Hypersensitivity pneumonitis – imaging findings on high-resolution CT

Congress:

ECR 2019

Poster Number:

C-0656

Type:

Educational Exhibit

Keywords:

Respiratory system, Lung, Thorax, CT-High Resolution, Education, Education and training

Authors:

P. G. J. Magalhaes¹, P. F. M. Azevedo², P. M. R. C. Patrão¹, S. Teixeira¹, F. Matos¹, G. D. Gerediaga¹, C. Albuquerque¹, D. Silva¹; ¹Viseu/PT, ²Vila Nova De Gaia/PT

DOI:

10.26044/ecr2019/C-0656

DOI-Link:

https://dx.doi.org/10.26044/ecr2019/C-0656

Fig. 1: Patient with acute HP.

Fig. 2: Ground glass opacities and a cyst in a patient with subacute HP.

Fig. 3: Numerous, ill-defined centrilobular nodules in a patient with subacute HP.

Fig. 4: Mosaic attenuation pattern in a patient with subacute HP.

Learning objectives

- Review the pathogenesis, etiology and clinical manifestations of hypersensitivity pneumonitis (HP); - Describe and illustrate high-resolution CT findings of hypersensitivity pneumonitis.

Background

Hypersensitivity pneumonitis (HP) is an inflammatory lung disease that appears secondarily to exposure and inhalation of a variety of organic and inorganic particles in a previously sensitized person. This exposure results in an immune response directed to the distal bronchioles and alveoli with the formation of granulomatous tissue. HP is often underdiagnosed, as clinical manifestations are mainly nonspecific and can be caused by more than 200 different antigens, including bacteria, mycobacteria, fungi, proteins, and chemicals. Tobacco appears to be a protective factor, however, if HP...

Findings and procedure details

Hypersensitivity pneumonitis is divided into three subtypes, each with typical clinical, laboratory and radiographic findings, although there may be some interposition. Acute hypersensitivity pneumonitis (Fig. 1): The radiologic diagnosis of acute hypersensitivity pneumonitis may be difficult due to clinical non-specificity and rapid resolution of symptoms. Often these patients are treated empirically for infections or asthma without proper diagnosis ever being made. However, even in the absence of a correct diagnosis clinical improvement of patients can occur by cessation of antigen exposure or administration of corticosteroids....

Conclusion

Hypersensitivity pneumonitis is a relatively frequent disease often underdiagnosed due to the non-specific character of its clinical or laboratory manifestations. However, a well-founded knowledge about the typical imaging findings of the various subtypes may allow the radiologist to be the key in the diagnosis of this “evasive” disease.

Personal information

References

Webb WR, Muller NL, Naidich DP. HighResolutionCT of the Lung. 4th ed: Lippincott Williams &Wilkins; 2008. Lacasse Y, Selman M, Costabel U, et al. Classification of hypersensitivity pneumonitis: a hypothesis. Int Arch Allergy Immunol 2009;149:161-6. Jan V. Hirschmann, MD. Sudhakar N. J. Pipavath, MBBS. Hypersensitivity Pneumonitis: A Historical, Clinical, and Radiologic Review. RadioGraphics 2009; 29:1921–1938. Lacasse, Y., Girard, M. & Cormier, Y. Recent Advances in Hypersensitivity Pneumonitis.Chest142,208–217 (2012). Coultas DB, Zumwalt RE, Black WC, Sobonya RE. The epidemiology of interstitial lung diseases. Am J Respir...