Interstitial lung abnormalities evolving to histologically proven nonspecific interstitial pneumonia

History of present illness

A 59-year-old woman underwent an abdominal computed tomography (CT) scan for suspected acute gallstones cholecystitis.

Imaging included the lower lung zones, where reticular alterations were incidentally found. Thus, she was referred to the pulmonology clinic.

Past medical history

The patient was a warehouse worker without any occupational exposure. She had never smoked cigarettes or had bird exposure. No family members had respiratory diseases. About 10 years earlier, she underwent a hysterectomy because of uterine fibroma. She was not taking any medication on a regular basis.

Physical examination and early clinical findings

At the pulmonology evaluation, the patient was alert and cooperative and just complained of shortness of breath during intense efforts like climbing stairs. She had no cough or chest pain. Her oxygen saturation at the pulse oximeter (SpO 2 ) was 96% while she was at rest in room air, with a respiratory rate of 15 breaths/min. Blood pressure was 125/80 mmHg, and heart rate was 70 bpm.

The physical examination revealed Velcro sounds at the lower pulmonary fields that endorsed the suspicion of interstitial lung disease. She had no clubbing, no hand joint deformities, and no peripheral edema.

Clinical course

Pulmonary function tests (PFTs) showed normal lung volumes with forced vital capacity (FVC) 96.3% predicted. Lung diffusion was slightly reduced (diffusing capacity of the lungs for carbon monoxide [DLCO] 78.8% predicted) although still within the lower limits of normal (LLN). A chest high-resolution CT (HRCT) scan confirmed the presence of interstitial lung abnormalities (ILAs) with a few bilateral ground-glass opacities and reticulation, mainly in the peripheral zones and lower lobes ( Fig 4.1 ).

Fig. 4.1

High-resolution CT (HRCT) scan of the chest showing mainly subpleural nonfibrotic interstitial lung abnormalities (ILAs).

The patient admitted sporadic arthralgias, but usually only after heavy work. At a rheumatological evaluation, there were no current signs of connective tissue disease (CTD), whereas the autoimmunity panel was negative except for low titer (1:40) antinuclear antibodies (ANAs).

At a first multidisciplinary evaluation, the specialists agreed on the diagnosis of ILAs, and the patient was informed about the current difficulty in establishing whether she had a disease that would progress to pulmonary fibrosis. She refused cryobiopsy as she was afraid of adverse events and she felt fine. Clinical, radiological, and functional follow-up was scheduled, with PFTs every 6 months and chest HRCT scan every 12 months.

In the following 3 years, the patient reported a progressive reduction of exercise tolerance with dyspnea when walking on flat ground.

Contextually, a deterioration in lung volumes and gas exchanges was observed ( Fig. 4.2 ): FVC decreased to 88.5%, then to 84.2%, and finally to 77.1% of predicted; DLCO reduced to 68.8%, then to 61.2%, and finally to 48.5% of predicted.

Fig. 4.2

Comparison of pulmonary function tests at the first observation (red lines) and 3 years later (blue lines). The development of lung restriction and impairment of lung diffusion is evident. (A) Flow-volume curve. (B) Volume-time curve. (C) Measured parameters. FEV 1 , forced expiratory volume in 1 second; LLN, lower limit of normal; FVC, forced vital capacity; RV, residual volume; TLC, total lung capacity. DLCO, diffusing capacity of the lungs for carbon monoxide.

At the 3-year follow-up, the patient covered a normal distance (420 m) at a 6-minute walk test (6MWT), although she experienced significant breathlessness and had a slight oxygen desaturation (mean SpO 2 94.2%, lowest SpO 2 88%).

Imaging also showed a worsened ILD with a greater extension of both the reticulation and the areas of hyperdensity with ground-glass pattern ( Fig. 4.3 ).

Fig. 4.3

HRCT of the chest showing a progression of the interstitial findings with a greater extension of subpleural reticulation and ground-glass opacities.

After a new multidisciplinary discussion, the execution of transbronchial cryobiopsy was proposed again to determine the ILD pattern.

The patient accepted and underwent transbronchial cryobiopsy as an outpatient procedure.

Blood tests confirmed that she had normal platelet counts, international normalized ratio (INR), and liver and kidney function. She received deep sedation using propofol and remifentanil and was intubated with a rigid tracheoscope. After a bronchoalveolar lavage with 150 mL of saline in the lateral segment of the middle lobe, transbronchial cryobiopsies at about 1 cm from the pleura were obtained using a 1.7 mm probe. The freezing time was 8 seconds for each biopsy. Two biopsy samples from two different sites of the middle lobe were obtained to improve diagnostic yield.

The procedure was complicated by iatrogenic pneumothorax requiring hospitalization, placement of a small-bore chest tube, and oxygen supplement. A lung expansion was promptly obtained. Drainage was maintained in the pleural space for 3 days. When there was no evidence of air leaks, the chest tube was closed for 24 hours and finally removed after a chest radiograph confirmed that pneumothorax had not recurred ( Figs. 4.4 , 4.5 , 4.6 ).

Fig 4.4

Chest radiograph immediately after the lung cryobiopsy. A right pneumothorax is evident.

Fig. 4.5

Chest radiograph after right chest tube placement. The lung is expanded on both inspiration and expiration.

Jun 15, 2024 | Posted by in CRITICAL CARE | Comments Off on Interstitial lung abnormalities evolving to histologically proven nonspecific interstitial pneumonia

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