Bronchiectasis

Epidemiology and Etiology

Definition

Bronchiectasis is a chronic disease in which there is permanent damage to the airways, causing abnormal bronchial dilation and mucosal 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.

Epidemiology

• 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 is estimated to be approximately 350,000–500,000 cases in the United States.
• Age:
  • Occurs at any age
  • Increased 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 with older age
• More common in women

Etiology

• Idiopathic Idiopathic Dermatomyositis (most common)
• Primary infection Primary infection Herpes Simplex Virus 1 and 2:
  • Bacterial:
    • Klebsiella Klebsiella Klebsiella are encapsulated gram-negative, lactose-fermenting bacilli. They form pink colonies on MacConkey agar due to lactose fermentation. The main virulence factor is a polysaccharide capsule. Klebsiella pneumoniae is the most important pathogenic species. Klebsiella species
    • Staphylococcus aureus Staphylococcus aureus Potentially pathogenic bacteria found in nasal membranes, skin, hair follicles, and perineum of warm-blooded animals. They may cause a wide range of infections and intoxications. Brain Abscess
    • Pseudomonas aeruginosa Pseudomonas aeruginosa A species of gram-negative, aerobic, rod-shaped bacteria commonly isolated from clinical specimens (wound, burn, and urinary tract infections). It is also found widely distributed in soil and water. P. Aeruginosa is a major agent of nosocomial infection. Pseudomonas
    • Mycobacterium tuberculosis Mycobacterium tuberculosis Tuberculosis (TB) is an infectious disease caused by Mycobacterium tuberculosis complex bacteria. The bacteria usually attack the lungs but can also damage other parts of the body. Approximately 30% of people around the world are infected with this pathogen, with the majority harboring a latent infection. Tuberculosis spreads through the air when a person with active pulmonary infection coughs or sneezes. Tuberculosis
    • Mycobacterium avium Mycobacterium avium A bacterium causing tuberculosis in domestic fowl and other birds. In pigs, it may cause localized and sometimes disseminated disease. The organism occurs occasionally in sheep and cattle. It should be distinguished from the m. avium complex, which infects primarily humans. Mycobacterium complex
    • Mycoplasma pneumoniae Mycoplasma pneumoniae Short filamentous organism of the genus mycoplasma, which binds firmly to the cells of the respiratory epithelium. It is one of the etiologic agents of non-viral primary atypical pneumonia in man. Mycoplasma
  • Viral:
    • Measles Measles Measles (also known as rubeola) is caused by a single-stranded, linear, negative-sense RNA virus of the family Paramyxoviridae. It is highly contagious and spreads by respiratory droplets or direct-contact transmission from an infected person. Typically a disease of childhood, measles classically starts with cough, coryza, and conjunctivitis, followed by a maculopapular rash. Measles Virus virus Virus Viruses are infectious, obligate intracellular parasites composed of a nucleic acid core surrounded by a protein capsid. Viruses can be either naked (non-enveloped) or enveloped. The classification of viruses is complex and based on many factors, including type and structure of the nucleoid and capsid, the presence of an envelope, the replication cycle, and the host range. Virology
    • Pertussis Pertussis Pertussis, or whooping cough, is a potentially life-threatening highly contagious bacterial infection of the respiratory tract caused by Bordetella pertussis. The disease has 3 clinical stages, the second and third of which are characterized by an intense paroxysmal cough, an inspiratory whoop, and post-tussive vomiting. Pertussis (Whooping Cough) virus Virus Viruses are infectious, obligate intracellular parasites composed of a nucleic acid core surrounded by a protein capsid. Viruses can be either naked (non-enveloped) or enveloped. The classification of viruses is complex and based on many factors, including type and structure of the nucleoid and capsid, the presence of an envelope, the replication cycle, and the host range. Virology
    • 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 virus Virus Viruses are infectious, obligate intracellular parasites composed of a nucleic acid core surrounded by a protein capsid. Viruses can be either naked (non-enveloped) or enveloped. The classification of viruses is complex and based on many factors, including type and structure of the nucleoid and capsid, the presence of an envelope, the replication cycle, and the host range. Virology
    • Herpes simplex Herpes Simplex A group of acute infections caused by herpes simplex virus type 1 or type 2 that is characterized by the development of one or more small fluid-filled vesicles with a raised erythematous base on the skin or mucous membrane. It occurs as a primary infection or recurs due to a reactivation of a latent infection. Congenital TORCH Infections virus Virus Viruses are infectious, obligate intracellular parasites composed of a nucleic acid core surrounded by a protein capsid. Viruses can be either naked (non-enveloped) or enveloped. The classification of viruses is complex and based on many factors, including type and structure of the nucleoid and capsid, the presence of an envelope, the replication cycle, and the host range. Virology
    • Adenovirus Adenovirus Adenovirus (member of the family Adenoviridae) is a nonenveloped, double-stranded DNA virus. Adenovirus is transmitted in a variety of ways, and it can have various presentations based on the site of entry. Presentation can include febrile pharyngitis, conjunctivitis, acute respiratory disease, atypical pneumonia, and gastroenteritis. Adenovirus
    • Respiratory syncytial virus Respiratory Syncytial Virus Respiratory syncytial virus (RSV) is an enveloped, single-stranded, linear, negative-sense RNA virus of the family Paramyxoviridae and the genus Orthopneumovirus. Two subtypes (A and B) are present in outbreaks, but type A causes more severe disease. Respiratory syncytial virus causes infections of the lungs and respiratory tract. Respiratory Syncytial Virus
  • Fungal:
    • Aspergillus Aspergillus A genus of mitosporic fungi containing about 100 species and eleven different teleomorphs in the family trichocomaceae. Echinocandins
    • Histoplasma capsulatum Histoplasma capsulatum Histoplasma/Histoplasmosis
• Bronchial obstruction:
  • Endobronchial tumors
  • Encroachment from hilar lymphadenopathy Lymphadenopathy Lymphadenopathy is lymph node enlargement (> 1 cm) and is benign and self-limited in most patients. Etiologies include malignancy, infection, and autoimmune disorders, as well as iatrogenic causes such as the use of certain medications. Generalized lymphadenopathy often indicates underlying systemic disease. Lymphadenopathy (right middle lobe syndrome)
  • Foreign body Foreign Body Foreign Body Aspiration aspiration
  • Mucous plug
• Pneumonitis Pneumonitis Human Herpesvirus 6 and 7:
  • Aspiration
  • Inhalation injury
• Congenital Congenital Chorioretinitis disorders:
  • 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
  • Young syndrome
  • Primary ciliary dyskinesia Ciliary dyskinesia Primary Ciliary Dyskinesia
  • Alpha-1 antitrypsin Alpha-1 antitrypsin Plasma glycoprotein member of the serpin superfamily which inhibits trypsin; neutrophil elastase; and other proteolytic enzymes. Alpha-1 Antitrypsin (AAT) Deficiency (AAT) deficiency
• Anatomic defects:
  • Bronchopulmonary sequestration
  • Congenital Congenital Chorioretinitis cartilage Cartilage Cartilage is a type of connective tissue derived from embryonic mesenchyme that is responsible for structural support, resilience, and the smoothness of physical actions. Perichondrium (connective tissue membrane surrounding cartilage) compensates for the absence of vasculature in cartilage by providing nutrition and support. Cartilage: Histology deficiency
  • Tracheobronchomegaly
• Lung disease:
  • Chronic obstructive pulmonary disease Pulmonary disease Diseases involving the respiratory system. Blastomyces/Blastomycosis
  • Asthma Asthma Asthma is a chronic inflammatory respiratory condition characterized by bronchial hyperresponsiveness and airflow obstruction. The disease is believed to result from the complex interaction of host and environmental factors that increase disease predisposition, with inflammation causing symptoms and structural changes. Patients typically present with wheezing, cough, and dyspnea. Asthma
• Hypersensitivity:
  • Allergic bronchopulmonary aspergillosis Allergic bronchopulmonary aspergillosis Hypersensitivity reaction (allergic reaction) to fungus aspergillus in an individual with long-standing bronchial asthma. It is characterized by pulmonary infiltrates, eosinophilia, elevated serum immunoglobulin e, and skin reactivity to aspergillus antigen. Aspergillus/Aspergillosis ( ABPA ABPA Hypersensitivity reaction (allergic reaction) to fungus aspergillus in an individual with long-standing bronchial asthma. It is characterized by pulmonary infiltrates, eosinophilia, elevated serum immunoglobulin e, and skin reactivity to aspergillus antigen. Aspergillus/Aspergillosis)
  • Hypersensitivity pneumonitis Pneumonitis Human Herpesvirus 6 and 7
• Immunodeficiency Immunodeficiency Chédiak-Higashi Syndrome states:
  • Hypogammaglobulinemia Hypogammaglobulinemia Selective IgA Deficiency
  • Complement deficiencies
  • HIV HIV Anti-HIV Drugs/ AIDS AIDS Chronic HIV infection and depletion of CD4 cells eventually results in acquired immunodeficiency syndrome (AIDS), which can be diagnosed by the presence of certain opportunistic diseases called AIDS-defining conditions. These conditions include a wide spectrum of bacterial, viral, fungal, and parasitic infections as well as several malignancies and generalized conditions. HIV Infection and AIDS
  • Immunosuppressive therapy
• Autoimmune diseases Autoimmune diseases Disorders that are characterized by the production of antibodies that react with host tissues or immune effector cells that are autoreactive to endogenous peptides. Selective IgA Deficiency/ connective tissue Connective tissue Connective tissues originate from embryonic mesenchyme and are present throughout the body except inside the brain and spinal cord. The main function of connective tissues is to provide structural support to organs. Connective tissues consist of cells and an extracellular matrix. Connective Tissue: Histology disorders: 
  • Rheumatoid arthritis Arthritis Acute or chronic inflammation of joints. Osteoarthritis
  • Sjögren syndrome Sjögren Syndrome Rheumatoid Arthritis
  • Systemic lupus erythematosus Systemic lupus erythematosus Systemic lupus erythematosus (SLE) is a chronic autoimmune, inflammatory condition that causes immune-complex deposition in organs, resulting in systemic manifestations. Women, particularly those of African American descent, are more commonly affected. Systemic Lupus Erythematosus 
  • Inflammatory bowel disease
  • 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

Pathophysiology

• The development of bronchiectasis typically results from:
  • An infection
  • Impaired mucous drainage
  • Airway Airway ABCDE Assessment obstruction
  • Impaired host defenses
• An inflammatory response occurs → tissue damage to the bronchial walls, including:
  • Smooth muscle
  • Elastic Elastic Connective Tissue: Histology fibers
• Bronchial walls dilate → impairs secretion Secretion Coagulation Studies clearance
• Organisms are able to colonize and cause infection → more bronchial damage and purulent sputum 
• Becomes a continuous cycle Cycle The type of signal that ends the inspiratory phase delivered by the ventilator Invasive Mechanical Ventilation of:
  • Bronchial damage
  • Bronchial dilation 
  • Impaired clearance of secretions 
  • Recurrent infection

Clinical Presentation

The signs and symptoms of bronchiectasis will slowly progress over years and are accompanied by periods of acute exacerbation.

Chronic symptoms

• Chronic cough
• Sputum production:
  • Mucopurulent
  • Thick
• 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
• Pleuritic chest pain Pain An unpleasant sensation induced by noxious stimuli which are detected by nerve endings of nociceptive neurons. Pain: Types and Pathways
• 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
• Hemoptysis Hemoptysis Hemoptysis is defined as the expectoration of blood originating in the lower respiratory tract. Hemoptysis is a consequence of another disease process and can be classified as either life threatening or non-life threatening. Hemoptysis can result in significant morbidity and mortality due to both drowning (reduced gas exchange as the lungs fill with blood) and hemorrhagic shock. Hemoptysis
• Rhinosinusitis

Advanced disease

Patients Patients Individuals participating in the health care system for the purpose of receiving therapeutic, diagnostic, or preventive procedures. Clinician–Patient Relationship may develop: 

• Pulmonary hypertension Pulmonary Hypertension Pulmonary hypertension (PH) or pulmonary arterial hypertension (PAH) is characterized by elevated pulmonary arterial pressure, which can lead to chronic progressive right heart failure. Pulmonary hypertension is grouped into 5 categories based on etiology, which include primary PAH, and PH due to cardiac disease, lung or hypoxic disease, chronic thromboembolic disease, and multifactorial or unclear etiologies. Pulmonary Hypertension
• Right heart failure Heart Failure A heterogeneous condition in which the heart is unable to pump out sufficient blood to meet the metabolic need of the body. Heart failure can be caused by structural defects, functional abnormalities (ventricular dysfunction), or a sudden overload beyond its capacity. Chronic heart failure is more common than acute heart failure which results from sudden insult to cardiac function, such as myocardial infarction. Total Anomalous Pulmonary Venous Return (TAPVR)
• Wasting and weight loss Weight loss Decrease in existing body weight. Bariatric Surgery

Acute exacerbation symptoms

Exacerbations of bronchiectasis are often heralded by the following:

• Increased sputum production over baseline: 
  • Increased viscosity
  • Purulence
  • Foul odor 
• Increased 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 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
• Low-grade fever Low-Grade Fever Erythema Infectiosum
• 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 and malaise Malaise Tick-borne Encephalitis Virus
• Pleuritic chest pain Pain An unpleasant sensation induced by noxious stimuli which are detected by nerve endings of nociceptive neurons. Pain: Types and Pathways

Physical exam

Nose Nose The nose is the human body’s primary organ of smell and functions as part of the upper respiratory system. The nose may be best known for inhaling oxygen and exhaling carbon dioxide, but it also contributes to other important functions, such as tasting. The anatomy of the nose can be divided into the external nose and the nasal cavity. Nose Anatomy (External & Internal) and throat Throat The pharynx is a component of the digestive system that lies posterior to the nasal cavity, oral cavity, and larynx. The pharynx can be divided into the oropharynx, nasopharynx, and laryngopharynx. Pharyngeal muscles play an integral role in vital processes such as breathing, swallowing, and speaking. Pharynx: Anatomy exam:

• Halitosis Halitosis An offensive, foul breath odor resulting from a variety of causes such as poor oral hygiene, dental or oral infections, or the ingestion of certain foods. Oral Cancer
• Nasal polyps

Pulmonary exam:

• Crackles
• Rhonchi Rhonchi Asthma
• 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

Evidence of chronic hypoxia Hypoxia Sub-optimal oxygen levels in the ambient air of living organisms. Ischemic Cell Damage:

• Digital clubbing Clubbing Cardiovascular Examination (uncommon)
• 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
• Plethora Plethora Neonatal Polycythemia (from secondary polycythemia Secondary Polycythemia Polycythemia Vera)

Evidence of right heart failure Heart Failure A heterogeneous condition in which the heart is unable to pump out sufficient blood to meet the metabolic need of the body. Heart failure can be caused by structural defects, functional abnormalities (ventricular dysfunction), or a sudden overload beyond its capacity. Chronic heart failure is more common than acute heart failure which results from sudden insult to cardiac function, such as myocardial infarction. Total Anomalous Pulmonary Venous Return (TAPVR):

• Peripheral edema Peripheral edema Peripheral edema is the swelling of the lower extremities, namely, legs, feet, and ankles. Edema
• Jugular venous distention
• Hepatomegaly

Diagnosis

Imaging

Bronchiectasis is diagnosed with the use of radiography.

Chest 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: 

• Usually the initial test performed
• Only 50% of cases will have abnormal findings.
• Diagnostic findings:
  • Thickening of the airway Airway ABCDE Assessment walls
  • Airway Airway ABCDE Assessment dilation
• Nondiagnostic findings:
  • Linear atelectasis Atelectasis Atelectasis is the partial or complete collapse of a part of the lung. Atelectasis is almost always a secondary phenomenon from conditions causing bronchial obstruction, external compression, surfactant deficiency, or scarring. Atelectasis
  • Irregular peripheral opacities from mucous plugs

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

• More sensitive and specific
• Findings:
  • Airway Airway ABCDE Assessment dilation: 
    • Parallel “tram lines” in a horizontal orientation Orientation Awareness of oneself in relation to time, place and person. Psychiatric Assessment
    • “Signet-ring” sign: cross-sectional finding of a dilated bronchus that is contiguous with a smaller pulmonary artery Pulmonary artery The short wide vessel arising from the conus arteriosus of the right ventricle and conveying unaerated blood to the lungs. Lungs: Anatomy
    • Nonuniform dilation (varicose)
    • Cystic Cystic Fibrocystic Change
    • Lack of bronchial tapering
  • Mucopurulent plugs with postobstructive air trapping (“tree-in-bud” pattern)
• Distribution:
  • Lower lobes → idiopathic Idiopathic Dermatomyositis (most cases)
  • Upper lobes → 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
  • Middle and lower lobe → primary ciliary dysfunction Ciliary dysfunction Primary Ciliary Dyskinesia

Pulmonary function testing Pulmonary Function Testing Pulmonary Function Tests

• ↓ Forced expiratory volume in 1 second (FEV₁)
• ↓ or normal 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)
• ↓ FEV₁/FVC ratio

Supporting evaluation

The evaluation for an underlying etiology may include:

• ↑ Eosinophils Eosinophils Granular leukocytes with a nucleus that usually has two lobes connected by a slender thread of chromatin, and cytoplasm containing coarse, round granules that are uniform in size and stainable by eosin. Innate Immunity: Phagocytes and Antigen Presentation → ABPA ABPA Hypersensitivity reaction (allergic reaction) to fungus aspergillus in an individual with long-standing bronchial asthma. It is characterized by pulmonary infiltrates, eosinophilia, e