Chronic Lung Disease

Chronic Linear, Reticular, Micronodular (Interstitial) Pattern

Chronic Interstitial Pattern

Checklist:

Is an abnormal radiograph an incidental finding in an asymptomatic patient?

Is the pathology depicted clear enough or should a high-resolution CT (HRCT) be performed? (Nowadays, HRCT should be performed in all cases where serious treatment such as steroids or other consequences are considered.) Is there any pertinent past medical history?

Is there any present or past exposure to occupational or recreational hazards that could cause chronic lung disease?

I The Case of Bob Coalfire

Chronic Lung Disease
Fig. 6.44 This is the CXR of Bob Coalfire.

Traces of a Life

Robert Coalfire (47) has done hard physical work all his life. Since his early retirement owing to osteoarthritis of his hip he has spent a lot of time in his little garden in Bribie close to the beach. He was busy with the spring clean-up there when the dyspnea that has plagued him for quite a while worsened considerably. His wife has finally forced him to see his doctor, who sent him directly to radiology to get a chest radiograph. Paul and Hannah are assigned to the chest imaging unit today. They analyze the image (Fig. 6.44) that comes up on their monitor and debate the differential diagnosis of generalized changes of the lung interstitium.

Silicosis: In silicosis two other typical manifestations are seen: the so-called progressive massive fibrosis conglomerate tumors of silicotic tissue that can become very large (Fig. 6.46b) and typical eggshell-type calcifications of hilar lymph nodes (Fig. 6.46a). Acute inflammatory processes can be treated with appropriate medication, but the

I Chronic Left Heart Insufficiency

• What Is Your Diagnosis?

Chronic left heart insufficiency: The continual vascular congestion in chronic left heart insufficiency causes a constant fluid overload of the interstitium. Over time the fluid is organized and a reactive scarring or fibrosis develops. This process is most pronounced in the areas of the highest hydrostatic pressure, that is, in the basal lung. In the CXR one may observe a fine micronodular pattern (Fig. 6.45).

Pneumoconiosis: Chronic occupational exposure to inorganic dusts (carbon, silica) and also fibers (asbestos) has dire consequences for the lung. The bronchi and the interstitium respond with an inflammatory reaction that eventually leads to an irreversible nodular rearrangement of the lung architecture (Fig. 6.46a). Bullae and overinfla-tions may occur as well fibrotic stranding and compaction of lung tissue.

I Chronic Left Heart Insufficiency

Carcinoma Basilar
Fig. 6.45 You see the basilar portion of a CXR in a patient with a severe and chronic mitral valve insufficiency. The constant fluid overload of the interstitium has produced a micronodular pattern.

I Silicosis

Eggshell Calcification Hilar Nodes

Fig. 6.46a These are micronodular changes as seen in pneu-moconioses. The hilar lymph nodes illustrate the typical "eggshell calcifications" of silicosis. b In addition to the micronodular pattern, silicosis may also present with large confluent granu

Fluid Overloaded Cxr

lomas (progressive massive fibrosis)—observe the right lung apex. This entity needs to be differentiated from bronchial carcinoma by careful longitudinal comparisons with previous films.

Fig. 6.46a These are micronodular changes as seen in pneu-moconioses. The hilar lymph nodes illustrate the typical "eggshell calcifications" of silicosis. b In addition to the micronodular pattern, silicosis may also present with large confluent granu lomas (progressive massive fibrosis)—observe the right lung apex. This entity needs to be differentiated from bronchial carcinoma by careful longitudinal comparisons with previous films.

fibrotic remnants and their consequences are more difficult to deal with.

Asbestosis: Exposure to asbestos fibers may result in pulmonary fibrosis (Fig. 6.47a) and pleural reactions, so-called asbestos-related pleural disease. Pleural effusions and pleural plaques occur. Often the plaques calcify in a characteristic fashion—a dense, thin calcification on top of a thick soft tissue plaque that has reminded German-speaking radiologists of the famous "Tafelberg," the flat-topped mountain in South Africa's Cape Town (Fig. 6.47a). In patients with recurring pleural effusions and pleural plaques, the lung may collapse and, because it is connected to the pleural abnormality by fibrous bands, may spiral up to form the so-called "rounded atelectases" (Fig. 6.47b).

Sarcoidosis: A chronic micronodular pattern is frequently found in sarcoidosis, a granulomatous disease that almost always manifests itself in the lung. Clinical symptoms may be absent or very nonspecific. Often the hilar and mediastinal lymph nodes are enlarged (Fig. 6.48a), which naturally necessitates the differentiation from lymphoma or tuberculosis. Occasionally the characteristic noncaseat-ing granulomas become very large. If the disease does not respond to therapy, severe lung fibrosis develops (Fig. 6.48b, c).

Miliary tuberculosis, histoplasmosis: Inactive miliary tuberculosis has already been dealt with (see Fig. 6.38b).

If you practice medicine in the Mississippi or Ohio River Valley, in Jamaica, or in a number of other attractive places, and if you handle a population of bat cave visitors, you have to consider histoplasmosis in your differential. Both entities may look alike.

Lymphangitic carcinomatosis: Micronodules along the major interstitial structures—that is, the fissures, bronchi, and the interlobar septae—are found in a malignant infiltration of the interstitium: lymphangitic carcinomatosis (see Fig. 6.34b). The infiltration tends to begin in the hilar region and then proceeds to perihilar lung. The differentiation to sarcoidosis is, of course, of paramount importance for the appropriate choice of therapy.

Idiopathic pulmonary fibrosis: Idiopathic pulmonary fibrosis may occur in patients without pulmonary risk factors. The basal lung shows thickened interstitial septae, bullae, and bronchiectasis. This appearance of the disease is also called "usual interstitial pneumonitis" (UIP, Fig. 6.49a) (also known in Canada and the United Kingdom as IPF, interstitial pulmonary fibrosis) and it is resistant to treatment. If at the same time acinar/alveolar opacities are detected in an HRCT, a desquamative interstitial pneumonitis (DIP, Fig. 6.49b) is more likely to be present. Differentiation between the two is essential since the alveolar component of DIP is successfully treated with corticoster-oids and its prognosis is much better. In severe cases,

I Asbestosis

Signs AsbestosisLung Bullae Prognosis

Fig. 6.47a In asbestosis, peripherally accentuated pulmonary fibrosis with scarring, small bullae, and bronchiectasis (long arrow) develops. The pathognomonic extensive pleural plaques often have a calcified flat and smooth top (short arrow), also called "Tafelberg" (tophats).

b In recurring and chronic pleural effusions, lung components may collapse and spiral up into a special kind of atelectasis: the so-called "round atelectasis," which must be differentiated from malignant lesions. The typical comet-tail sign (arrows) that shows the spiral course of the pulmonary vessels into the lesion helps in the differentiation. If the radiographic appearance suggests rounded atelectasis, simple follow-up imaging may be scheduled to assess stability or resolution over time.

Rounded Atelectasis Comet Tail Sign

I Sarcoidosis

Causes Enlarged HilumAbnormal Pulmonary Lymph Nodes Pictures
Fig. 6.48a The central lung parenchyma (also see b) has an abnormal micronodular appearance. The hilum is notably enlarged— lymph nodes full of noncaseating granulomas are the cause of the change.

I Sarcoidosis

Micro Nodular Sarcoid TransplantTreatment Options For Cystic Fibrosis

particularly of UIP, lung transplantation is the only treatment option.

Cystic fibrosis: If Mr. Coalfire were younger, severe generalized changes of the lung architecture could point to cystic fibrosis (Fig. 6.50).* The rather typical pattern is due to dilated bronchi some of which are plugged with viscous mucus.

*Only state-of-the-art constant mucolytic and antibiotic therapy lets these patients reach adulthood. They suffer from recurring bouts of pulmonary infections.

Lymphangioleiomyomatosis: Lymphangioleiomyomato-sis is a disease that occurs almost exclusively in young women, characterized by proliferation of atypical smooth muscle in pulmonary lymphatic vessels, blood vessels, and airways. Gradually progressive interstitial lung disease, recurrent chylous pleural effusions, and recurrent pneumothoraces are among the sequelae of this disease, which leads to the demise of the patient unless lung transplantation is performed. There is a multitude of other special diseases of the pulmonary interstitium. They are difficult to discriminate and, as a student and nonpulmonol-ogist, you will not be asked to do so.

• Diagnosis: Hannah and Paul are a little exhausted after browsing through the differential. They have agreed that

| Idiopathic Lung Fibrosis_

a "Usual interstitial pneumonitis" (UIP)/idiopathic pulmonary fibrosis (IPF)

a "Usual interstitial pneumonitis" (UIP)/idiopathic pulmonary fibrosis (IPF)

Structures Interstitial Lung Disease

Fig. 6.49a The fine linear and reticular structures in the periphery— much like Kerley lines—indicate changes of the interstitium in pulmonary fibrosis. The heart is small, the vascular filling is normal, and there are no clinical signs of pulmonary venous congestion. b Additional alveolar opacities in desquamative interstitial pneumonitis (DIP) point to an active process potentially responsive to therapy with corticosteroids.

b "Desquamative interstitial pneumonitis" (DIP)

b "Desquamative interstitial pneumonitis" (DIP)

Desquamative Interstitial Pneumonitis

this could very well be a case of idiopathic lung fibrosis. They have talked to the patient and have not found anything in the way of an occupational risk: Mr. Coalfire was a bricklayer all his life and has always enjoyed the fresh air—OK, OK, he has smoked quite a bit but quit about 8 years ago. An HRCT will verify the diagnosis and determine whether therapy with steroids has a fair chance of success.

f Generations of gray-haired radiologists plusthe WHO have i committed themselves to the classification of micronodules in CXRs—mainly to classify findings in occupation-ally exposed workers with lung disease to determine their entitlement to worker's compensation. High-resolution chest CT has facilitated this effort enormously. Fortunately, the number of exposed workers decreases continuously as occupational legislation is improved and enforced and as technology moves on.

I Cystic Fibrosis

Label Anatomy Chest Radiograph
Fig. 6.50 The generalized, irregularly dilated bronchi in cystic fibrosis produce the characteristic bullous pattern. This patient is currently in the intensive care unit for a relapsing pneumonia.
Label Anatomy Chest Radiograph
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Responses

  • EVAN
    Does pleural plaque become mesolima in canada?
    5 years ago
  • Kyösti
    Can systemic lupus erythematosus cause calcified hilar lymph nodes?
    9 months ago

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