Chapter 12 Lung

Organ Failure

When gas exchange across the alveolar-capillary membrane is compromised to the point oxygen saturation is insufficient to support life Also have CO2 levels elevated resulting in acidosis when destroys enzymatic activity Ketones are perceivable Manifestation of lung failure can be Acute with sudden death Large pulmonary emboli Atelectasis (at-uh-LEK-tuh-sis) of both lungs- the collapse or closure of a lung resulting in reduced or absent gas exchange Usually a long chronic process Respiratory failure associated with Cor pulmonale Right heart failure Peripheral edema Cirrhosis of the liver

Pulmonary Fibrosis

a lung disease that occurs when lung tissue becomes damaged and scarred

Cyanosis

blue color of mucous membranes or skin; results from inadequate oxygen saturation of the blood

How is fungal pneumonia treated?

can be treated with antifungal drugs and sometimes by surgical debridement

Atelectasis

collapsed lung -due to external pressure on the lungs -due to obstruction of bronchus

Hemoptysis

coughing up blood; suggests cancer or tuberculosis

Trachypnea

increased respiratory rate; occurs with poorly oxygenated blood also while frightened or anxious

Pulmonary Embolism (PE)

is a blockage of an artery in the lungs by a substance that has traveled from elsewhere in the body through the bloodstream (embolism). Symptoms of a PE may include shortness of breath, chest pain particularly upon breathing in, and coughing up blood. Signs of a PE include low blood oxygen levels, rapid breathing, rapid heart rate, and sometimes a mild fever. Severe cases can lead to passing out, abnormally low blood pressure, and sudden death. PE usually results from a blood clot in the leg that travels to the lung. The risk of blood clots is increased by cancer, prolonged bed rest, smoking, stroke, certain genetic conditions, pregnancy, obesity, and after some types of surgery. Large or numerous embolism can lead to Pulmonary infarcts but it is rare

Acute respiratory distress syndrome (ARDS) (Noninfectious Interstitial Lung Disease)

is a medical condition occurring in critically ill patients characterized by widespread inflammation in the lungs. ARDS is not a particular disease, rather it is a clinical phenotype which may be triggered by various pathologies such as trauma, pneumonia and sepsis. The hallmark of ARDS is diffuse injury to cells which form the alveolar barrier, surfactant dysfunction, activation of the innate immune response, and abnormal coagulation. In effect, ARDS results in impaired gas exchange within the lungs at the level of the microscopic alveoli. Causes diffuse alveolar damage secondary to inflammation and edema The syndrome is associated with a high mortality rate between 20 and 50%. The mortality rate with ARDS varies widely based on severity, the patient's age, and the presence of other underlying medical conditions. Although the terminology of "adult respiratory distress syndrome" has at times been used to differentiate ARDS from "infant respiratory distress syndrome" in neonates, international consensus is that "acute respiratory distress syndrome" is the best term because ARDS can affect those of all ages.

Chronic bronchitis

is a more serious condition that develops over time rather than striking suddenly. It's characterized by recurrent episodes of bronchitis that last for several months or years. Clinical defined as a persistent cough with sputum production for a least 3 months in at least 2 consecutive years The constant inflammation in the lining of the bronchial tubes causes excessive amounts of sticky mucus to build up in the airways. This restricts the amount of airflow going into and out of the lungs. The blockage in airflow gets worse over time, resulting in breathing difficulties and increased mucus production in the lungs. Many people who have chronic bronchitis eventually develop emphysema. Together, the two conditions are referred to as chronic obstructive pulmonary disease, or COPD. Chronic bronchitis is most commonly caused by cigarette smoking. Over 90 percent of those with the disease have a history of smoking. Inhaling cigarette smoke temporarily paralyzes the cilia, so frequent smoking over an extended period can severely damage the cilia. Chronic bronchitis may develop over time due to this damage.

Pneumoconiosis (Noninfectious Interstitial Lung Disease)

is an occupational lung disease and a restrictive lung disease caused by the inhalation of dust, often in mines and from agriculture. Particles that are 1 to 5 μm in diameter are the most dangerous, because they get lodged at the bifurcation of the distal airways. Macrophages accumulate and engulf the trapped particulates. The more reactive particles trigger the macrophages to release a number of products that mediate an inflammatory response and initiate fibroblast proliferation and collagen deposition.

Asthma (obstructive pulmonary disease)

Is a common long term inflammatory disease of the airways of the lungs. It is characterized by variable and recurring symptoms, reversible airflow obstruction, and bronchospasm. Symptoms include episodes of wheezing, coughing, chest tightness, and shortness of breath. These episodes may occur a few times a day or a few times per week. Depending on the person they may become worse at night or with exercise. Asthma is thought to be caused by a combination of genetic and environmental factors. Environmental factors include exposure to air pollution and allergens. Other potential triggers include medications such as aspirin and beta blockers. There is no cure for asthma. Symptoms can be prevented by avoiding triggers, such as allergens and irritants, and by the use of inhaled corticosteroids. Long-acting beta agonists (LABA) or antileukotriene agents may be used in addition to inhaled corticosteroids if asthma symptoms remain uncontrolled. Brittle asthma is a severe asthma with persistent tightness, coughing, or wheezing between attacks and may require hospitalization.

Bronchitis (chronic obstructive pulmonary disease)

Is an inflammation of the lining of the bronchial tubes. People who have bronchitis often have a persistent cough that brings up thickened, discolored mucus. They may also experience wheezing, chest pain, and shortness of breath. May be either acute or chronic.

Emphysema (obstructive pulmonary disease)

Is one of the diseases that comprises COPD. Emphysema involves gradual damage of lung tissue, specifically thinning and destruction of the alveoli or air sacs. Emphysema is usually accompanied by chronic bronchitis, with almost-daily or daily cough and phlegm. People with emphysema experience shortness of breath with activities In emphysema, the inner walls of the air sacs weaken and eventually rupture — creating one larger air space instead of many small ones. This reduces the surface area of the lungs and, in turn, the amount of oxygen that reaches your bloodstream.

FEV1/FVC

if the ratio is normal=normal or restrictive disease if the ratio is decreased=obstructive disease

Restrictive lung diseases

-characterized by low lung volumes -diseases that destroy the lung's elastic property -can be an inflammatory disease resulting in the lung tissue adhere to the chest wall -muscular disease of the respiratory muscles -diseases affecting the connective tissue reducing the elasticity of the lungs

Hypersensitivity pneumonitis (chronic diffuse interstitial disease)

A disease of the lungs in which your lungs become inflamed as an allergic reaction to inhaled dust, fungus, molds, or chemicals; repeated exposure can lead to end-stage pulmonary fibrosis

Sacrcoidosis

A fibrotic disease of unknown cause that may affect any organ, including the lungs involves abnormal collections of inflammatory cells that form lumps known as granulomas. The disease usually begins in the lungs, skin, or lymph nodes. Less commonly affected are the eyes, liver, heart, and brain. Any organ, however, can be affected. The signs and symptoms depend on the organ involved. Often there are no, or only mild, symptoms. When it affects the lungs there may be wheezing, cough, shortness of breath, or chest pain The cause of sarcoidosis is unknown. Believe it may be due to an immune reaction to a trigger such as an infection or chemicals in those who are genetically predisposed

Non-small cell carcinoma (NSCLC)

Any type of epithelial lung cancer other than small cell lung carcinoma (SCLC). NSCLC accounts for about 85% of all lung cancers. As a class, NSCLCs are relatively insensitive to chemotherapy, compared to small cell carcinoma. When possible, they are primarily treated by surgical resection with curative intent, although chemotherapy is increasingly being used both pre-operatively More common, less responsive to chemo, but highly treatable with surgery

Lung cancer

Most common cause of cancer death in the US Most common site of metastatic cancer spread by the blood stream from other sites Commonly from breast, prostate and colon cancer Most arise from bronchial epithelium stem cells and are termed bronchogenic carcinomas

Cystic Fibrosis

-CF is inherited in an autosomal recessive manner. It is caused by the presence of mutations in the gene for the cystic fibrosis transmembrane conductance regulator (CFTR) protein. -Those with a single working copy are carriers and otherwise mostly normal. -CFTR is involved in production of sweat, digestive fluids, and mucus. When CFTR is not functional, secretions which are usually thin instead become thick. -Lung infections are treated with antibiotics which may be given intravenously, inhaled, or by mouth. Lung transplantation may be an option if lung function continues to worsen. Pancreatic enzyme replacement and fat-soluble vitamin supplementation are important. -Airway clearance techniques such as chest physiotherapy have some short-term benefit. -The average life expectancy is between 42 and 50 years in the developed world. Lung problems are responsible for death in 80% of people with cystic fibrosis. -CF is most common among people of Northern European ancestry and affects about one out of every 3,000 newborns. About one in 25 people is a carrier. It is least common in Africans and Asians.

Aspergillus (most common fungal pneumonia)

-Found in soils worldwide -Host response is most varied -The fungus can form tightly packed colonies in the lungs called fungus balls; Don't normally elicit a response -In immunocompromised the fungus can become invasive and spread with the patient succumbing to a septic-shock-like illness

Coccidioides also called "Valley Fever"(most common fungal pneumonia)

-Found in southwestern US -Infection typically occurs after digging in the soils infected with the fungal spores -Triggers a neutrophilic pneumonia that over time leads to destruction of lung tissue with fibrosis

Crytococcus (most common fungal pneumonia)

-Found where ever there are pigeons -Triggers a neutrophilic pneumonia that over time leads to destruction of lung tissue with fibrosis -Common to spread to the meninges of the brain of immunocompromised

Cystic Fibrosis

-Genetic disease that results in thickened mucus -Affects the cells that produce mucus, sweat, and digestive juices. It causes these fluids to become thick and sticky. They then plug up tubes, ducts, and passageways. -Symptoms vary and can include cough, repeated lung infections, inability to gain weight, and fatty stool

Hyaline Membrane Disease (HMD)

-Infant respiratory distress syndrome (IRDS), also called neonatal respiratory distress syndrome, respiratory distress syndrome of newborn, or increasingly surfactant deficiency disorder (SDD), and previously called hyaline membrane disease (HMD), -Is a syndrome in premature infants caused by insufficient surfactant production. -It can also be a consequence of neonatal infection and genetic problem with the production of surfactant. -Microscopically, the lung is characterized by collapsed air-spaces alternating with hyper-expanded areas, vascular congestion and, in time, hyaline membranes. Hyaline membranes are composed of fibrin, cellular debris, and red blood cells. -IRDS affects about 1% of newborn infants and is the leading cause of death in preterm infants. -The incidence decreases with advancing gestational age, from about 50% in babies born at 26-28 weeks, to about 25% at 30-31 weeks. -The syndrome is more frequent in infants of diabetic mothers and in the second born of premature twins -Surfactant production can be stimulated by glucocorticoid administration

4 Categories of inflammatory/degenerative lung diseases

-Infections -chronic obstructive pulmonary diseases -acute and chronic noninfectious interstitial diseases -Vascular diseases

Histoplasma (most common fungal pneumonia)

-Mainly in the central US -Immune response results in formation of granulomatous due to the macrophages being unable to kill the pathogen thus mimics tuberculosis -Common to lead to eye infections

Blastomyces (most common fungal pneumonia)

-Mainly in the southeastern and Midwest -Triggers a neutrophilic pneumonia that over time leads to destruction of lung tissue with fibrosis

Fungal Pneumonia (infections)

-Most are not primary human pathogens but grow in the soil or droppings of birds and bats for example -Fungi typically enter the lung with inhalation of their spores, though they can reach the lung through the bloodstream if other parts of the body are infected. Also, fungal pneumonia can be caused by reactivation of a latent infection. -Once inside the alveoli, fungi travel into the spaces between the cells and also between adjacent alveoli through connecting pores. This invasion triggers the immune system to respond by sending white blood cells responsible for attacking microorganisms (neutrophils) to the lungs. -The neutrophils engulf and kill the offending organisms but also release cytokines which result in a general activation of the immune system. This results in the fever, chills, and fatigue common in both bacterial and fungal pneumonia. -The neutrophils and fluid leaked from surrounding blood vessels fill the alveoli and result in impaired oxygen transportation.

Asthma

-Nondestructive lung disease most common in children and young adults -Due to stimulates that trigger constriction of smooth muscle within bronchioles (triggers include pollens, dust, cold, exercise, cigarette smoke, etc.)

Tuberculosis (infections)

-One of the most common causes of death in the world -Once thought to be near eradication, a resurgence occurred and strains of TB are now resistant to many standard therapies -Tuberculosis generally affects the lungs, but can also affect other parts of the body. Most infections do not have symptoms, in which case it is known as latent tuberculosis. About 10% of latent infections progress to active disease which, if left untreated, kills about half of those infected. -The classic symptoms of active TB are a chronic cough with blood-containing sputum, fever, night sweats, and weight loss. -Tuberculosis is spread through the air when people who have active TB in their lungs cough, spit, speak, or sneeze. People with latent TB do not spread the disease. Active infection occurs more often in people with HIV/AIDS and in those who smoke. -Diagnosis of active TB is based on chest X-rays, as well as microscopic examination and culture of body fluids. Diagnosis of latent TB relies on the tuberculin skin test (TST) or blood tests.

Visualization of lung tissue

-Radiography -Microscopic examination of sputum -Bronchoscopy Biopsy taken during bronchoscopy

Structure of the Respiratory Membrane

-Type I alveolar cell -Basement membrane (basal lamina) -Endothelial cell

Alveoli are made of

-Type I pneumocytes: responsible for gas exchange -Type II pneumocytes: responsible for surfactant secretion -Also contains a resident macrophage- alveolar macrophage

Alpha-1 antitrypsin deficiency

-genetic disorder that causes defective production of alpha 1-antitrypsin (A1AT), leading to decreased A1AT activity in the blood and lungs, and deposition of excessive abnormal A1AT protein in liver cells -A1AT is produced in the liver, and one of its functions is to protect the lungs from neutrophil elastase, an enzyme that can disrupt connective tissue. -Severe A1AT deficiency causes emphysema or COPD in adults (especially if they are exposed to cigarette smoke). -It is treated through avoidance of damaging inhalants and, in severe cases, by intravenous infusions of the A1AT protein or by transplantation of the liver or lungs -Produces emphysema in the absence of smoking

Pneumonia

-infection of lungs -bacterial: common in debilitated terminally ill -viral: common but rarely cause death

Functions of the lungs

-involved in detoxification and excretion of certain toxins and metabolites -contains Angiotensin converting enxymes (ACE) -site of clot removal

Pneumonitis

-less specific term indicating inflammation of the lungs -may be viral or hypersensitivity reaction to dust, mold, bird droppings, etc.

Obstructive pulmonary diseases

-occurs when there is partial impediment of the flow of air through the bronchi; results in inadequate ventilation; includes emphysema, chronic bronchitis, asthma, and bronchiectasis; all have similar symptoms which include wheexing, cough, difficulty breathing, abnormal rapid breathing, and near-normal FVC but marked by decreased FEV1

Obstructive lung diseases

-those diseases that prevent the outflow of air through bronchial tree -are characterized by a loss of elastic recoil, which makes the lungs likely to collapse on exhalation, thus trapping air in the lungs

During expiration

-volume of the thoracic cavity and thus the lungs decrease -intrapulmonary or intraalveolar pressure increased to greater than atmospheric and air leaves the lungs

During inspiration

-volume of the thoracic cavity and thus the lungs increase -intrapulmonary or intraalveolar pressure drops to less than atmospheric and air fills the lungs

What is responsible for the pressure changes in the lungs?

Boyle's Law -if you increase the volume the pressure decreases -if you decrease the volume the pressure increases

Causes of emphysema

Cigarette smoking is the major cause Other inhaled toxins also lead to emphysema and COPD, including work-related ones. In developing countries, smoke from indoor cooking and heating is also an important cause. Other risk factors -Low body weight -Childhood respiratory disorders -Exposure to passive cigarette smoke -Air pollution -Occupational dust (mineral dust, cotton dust, for example) -Inhaled chemicals (coal, grains, isocyanates, cadmium, for example). Genetics are responsible for a rare form of COPD - emphysema can be caused by α1-antitrypsin deficiency. The protein is necessary for protecting the lungs against neutrophil elastase destruction of alveolar tissue.

Chronic diffuse interstitial diseases (Noninfectious Interstitial Lung Disease)

Develops slowly due to repeated exposure to irritants and often causes lung fibroses Fibrosis leads to restrictive lung disease The process of fibrosis leads to large air spaces separated form each other by fibrous bands = honeycomb lung

Pulmonary edema (Noninfectious Interstitial Lung Disease)

Fluid accumulation in the tissue and air spaces of the lungs. It leads to impaired gas exchange and may cause respiratory failure. Treatment is focused on three aspects: firstly improving respiratory function, secondly, treating the underlying cause, and thirdly avoiding further damage to the lung. Pulmonary edema, especially acute, can lead to fatal respiratory distress or cardiac arrest due to hypoxia. It is due to either failure of the left ventricle of the heart to remove blood adequately from the pulmonary circulation (cardiogenic pulmonary edema), or an injury to the lung parenchyma or vasculature of the lung (noncardiogenic pulmonary edema). Other causes include Inhalation of hot or toxic gases Pulmonary contusion, i.e., high-energy trauma (e.g. vehicle accidents) Aspiration, e.g., gastric fluid Swimming induced pulmonary edema also known as immersion pulmonary edema Transfusion Associated Circulatory Overload (TACO) occurs when multiple blood transfusions or blood-products (plasma, platelets, etc.) are transfused over a short period of time.

Noninfectious Interstitial Lung Disease

Results of diseases of the interstitium (alveolar wall) Inflammation leading to edema Inflammation leading to fibrosis Decrease in ventilation as seen with drop in FEV1 Symptoms include Difficult or labored breathing(Dyspnea) Abnormally rapid breathing (Tachypnea) cyanosis

Small cell carcinoma

Strongly associated with smoking Are derived form the neuroendocrine cell lineage Can see endocrine complications May produce vasoactive amines triggering Flushing, diarrhea, cyanosis (carcinoid syndrome) Respond to chemo but not curable with surgery and rapidly fatal Small-cell carcinoma of the lung usually presents in the central airways and infiltrates the submucosa leading to narrowing of bronchial airways. Almost always detected when it has spread widely in the chest cavity and beyond Makes surgery impossible Common symptoms include cough, dyspnea, weight loss, and debility. Over 70% of patients with small-cell carcinoma present with metastatic disease; common sites include liver, adrenals, bone, and brain.

Mucociliary Escaltor

The epithelia that lines the respiratory tract contains numerous goblet cells producing mucus and the ciliated columnar epithelial cells line the tracheobronchial tree and help move mucus and particles trapped in the mucus to the oropharynx to be expectorated

What is the main function of the lungs?

The transfer of oxygen from the atmosphere to the blood and carbon dioxide from the blood to the atmosphere

Acute bronchitis

develops from a cold or other respiratory infection, and often improves within a few days without lasting effects

Dyspnea

difficulty breathing

Interstitial pneumonia or pneumonitis (infections)

diffuse and affects alveolar walls instead of the alveolar spaces; are typically associated with upper respiratory tract infections; can be mild and unnoticed to severe; common causes are viral (influenza and rubella) and mycoplasma pneumonia is most common cause

Hypercapnia

elevated CO2

Pneumonitis

general term that refers to inflammation of lung tissue

Apenea

lack of breathing

Lobar Pneumonia (infections)

located to a single area usually one lobe; commonly caused by Streptococcus pneumonia; was most common until advent of antibiotics which are very effective

Hypoxemia

low O2

Factors that aid expiration

lungs have the tendency to collapse due to: -elastic recoil due to the presence of connective tissue containing large amount of elastin fibers -surfactant- a phosphlipid produced late in development that reduces surface tension

Cough

material coughed up is termed sputum

Forced Vital Capacity (FVC)

maximum amount exhaled after a maximal inspiration

Forced Expiratory Volume (FEV1)

maximum amount of exhaled in 1 second

Diffusing Capacity of the lung (DL)

measures the transfer of gas from air in the lung to the RBCs in the lung blood vessels; it is part of a comprehensive series of tests to determine the overall ability of the lung to transport gas into and out of the blood; decreased in diseases with destroyed alveolar walls such as inflammation or fibrosis

Spirometry

measures the volume of air flowing into and out of the lungs during forced inspiration and expiration

Cystic Fibrosis

most common genetic disease of people of European heritage; results in the production of thick mucus secretions; this results in reduced clearance by the mucociliary escalator leading to increased infections and resulting damage to the lungs

Pulmonary ventilation

movement of air into and out of the respiratory tract; air flows from the area of high pressure to an area of low pressure

Bronchopneumonia (infections)

multifocal and affects bronchi; many causes but two distinct forms: legionnaire disease and aspiration pneumonia; is a common cause of death in immunosuppressed patirents; more difficult to diagnose and treat than lobar; usually resolved with treatment without mesidual damage but may have scars and in severe cases can form abcesses and empyema

Organs of the Respiratory System

nose pharynx larynx trachea bronchi lungs

Pneumoconiosis

occupational lung disease and a restrictive lung disease caused by the inhalation of dust

Orthopnea

positional dyspnea; difficulty breathing while recumbent

Inspiration

pressure drops in the lungs and air flow into lungs

Expiration

pressure rises in the lungs and air flow out

Percussion

tapping on the chest to determine whether air filled or fluid filled

Chronic Obstructive Pulmonary Disease (COPD)

the combination of chronic bronchitis and emphysema; occurs almost exclusively in smokers; most common cause of lung transplants

Alveoli

the functional gas exchange unit of the lung

Blood gas measurements

the ultimate measure of pulmonary function

Auscultation

using a stethoscope to listen to the chest