Fibrothorax is a medical condition characterised by severe scarring ( fibrosis) and fusion of the layers of the pleural space surrounding the

lung The lungs are the primary Organ (biology), organs of the respiratory system in many animals, including humans. In mammals and most other tetrapods, two lungs are located near the Vertebral column, backbone on either side of the heart. Their ...

s resulting in decreased movement of the lung and ribcage. The main symptom of fibrothorax is

shortness of breath Shortness of breath (SOB), 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 discomfort that con ...

. There also may be recurrent fluid collections surrounding the lungs. Fibrothorax may occur as a complication of many diseases, including infection of the pleural space known as an empyema or bleeding into the pleural space known as a haemothorax. Fibrosis in the pleura may be produced intentionally using a technique called pleurodesis to prevent recurrent punctured lung (

pneumothorax A pneumothorax is collection of air in the pleural space between the lung and the chest wall. Symptoms typically include sudden onset of sharp, one-sided chest pain and dyspnea, shortness of breath. In a minority of cases, a one-way valve is ...

), and the usually limited fibrosis that this produces can rarely be extensive enough to lead to fibrothorax. The condition is most often diagnosed using an

X-ray An X-ray (also known in many languages as Röntgen radiation) is a form of high-energy electromagnetic radiation with a wavelength shorter than those of ultraviolet rays and longer than those of gamma rays. Roughly, X-rays have a wavelength ran ...

CT scan A computed tomography scan (CT scan), formerly called computed axial tomography scan (CAT scan), is a medical imaging technique used to obtain detailed internal images of the body. The personnel that perform CT scans are called radiographers or ...

, the latter more readily detecting mild cases. Fibrothorax is often treated conservatively with

watchful waiting Watchful waiting (also watch and wait or WAW) is an approach to a medical problem in which time is allowed to pass before medical intervention or therapy is used. During this time, repeated testing may be performed. Related terms include ''expe ...

but may require surgery. The outlook is usually good as long as there is no underlying pulmonary fibrosis or complications following surgery. The disease is highly uncommon.

Signs and symptoms

Signs

Reduced movement of the ribcage during breathing, reduced breath sounds on the affected side(s), and a dull feeling when the chest is pressed are common signs observed during examination for fibrothorax. Sharp chest pain with deep breaths or coughing may be seen in some cases. Severe cases of fibrothorax can lead to

respiratory failure Respiratory failure results from inadequate gas exchange by the respiratory system, meaning that the arterial oxygen, carbon dioxide, or both cannot be kept at normal levels. A drop in the oxygen carried in the blood is known as hypoxemia; a r ...

due to inadequate

ventilation Ventilation may refer to: * Ventilation (physiology), the movement of air between the environment and the lungs via inhalation and exhalation ** Mechanical ventilation, in medicine, using artificial methods to assist breathing *** Respirator, a ma ...

and cause abnormally high levels of carbon dioxide in the bloodstream.

Symptoms

The condition only causes symptoms if the visceral pleura is affected. Although fibrothorax may not cause any symptoms, people affected by the disorder may report

. Persistent, recurrent

pleural effusion A pleural effusion is accumulation of excessive fluid in the pleural space, the potential space that surrounds each lung. Under normal conditions, pleural fluid is secreted by the parietal pleural capillaries at a rate of 0.6 millilitre per kilog ...

s are a possible symptom, caused by the persistent cavity formed by the hardening pleura around the original fluid collection. Shortness of breath tends to develop gradually and may worsen over time. Less commonly, fibrothorax may cause chest discomfort or a dry

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

. Fibrothorax may occur as a complication of other diseases. Symptoms of the underlying problem are sometimes seen, for example, fever in cases of empyema.

Causes

Fibrothorax is often a complication of other diseases that cause

inflammation Inflammation (from ) is part of the biological response of body tissues to harmful stimuli, such as pathogens, damaged cells, or irritants. The five cardinal signs are heat, pain, redness, swelling, and loss of function (Latin ''calor'', '' ...

of the pleura. These include infections such as an empyema or

tuberculosis Tuberculosis (TB), also known colloquially as the "white death", or historically as consumption, is a contagious disease usually caused by ''Mycobacterium tuberculosis'' (MTB) bacteria. Tuberculosis generally affects the lungs, but it can al ...

, or bleeding within the pleural space known as a haemothorax. Exposure to certain substances, such as

asbestos Asbestos ( ) is a group of naturally occurring, Toxicity, toxic, carcinogenic and fibrous silicate minerals. There are six types, all of which are composed of long and thin fibrous Crystal habit, crystals, each fibre (particulate with length su ...

, can cause generalised fibrosis of the lungs, which may involve the pleura and lead to fibrothorax. Less common causes of fibrothorax include collagen vascular diseases such as

systemic lupus erythematosus Lupus, formally called systemic lupus erythematosus (SLE), is an autoimmune disease in which the body's immune system mistakenly attacks healthy tissue in many parts of the body. Symptoms vary among people and may be mild to severe. Common ...

sarcoidosis Sarcoidosis (; also known as Besnier–Boeck–Schaumann disease) is a disease involving abnormal collections of White blood cell, inflammatory cells that form lumps known as granulomata. The disease usually begins in the lungs, skin, or lymph n ...

, and

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

;

kidney failure Kidney failure, also known as renal failure or end-stage renal disease (ESRD), is a medical condition in which the kidneys can no longer adequately filter waste products from the blood, functioning at less than 15% of normal levels. Kidney fa ...

leading to uraemia; and side effects of certain medications. The medications most commonly associated with pleural fibrosis are the ergot

alkaloid Alkaloids are a broad class of natural product, naturally occurring organic compounds that contain at least one nitrogen atom. Some synthetic compounds of similar structure may also be termed alkaloids. Alkaloids are produced by a large varie ...

s bromocriptine, pergolide, and methysergide. Fibrothorax may also occur without a clear underlying cause, in which case it is known as

idiopathic An idiopathic disease is any disease with an unknown cause or mechanism of apparent spontaneous origin. For some medical conditions, one or more causes are somewhat understood, but in a certain percentage of people with the condition, the cause ...

fibrothorax. A technique called pleurodesis can be used to intentionally create scar tissue within the pleural space, usually as a treatment for repeated episodes of a punctured lung, known as a

, or for pleural effusions caused by

cancer Cancer is a group of diseases involving Cell growth#Disorders, abnormal cell growth with the potential to Invasion (cancer), invade or Metastasis, spread to other parts of the body. These contrast with benign tumors, which do not spread. Po ...

. While this procedure usually generates only limited scar tissue, in rare cases a fibrothorax can develop.

Mechanism

Fibrosis can affect one or both of the two layers of tissue forming the

pleura The pleurae (: pleura) are the two flattened closed sacs filled with pleural fluid, each ensheathing each lung and lining their surrounding tissues, locally appearing as two opposing layers of serous membrane separating the lungs from the med ...

—the visceral pleura adjacent to the

and the parietal pleura adjacent to the ribcage. The term fibrothorax implies severe fibrosis affecting both the visceral and the outer (parietal) pleura, fusing the lung to the chest wall. The condition starts as an undrained pleural effusion. Over time, the undrained pleural effusion causes sustained inflammation of the pleura, which can then lead to deposition of

fibrin Fibrin (also called Factor Ia) is a fibrous protein, fibrous, non-globular protein involved in the Coagulation, clotting of blood. It is formed by the action of the protease thrombin on fibrinogen, which causes it to polymerization, polymerize. ...

in the pleura and the development of a fibrotic scar. Eventually, a "peel" that is rich in

collagen Collagen () is the main structural protein in the extracellular matrix of the connective tissues of many animals. It is the most abundant protein in mammals, making up 25% to 35% of protein content. Amino acids are bound together to form a trip ...

forms around the fluid collection. From this point, the illness can no longer be treated with

thoracentesis Thoracentesis , also known as thoracocentesis (), pleural tap, needle thoracostomy, or needle decompression (often used term), is an invasive medical procedure to remove fluid or air from the pleural space for diagnostic or therapeutic purposes. ...

, since the fluid will return to the cavity maintained by the peel. Over time, generally over the years, the fibrotic scar tissue slowly tightens and thickens, contracting the contents of one or both halves of the chest and reducing the mobility of the ribs. The peel can become deeper than 2 cm. Within the chest, the lung is compressed and unable to expand (trapped lung), making it vulnerable to collapse and causing breathlessness. Restrictive lung disease from fibrothorax may occur when pleural fibrosis is so severe that it involves the diaphragm and ribcage and results primarily from decreased rib movement.

Microscopic

At the microscopic level, collagen fibres deposit in a basket weave pattern and form scar tissue. Usually, the underlying condition has to cause intense inflammation of the pleura, though it is unclear exactly how this results in fibrosis. The precise mechanisms producing the fibrosis are not entirely clear. However, research indicates a protein called Transforming Growth Factor beta ( TGF-β) plays a central role in producing fibrothorax. Anti-TGF-β antibodies prevent fibrothorax in empyema in animal models.

Diagnosis

A fibrothorax can typically be diagnosed by taking an appropriate medical history in combination with the use of appropriate imaging techniques such as a plain chest X-ray or CT scan. These imaging techniques can detect fibrothorax and pleural thickening that surround the lungs. The presence of a thickened peel with or without calcification are common features of fibrothorax when imaged. CT scans can more readily differentiate whether pleural thickening is due to extra fat deposition or true pleural thickening than X-rays. If a fibrothorax is severe, the thickening may restrict the lung on the affected side causing a loss of lung volume. Additionally, the

mediastinum The mediastinum (from ;: mediastina) is the central compartment of the thoracic cavity. Surrounded by loose connective tissue, it is a region that contains vital organs and structures within the thorax, mainly the heart and its vessels, the eso ...

may be physically shifted toward the affected side. A reduction in the size of one side of the chest (hemithorax) on an X-ray or CT scan of the chest suggests chronic scarring. Signs of the underlying disease causing the fibrothorax are also occasionally seen on the X-ray. A

may show features similar to those seen on a plain X-ray. Lung function testing typically demonstrates findings consistent with restrictive lung disease. File:PMC4430632 CRIC2015-851624.001.png, Extensive left-sided fibrothorax File:PMC2822323 LI-25-82-g001.png, Chest radiograph displaying inhomogeneous opacification of the left half of the chest that is fibrothorax File:13244 2016 486 Fig14 HTML.jpg, Chest

(left) and

(right) demonstrating fibrothorax File:Pleural fibrosis & calcification.jpg, Autopsy specimen showing extensive pleural fibrosis

Treatment

Non-surgical

Conservative non-surgical treatment of fibrothorax is generally done by treating its underlying cause and is reserved for milder cases.

Tobacco smoking Tobacco smoking is the practice of burning tobacco and ingesting the resulting smoke. The smoke may be inhaled, as is done with cigarettes, or released from the mouth, as is generally done with pipes and cigars. The practice is believed to hav ...

cessation is strongly recommended since tobacco smoke exposure can worsen fibrosis. Severe cases of fibrothorax may require supportive

mechanical ventilation Mechanical ventilation or assisted ventilation is the Medicine, medical term for using a ventilator, ventilator machine to fully or partially provide artificial ventilation. Mechanical ventilation helps move air into and out of the lungs, wit ...

if the affected person is unable to breathe adequately on their own. In cases of fibrothorax caused by medication, it is recommended that the offending medications be stopped. Ergot alkaloid medications, which can worsen pleural fibrosis, are typically avoided. Cases of fibrothorax attributable to medication typically stop worsening if the provoking medication is stopped. In some situations, medication-induced fibrothorax improves after stopping the causative medication but fibrothorax usually does not completely resolve. Watchful waiting is appropriate for milder cases of fibrothorax in certain situations. Fibrothorax caused by

, empyema, or haemothorax often improves spontaneously 3–6 months after the precipitating illness.

Corticosteroid Corticosteroids are a class of steroid hormones that are produced in the adrenal cortex of vertebrates, as well as the synthetic analogues of these hormones. Two main classes of corticosteroids, glucocorticoids and mineralocorticoids, are invo ...

s are commonly used to treat fibrothorax but are not well-supported by available evidence.

Surgical

In severe cases of fibrothorax that are compromising a person's ability to breathe, the scar tissue (fibrous peel) causing fibrothorax can be surgically removed using a technique called decortication. However, surgical decortication is an invasive procedure which carries the risk of complications including a small risk of death, and is therefore generally only considered if severe symptoms are present and have been for many months. Surgical decortication is generally considered for people with fibrothoraces that are severe, causing significant shortness of breath, and have otherwise relatively healthy lungs since this enhances the likelihood of a better outcome. Surgical removal of the pleura ( pleurectomy) may be performed in refractory cases, as often happens when

asbestosis Asbestosis is long-term inflammation and pulmonary fibrosis, scarring of the human lung, lungs due to asbestos fibers. Symptoms may include shortness of breath, cough, wheezing, and chest pain, chest tightness. Complications may include lung canc ...

is the cause.

Prognosis

Fibrothorax complicating another condition, such as tuberculous pleuritis, empyema, or acute haemothorax often spontaneously resolves in 3-6 months. The prognosis after surgical decortication is variable and depends on the health of the underlying lung before the procedure takes place. If the lung was otherwise healthy, then certain aspects of lung function, such as

vital capacity Vital capacity (VC) is the maximum amount of air a person can expel from the lungs after a maximum inhalation. It is equal to the sum of inspiratory reserve volume, tidal volume, and expiratory reserve volume. It is approximately equal to Force ...

, may improve after decortication. If, however, the lung had significant disease, then lung function often does not improve and may even deteriorate after such intervention. The duration of fibrothorax does not affect prognosis. The mortality of surgery is less than 1% overall, but rises to 4-6% in the elderly. Other factors predicting poorer surgical outcomes include intraoperative complications, incomplete surgery, lung disease beyond the fibrothorax being treated, and specific causes of fibrothorax such as asbestosis.

Epidemiology

Sporadic cases are rarely reported in the medical literature, for example, due to

iatrogenic Iatrogenesis is the causation of a disease, a harmful complication, or other ill effect by any medical activity, including diagnosis, intervention, error, or negligence." Iatrogenic", ''Merriam-Webster.com'', Merriam-Webster, Inc., accessed 27 ...

or postoperative complications. Fibrothorax is rare in developed countries, mainly due to a lower incidence of tuberculosis. The condition is far more common in workers exposed to asbestos, with 5–13.5% of those exposed subsequently developing some degree of pleural fibrosis, sometimes not diagnosed until decades after the initial exposure.

References

{{Respiratory pathology Diseases of pleura Disorders of fascia