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Pulmonary Fibrosis

Idiopathic Idiopathic Dermatomyositis pulmonary fibrosis Fibrosis Any pathological condition where fibrous connective tissue invades any organ, usually as a consequence of inflammation or other injury. Bronchiolitis Obliterans is a specific entity of the major idiopathic Idiopathic Dermatomyositis interstitial pneumonia Pneumonia Pneumonia or pulmonary inflammation is an acute or chronic inflammation of lung tissue. Causes include infection with bacteria, viruses, or fungi. In more rare cases, pneumonia can also be caused through toxic triggers through inhalation of toxic substances, immunological processes, or in the course of radiotherapy. Pneumonia classification of interstitial lung diseases Interstitial Lung Diseases Interstitial lung diseases are a heterogeneous group of disorders characterized by the inflammation and fibrosis of lung parenchyma, especially the pulmonary connective tissue in the alveolar walls. It may be idiopathic (e.g., idiopathic pulmonary fibrosis) or secondary to connective tissue diseases, medications, malignancies, occupational exposure, or allergens. Interstitial Lung Diseases. As implied by the name, the exact causes are poorly understood. Patients Patients Individuals participating in the health care system for the purpose of receiving therapeutic, diagnostic, or preventive procedures. Clinician–Patient Relationship often present in the moderate to advanced stage with progressive dyspnea Dyspnea Dyspnea is the subjective sensation of breathing discomfort. Dyspnea is a normal manifestation of heavy physical or psychological exertion, but also may be caused by underlying conditions (both pulmonary and extrapulmonary). Dyspnea and nonproductive cough. The diagnosis is made by characteristic imaging findings, pulmonary function testing Pulmonary Function Testing Pulmonary Function Tests that indicates restrictive lung disease, and (if necessary) lung biopsy Lung Biopsy Antineutrophil Cytoplasmic Antibody (ANCA)-Associated Vasculitis. Options are limited for therapies to slow progression. Lung transplantation Lung transplantation The transference of either one or both of the lungs from one human or animal to another. Organ Transplantation is the only curative intervention if the patient is a candidate for one.

Last updated: 31 May, 2022

Editorial responsibility: Stanley Oiseth, Lindsay Jones, Evelin Maza

Definition and Epidemiology

Definition

Idiopathic Idiopathic Dermatomyositis pulmonary fibrosis Fibrosis Any pathological condition where fibrous connective tissue invades any organ, usually as a consequence of inflammation or other injury. Bronchiolitis Obliterans (IPF) is the most common type of interstitial lung disease ( ILD ILD Interstitial lung diseases are a heterogeneous group of disorders characterized by the inflammation and fibrosis of lung parenchyma, especially the pulmonary connective tissue in the alveolar walls. It may be idiopathic (e.g., idiopathic pulmonary fibrosis) or secondary to connective tissue diseases, medications, malignancies, occupational exposure, or allergens. Interstitial Lung Diseases) and is characterized by chronic, progressive, irreversible fibrosis Fibrosis Any pathological condition where fibrous connective tissue invades any organ, usually as a consequence of inflammation or other injury. Bronchiolitis Obliterans of the lung parenchyma.

Epidemiology

IPF has been difficult to study because of its rarity and evolution in diagnostic practices.

  • Incidence Incidence The number of new cases of a given disease during a given period in a specified population. It also is used for the rate at which new events occur in a defined population. It is differentiated from prevalence, which refers to all cases in the population at a given time. Measures of Disease Frequency and prevalence Prevalence The total number of cases of a given disease in a specified population at a designated time. It is differentiated from incidence, which refers to the number of new cases in the population at a given time. Measures of Disease Frequency:
    • Uncommon
    • Higher in North America and Europe than in the rest of the world
    • Estimated prevalence Prevalence The total number of cases of a given disease in a specified population at a designated time. It is differentiated from incidence, which refers to the number of new cases in the population at a given time. Measures of Disease Frequency in the United States: 10–60 per 100,000
    • Likely underappreciated in terms of its occurrence and public health impact (e.g., health care costs and resource utilization)
  • Occurs primarily in elderly individuals (> 65 years) 
  • More often seen in men

Etiology and Pathophysiology

Etiology

The cause of IPF remains largely unclear. However, in the current hypothesis Hypothesis A hypothesis is a preliminary answer to a research question (i.e., a “guess” about what the results will be). There are 2 types of hypotheses: the null hypothesis and the alternative hypothesis. Statistical Tests and Data Representation regarding the pathogenesis of IPF, the following exposures may lead to the initial alveolar epithelial injury:

  • Tobacco smoke (most common)
  • Environmental pollutants and dust
  • Viral infections Infections Invasion of the host organism by microorganisms or their toxins or by parasites that can cause pathological conditions or diseases. Chronic Granulomatous Disease
  • GERD GERD Gastroesophageal reflux disease (GERD) occurs when the stomach acid frequently flows back into the esophagus. This backwash (acid reflux) can irritate the lining of the esophagus, causing symptoms such as retrosternal burning pain (heartburn). Gastroesophageal Reflux Disease (GERD) 
  • Chronic microaspiration 
  • Obstructive sleep apnea Sleep apnea Repeated cessation of breathing for > 10 seconds during sleep and results in sleep interruption, fatigue, and daytime sleepiness. Obstructive Sleep Apnea

Pathophysiology

The underlying mechanism is poorly understood.

  • Environmental exposure and possible genetic predisposition → recurrent alveolar epithelial damage
  • Migration and activation of fibroblasts Fibroblasts Connective tissue cells which secrete an extracellular matrix rich in collagen and other macromolecules. Sarcoidosis → myofibroblast transformation Transformation Change brought about to an organism’s genetic composition by unidirectional transfer (transfection; transduction, genetic; conjugation, genetic, etc.) and incorporation of foreign DNA into prokaryotic or eukaryotic cells by recombination of part or all of that DNA into the cell’s genome. Bacteriology
  • Failure of normal myofibroblast apoptosis Apoptosis A regulated cell death mechanism characterized by distinctive morphologic changes in the nucleus and cytoplasm, including the endonucleolytic cleavage of genomic DNA, at regularly spaced, internucleosomal sites, I.e., DNA fragmentation. It is genetically-programmed and serves as a balance to mitosis in regulating the size of animal tissues and in mediating pathologic processes associated with tumor growth. Ischemic Cell Damage → exaggerated extracellular matrix Extracellular matrix A meshwork-like substance found within the extracellular space and in association with the basement membrane of the cell surface. It promotes cellular proliferation and provides a supporting structure to which cells or cell lysates in culture dishes adhere. Hypertrophic and Keloid Scars accumulation → lung parenchyma destruction and scarring Scarring Inflammation
  • Additional mediators of profibrotic changes include:
    • Transforming growth factor beta
    • Fibroblast growth factor Fibroblast growth factor A family of small polypeptide growth factors that share several common features including a strong affinity for heparin, and a central barrel-shaped core region of 140 amino acids that is highly homologous between family members. Although originally studied as proteins that stimulate the growth of fibroblasts this distinction is no longer a requirement for membership in the fibroblast growth factor family. X-linked Hypophosphatemic Rickets 2
    • Platelet-derived growth factor Platelet-derived growth factor Mitogenic peptide growth hormone carried in the alpha-granules of platelets. It is released when platelets adhere to traumatized tissues. Connective tissue cells near the traumatized region respond by initiating the process of replication. Hypertrophic and Keloid Scars (PDGF)
    • Matrix metalloproteinase 7 (MMP-7)
  • Consequence: ↓ gas exchange Gas exchange Human cells are primarily reliant on aerobic metabolism. The respiratory system is involved in pulmonary ventilation and external respiration, while the circulatory system is responsible for transport and internal respiration. Pulmonary ventilation (breathing) represents movement of air into and out of the lungs. External respiration, or gas exchange, is represented by the O2 and CO2 exchange between the lungs and the blood. Gas Exchange → chronic hypoxic respiratory failure Respiratory failure Respiratory failure is a syndrome that develops when the respiratory system is unable to maintain oxygenation and/or ventilation. Respiratory failure may be acute or chronic and is classified as hypoxemic, hypercapnic, or a combination of the two. Respiratory Failure

Clinical Presentation

Symptoms

Patients Patients Individuals participating in the health care system for the purpose of receiving therapeutic, diagnostic, or preventive procedures. Clinician–Patient Relationship with IPF can have variable Variable Variables represent information about something that can change. The design of the measurement scales, or of the methods for obtaining information, will determine the data gathered and the characteristics of that data. As a result, a variable can be qualitative or quantitative, and may be further classified into subgroups. Types of Variables presentations, and early in its course, IPF can be asymptomatic. 

  • Presentation of symptoms suggests a moderate to advanced stage:
    • Chronic dyspnea Dyspnea Dyspnea is the subjective sensation of breathing discomfort. Dyspnea is a normal manifestation of heavy physical or psychological exertion, but also may be caused by underlying conditions (both pulmonary and extrapulmonary). Dyspnea
      • Initially exertional (nearly universal)
      • Progressive, eventually occurring at rest
    • Chronic nonproductive cough
    • Reduced exercise tolerance Tolerance Pharmacokinetics and Pharmacodynamics
  • Associated systemic symptoms are uncommon but can include:
    • Fatigue Fatigue The state of weariness following a period of exertion, mental or physical, characterized by a decreased capacity for work and reduced efficiency to respond to stimuli. Fibromyalgia
    • Low-grade fever Fever Fever is defined as a measured body temperature of at least 38°C (100.4°F). Fever is caused by circulating endogenous and/or exogenous pyrogens that increase levels of prostaglandin E2 in the hypothalamus. Fever is commonly associated with chills, rigors, sweating, and flushing of the skin. Fever
    • Weight loss Weight loss Decrease in existing body weight. Bariatric Surgery
    • Myalgias Myalgias Painful sensation in the muscles. Tick-borne Encephalitis Virus

Physical exam

General findings:

  • Bibasilar fine inspiratory (“Velcro-like”) crackles on auscultation 
  • End-inspiratory “squeaks” in advanced disease with bronchiectasis Bronchiectasis Bronchiectasis is a chronic disease of the airways that results from permanent bronchial distortion. This results from a continuous cycle of inflammation, bronchial damage and dilation, impaired clearance of secretions, and recurrent infections. Bronchiectasis
  • Digital clubbing Clubbing Cardiovascular Examination 

Patients Patients Individuals participating in the health care system for the purpose of receiving therapeutic, diagnostic, or preventive procedures. Clinician–Patient Relationship can present with pulmonary hypertension Hypertension Hypertension, or high blood pressure, is a common disease that manifests as elevated systemic arterial pressures. Hypertension is most often asymptomatic and is found incidentally as part of a routine physical examination or during triage for an unrelated medical encounter. Hypertension ( PH pH The quantitative measurement of the acidity or basicity of a solution. Acid-Base Balance) and cor pulmonale Cor Pulmonale Cor pulmonale is right ventricular (RV) dysfunction caused by lung disease that results in pulmonary artery hypertension. The most common cause of cor pulmonale is chronic obstructive pulmonary disease. Dyspnea is the usual presenting symptom. Cor Pulmonale: 

  • Pitting edema Edema Edema is a condition in which excess serous fluid accumulates in the body cavity or interstitial space of connective tissues. Edema is a symptom observed in several medical conditions. It can be categorized into 2 types, namely, peripheral (in the extremities) and internal (in an organ or body cavity). Edema (pedal or sacral)
  • Jugular venous distention
  • Cyanosis Cyanosis A bluish or purplish discoloration of the skin and mucous membranes due to an increase in the amount of deoxygenated hemoglobin in the blood or a structural defect in the hemoglobin molecule. Pulmonary Examination 
  • Split second heart sound with dominant P2 component
Nail clubbing

Nail clubbing Clubbing Cardiovascular Examination:
Clubbed nails are abnormal, rounded nail beds often seen in association with conditions causing chronic hypoxemia Hypoxemia Neonatal Respiratory Distress Syndrome, such as cystic Cystic Fibrocystic Change fibrosis Fibrosis Any pathological condition where fibrous connective tissue invades any organ, usually as a consequence of inflammation or other injury. Bronchiolitis Obliterans or interstitial lung disease.

Image: “Nail clubbing Clubbing Cardiovascular Examination” by Department of Internal Medicine, Cleveland Clinic Florida, 2950 Cleveland Clinic Boulevard, Weston, FL 33331, USA. License: CC BY 3.0

Diagnosis

Idiopathic Idiopathic Dermatomyositis pulmonary fibrosis Fibrosis Any pathological condition where fibrous connective tissue invades any organ, usually as a consequence of inflammation or other injury. Bronchiolitis Obliterans is diagnosed by a combination of radiologic, pathologic, and clinical investigations.

Important patient history

It is critical to obtain the following on top of a complete medical history to ensure that other causes of ILD ILD Interstitial lung diseases are a heterogeneous group of disorders characterized by the inflammation and fibrosis of lung parenchyma, especially the pulmonary connective tissue in the alveolar walls. It may be idiopathic (e.g., idiopathic pulmonary fibrosis) or secondary to connective tissue diseases, medications, malignancies, occupational exposure, or allergens. Interstitial Lung Diseases are excluded: 

  • Occupational history
  • Recreational history
  • Environmental history
  • Risk factors for HIV HIV Anti-HIV Drugs 
  • Radiation Radiation Emission or propagation of acoustic waves (sound), electromagnetic energy waves (such as light; radio waves; gamma rays; or x-rays), or a stream of subatomic particles (such as electrons; neutrons; protons; or alpha particles). Osteosarcoma exposure
  • Notable medications associated with pulmonary fibrosis Fibrosis Any pathological condition where fibrous connective tissue invades any organ, usually as a consequence of inflammation or other injury. Bronchiolitis Obliterans:
    • Amiodarone
    • Bleomycin Bleomycin A complex of related glycopeptide antibiotics from streptomyces verticillus consisting of bleomycin a2 and b2. It inhibits DNA metabolism and is used as an antineoplastic, especially for solid tumors. Antitumor Antibiotics
    • Nitrofurantoin
    • Methotrexate Methotrexate An antineoplastic antimetabolite with immunosuppressant properties. It is an inhibitor of tetrahydrofolate dehydrogenase and prevents the formation of tetrahydrofolate, necessary for synthesis of thymidylate, an essential component of DNA. Antimetabolite Chemotherapy

Pulmonary function tests

Typical findings:

  • Restrictive ventilatory defect
  • ↓ Diffusing capacity of the lung for carbon monoxide Carbon monoxide Carbon monoxide (CO). A poisonous colorless, odorless, tasteless gas. It combines with hemoglobin to form carboxyhemoglobin, which has no oxygen carrying capacity. The resultant oxygen deprivation causes headache, dizziness, decreased pulse and respiratory rates, unconsciousness, and death. Carbon Monoxide Poisoning ( DLCO DLCO Pulmonary Function Tests)

Measurements:

  • Static lung volumes using body plethysmography typically reveal ↓ lung volumes (restriction) such as:
    • Vital capacity Vital capacity The volume of air that is exhaled by a maximal expiration following a maximal inspiration. Ventilation: Mechanics of Breathing
    • Functional residual capacity Functional residual capacity The volume of air remaining in the lungs at the end of a normal, quiet expiration. It is the sum of the residual volume and the expiratory reserve volume. Common abbreviation is frc. Ventilation: Mechanics of Breathing (FRC)
    • Total lung capacity Total lung capacity The volume of air contained in the lungs at the end of a maximal inspiration. It is the equivalent to each of the following sums: vital capacity plus residual volume; inspiratory capacity plus functional residual capacity; tidal volume plus inspiratory reserve volume plus functional residual capacity; or tidal volume plus inspiratory reserve volume plus expiratory reserve volume plus residual volume. Ventilation: Mechanics of Breathing (TLC)
    • Forced vital capacity Vital capacity The volume of air that is exhaled by a maximal expiration following a maximal inspiration. Ventilation: Mechanics of Breathing (FVC)
  • Normal or ↑ forced expiratory volume in 1 second (FEV1)/FVC ratio
  • Static pressure–volume curve shifted downward and to the right → ↓ lung compliance Compliance Distensibility measure of a chamber such as the lungs (lung compliance) or bladder. Compliance is expressed as a change in volume per unit change in pressure. Veins: Histology

Imaging

Chest X-ray Chest X-ray X-ray visualization of the chest and organs of the thoracic cavity. It is not restricted to visualization of the lungs. Pulmonary Function Tests:

High-resolution CT High-resolution CT Imaging of the Lungs and Pleura ( HRCT HRCT Pulmonary Function Tests) scan:

  • Significantly more sensitive and specific for the diagnosis of IPF
  • Features (predominantly seen in the lower lobes):
    • Peripheral and subpleural reticular septal thickening
    • Traction bronchiectasis Bronchiectasis Bronchiectasis is a chronic disease of the airways that results from permanent bronchial distortion. This results from a continuous cycle of inflammation, bronchial damage and dilation, impaired clearance of secretions, and recurrent infections. Bronchiectasis
    • Honeycombing cysts Cysts Any fluid-filled closed cavity or sac that is lined by an epithelium. Cysts can be of normal, abnormal, non-neoplastic, or neoplastic tissues. Fibrocystic Change
    • Lung architectural distortion Distortion Defense Mechanisms
    • Superimposed ground-glass opacities may be seen.
Patient with pulmonary fibrosis

CT image from a patient with pulmonary fibrosis Fibrosis Any pathological condition where fibrous connective tissue invades any organ, usually as a consequence of inflammation or other injury. Bronchiolitis Obliterans:
A basilar reticular pattern is seen.

Image: “Patient with pulmonary fibrosis Fibrosis Any pathological condition where fibrous connective tissue invades any organ, usually as a consequence of inflammation or other injury. Bronchiolitis Obliterans” by Department of Respiratory Medicine, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, #1 Shuaifuyuan Street, Beijing, Dongcheng District 100730, China. License: CC BY 2.0

Lung biopsy Lung Biopsy Antineutrophil Cytoplasmic Antibody (ANCA)-Associated Vasculitis

Surgical specimens can be obtained using video-assisted thoracoscopic surgery (VATS). Patients Patients Individuals participating in the health care system for the purpose of receiving therapeutic, diagnostic, or preventive procedures. Clinician–Patient Relationship with IPF may show a pattern of usual interstitial pneumonia Pneumonia Pneumonia or pulmonary inflammation is an acute or chronic inflammation of lung tissue. Causes include infection with bacteria, viruses, or fungi. In more rare cases, pneumonia can also be caused through toxic triggers through inhalation of toxic substances, immunological processes, or in the course of radiotherapy. Pneumonia:

  • Alternating zones of normal and abnormal lung tissue
  • Fibrosis Fibrosis Any pathological condition where fibrous connective tissue invades any organ, usually as a consequence of inflammation or other injury. Bronchiolitis Obliterans
  • Fibroblast foci (areas of active fibroproliferation)
  • Honeycombing patterns

Bronchoscopy Bronchoscopy Endoscopic examination, therapy or surgery of the bronchi. Laryngomalacia and Tracheomalacia

Supporting laboratory evaluation

The following can be performed to exclude other causes of ILD ILD Interstitial lung diseases are a heterogeneous group of disorders characterized by the inflammation and fibrosis of lung parenchyma, especially the pulmonary connective tissue in the alveolar walls. It may be idiopathic (e.g., idiopathic pulmonary fibrosis) or secondary to connective tissue diseases, medications, malignancies, occupational exposure, or allergens. Interstitial Lung Diseases and will be guided by clinical suspicion:

  • Erythrocyte sedimentation rate Erythrocyte Sedimentation Rate Soft Tissue Abscess and CRP
  • Antinuclear antibodies Antibodies Immunoglobulins (Igs), also known as antibodies, are glycoprotein molecules produced by plasma cells that act in immune responses by recognizing and binding particular antigens. The various Ig classes are IgG (the most abundant), IgM, IgE, IgD, and IgA, which differ in their biologic features, structure, target specificity, and distribution. Immunoglobulins: Types and Functions
  • Rheumatoid factor Rheumatoid factor Antibodies found in adult rheumatoid arthritis patients that are directed against gamma-chain immunoglobulins. Autoimmune Hepatitis and anti–cyclic citrullinated peptide antibodies Antibodies Immunoglobulins (Igs), also known as antibodies, are glycoprotein molecules produced by plasma cells that act in immune responses by recognizing and binding particular antigens. The various Ig classes are IgG (the most abundant), IgM, IgE, IgD, and IgA, which differ in their biologic features, structure, target specificity, and distribution. Immunoglobulins: Types and Functions
  • Aldolase Aldolase Becker Muscular Dystrophy and CK
  • Myositis-specific antibodies Antibodies Immunoglobulins (Igs), also known as antibodies, are glycoprotein molecules produced by plasma cells that act in immune responses by recognizing and binding particular antigens. The various Ig classes are IgG (the most abundant), IgM, IgE, IgD, and IgA, which differ in their biologic features, structure, target specificity, and distribution. Immunoglobulins: Types and Functions
  • Anti-SSA/Ro and anti-SSB/La antibodies Antibodies Immunoglobulins (Igs), also known as antibodies, are glycoprotein molecules produced by plasma cells that act in immune responses by recognizing and binding particular antigens. The various Ig classes are IgG (the most abundant), IgM, IgE, IgD, and IgA, which differ in their biologic features, structure, target specificity, and distribution. Immunoglobulins: Types and Functions
  • Serum ACE level

Management

Pharmacologic therapy

There are limited options for pharmacologic treatment in patients Patients Individuals participating in the health care system for the purpose of receiving therapeutic, diagnostic, or preventive procedures. Clinician–Patient Relationship with IPF, and none provide a cure.

Antifibrotic agents:

  • Approved for delaying progression
  • Do not significantly improve mortality Mortality All deaths reported in a given population. Measures of Health Status
  • Options:
    • Pirfenidone 
    • Nintedanib

PH pH The quantitative measurement of the acidity or basicity of a solution. Acid-Base Balance management:

GERD GERD Gastroesophageal reflux disease (GERD) occurs when the stomach acid frequently flows back into the esophagus. This backwash (acid reflux) can irritate the lining of the esophagus, causing symptoms such as retrosternal burning pain (heartburn). Gastroesophageal Reflux Disease (GERD) management:

Nonpharmacologic therapy

  • Long-term oxygen therapy when patients Patients Individuals participating in the health care system for the purpose of receiving therapeutic, diagnostic, or preventive procedures. Clinician–Patient Relationship resting or ambulatory saturations are < 88% 
  • Pulmonary rehabilitation:
    • Alleviate the overt symptoms.
    • Improve functional status.
    • May include: 
      • Exercise training
      • Smoking Smoking Willful or deliberate act of inhaling and exhaling smoke from burning substances or agents held by hand. Interstitial Lung Diseases cessation
      • Psychosocial assistance
      • Supportive care
  • Vaccinations:
    • Influenza Influenza Influenza viruses are members of the Orthomyxoviridae family and the causative organisms of influenza, a highly contagious febrile respiratory disease. There are 3 primary influenza viruses (A, B, and C) and various subtypes, which are classified based on their virulent surface antigens, hemagglutinin (HA) and neuraminidase (NA). Influenza typically presents with a fever, myalgia, headache, and symptoms of an upper respiratory infection. Influenza Viruses/Influenza
    • Pneumonia Pneumonia Pneumonia or pulmonary inflammation is an acute or chronic inflammation of lung tissue. Causes include infection with bacteria, viruses, or fungi. In more rare cases, pneumonia can also be caused through toxic triggers through inhalation of toxic substances, immunological processes, or in the course of radiotherapy. Pneumonia
  • Lung transplantation Lung transplantation The transference of either one or both of the lungs from one human or animal to another. Organ Transplantation:
    • The only definitive treatment 
    • Bilateral lung transplantation Lung transplantation The transference of either one or both of the lungs from one human or animal to another. Organ Transplantation is more commonly used than single lung transplantation Lung transplantation The transference of either one or both of the lungs from one human or animal to another. Organ Transplantation.
    • Early referral should be considered.
  • Palliative care:
    • Focus Focus Area of enhancement measuring < 5 mm in diameter Imaging of the Breast on reducing symptoms and improving comfort.
    • Use is not limited to end-of-life care.

Complications and Prognosis

Complications

  • Respiratory infections Infections Invasion of the host organism by microorganisms or their toxins or by parasites that can cause pathological conditions or diseases. Chronic Granulomatous Disease
  • Thromboembolic disease
  • Lung cancer Lung cancer Lung cancer is the malignant transformation of lung tissue and the leading cause of cancer-related deaths. The majority of cases are associated with long-term smoking. The disease is generally classified histologically as either small cell lung cancer or non-small cell lung cancer. Symptoms include cough, dyspnea, weight loss, and chest discomfort. Lung Cancer
  • Type 3 Type 3 Spinal Muscular Atrophy PH pH The quantitative measurement of the acidity or basicity of a solution. Acid-Base Balance and cor pulmonale Cor Pulmonale Cor pulmonale is right ventricular (RV) dysfunction caused by lung disease that results in pulmonary artery hypertension. The most common cause of cor pulmonale is chronic obstructive pulmonary disease. Dyspnea is the usual presenting symptom. Cor Pulmonale
  • Respiratory failure Respiratory failure Respiratory failure is a syndrome that develops when the respiratory system is unable to maintain oxygenation and/or ventilation. Respiratory failure may be acute or chronic and is classified as hypoxemic, hypercapnic, or a combination of the two. Respiratory Failure

Prognosis Prognosis A prediction of the probable outcome of a disease based on a individual’s condition and the usual course of the disease as seen in similar situations. Non-Hodgkin Lymphomas

IPF progression is associated with an estimated median Median After arranging the data from loWest to highest, the median is the middle value, separating the lower half from the upper half of the data set. Measures of Central Tendency and Dispersion survival time of up to 5 years following the diagnosis.

  • The rate of decline and progression to death in patients Patients Individuals participating in the health care system for the purpose of receiving therapeutic, diagnostic, or preventive procedures. Clinician–Patient Relationship with IPF may take several clinical forms: 
    • Slow physiologic deterioration with worsening severity of dyspnea Dyspnea Dyspnea is the subjective sensation of breathing discomfort. Dyspnea is a normal manifestation of heavy physical or psychological exertion, but also may be caused by underlying conditions (both pulmonary and extrapulmonary). Dyspnea
    • Rapid deterioration and progression to death
    • Periods of relative stability interposed with periods of acute respiratory decline
  • Acute respiratory failure Respiratory failure Respiratory failure is a syndrome that develops when the respiratory system is unable to maintain oxygenation and/or ventilation. Respiratory failure may be acute or chronic and is classified as hypoxemic, hypercapnic, or a combination of the two. Respiratory Failure is a common cause of hospital admission and death, and can result from:
    • Disease progression
    • Pneumonia Pneumonia Pneumonia or pulmonary inflammation is an acute or chronic inflammation of lung tissue. Causes include infection with bacteria, viruses, or fungi. In more rare cases, pneumonia can also be caused through toxic triggers through inhalation of toxic substances, immunological processes, or in the course of radiotherapy. Pneumonia
    • Pulmonary hypertension Hypertension Hypertension, or high blood pressure, is a common disease that manifests as elevated systemic arterial pressures. Hypertension is most often asymptomatic and is found incidentally as part of a routine physical examination or during triage for an unrelated medical encounter. Hypertension 

Differential Diagnosis

  • Sarcoidosis Sarcoidosis Sarcoidosis is a multisystem inflammatory disease that causes noncaseating granulomas. The exact etiology is unknown. Sarcoidosis usually affects the lungs and thoracic lymph nodes, but it can also affect almost every system in the body, including the skin, heart, and eyes, most commonly. Sarcoidosis: granulomatous disorder affecting multiple organ systems without a known etiology: The most common presenting findings include pulmonary reticular opacities, bilateral hilar adenopathy, and skin Skin The skin, also referred to as the integumentary system, is the largest organ of the body. The skin is primarily composed of the epidermis (outer layer) and dermis (deep layer). The epidermis is primarily composed of keratinocytes that undergo rapid turnover, while the dermis contains dense layers of connective tissue. Skin: Structure and Functions, joint, or eye lesions. Patients Patients Individuals participating in the health care system for the purpose of receiving therapeutic, diagnostic, or preventive procedures. Clinician–Patient Relationship are often asymptomatic, though may present with cough, dyspnea Dyspnea Dyspnea is the subjective sensation of breathing discomfort. Dyspnea is a normal manifestation of heavy physical or psychological exertion, but also may be caused by underlying conditions (both pulmonary and extrapulmonary). Dyspnea, fever Fever Fever is defined as a measured body temperature of at least 38°C (100.4°F). Fever is caused by circulating endogenous and/or exogenous pyrogens that increase levels of prostaglandin E2 in the hypothalamus. Fever is commonly associated with chills, rigors, sweating, and flushing of the skin. Fever, and malaise Malaise Tick-borne Encephalitis Virus. Diagnosis involves imaging, elevated serum ACE levels, and BAL and often requires a biopsy Biopsy Removal and pathologic examination of specimens from the living body. Ewing Sarcoma. Management is usually with glucocorticoids Glucocorticoids Glucocorticoids are a class within the corticosteroid family. Glucocorticoids are chemically and functionally similar to endogenous cortisol. There are a wide array of indications, which primarily benefit from the antiinflammatory and immunosuppressive effects of this class of drugs. Glucocorticoids.
  • Hypersensitivity pneumonitis Hypersensitivity Pneumonitis Hypersensitivity pneumonitis (HP), previously called extrinsic allergic alveolitis, is an immunologically induced inflammatory disease affecting the alveoli, bronchioles, and lung parenchyma. It is caused by repeated inhalation of an inciting agent in a susceptible host that triggers first a type III (complement-mediated) hypersensitivity reaction in the acute phase and then a type IV (delayed) reaction in the subacute and chronic phases. Hypersensitivity Pneumonitis: immunologically induced inflammatory disease affecting the alveoli Alveoli Small polyhedral outpouchings along the walls of the alveolar sacs, alveolar ducts and terminal bronchioles through the walls of which gas exchange between alveolar air and pulmonary capillary blood takes place. Acute Respiratory Distress Syndrome (ARDS), bronchioles Bronchioles The small airways branching off the tertiary bronchi. Terminal bronchioles lead into several orders of respiratory bronchioles which in turn lead into alveolar ducts and then into pulmonary alveoli. Bronchial Tree: Anatomy, and lung parenchyma resulting from exposure to inhaled antigens: Patients Patients Individuals participating in the health care system for the purpose of receiving therapeutic, diagnostic, or preventive procedures. Clinician–Patient Relationship may develop cough, dyspnea Dyspnea Dyspnea is the subjective sensation of breathing discomfort. Dyspnea is a normal manifestation of heavy physical or psychological exertion, but also may be caused by underlying conditions (both pulmonary and extrapulmonary). Dyspnea, and fatigue Fatigue The state of weariness following a period of exertion, mental or physical, characterized by a decreased capacity for work and reduced efficiency to respond to stimuli. Fibromyalgia. HRCT HRCT Pulmonary Function Tests will show diffuse, poorly defined centrilobular micronodules or ground-glass opacities. Pulmonary function tests are variable Variable Variables represent information about something that can change. The design of the measurement scales, or of the methods for obtaining information, will determine the data gathered and the characteristics of that data. As a result, a variable can be qualitative or quantitative, and may be further classified into subgroups. Types of Variables. Management includes avoiding the inciting agent and administering steroids Steroids A group of polycyclic compounds closely related biochemically to terpenes. They include cholesterol, numerous hormones, precursors of certain vitamins, bile acids, alcohols (sterols), and certain natural drugs and poisons. Steroids have a common nucleus, a fused, reduced 17-carbon atom ring system, cyclopentanoperhydrophenanthrene. Most steroids also have two methyl groups and an aliphatic side-chain attached to the nucleus. Benign Liver Tumors in subacute and chronic cases.
  • Pneumoconiosis Pneumoconiosis Pneumoconiosis is an occupational disease that results from the inhalation and deposition of mineral dusts and other inorganic particles in the lung. It can be categorized according to the type of causative particle involved or by the type of response provoked. Pneumoconiosis: occupational disease that results from inhalation of inorganic particles into the lungs Lungs Lungs are the main organs of the respiratory system. Lungs are paired viscera located in the thoracic cavity and are composed of spongy tissue. The primary function of the lungs is to oxygenate blood and eliminate CO2. Lungs: Anatomy: In the lungs Lungs Lungs are the main organs of the respiratory system. Lungs are paired viscera located in the thoracic cavity and are composed of spongy tissue. The primary function of the lungs is to oxygenate blood and eliminate CO2. Lungs: Anatomy, these particles can cause chronic inflammation Inflammation Inflammation is a complex set of responses to infection and injury involving leukocytes as the principal cellular mediators in the body’s defense against pathogenic organisms. Inflammation is also seen as a response to tissue injury in the process of wound healing. The 5 cardinal signs of inflammation are pain, heat, redness, swelling, and loss of function. Inflammation and fibrosis Fibrosis Any pathological condition where fibrous connective tissue invades any organ, usually as a consequence of inflammation or other injury. Bronchiolitis Obliterans. Patients Patients Individuals participating in the health care system for the purpose of receiving therapeutic, diagnostic, or preventive procedures. Clinician–Patient Relationship will have progressive dyspnea Dyspnea Dyspnea is the subjective sensation of breathing discomfort. Dyspnea is a normal manifestation of heavy physical or psychological exertion, but also may be caused by underlying conditions (both pulmonary and extrapulmonary). Dyspnea and dry cough Dry Cough Strongyloidiasis. Chest X-ray Chest X-ray X-ray visualization of the chest and organs of the thoracic cavity. It is not restricted to visualization of the lungs. Pulmonary Function Tests findings can vary depending on the causative particle, but may include ground-glass opacities, calcifications, lung nodules, and pleural irregularities. Management is mainly symptomatic.
  • Chronic obstructive pulmonary disease Chronic obstructive pulmonary disease Chronic obstructive pulmonary disease (COPD) is a lung disease characterized by progressive, largely irreversible airflow obstruction. The condition usually presents in middle-aged or elderly persons with a history of cigarette smoking. Signs and symptoms include prolonged expiration, wheezing, diminished breath sounds, progressive dyspnea, and chronic cough. Chronic Obstructive Pulmonary Disease (COPD) ( COPD COPD Chronic obstructive pulmonary disease (COPD) is a lung disease characterized by progressive, largely irreversible airflow obstruction. The condition usually presents in middle-aged or elderly persons with a history of cigarette smoking. Signs and symptoms include prolonged expiration, wheezing, diminished breath sounds, progressive dyspnea, and chronic cough. Chronic Obstructive Pulmonary Disease (COPD)): lung disease characterized by progressive, largely irreversible airflow obstruction: Symptoms include progressive dyspnea Dyspnea Dyspnea is the subjective sensation of breathing discomfort. Dyspnea is a normal manifestation of heavy physical or psychological exertion, but also may be caused by underlying conditions (both pulmonary and extrapulmonary). Dyspnea and chronic cough. Prolonged expiration Expiration Ventilation: Mechanics of Breathing, wheezing Wheezing Wheezing is an abnormal breath sound characterized by a whistling noise that can be relatively high-pitched and shrill (more common) or coarse. Wheezing is produced by the movement of air through narrowed or compressed small (intrathoracic) airways. Wheezing, and/or diminished breath sounds may be noted on physical exam. Unlike IPF, pulmonary function testing Pulmonary Function Testing Pulmonary Function Tests is consistent with obstruction. Management includes smoking Smoking Willful or deliberate act of inhaling and exhaling smoke from burning substances or agents held by hand. Interstitial Lung Diseases cessation, pulmonary rehabilitation, and pharmacotherapy.
  • Congestive heart failure Congestive heart failure Congestive heart failure refers to the inability of the heart to supply the body with normal cardiac output to meet metabolic needs. Echocardiography can confirm the diagnosis and give information about the ejection fraction. Congestive Heart Failure: inability to produce normal cardiac output Cardiac output The volume of blood passing through the heart per unit of time. It is usually expressed as liters (volume) per minute so as not to be confused with stroke volume (volume per beat). Cardiac Mechanics to meet metabolic needs: Patients Patients Individuals participating in the health care system for the purpose of receiving therapeutic, diagnostic, or preventive procedures. Clinician–Patient Relationship present with dyspnea Dyspnea Dyspnea is the subjective sensation of breathing discomfort. Dyspnea is a normal manifestation of heavy physical or psychological exertion, but also may be caused by underlying conditions (both pulmonary and extrapulmonary). Dyspnea, hypoxia Hypoxia Sub-optimal oxygen levels in the ambient air of living organisms. Ischemic Cell Damage, and peripheral edema Edema Edema is a condition in which excess serous fluid accumulates in the body cavity or interstitial space of connective tissues. Edema is a symptom observed in several medical conditions. It can be categorized into 2 types, namely, peripheral (in the extremities) and internal (in an organ or body cavity). Edema. BNP BNP A peptide that is secreted by the brain and the heart atria, stored mainly in cardiac ventricular myocardium. It can cause natriuresis; diuresis; vasodilation; and inhibits secretion of renin and aldosterone. It improves heart function. It contains 32 amino acids. Renal Sodium and Water Regulation will be elevated, and pulmonary edema Edema Edema is a condition in which excess serous fluid accumulates in the body cavity or interstitial space of connective tissues. Edema is a symptom observed in several medical conditions. It can be categorized into 2 types, namely, peripheral (in the extremities) and internal (in an organ or body cavity). Edema may be seen on X-ray X-ray Penetrating electromagnetic radiation emitted when the inner orbital electrons of an atom are excited and release radiant energy. X-ray wavelengths range from 1 pm to 10 nm. Hard x-rays are the higher energy, shorter wavelength x-rays. Soft x-rays or grenz rays are less energetic and longer in wavelength. The short wavelength end of the x-ray spectrum overlaps the gamma rays wavelength range. The distinction between gamma rays and x-rays is based on their radiation source. Pulmonary Function Tests examination. Echocardiography Echocardiography Ultrasonic recording of the size, motion, and composition of the heart and surrounding tissues. The standard approach is transthoracic. Tricuspid Valve Atresia (TVA) will confirm the diagnosis. Management relies on diuresis and medical optimization of cardiac function with beta-blockers Beta-blockers Drugs that bind to but do not activate beta-adrenergic receptors thereby blocking the actions of beta-adrenergic agonists. Adrenergic beta-antagonists are used for treatment of hypertension, cardiac arrhythmias, angina pectoris, glaucoma, migraine headaches, and anxiety. Class 2 Antiarrhythmic Drugs (Beta Blockers) and ACE inhibitors ACE inhibitors Truncus Arteriosus.

References

  1. Maher, T. M., Strek, M. E. (2019). Antifibrotic therapy for idiopathic pulmonary fibrosis: time to treat. Respiratory Research 20(1). https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6731623/
  2. Weerakkody, Y. (n.d.). Usual interstitial pneumonia: radiology reference article. Retrieved April 2, 2021, from https://radiopaedia.org/articles/usual-interstitial-pneumonia?lang=us
  3. Lederer, D. J., Martinez, F. J. (2018). Idiopathic pulmonary fibrosis. New England Journal of Medicine 378:1811–1823.
  4. Waxman, A., Restrepo-Jaramillo, R., Thenappan, T., Ravichandran, A., Engel, P., Bajwa, A., Nathan, S. D. (2021). Inhaled treprostinil in pulmonary hypertension due to interstitial lung disease. New England Journal of Medicine 384:325–334.
  5. Godfrey, A. M. K., Ouellette, D. R. (2019). Idiopathic pulmonary fibrosis (IPF). In Soo Hoo, G. W. (Ed.), Medscape. Retrieved April 13, 2021, from https://emedicine.medscape.com/article/301226-overview
  6. Lee, J. (2019). Idiopathic pulmonary fibrosis. MSD Manual Professional Version. Retrieved April 13, 2021, from https://www.msdmanuals.com/professional/pulmonary-disorders/interstitial-lung-diseases/idiopathic-pulmonary-fibrosis
  7. Krishna, R., Chapman, K., Ullah, S. (2020). Idiopathic pulmonary fibrosis. StatPearls. Retrieved April 13, 2021, from https://www.ncbi.nlm.nih.gov/books/NBK448162/
  8. King, T. E., Jr. (2021). Clinical manifestations and diagnosis of idiopathic pulmonary fibrosis. In Hollingsworth, H. (Ed.), UpToDate. Retrieved April 13, 2021, from https://www.uptodate.com/contents/clinical-manifestations-and-diagnosis-of-idiopathic-pulmonary-fibrosis
  9. King, T. E., Jr. (2020). Treatment of idiopathic pulmonary fibrosis. In Hollingsworth, H. (Ed.), UpToDate. Retrieved April 13, 2021, from https://www.uptodate.com/contents/treatment-of-idiopathic-pulmonary-fibrosis
  10. Raghu, G. (2019). Pathogenesis of idiopathic pulmonary fibrosis. In Hollingsworth, H. (Ed.), UpToDate. Retrieved April 13, 2021, from https://www.uptodate.com/contents/pathogenesis-of-idiopathic-pulmonary-fibrosis

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