Caplan's syndrome (or Caplan disease or rheumatoid pneumoconiosis) is a combination of rheumatoid arthritis (RA) and pneumoconiosis that manifests as intrapulmonary nodules, which appear homogeneous and well-defined on chest X-ray.

Signs and symptoms

Caplan syndrome presents with

cough A cough is a sudden expulsion of air through the large breathing passages that can help clear them of fluids, irritants, foreign particles and microbes. As a protective reflex, coughing can be repetitive with the cough reflex following three ph ...

and

shortness of breath Shortness of breath (SOB), also medically known as dyspnea (in AmE) or dyspnoea (in BrE), is an uncomfortable feeling of not being able to breathe well enough. The American Thoracic Society defines it as "a subjective experience of breathing di ...

in conjunction with features of rheumatoid arthritis, such as painful joints and morning stiffness. Examination should reveal tender, swollen

metacarpophalangeal joint The metacarpophalangeal joints (MCP) are situated between the metacarpal bones and the proximal phalanges of the fingers. These joints are of the condyloid kind, formed by the reception of the rounded heads of the metacarpal bones into shallow ca ...

s and rheumatoid nodules; auscultation of the chest may reveal diffuse

crackles Crackles are the clicking, rattling, or crackling noises that may be made by one or both lungs of a human with a respiratory disease during inhalation. They are usually heard only with a stethoscope ("on auscultation"). Pulmonary crackles are a ...

that do not disappear on coughing or taking a deep breath. Caplan syndrome is a nodular condition of the lung occurring in dust-exposed persons with either a history of

rheumatoid arthritis Rheumatoid arthritis (RA) is a long-term autoimmune disorder that primarily affects joints. It typically results in warm, swollen, and painful joints. Pain and stiffness often worsen following rest. Most commonly, the wrist and hands are invol ...

(RA) or who subsequently develop RA within the following 5–10 years. The nodules in the lung typically occur bilaterally and peripherally, on a background of simple coal workers' pneumoconiosis. There are usually multiple nodules, varying in size from 0.5 to 5.0 cm. The nodules typically appear rapidly, often in only a few weeks. Nodules may grow, remain unchanged in size, resolve, or disappear and then reappear. They can cavitate, calcify, or develop air-fluid levels. Grossly, they can resemble a giant silicotic nodule. Histologically, they usually have a necrotic center surrounded by a zone of plasma cells and lymphocytes, and often with a peripheral inflammatory zone made of macrophages and neutrophils.

Causes

Caplan syndrome occurs only in patients with both RA and pneumoconiosis related to mining dust (coal, asbestos, silica). The condition occurs in miners (especially those working in anthracite coal-mines),

asbestosis Asbestosis is long-term inflammation and scarring of the lungs due to asbestos fibers. Symptoms may include shortness of breath, cough, wheezing, and chest tightness. Complications may include lung cancer, mesothelioma, and pulmonary heart d ...

, silicosis and other pneumoconioses. There is probably also a genetic predisposition, and smoking is thought to be an aggravating factor.

Pathophysiology

The presence of rheumatoid arthritis alters how a person's immune system responds to foreign materials, such as dust from a coal mine. When a person with rheumatoid arthritis is exposed to such offensive materials, they are at an increased risk of developing pneumoconiosis.

Diagnosis

* Chest radiology shows multiple, round, well defined nodules, usually 0.5-2.0 cm in diameter, which may cavitate and resemble

tuberculosis Tuberculosis (TB) is an infectious disease usually caused by '' Mycobacterium tuberculosis'' (MTB) bacteria. Tuberculosis generally affects the lungs, but it can also affect other parts of the body. Most infections show no symptoms, i ...

. *

Lung function tests Pulmonary function testing (PFT) is a complete evaluation of the respiratory system including patient history, physical examinations, and tests of pulmonary function. The primary purpose of pulmonary function testing is to identify the severity ...

may reveal a mixed restrictive and obstructive ventilatory defect with a loss of lung volume. There may also be irreversible airflow limitation and a reduced

DLCO DLCO or TLCO ( diffusing capacity or transfer factor of the lung for carbon monoxide (CO),) is the extent to which oxygen passes from the air sacs of the lungs into the blood. Commonly, it refers to the test used to determine this parameter. It was ...

. * Rheumatoid factor, antinuclear antibodies, and non-organ specific antibodies may be present in the serum. * Silicosis and

must be considered in the differential with TB.

Management

Once tuberculosis has been excluded, treatment is with steroids. All exposure to coal dust must be stopped, and

smoking cessation Smoking cessation, usually called quitting smoking or stopping smoking, is the process of discontinuing tobacco smoking. Tobacco smoke contains nicotine, which is addictive and can cause dependence. As a result, nicotine withdrawal often m ...

should be attempted. Rheumatoid arthritis should be treated normally with early use of

DMARDs Disease-modifying antirheumatic drugs (DMARDs) comprise a category of otherwise unrelated disease-modifying drugs defined by their use in rheumatoid arthritis to slow down disease progression. The term is often used in contrast to nonsteroida ...

Prognosis

The nodules may pre-date the appearance of rheumatoid arthritis by several years. Otherwise prognosis is as for RA; lung disease may remit spontaneously, but pulmonary fibrosis may also progress.

Epidemiology

Incidence is currently 1 in 100,000 people but is likely to fall as the coal mining industry declines. It has also been shown to occur in cases of complicated silicosis (marked by progressive massive pneumoconiosis).

History

The syndrome is named after Dr. Anthony Caplan, a physician on the Cardiff Pneumoconiosis Panel, who identified the constellation of findings as a distinct entity in a 1953 publication. He followed this with further articles exploring the disease. Caplan syndrome was originally described in coal miners with progressive massive fibrosis.

References

External links

* {{DEFAULTSORT:Caplan Syndrome Syndromes affecting the respiratory system