Allergic Bronchopulmonary Aspergillosis

Definition

Definition of Allergic Bronchopulmonary Aspergillosis
Allergic bronchopulmonary aspergillosis (ABPA) is an immunologic pulmonary disorder caused by hypersensitivity to Aspergillus fumigatus. Clinically, a patient presents with chronic asthma, recurrent pulmonary infiltrates, and bronchiectasis. The population prevalence of ABPA is not clearly known, but the prevalence in asthma clinics is reported to be around 13%. The disorder needs to be detected before bronchiectasis has developed because the occurrence of bronchiectasis is associated with poorer outcomes. Because many patients with ABPA may be minimally symptomatic or asymptomatic, a high index of suspicion for ABPA should be maintained while managing any patient with bronchial asthma whatever the severity or the level of control. This underscores the need for routine screening of all patients with asthma with an Aspergillus skin test. Finally, there is a need to update and revise the criteria for the diagnosis of ABPA. This review summarizes the advances in the diagnosis and management of ABPA using a systematic search methodology.

Symptoms

Symptoms of Allergic Bronchopulmonary Aspergillosis
Patients with allergic bronchopulmonary aspergillosis often have symptoms of poorly controlled asthma, with wheezing, cough, shortness of breath and exercise intolerance. They also have symptoms reminding of bronchiectasis, such as chronic sputum production, coughing up brownish mucoid plugs or even blood (the latter is called hemoptysis), and recurrent infections (with fever and malaise). However, since the infiltrates in ABPA indicate eosinophilic pneumonia, they do not respond to treatment with antibiotics. There may be unexplained worsening of asthma or cystic fibrosis.

Causes

Causes of Allergic Bronchopulmonary Aspergillosis
The disorder differs from typical pneumonias caused by bacteria, viruses, and most fungi, in that the fungus does not actually invade the lung tissue and directly destroy it. The fungus colonizes the mucus in the airways of people with asthma or cystic fibrosis (both of whom tend to have increased amounts of mucus) and causes recurrent allergic inflammation in the lung. The tiny air sacs of the lungs (alveoli) become packed primarily with eosinophils. Increased numbers of mucus-producing cells may also appear. If the disease has caused extensive damage, inflammation may cause the central airways to widen permanently, a condition called bronchiectasis. Eventually, the lungs are likely to become scarred.

Diagnosis

Diagnosis of Allergic Bronchopulmonary Aspergillosis
A complete blood count usually reveals eosinophilia more than 10% and there is a raised serum IgE more than 1000 ng/ml.

Chest radiography shows various transient abnormalities:

1. consolidation, infiltrates or collapse
2. thickened bronchial wall markings
3. peripheral shadows
4. signs of bronchiectasis, typically in a central location

Aspergillus specific tests:

1. precipitating antibodies to aspergillus species in >90% of cases
2. aspergillus-specific IgE RAST test
3. skin-prick test is almost always positive to Aspergillus fumigatus

Fungal hyphae may be seen in the sputum.

Treatment

Treatment of Allergic Bronchopulmonary Aspergillosis
The aim of treatment is to suppress the immune reaction to the fungus and to control bronchospasm.

The immune reaction is suppressed using oral corticosteroids:

1. a high dose of prednisolone or prednisone (30 to 45 mg per day) in acute attacks
2. a lower maintenance dose (5–10 mg per day)

Prognosis

Prognosis of Allergic Bronchopulmonary Aspergillosis
There is no current cure for ABPA, but management of the inflammation and scarring using itraconazole and steroids usually succeeds in stabilising the symptoms for many years.

Prevention

Prevention of Allergic Bronchopulmonary Aspergillosis
Consult with your doctor.