Asbestosis vs Silicosis? Location, Location, Lung Disease

October 6, 2014

When you want to distinguish between asbestosis and silicosis, what imaging finding is inconsistent with the former disease?

Third in a Series

Breathing is a good thing, but inhaling certain contaminants in the air is not. Take asbestos and silica, for instance. Asbestos-which can be inhaled from insulating materials and during brake production and even acquired secondhand from contaminated workers’ clothing-can cause pleural disease, interstitial lung disease, and mesothelioma. Silica-which can be inhaled in the mining industry, in glass production, and with sandblasting-can cause massive lung fibrosis, cancer, and respiratory failure.

How should questions be handled when you have to tell these air contaminants apart? I attended an Internal Medicine Board Review,1 and although I am not recertifying this year, I received some valuable guidance.

Let’s look at 3 clinical questions followed by background and points about these contaminants that might help you improve your approach to test questions and to patient care.

Question 1: Which of the following imaging findings is inconsistent with asbestosis?

A. Pleural-based plaques

B. A pleural effusion

C. Reticulonodular infiltrates

D. Upper lobe predominance

E. Reduced lung volumes

 

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For Answer, Discussion, and Next Question, CLICK HERE.

 

Answer: D. Upper lobe predominance

Asbestos and silica can be approached with the realtor’s mantra: location, location, location. Asbestosis is a lower lung–predominant disease, and silicosis is an upper lobe–predominant pathology. All of the other choices save “upper lobe predominance” are associated with asbestos-mediated lung diseases.

Let’s try another question, again looking for the incorrect choice.

Question 2: A 53-year-old man who has demolished old buildings (insulating products and all) and has coworkers who have received a diagnosis of asbestosis comes to ask whether he has asbestosis.

Which statement regarding lung disease with asbestosis is wrong?

A. A benign effusion is one of the earliest signs of asbestos exposure.

B. Pleural thickening is indicative of asbestos exposure.

C. Pleural plaques are typically not symptomatic.

D. Even low level exposures to asbestos are associated with mesothelioma.

E. Rounded atelectasis occurs after asbestos exposure is benign but can be confused with malignancy.

 

Please leave your answer/comment below.

For Answer, Discussion, and Next Question, CLICK HERE

 

 

Answer: B. Pleural thickening is indicative of asbestos exposure.

For a diagnosis of asbestosis, pulmonary parenchymal scarring must be present. Pleural disease alone is not enough. Furthermore, patients with any exposure to asbestos are at increased risk for mesothelioma-even in the absence of pulmonary or pleural disease.

Now, moving on to asbestos’ partner in lung pathology-silica.

Question 3: Which of the following statements regarding silica exposure and disease is wrong?

A. Silicosis is noticed as a predominantly lower zone lung disease.

B. Progressive massive fibrosis is a silicosis-associated complication.

C. Patients with silicosis have an increased incidence of tuberculosis.

D. The incidence of rheumatoid arthritis and scleroderma is increased in persons with silicosis.

 

Please leave your answer/comment below.

For Answer, Discussion, and Next Question, CLICK HERE

 

Answer: A. Silicosis is noticed as a predominantly lower zone lung disease.

If you focused on location, location, location, you got it right. Silicosis is upper lobe predominant. One way to remember that important fact is to keep in mind that tuberculosis is also upper lobe predominant and its incidence is increased in persons with silicosis. All patients with silicosis should undergo purified protein derivative testing. Yes, the same for an increased incidence of scleroderma and rheumatoid arthritis.

A few facts, beginning with the location of lung pathology on imaging, will be what you need to answer questions about inorganic inhalations of asbestos and silica.

Editor’s note: This article is the third in a series on preparation for recertification exams and gaining clinical knowledge from the questions that are asked. The first article covered questions about headache, corneal ulcer, and laparoscopic surgery with asthma (link below). The second article focused on Helicobacter pylori infection (link below). Upcoming articles will look at cardiac stress tests, kidney disease, and hypertension.

Article #1:Preparing for Your Recertication Exams? 9 Helpful Hints for Busy Physicians

Article #2:Preparing for Recertification? A Primer on H. Pylori

 

Certification Exams: Save the Date!

Fall 2014: exam dates are October 8, 14, 30, and 31; to take the exam, enrollment in the ABIM Maintenance of Certification must have been completed by August 1; a seat must be scheduled between May 1 and August 15.

Spring 2015: exam dates are April 14, 15, and 17, 2015; to take the exam, enrollment in the ABIM Maintenance of Certification must have been completed by February 14, 2015; a seat must be scheduled between December 1, 2014, and February 28, 2015.

Fall 2015: exam dates are October 2, 13, 16, and 26, 2015; to take the exam, enrollment in the ABIM Maintenance of Certification must have been completed by August 1, 2015; a seat must be scheduled between May 1, 2015, and August 15, 2015.

For ABIM Exam Guide, click here.

 

References:

1. Stoller JK, Nielsen C, Buccola J, Brateanu A. The Cleveland Clinic Foundation Intensive Review of Internal Medicine. 6th ed. Philadelphia: Wolters Kluwer; 2014:214-216.