Acquired Angioedema | Causes, Symptoms & Treatments

Introduction

Acquired angioedema (AAE) is defined as a deficiency in the C1 esterase inhibitor.

It is a rare disorder characterized by recurring angioedema without urticaria that may be linked to lymphoproliferative disorders (LPD).

It can cause severe abdominal pain that mimics an acute surgical abdomen.

Clinically, it is characterized by recurrent episodes of edema of the face, extremities, and genitalia as well as swelling of the mucosa of the gastrointestinal tract and the upper airways.

The swellings are painful and interfere with daily activities, and edema of the upper airways can be fatal.

Acquired angioedema is classified into two types: AAE-I and AAE-II.

AAE-I has been linked to a number of other diseases, the most common of which are B-cell lymphoproliferative disorders.

AAE-II can be defined by the presence of an autoantibody directed against the C1-inhibitor molecule.

Differentiating AAE-I from AAE-II is vital because each type requires different therapeutic interventions.

Causes of Acquired Angioedema

AAE results from an acquired deficiency of (C1-INH), which can be caused by consumption (type 1) or inactivation (type 2).

This increased catabolism can be caused by an autoimmune disorder (such as systemic lupus erythematosus) or a malignant tumor (such as lymphoma).

Swelling episodes can be triggered by a variety of factors, including mild trauma (such as dental work), viral illness, cold exposure, pregnancy, certain foods, or emotional stress.

When Do Symptoms of Acquired Angioedema Begin?

Symptoms of this disease may start to appear as an Adult.

Symptoms of Acquired Angioedema

The primary symptom is swelling usually affects the face, mouth, and upper airways which can be severe. Itching and urticaria don’t occur.

AAE patients may experience swelling of the lips, tongue, limbs, or genitalia.

Patients may experience edema of the upper airway, which can be fatal, as well as edema of the lining of the digestive tract, which can result in nausea and abdominal pain.

Diagnosis of Acquired Angioedema

Measurement of complement levels

Clinicians should suspect acquired C1 inhibitor deficiency or hereditary angioedema if angioedema is not accompanied by urticaria, recurs without apparent cause, or is triggered by local trauma.

Clinicians should consider hereditary angioedema if family members have it

Measurements of the levels of C4, C1 inhibitor, and C1q (a component of C1).

Hereditary angioedema (types 1 and 2) or acquired C1 inhibitor deficiency is confirmed by: –

Low C4 levels, even between episodes.
Decreased C1 inhibitor level or function.

Other findings include

Acquired C1 inhibitor deficiency: Low C1q levels.

Treatment of Acquired Angioedema

Acute attacks can be resolved by administering plasma-derived or recombinant C1-INH, but some patients experience non-responsiveness.

Icatibant, a bradykinin B2 receptor antagonist, has been shown to alleviate AAE symptoms and was well tolerated.

Ecallantide, a potent bradykinin pathway inhibitor, has also shown promise in the treatment of AAE, it is also considered another treatment option for patients who have developed resistance to C1-INH replacement.

If neither of these treatments is available, fresh frozen plasma (FFP) may be used.

It is also important to remember that treating an underlying causative condition can lead to an improvement in AAE.

Rituximab efficacy has been shown to be variable in AAE.

Unfortunately, standard epinephrine, corticosteroid, and antihistamine regimens do not have much effect on AAE and are not recommended for this medical condition.

Summary