicos ou mediados por bradicinina. As causas mais comuns de angioedema mediado por histamina são alimentos, medicamentos, ferroada de insetos e idiopática. Quando o mediador é a bradicinina, os desencadeantes são os inibidores da enzima conversora de angiotensina e fatores relacionados ao angioedema adquirido com deficiência do inibidor de C1 ou angioedema hereditário que são menos comuns, mas muito importantes pela possibilidade de desfecho fatal. O angioedema hereditário é uma doença rara, caracterizada por crises de edema que acometem o tecido subcutâneo e mucosas de vários órgãos, manifestando-se principalmente por crises de angioedema e dor abdominal. Esse tipo de angioedema não responde ao tratamento usual com adrenalina, anti-histamínicos e corticosteroides. Assim, se não identificados e tratados adequadamente, esses pacientes têm risco de morte por edema de laringe estimado em 25% a 40%. O tratamento do angioedema hereditário mudou drasticamente nos últimos anos, com o desenvolvimento de novos e eficientes fármacos para as crises: inibidor de C1 derivado de plasma, inibidor de C1 recombinante humano, antagonista do receptor B2 da bradicinina (icatibanto) e o inibidor da calicreína (ecalantide). No Brasil, até o momento, estão liberados para uso o inibidor de C1 derivado de plasma e o icatibanto. O manejo correto desses pacientes na emergência evita cirurgias desnecessárias e, principalmente, desfechos fatais.

ABSTRACT Angioedema attacks are common causes of emergency care, and due to the potential for severity, it is important that professionals who work in these services know their causes and management. The mechanisms involved in angioedema without urticaria may be histamine- or bradykinin-mediated. The most common causes of histamine-mediated angioedema are foods, medications, insect sting and idiopathic. When the mediator is bradykinin, the triggers are angiotensin-converting enzyme inhibitors and factors related to acquired angioedema with deficiency of C1-inhibitor or hereditary angioedema, which are less common, but very important because of the possibility of fatal outcome. Hereditary angioedema is a rare disease characterized by attacks of edema that affect the subcutaneous tissue and mucous membranes of various organs, manifesting mainly by angioedema and abdominal pain. This type of angioedema does not respond to the usual treatment with epinephrine, antihistamines and corticosteroids. Thus, if not identified and treated appropriately, these patients have an estimated risk of mortality from laryngeal edema of 25% to 40%. Hereditary angioedema treatment has changed dramatically in recent years with the development of new and efficient drugs for attack management: plasma-derived C1 inhibitor, recombinant human C1-inhibitor, bradykinin B2 receptor antagonist (icatibant), and the kallikrein inhibitor (ecallantide). In Brazil, plasma-derived C1 inhibitor and icatibant have already been approved for use. Proper management of these patients in the emergency department avoids unnecessary surgery and, especially, fatal outcomes.

CONTEXTO E OBJETIVO: O angioedema hereditário (AEH) com deficiência de inibidor de C1 manifesta-se por episódios recorrentes de edema envolvendo pele, trato respiratório superior e gastrointestinal. Pode ser letal por asfixia. O objetivo foi avaliar a resposta à terapia dos ataques com icatibanto, inibidor do receptor de bradicinina, recentemente introduzido no Brasil.TIPO DE ESTUDO E LOCAL: Estudo experimental prospectivo de coorte, sem grupo controle, da eficácia e segurança do icatibanto em paciente com AEH.MÉTODOS: Pacientes com diagnóstico confirmado de AEH foram incluídos de acordo com os sintomas, independentemente do tempo de início do ataque. Icatibanto foi administrado segundo protocolo aprovado no Brasil. A gravidade do sintoma foi estabelecida continuamente e os eventos adversos foram monitorados.RESULTADOS: 24 ataques em 20 pacientes com AEH foram tratados (19 F:1 M; 19-55 anos; mediana 29 anos). Os sintomas foram: edema subcutâneo (22/24), dor abdominal (15/24) e obstrução de vias aéreas superiores (10/24). O tempo para o início do alívio foi: 5-10 minutos, 5/24 (20,8%); 10-20, 5/24 (20,8%); 20-30, 8/24 (33,4%); 30-60, 5/24 (20,8%) e 2 horas, 1/24 (4,3%). O tempo para a resolução completa variou de 4,3-33,4 horas. Somente efeitos adversos nos locais das injeções foram relatados. Eritema leve a moderado e/ou sensação de ardor foram relatados por 15/24 pacientes, prurido em 3, e 6 não tiveram efeitos adversos.CONCLUSÃO: Pacientes com AEH tipo I receberam icatibanto com pronta resposta; a maioria teve melhora na gravidade dos sintomas em 30 minutos. Eventos adversos locais ocorreram em 75% dos pacientes.

CONTEXT AND OBJECTIVE: Hereditary angioedema (HAE) with C1 inhibitor deficiency manifests as recurrent episodes of edema involving the skin, upper respiratory tract and gastrointestinal tract. It can be lethal due to asphyxia. The aim here was to evaluate the response to therapy for these attacks using icatibant, an inhibitor of the bradykinin receptor, which was recently introduced into Brazil.DESIGN AND SETTING: Prospective experimental single-cohort study on the efficacy and safety of icatibant for HAE patients.METHODS: Patients with a confirmed HAE diagnosis were enrolled according to symptoms and regardless of the time since onset of the attack. Icatibant was administered in accordance with the protocol that has been approved in Brazil. Symptom severity was assessed continuously and adverse events were monitored.RESULTS: 24 attacks in 20 HAE patients were treated (female/male 19:1; 19-55 years; median 29 years of age). The symptoms were: subcutaneous edema (22/24); abdominal pain (15/24) and upper airway obstruction (10/24). The time taken until onset of relief was: 5-10 minutes (5/24; 20.8%); 10-20 (5/24; 20.8%); 20-30 (8/24; 33.4%); 30-60 (5/24; 20.8%); and 2 hours (1/24; 4.3%). The time taken for complete resolution of symptoms ranged from 4.3 to 33.4 hours. Adverse effects were only reported at injection sites. Mild to moderate erythema and/or feelings of burning were reported by 15/24 patients, itching by 3 and no adverse effects in 6.CONCLUSION: HAE type I patients who received icatibant responded promptly; most achieved improved symptom severity within 30 minutes. Local adverse events occurred in 75% of the patients.