Allergic Bronchopulmonary Aspergillosis

Aka: Allergic Bronchopulmonary Aspergillosis, ABPA

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II. Epidemiology

  1. Worldwide Prevalence: 4 Million

III. Pathophysiology

  1. Immunologic disorder caused by Hypersensitivity to Aspergillus Fumigatus
    1. Aspergillus Fumigatus colonization of airways and mucus resulting in Asthma and Bronchiectasis
    2. A. fumigatus germinate into hyphae, resulting in T Cell response
    3. A. fumigatus is most common, but A. niger, A. flavus and A. clavatus may also cause ABPA
  2. Bronchial Asthma
    1. Due to IgE mediated Hypersensitivity (Type 1 Hypersensitivity Reaction)
  3. Bronchiectasis
    1. Due to immune complex deposition and cell mediated reaction in proximal airways (Type 4 Hypersensitivity)

IV. Risk Factors

  1. Cystic Fibrosis
  2. Asthma
  3. Immunocompromised State
  4. Genetic predisposition (esp. HLA-DR2 or HLA-DR5)

V. Symptoms

  1. General
    1. Anorexia
    2. Fatigue
    3. Generalized myalgias
    4. Low grade fever
    5. Weight loss
  2. Respiratory
    1. Wheezing (related to Asthma)
    2. Productive Cough
      1. Brown mucus plugs
      2. Blood-tinged Sputum
    3. Dyspnea
    4. Pleuritic Chest Pain

VI. Signs

  1. Wheezing
  2. Rhonchi
  3. Rales (Bronchiectasis, esp. Cystic Fibrosis)

VII. Associated Conditions

  1. Asthma
  2. Cystic Fibrosis
  3. Allergic Fungal Sinusitis

VIII. Labs

  1. Peripheral Eosinophilia
  2. Serum precipitans to a. fumigatus
    1. Serum Aspergillus >27 mg/L
  3. Serum IgE increased
    1. Total Serum IgE typically >1000 ng/ml
  4. Aspergillus skin test
    1. Immediate wheal and flare reaction to a. fumigatus

IX. Imaging

  1. Chest XRay
    1. Recurrent and fleeting Pulmonary Infiltrates and Bronchiectasis primarily in the upper lobes
  2. High Resolution CT Chest
    1. Preferred to assist in diagnosis, exclude other causes, identify Bronchiectasis distribution

X. Diagnosis

  1. Multiple diagnostic protocols based on clinical presentation, lab and imaging
    1. Bronchial Asthma
    2. Central Bronchiectasis
    3. Fleeting Pulmonary Infiltrates
  2. ISHAM Criteria
    1. Bronchial Asthma or Cystic Fibrosis AND
    2. Type 1 Aspergillus skin test reaction or elevated serum IgE to A. fumigatus AND
    3. Two of three minor criteria positive
      1. Serum IgG or IgM Antibody to A. fumigatus
      2. Imaging opacities consistent with ABPA
      3. Total serum Eosinophils >500 IU/ml if steroid naive (otherwise >1000 IU/ml)
  3. Rosenberg-Patterson Criteria (1977)
    1. Diagnosis: 6 of 8 major criteria positive is highly suggestive of Allergic Bronchopulmonary Aspergillosis
    2. Major Criteria (Mnemonic: ARTEPICS)
      1. Asthma (Bronchial)
      2. Radiographs with fleeting pulmonary opacities
      3. Test positive for immediate cutaneous Hypersensitivity to AspergillusAntigen (wheal and flare reaction)
      4. Eosinophilia in peripheral blood (>1000/mm3)
      5. Precipitating Antibody to AspergillusAntigen
      6. IgE serum levels increased (>1000 IU/ml)
      7. Central or proximal Bronchiectasis (medial two thirds of a high resolution CT)
      8. Serum A Fumigatus specific IgG and IgE levels >2 S.D. above that of Aspergillus hypersensitive Asthma samples
    3. Minor Criteria
      1. Aspergillus delayed skin reaction (type 3)
      2. Brownish-black mucus plugs
      3. Sputum positive for A Fumigatus
        1. Sputum Culture positive or fungal hyphae and Eosinophils on microscopy
  4. References
    1. Boloor and Nayak (2018) Exam Preparatory Manual, Jaypee Brothers Medical Pub
    2. Patel (2019) Cureus 11(4):e4550 +PMID: 31275774 [PubMed]
    3. Saxena (2021) J Allergy Clin Immunol Pract 9(1):328-35 +PMID: 32890756 [PubMed]

XI. Differential Diagnosis

  1. Severe Asthma
  2. COPD
  3. Cystic Fibrosis
  4. Bronchiectasis
  5. Churg-Strauss Syndrome
  6. Eosinophilic Pneumonia
  7. Pulmonary Tuberculosis
  8. Hypersensitivity Pneumonitis
  9. Other Fungal Pneumonia

XII. Management

  1. Early diagnosis and management offers best prognosis (before Bronchiectasis develops)
  2. Long-term use of Systemic Corticosteroids
    1. Starting at 0.5 to 1 mg/kg for first 2 weeks
    2. Slow taper over 3-5 months
  3. Oral Antifungals
    1. Itraconazole 200 mg twice daily for 16 weeks
      1. Often continued at 200 mg daily or every other day while Corticosteroid dependent
    2. Other Antifungals
      1. Voriconazole
      2. Posaconazole
  4. Other medications to consider
    1. Omalizumab (esp. in Asthma)

XIII. Compolications

  1. Severe, refractory Asthma
  2. Invasive Aspergillosis or chronic pulmonary Aspergillosis
  3. Pulmonary Fibrosis
  4. Emphysema
  5. Recurrent lung infection

XIV. References

  1. Sisodia and Bajaj (2021) Allergic Bronchopulmonary Aspergillosis, StatPearls, accessed 11/12/2021
  2. Stevens (2003) Clin Infect Dis 37:S225-64 [PubMed]
  3. Agarwal (2013) Clin Exp Allergy 43(8):850-73 [PubMed]
  4. Agarwal (2016) Expert Rev Respir Med 10(12):1317-34 [PubMed]

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