Occupational Medicine · Supplementary · from Occupational Medicine

Case 1: Occupational Asbestosis

Patient Presentation

Demographics: 67-year-old male retired shipyard insulation worker

Chief Complaint: "I've had a dry cough and shortness of breath that's been getting worse over the past 2 years."

History of Present Illness: Mr. J.P. presents to the occupational medicine clinic referred by his primary care physician for progressive dyspnea on exertion and a persistent dry, non-productive cough. He reports that he first noticed exercise intolerance approximately 3 years ago when he could no longer walk 18 holes of golf without stopping to rest. Over the past year, he has become dyspneic walking one block on flat ground and can only climb one flight of stairs before needing to pause.

He worked as an insulation installer and pipe fitter at a naval shipyard from 1978 to 2003 (25 years). He reports heavy daily exposure to chrysotile and amosite asbestos during ship construction and repair, particularly during the 1980s when asbestos-containing materials were still widely used. Personal protective equipment was inconsistently provided and respiratory protection was limited to simple dust masks when available. He also reports bystander exposure from adjacent asbestos removal operations.

He denies hemoptysis, chest pain, weight loss, or night sweats. He has noted increasing fatigue and has reduced his activities significantly. He was seen by pulmonology 6 months ago and started on an inhaler with minimal improvement.

Past Medical History:

• Hypertension (well-controlled)
• Benign prostatic hyperplasia
• Bilateral knee osteoarthritis
• No prior lung disease diagnosis

Medications:

• Lisinopril 20 mg daily
• Tamsulosin 0.4 mg daily
• Tiotropium bromide 18 mcg inhaled daily
• Acetaminophen 500 mg PRN

Social History:

• Former smoker: 15 pack-year history (quit 1998)
• Married, 3 children
• Retired since 2003; previously active in home woodworking
• No current occupational exposures
• Moderate alcohol use (2-3 beers per week)

Family History:

• Father: died of myocardial infarction age 72
• Mother: alive, age 89, with dementia
• No family history of lung disease or malignancy

Physical Examination

• Vital Signs: BP 132/78 mmHg, HR 88 bpm, RR 20, SpO2 92% on room air (89% with ambulation), Temp 36.6°C, BMI 26.8 kg/m²
• General: Thin-appearing elderly male, mildly tachypneic at rest
• Chest/Pulmonary: Bilateral end-inspiratory fine crackles ("velcro rales") at both lung bases, extending to mid-zones; no wheezing; diminished breath sounds at bases
• Cardiovascular: Regular rate and rhythm, prominent P2 (suggesting pulmonary hypertension), no peripheral edema
• Extremities: Digital clubbing present in all fingers (grade 3); no cyanosis at rest
• Skin: No rashes or lesions; no evidence of pleural plaques palpable on chest wall

Workup and Results

Laboratory Studies:

Imaging/Additional Studies:

• Chest X-ray: Bilateral irregular opacities predominantly in lower zones (ILO classification: profusion 2/2, shape/size s/t); bilateral diaphragmatic calcified pleural plaques; blunting of costophrenic angles bilaterally
• HRCT Chest: Bilateral subpleural reticular opacities with honeycombing in lower lobes; traction bronchiectasis; ground-glass opacities at periphery of both lower lobes; bilateral calcified pleural plaques on diaphragmatic and posterolateral parietal pleura; no pleural effusion; no lung masses
• Pulmonary Function Tests: FVC 2.18 L (58% predicted), FEV1 1.92 L (68% predicted), FEV1/FVC ratio 0.88 (normal — restrictive pattern), DLCO 42% predicted (severely reduced), TLC 4.1 L (62% predicted)
• 6-Minute Walk Test: Distance 285 m (predicted ~520 m); SpO2 decreased from 92% to 84% with exertion; Borg dyspnea scale 7/10 at completion
• Echocardiogram: Estimated RVSP 48 mmHg (elevated); mild RV dilation; normal LV function, EF 60%

Clinical Image

High-resolution CT scan illustration showing characteristic bilateral lower lobe subpleural reticular opacities, honeycombing, and calcified pleural plaques in asbestosis. Source: Educational illustration.

Diagnosis

Asbestosis with Secondary Pulmonary Hypertension

Key Diagnostic Criteria:

• Reliable history of significant asbestos exposure (25 years, heavy occupational exposure with inadequate respiratory protection)
• Appropriate latency period (>15 years from first exposure to symptom onset)
• Radiographic evidence: bilateral lower-lobe predominant interstitial fibrosis with honeycombing on HRCT; calcified pleural plaques (hallmark of asbestos exposure)
• Restrictive physiology on PFT with severely reduced DLCO
• Exclusion of other causes of pulmonary fibrosis (negative autoimmune serologies, no drug-related causes)
• Clinical findings: bilateral basilar crackles and digital clubbing

Treatment Plan

1. Supportive care: Supplemental oxygen therapy — 2-3 L/min via nasal cannula to maintain SpO2 ≥90% at rest and with exertion
2. Pulmonary rehabilitation: 8-12 week supervised program with aerobic conditioning and breathing retraining
3. Antifibrotic therapy consideration: Referral to ILD specialist for evaluation of nintedanib (FDA-approved for progressive fibrosing ILD; emerging evidence in asbestosis with progressive phenotype)
4. Pulmonary hypertension management: Right heart catheterization to confirm; consider pulmonary vasodilator therapy if confirmed pre-capillary PH
5. Surveillance for malignancy: Annual low-dose CT chest for lung cancer screening (combined asbestos exposure + smoking history confers multiplicative risk); serial mesothelin levels for mesothelioma surveillance
6. Vaccinations: Annual influenza; pneumococcal (PCV20); COVID-19 booster; RSV vaccination
7. Workers' compensation: Assist with filing occupational disease claim; comprehensive occupational exposure documentation
8. Advance care planning: Discussion of disease trajectory and goals of care given progressive nature

Key Learning Points

• Asbestosis is a dose-dependent pneumoconiosis with a latency period of 15-40 years; it is characterized by bilateral lower-lobe predominant interstitial fibrosis indistinguishable from UIP pattern except by exposure history and presence of pleural plaques
• Calcified pleural plaques are the most specific radiographic marker of prior asbestos exposure but are distinct from asbestosis (parenchymal disease); plaques alone do not cause functional impairment
• The combination of asbestos exposure and cigarette smoking has a multiplicative (not merely additive) effect on lung cancer risk, increasing risk by approximately 50-90 fold compared to the unexposed non-smoker
• Asbestosis is a progressive disease with no cure; management is supportive, with emerging evidence for antifibrotic agents in progressive fibrosing phenotypes
• Occupational medicine physicians play a critical role in exposure documentation, workers' compensation advocacy, and malignancy surveillance in asbestos-exposed populations

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