Symptoms of idiopathic pulmonary fibrosis are nonspecific, with dyspnea and non-productive cough being the most common. Some nonspecific, systemic symptoms like weight loss, fever, and myalgia also may be present. Specific symptoms of the disease may develop gradually and may take one to two years to manifest. About 5% of the patients may remain asymptomatic, but can be diagnosed using a chest radiograph. Bibasilar inspiratory crackles are common among patients with this disease. About half of the patients may also show digital clubbing [3]. Pulmonary hypertension is common among patients with idiopathic pulmonary fibrosis.

Many patients ignore shortness of breath, considering it as a part of ageing, but symptoms may worsen in time and necessitate medical attention. With disease progression, many patients face exacerbations and this may be followed by a short period of improvement. As symptoms become severe, oxygen levels reduce in different organs and increase pressure in lungs. This may lead to heart failure.

• Fatigue

  Almost all patients reported at least one adverse event, and more patients on interferon gamma-1b group had constitutional signs and symptoms (influenza-like illness, fatigue, fever, and chills) than did those on placebo. [ncbi.nlm.nih.gov]

  Other possible symptoms include weight loss and fatigue. With later-stage IPF, enlargement or clubbing of the fingertips may develop. [upmc.com]

  Symptoms include persistent, dry cough, shortness of breath and fatigue. There is no known cure. [medicalxpress.com]

  Fatigue. Weight loss. Clubbing, a widening and rounding of the tips of the fingers. Swelling of the legs. Cleveland Clinic News & More Cleveland Clinic News & More [my.clevelandclinic.org]

• Weight Loss

  Other possible symptoms include weight loss and fatigue. With later-stage IPF, enlargement or clubbing of the fingertips may develop. [upmc.com]

  Weight loss. Clubbing, a widening and rounding of the tips of the fingers. Swelling of the legs. Cleveland Clinic News & More Cleveland Clinic News & More [my.clevelandclinic.org]

  Some of the common symptoms include dry cough, shortness of breath, weight loss, fever, and muscle pain. [symptoma.com]

• Fever

  The patient described in the present case study was a 65-yr-old male who presented with exertional dyspnoea and fever of 2 weeks' duration. He had no history of chronic lung disease or physiological or radiological hallmarks of pre-existing disease. [ncbi.nlm.nih.gov]

  Some of the common symptoms include dry cough, shortness of breath, weight loss, fever, and muscle pain. [symptoma.com]

  Patients were considered to have pneumonia if they had a fever or wet cough, increased white blood cell (WBC) count or C-reactive protein (CRP) level, and a newly developed focal infiltrate on imaging. [pulmonologyadvisor.com]

• Weakness

  A 65-year-old man, diagnosed with IPF in 2007, was being monitored by a conventional pulmonologist while being treated with weekly acupuncture targeting a Chinese medicine diagnosis of spleen dampness and lung qi weakness and with botanical medicine targeting [ncbi.nlm.nih.gov]

  For each diagnosis and treatment question, the committee graded the quality of the evidence available (high, moderate, low, or very low), and made a recommendation (yes or no, strong or weak). Recommendations were based on majority vote. [doi.org]

• Cough

  Cough was more prevalent during wakefulness with a median cough-index of 14.8/h (IQR 10.9, 16.8) and 1.6/h (IQR 1.3-2.8) during sleep, p = 0.0039. [ncbi.nlm.nih.gov]

  Cough Suppression Cough can be one of the most vexing symptoms of Idiopathic Pulmonary Fibrosis. The severity of cough is not related to the severity of the fibrosis. Some patients with early/mild disease have severe cough. [pulmonaryfibrosismd.com]

  People may cough, have difficulty breathing, and feel tired. Pulmonary rehabilitation, lung transplantation, and drugs such as pirfenidone and nintedanib, are treatments. [msdmanuals.com]

• Dyspnea

  Also, improvements in some measures of dyspnea and health-related quality of life were observed. To demonstrate that bosentan delays IPF worsening or death. [ncbi.nlm.nih.gov]

  Also, improvements in some measures of dyspnea and health-related quality of life were observed. Objectives : To demonstrate that bosentan delays IPF worsening or death. [oadoi.org]

• Dry Cough

  A man in his mid-60's with idiopathic pulmonary fibrosis and hepatitis B-related liver cirrhosis developed exertional dyspnea and a dry cough lasting for three months. [ncbi.nlm.nih.gov]

  Typical early symptoms of IPF include shortness of breath during periods of activity and a dry cough. Other possible symptoms include weight loss and fatigue. With later-stage IPF, enlargement or clubbing of the fingertips may develop. [upmc.com]

• Exertional Dyspnea

  A 71-year-old man developed exertional dyspnea and was diagnosed with IPF. [ncbi.nlm.nih.gov]

  Symptoms and signs develop over months to years and include exertional dyspnea, cough, and fine (Velcro) crackles. Diagnosis is based on history, physical examination, high-resolution CT, and/or lung biopsy, if necessary. [msdmanuals.com]

  Most patients present with exertional dyspnea and a nonproductive cough. Such symptoms can be shared with a variety of pulmonary and cardiac diseases. [emedicine.medscape.com]

• Chronic Cough

  It was hypothesised that, like chronic cough patients, IPF patients have increased airway TRP receptor expression. Bronchial biopsies were obtained from 16 patients with IPF, 11 patients with idiopathic chronic cough and 8 controls without cough. [ncbi.nlm.nih.gov]

  This review summarises the latest insights on chronic cough in IPF. Characteristics and demographics of chronic cough Chronic cough is defined as a cough lasting for at least 8 weeks. [err.ersjournals.com]

  Symptoms of IPF include: Shortness of breath during exertion Chronic cough Diagnosis of Idiopathic Pulmonary Fibrosis (IPF) IPF is not the only disease that can cause scarring of the lung. [pennmedicine.org]

• Heart Failure

  Strain on the heart may cause the right ventricle to enlarge, eventually resulting in right-sided heart failure. Through a stethoscope, doctors often hear crackling sounds in the lungs. [msdmanuals.com]

  Right ventricular heart failure. Coronary heart disease. [patient.info]

  Adventitious sounds associated with heart failure and pneumonia are higher in frequency and quite distinct from fine crackles of IPF [ 15, 31 ], and rales are present in only one in four patients with left heart congestion due to systolic heart failure [dx.doi.org]

• Heart Disease

  Part of the National Institutes of Health, the National Heart, Lung, and Blood Institute (NHLBI) plans, conducts, and supports research related to the causes, prevention, diagnosis, and treatment of heart, blood vessel, lung, and blood diseases; and sleep [nih.gov]

  This is caused by heart disease or the decreased amount of oxygen that the body gets due to the inefficient, affected alveoli. This gets worse with physical activity since the body is trying to get more oxygen. Constant Dry cough. [stemcellthailand.org]

  This can be seen with cystic fibrosis, congenital cyanotic heart disease, and several other diseases. The tips of the fingers enlarge and the nails become extremely curved from front to back. [mountsinai.org]

• Cyanosis

  As the disease progresses, the level of oxygen in the blood decreases, and the skin may take on a bluish tinge (called cyanosis) and the ends of the fingers may become thick or club-shaped (see figure Recognizing Finger Clubbing). [msdmanuals.com]

  […] condition characterized by scarring and fibrosis of alveolar septae more common in middle-aged men, possibly related to collagen vascular disease, with positive 'rheumatoid' serology Clinical Aggressive–rapid onset of dyspnea, orthopnea, hemoptysis, cyanosis [medical-dictionary.thefreedictionary.com]

  The physical exam may find that you have: Abnormal breath sounds called crackles Bluish skin (cyanosis) around the mouth or fingernails due to low oxygen (with advanced disease) Enlargement and curving of the fingernail bases, called clubbing (with advanced [uihc.org]

  Physical findings: Symptoms of IPF include abnormal breath sounds (cackles) and, in advanced disease: blue-colored skin (cyanosis) around the mouth or in the fingernails (due to low oxygen) and clubbing of the fingers and toes. [secure.ssa.gov]

• Hypotension

  Some patients report a numb sensation in their head, and others have reported blurred vision caused by hypotension behind the eye due to a lack of oxygen and pressure; these patients have also reported severe head pains, many of which lead to permanent [en.wikipedia.org]

  Short-term phenylephrine infusions for transient hypotension were necessary in two of three subjects who had TPE during mechanical ventilation (#1 and #2). [journals.plos.org]

  Orthostatic hypotension was not observed as a serious adverse event in the sildenafil group. [doi.org]

• Arthralgia

  Extrapulmonary features may include arthralgia, muscle pains and skin rashes. Obstructive sleep apnoea may be a common presenting feature. [patient.info]

  Some of these systemic symptoms include weight loss, low-grade fevers, fatigue, arthralgias, or myalgias. [emedicine.medscape.com]

  […] of connective tissue disease–related ILD (CTD-ILD) which usually does not require invasive diagnostic modalities such as surgical lung biopsy for diagnosis.24⇓–26 Therefore, specific attention should be given to connective tissue symptoms and signs (arthralgias [jabfm.org]

• Myalgia

  Constitutional symptoms, such as low-grade fever and myalgias, are uncommon. The classic sign of IPF is fine, dry, inspiratory crackles (Velcro crackles) at both bases. Clubbing is present in about 50% of cases. [msdmanuals.com]

  Some nonspecific, systemic symptoms like weight loss, fever, and myalgia also may be present. Specific symptoms of the disease may develop gradually and may take one to two years to manifest. [symptoma.com]

  Some of these systemic symptoms include weight loss, low-grade fevers, fatigue, arthralgias, or myalgias. [emedicine.medscape.com]

• Withdrawn

  Patients were considered to have withdrawn from the study if they discontinued the follow-up visits for any reason. [doi.org]

Many of the non-specific symptoms resembling that of respiratory and cardiac diseases along with bibasilar inspiratory crackle are suggestive of idiopathic pulmonary fibrosis. Chest radiography may be abnormal with reticular opacities, particularly in the lower lobe of the lungs. To get a more sensitive and specific image of the organ, high-resolution computed tomography (HRCT) is recommended. HRCT images give the characteristic, subpleural, reticular opacities that help in confirmation. Opacities refer to regions of tissue scarring and honey combing. Differential diagnosis of reticular opacities include heart failure, bronchiolitis–associated interstitial lung disease, and hypersensitivity pneumonitis. Thus the definitive diagnosis of this condition depends on subpleural reticular opacities and honey combing without any of the other features like cysts, extensive abnormalities, or micronodules [7].

Pulmonary function tests reveal ventilator defect and reduced diffusion of carbon dioxide [13]. Results of this test is used along with clinical and radiographic findings in the diagnosis of idiopathic pulmonary fibrosis. Pulmonary function test may reveal reduced levels of total lung capacity. Biopsy of the affected tissue is the best way to distinguish idiopathic pulmonary fibrosis from other pulmonary diseases.

Histology tests show characteristic interstitial pneumonia with variegated tissue structure in lungs. Healthy tissue is alternated with interstitial inflammation and fibrosis. Small zones of heavy lung injury can be spotted in between collagen deposits. These areas or foci of fibroblasts help in definitive diagnosis of the condition. Presence of dilated bronchioles distributed between fibrosis, called the honey comb structure, is also characteristic of idiopathic pulmonary fibrosis. Diagnosis of idiopathic pulmonary fibrosis is based on the presence of usual interstitial pneumonia pattern in the lung tissue in the absence of any other known causes of interstitial lung disease.

• Pulmonary Infiltrate

  pulmonary infiltrates, and varying. .. [nejm.org]

  […] tool=bestpractice.com It is the most common form of the group of interstitial lung diseases also known as idiopathic interstitial pneumonias, which share clinical features of shortness of breath; diffuse pulmonary infiltrates on imaging; and varying degrees [bestpractice.bmj.com]

  stage III (pulmonary infiltrates without BHL) and stage IV (pulmonary fibrosis), according to established criteria. 20 Patients with sarcoidosis for whom lung function tests at presentation and 4 years were available (n=140) were also categorised into [doi.org]

  Acute exacerbation of IPF was defined using the following criteria proposed by Kondoh et al. 7 and Akira et al. 8. 1) Acute worsening of dyspnoea within 1 month of presentation. 2) New pulmonary infiltrates on a chest radiograph or computed tomography [erj.ersjournals.com]

• Decreased Forced Vital Capacity

  […] total lung capacity (TLC) Decreased forced vital capacity (FVC) Decreased diffusing capacity of the lung for carbon monoxide (DLCO) Reduced diffusing capacity is mainly due to ventilation-perfusion mismatch from ventilation of lung tissue with capillary [pathologyoutlines.com]

A complete cure or an optimal therapy for the condition is not defined. Idiopathic pulmonary fibrosis has comorbid conditions like gastroesophageal reflux disease, obstructive sleep apnea, and coronary artery disease. Thus, optimal treatment of the disease should include the treatment of comorbid conditions. Most of the treatment modalities aim at improving the symptoms and preventing complications. Anti-inflammatory medications and immune modulators were used earlier, based on the theory that idiopathic pulmonary fibrosis is caused by inflammation of the lungs followed by fibrosis.

Controlling gastroesophageal reflux disease with appropriate medication is found to reduce fibrosis of lung tissue. Patients who are smokers are recommended to quit smoking. Oxygen therapy is suggested for patients with hypoxemia. Immunization against influenza virus and pneumococcus is important to prevent complications. For those with forced vital capacity between 50% and 80%, pirfenidone is recommended. Corticosteroids, alone or in combination with cyclophosphamide, are used in exacerbations. Pulmonary rehabilitation is also suggested for most of the patients. N-acetylcysteine is used in some countries. Lung transplantation is a recommended therapy and is found to be more beneficial than medications. Patients for this surgical method are chosen on a basis of a lung allocation score. The five-year survival rates after transplantation is reported to be 50-56% [7].

The rate of disease progression varies from person to person. In some people, medication may reduce the progression, while in others the condition may remain stable for long periods. Some patients may have exacerbations resulting in respiratory troubles. Lung transplantation is found to improve the condition in many patients. One of the studies report the mean life expectancy in patients with idiopathic pulmonary fibrosis to be around 3-5 years. Death rate is found to be related to aging. One of the most common cause of death due to idiopathic pulmonary fibrosis is an acute exacerbation of the condition. The mortality rate of the condition is found to be around 58-64 deaths in a million [12].

The actual etiology of the disease is not known. It was thought earlier that general inflammation of the lungs gradually leads to fibrosis. This theory lost consensus and was replaced by activation of fibroblasts as the prominent cause of fibrosis [3]. Epithelial injury followed by activation of fibroblasts is thought to initiate a chain of events that result in alveolitis. Lung shows healthy tissue interspersed with interstitial tissue inflammation, fibrosis and a honeycomb structure. Studies report the link between idiopathic pulmonary fibrosis with various occupations that expose an individual to dust or fume, like industrial car cleaning, dairy, diamond polishing, gold extraction, and welding. Presence of silica, and metals like iron and nickel in the lungs is found to increase the risk of this condition [4]. Smoking and certain medications like amiodarone, nitrofurantoin also may lead to interstitial lung disease. Pulmonary fibrosis may result as a complication of some infections including that of Mycoplasma pneumoniae, Influenza A2 virus, and Legionella pneumophilia.

Estimates of prevalence of this condition are limited. Prevalence from different part of the world ranges from 7 to 20 cases per 100,000 among the general population [5]. It can occur in any age group, but the mean age of prevalence is reported to be around 66.9 years. Prevalence was higher among males than females in the ratio 20:13 in 100,000 people. The incidence rate among adults above the age of 60 years was reported to be 8.8 cases per 100,000 [6]. Racial, geographical and ethnic influences on the incidence of this condition is still not known [7]. Differences in diagnostic criteria, exposure to risk factors and labeling by physicians may affect the incidence and prevalence rate in different parts of the world. Mortality rate for this disease was found to be highest in United States. The rate seems to be increasing in some countries like United States, England and Australia. There are some who believe that idiopathic pulmonary fibrosis might run in families, but the majority view goes against this and there is no clear consensus on this issue.

An earlier hypothesis stating inflammation of lung tissue leads to fibrosis, was rejected later. A more recent theory puts forward inflammation of epithelial tissue followed by activation of fibroblasts as the main steps leading to pulmonary fibrosis. Homeostasis of epithelial tissue is changed by a number of endogenous and exogenous factors that trigger a chain of events resulting in fibrosis [8]. The first step in the cascade is the damage in epithelial tissue of alveoli due to environmental triggers like pollution, viral infection, gastroesophageal reflux disease, and smoke. The epithelial tissue then tries to heal the affected tissue. In idiopathic pulmonary fibrosis, anomalous wound healing commences wherein the mesenchymal cells are activated resulting in the formation of a fibroblastic foci. Activated cells release cytokines and other growth factors which in turn trigger proliferation of fibroblasts. This is followed by fibrogenesis and secretion of extracellular matrix. Accumulated extracellular matrix in the tissue then causes contraction of tissue [9]. Myofibroblasts of the wound healing tissue loses its apoptopic ability proliferating continuously. A study conducted on the lung tissue from idiopathic pulmonary fibrosis patients shows that deficiency of prostaglandin E2 results in increased cell death of epithelial cells and reduced apoptosis of fibroblasts cells, the two most common reasons for progressive fibrosis of tissue [10]. Mutation in telomerase resulting in loss of epithelial cells in alveoli is a probable genetic explanation given for the occurrence [11].

As etiology of this condition is not known, prevention is not possible. Quitting smoking and avoiding exposure to environmental triggers are very important in reducing the risk of developing idiopathic pulmonary fibrosis. Those who are at a higher risk of developing this condition in any of the occupations, should wear breathing devices to limit exposure to chemicals.

Idiopathic pulmonary fibrosis is the most common type of fibrosing alveolitis with an unknown etiology. This progressive condition that results in scarring of lung tissue has a poor prognosis [1]. It is mostly seen in older adults in the age group of 50 to 70 years and develops gradually over a period of six months. Signs and symptoms of the disease are not specific, and very often diagnosis may take more than a year or two [2]. The actual cause of the condition is not yet known and there are no proven treatment modalities for the disease. Histology of the lungs shows signs of usual interstitial pneumonia. Inflammation and fibrosis of lung tissue are the most characteristic features of this disease. In many cases lung transplantation is the only known effective method to improve the condition.

Idiopathic pulmonary fibrosis is a debilitating condition characterized by scarring and damage of lungs. Scarring or fibrosis of lungs results in shortness of breath. It is a rare condition and is more common in older adults, particularly in those above 50 years of age. Prevalence is also more common among men when compared to women. The damage to lungs caused by the disease is irreversible, but many treatment modalities are available to improve symptoms of the disease.

The actual cause of the disease is not defined. Smoking, exposure to harmful chemicals, and certain infections are known to increase the risk of developing this condition. Progress of the disease varies from person to person. In some people the progress happens very fast, while in some it is slow. In some others the condition may remain the same without any significant changes. Most of the symptoms of the condition are nonspecific. Some of the common symptoms include dry cough, shortness of breath, weight loss, fever, and muscle pain.
A complete physical examination, particularly the sound of breathing pattern, is used to diagnose abnormalities in the structure and function of lungs. Imaging techniques like chest X-ray, CT scan and echocardiogram help in determining the location and extent of damage to lungs. Pulmonary function test, oximetry and exercise stress test are useful in monitoring lung function. Biopsy of the affected tissue is a confirmatory diagnostic test for idiopathic pulmonary fibrosis.

Complete cure for this condition is not yet available. Most of the treatment modalities used are useful in reducing the progress of the disease. Steroids, alone or in combination with immunosuppressant, represent the most common medication used for treating idiopathic pulmonary fibrosis. Oxygen therapy is used to reduce complications due to low oxygen levels. Lung transplantation is a suitable option for many people and is known to improve the condition in more than 50% of the patients. Pulmonary rehabilitation exercises are helpful in improving the functioning of lungs.

1. American Thoracic Society/European Respiratory Society International Multidisciplinary Consensus Classification of the Idiopathic Interstitial Pneumonias. This joint statement of the American Thoracic Society (ATS), and the European Respiratory Society (ERS) was adopted by the ATS board of directors, June 2001 and by the ERS Executive Committee, June 2001. Am J Respir Crit Care Med. 2002; 165(2): 277-304.
2. Ley B, Collard HR, King TE Jr. Clinical course and prediction of survival in idiopathic pulmonary fibrosis. Am J Respir Crit Care Med. 2011; 183(4): 431-40.
3. Kim DS, Collard HR, King TE Jr. Classification and natural history of the idiopathic interstitial pneumonias. Proc Am Thorac Soc; 3(4): 285-92.
4. McAnulty RJ, Laurent GJ. Pathogenesis of lung fibrosis and potential new therapeutic strategies. Exp Nephrol. 1995; 3: 96-107. 
5. Hodgson U, Laitinen T, Tukiainen P. Nationwide prevalence of sporadic and familial idiopathic pulmonary fibrosis: evidence of founder effect among multiplex families in Finland. Thorax. 2000; 57(4): 338-42. 
6. Fernandez Perez ER, Daniels CE, Schroeder DR, et al. Incidence, prevalence, and clinical course of idiopathic pulmonary fibrosis: a population-based study. Chest. 2010; 137(1): 129-37.
7. Raghu G, Collard HR, Egan JJ, Martinez FJ, Behr J, Brown KK. An Official ATS/ERS/JRS/ALAT Statement: Idiopathic Pulmonary Fibrosis: Evidence-based Guidelines for Diagnosis and Management. Am J Respir Crit Care Med. 2011; 183(6): 788-824.
8. Verma S, Slutsky AS. Idiopathic pulmonary fibrosis--new insights. N Engl J Med. Mar 29 2007;356 (13): 1370-2.
9. Harari S, Caminati A. IPF: new insight on pathogenesis and treatment. Allergy. 2010; 65(5): 537-53.
10. Maher TM, Evans IC, Bottoms SE, Mercer PF, Thorley AJ, Nicholson AG. Diminished prostaglandin E2 contributes to the apoptosis paradox in idiopathic pulmonary fibrosis. Am J Respir Crit Care Med. 2010; 182(1): 73-82.
11. Armanios MY, Chen JJ, Cogan JD, et al. Telomerase mutations in families with idiopathic pulmonary fibrosis. N Engl J Med. 2007; 356(13): 1317-26.
12. Olson AL, Swigris JJ, Lezotte DC, Norris JM, Wilson CG, Brown KK. Mortality from pulmonary fibrosis increased in the United States from 1992 to 2003. Am J Respir Crit Care Med. 2007; 176(3): 277-84.
13. Martinez FJ, Flaherty K. Pulmonary function testing in idiopathic interstitial pneumonias. Proc Am Thorac Soc. 2006; 3(4): 315-21.