Allergic bronchopulmonary aspergillosis
Allergic bronchopulmonary aspergillosis (ABPA) is an allergic lung disorder triggered by the fungus Aspergillus fumigatus. This condition is especially prevalent among individuals with pre-existing respiratory issues like asthma or cystic fibrosis. Inhalation of this common fungus, found in decaying vegetation, soil, and dust, leads to an allergic reaction that exacerbates respiratory symptoms, resulting in inflammation and potential damage to the lungs. Symptoms typically mirror those of progressive asthma, including shortness of breath, wheezing, and chest pain, with more severe cases potentially leading to bronchiectasis, characterized by the widening of the bronchi due to inflammation.
Diagnosing ABPA can be challenging, often requiring multiple tests to confirm its presence, as it shares similarities with non-ABPA-induced asthma. Treatment generally involves corticosteroids to suppress the allergic reaction and antifungal medications to manage the fungal infection. Due to the environmental prevalence of Aspergillus, complete avoidance is difficult; therefore, preventive measures focus on minimizing exposure and maintaining lung health through regular medical monitoring and treatment. Understanding the risk factors, symptoms, and treatment options is essential for managing this complex respiratory condition effectively.
Allergic bronchopulmonary aspergillosis
- ANATOMY OR SYSTEM AFFECTED: Lungs, respiratory system
Definition
Allergic bronchopulmonary aspergillosis (ABPA) is an allergic lung disorder. It is related to the fungus Aspergillus fumigatus (AF). ABPA can also occur as a lung infection that spreads to other parts of the body (more common in persons with suppressed immune systems) and as a fungal growth (aspergilloma) in a lung cavity that has healed from a previous lung disease or infection.
Causes
ABPA is caused by an allergic reaction to inhaled AF, a common fungus. AF grows and flourishes in decaying vegetation and in soil, certain foods, dust, and water. The allergic reaction worsens respiratory symptoms in people with asthma or cystic fibrosis. The inhaled AF colonizes mucus in the lungs, causing sensitization to AF, recurring allergic inflammation of the lungs, and packing of the alveoli (tiny air sacs in the lungs) with eosinophils (a type of white blood cell involved in certain allergic reactions and infections with parasites).
Risk Factors
Risk factors for ABPA include asthma; cystic fibrosis; tuberculosis; sarcoidosis; human immunodeficiency virus (HIV); acquired immunodeficiency syndrome (AIDS); lowered immune resistance, as occurs with certain cancers or chemotherapy, or after organ transplants; use of steroid or antimicrobial medications; and hospitalization.
Symptoms
Symptoms of ABPA are usually those of progressive asthma. These include shortness of breath, wheezing, weakness, malaise, unintended weight loss, and chest pain. As ABPA progresses, other symptoms may occur, including the production of thick, brownish, or bloody sputum and a low-grade fever. In severe, long-term cases, ABPA can cause bronchiectasis, the widening of areas of the bronchus usually caused by inflammation and scarring of the lungs.
Screening and Diagnosis
Screening includes a chest X-ray to check the lungs; immunological tests; blood tests for high levels of eosinophils and antibodies suggesting an allergic reaction to AF; skin prick tests for allergic sensitivity by placing small amounts of AF in the skin; and pulmonary function tests to monitor the breathing capacity of the lungs. An understanding of predisposing conditions is critical.
Because ABPA can appear similar to non-ABPA-induced asthma, it is often difficult to determine to what extent ABPA is contributing to symptoms. Therefore, ABPA is typically diagnosed after several repeat tests for ABPA are positive over a number of months or years.
Treatment and Therapy
The goals of treatment include suppressing the allergic reaction to AF, minimizing lung inflammation, and preventing AF from colonizing the lungs. ABPA is usually treated with two medications: prednisone (an oral corticosteroid medication) and antifungal drugs, such as itraconazole (Sporanox), amphotericin B, or voriconazole.
Prevention and Outcomes
Avoiding exposure to AF is the best way to prevent ABPA. However, this is difficult because AF is so prevalent in the environment. Guidelines to help prevent exposure to AF include avoiding areas with decaying vegetation and standing water; keeping the home as dust-free as possible; and remaining in air-filtered, air-conditioned environments whenever possible. Measures to avoid symptoms and prevent permanent lung damage caused by ABPA include ongoing testing and monitoring of ABPA and early and continuing medical treatment for the disease.
Bibliography
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