Screening for hereditary angioedema (HAE) at 13 emergency centers in Osaka, Japan: A prospective observational study

Abstract

Hereditary angioedema (HAE) with deficiency of C1 inhibitor (C1-INH) is an autosomal-dominant disease characterized by recurrent episodes of potentially life-threatening angioedema. The objective is to study the incidence of HAE among patients who visit the emergency department.This was a 3-year prospective observational screening study involving 13 urban tertiary emergency centers in Osaka prefecture, Japan. Patients were included if they met the following criteria: unexplained edema of the body, upper airway obstruction accompanied by edema, anaphylaxis, acute abdomen with intestinal edema (including ileus and acute pancreatitis), or asthma attack. C1-INH activity and C4 level were measured at the time of emergency department admission during the period between July 2011 and June 2014.This study comprised 66 patients with a median age of 54.0 (IQR: 37.5-68.3) years. Three patients were newly diagnosed as having HAE, and 1 patient had already been diagnosed as having HAE. C1-INH activity levels of the patients with HAE were below the detection limit (<25%), whereas those of non-HAE patients (n = 62) were 106% (IQR: 85.5%-127.0%) (normal range, 70%-130%). The median level of C4 was significantly lower in the patients with HAE compared with those without HAE (1.2 [IQR: 1-3] mg/dL vs 22 [IQR: 16.5-29.5] mg/dL, P < 0.01) (normal range, 17-45 mg/dL).Three patients with undiagnosed HAE were diagnosed as having HAE in the emergency department during the 3-year period. If patients have signs and symptoms suspicious of HAE, the levels of C1-INH activity and C4 should be measured.

Figure 1

Photographs of a patient with hereditary angioedema (Case 1). Facial edema was apparent on admission (side view, A; front view, B). Facial edema had completely resolved by day 8 (side view, C; front view, D).

Figure 2

Neck CT images during an attack of hereditary angioedema (Case 1). On admission, facial edema was apparent, and she had difficulty in speaking. CT examination revealed laryngeal edema (transverse plane, A; coronal plane, B), and the risk of airway obstruction was present. Arrow, laryngeal edema. CT = computed tomography.

Figure 3

Abdominal CT images during an attack of hereditary angioedema (Case 2). On admission, the patient had abdominal pain and vomiting. Abdominal CT examination revealed intestinal edema (arrow) and ascites (arrowheads). The physician suspected an attack of HAE on the basis of these images and the patient's medical history. CT = computed tomography, HAE = hereditary angioedema.