Respiratory System

1. COPD- Respiratory Failure

Diksha Bhatla 01 Jan 1970

CHRONIC OBSTRUCTIVE AIRWAYS DISEASES 

Chronic Obstructive Airways Diseases (COPD) is a lung disease that includes — 

1. Respiratory failure 

2. Bronchitis 

3. Emphysema 

Respiratory Failure 

Respiratory failure is inadequate gas exchange by the respiratory system, with the result that levels of arterial oxygen, carbon dioxide or both cannot be maintained within their normal ranges. A drop in blood oxygenationis known as hypoxemia; a rise in arterial carbon dioxide levels is called hypercapnia. The normal reference values are: oxygen PaO2 more than 80 mmHg (11 kPa), and carbon dioxide PaCO2 lesser than 45 mmHg (6.0 kPa). It is classified into type I or type II which relates to the absence or presence of hypercapnia respectively. 

Hypoxemic respiratory failure (type I): 

It is characterized by an arterial oxygen tension (Pa O2) lower than 60 mm Hg with a normal or low arterial carbon dioxide tension (Pa CO2). This is the most common form of respiratory failure, and it can be associated with virtually all acute diseases of the lung, which generally involve fluid filling or collapse of alveolar units. Some examples of type I respiratory failure is cardiogenic or non-cardiogenic pulmonary edema, pneumonia and pulmonary hemorrhage. 

Hypercapnic respiratory failure (type II): It is characterized by a PaCO2 higher than 50 mm Hg. Hypoxemia is common in patients with hypercapnic respiratory failure who are breathing room air. The pH depends on the level of bicarbonate, which, in turn, is dependent on the duration of hypercapnia. Common etiologies include drug overdose, neuromuscular disease, chest wall abnormalities, and severe airway disorders (e.g, asthma and chronic obstructive pulmonary disease). 

Causes 

Common causes of type I (hypoxemic) respiratory failure include the following: 

• Pneumothorax

• Pulmonary embolism

• Pulmonary arterial hypertension

• Pneumoconiosis

• Granulomatous lung diseases

• Cyanotic congenital heart disease

• Bronchiectasis

• Acute respiratory distress syndrome (ARDS)

• Fat embolism syndrome

• Kyphoscoliosis

• Obesity

Symptoms 

A majority of patients with respiratory failure are short of breath. Both low oxygen and high carbon dioxide can impair mental functions. Patient may become confused and disoriented and find it impossible to carry out their normal activities and work.

• Marked CO2 excess can cause headaches
  and, in time, a semiconscious state, restlessness, anxiety, confusion, seizures, or even coma.
• Polycythaemia is a complication of long- standing hypoxaemia.
  

• Corpulmonale (failure of the right side of the heart): Pulmonary hypertension is frequently present and may induce right ventricular failure, leading to hepatomegaly and peripheral oedema.

• Physical examination may show a patient who is breathing rapidly, is restless and has a rapid pulse.

• Lung disease may cause abnormal sounds; wheezing in asthma, “crackles” in obstructive lung disease.

Complications 

• Pulmonary fibrosis.

• Collapsed lung (pneumothorax).

• Blood clots.

• Infections.

• Abnormal lung function.

• Memory, cognitive and emotional problems.

Treatment 

The goals of treatment for respiratory failure are to increase oxygenation and 

improve ventilation. Treatment depends on the severity of the respiratory failure and the cause. Acute respiratory failure treatment will address the underlying cause and include ventilation and oxygenation as needed. Exacerbation of chronic respiratory failure by infection may require hospitalization, and treatment may include oxygenation and ventilator Bronchodilators may improve patency. 

support airway.Multiple options are available for the treatment of respiratory failure. Examples include: 

• Antibiotics to prevent and treat respiratory infections.

• Bi-level positive airway pressure (BiPAP).

• Bronchodilators, like anticholinergics, such as tiotropium or β-agonists, such
as Albuterol.

• Continuous positive airway pressure (CPAP).

• Inhaled steroid medications to decrease inflammation

• Mechanical ventilation, if oxygen therapy is not sufficient to increase blood oxygen levels.

• Oxygen therapy to increase blood oxygen levels.

• Tracheostomy, a hole made in the front of the neck to help breathing.

• A patient whose breathing remains very poor will require a ventilator to aid
breathing.

• Suctioning the lungs through a small plastic tube passed through the nose, in order to remove secretions from the airways that the patient cannot cough up.

2. Emphysema COPD

Diksha Bhatla 01 Jan 1970

Emphysema 

Emphysema is a long-term, progressive disease of the lungs that primarily causes shortness of breath due to over-inflation of the alveoli (air sacs in the lung). In people with emphysema the lung tissues involved in exchange of gases (oxygen and carbon dioxide) is impaired or destroyed. It is included in a group of diseases called chronic obstructive pulmonary disease or COPD. Emphysema is called an obstructive lung disease because the destruction of lung tissue around smaller airways (bronchioles), makes these airways unable to hold their shape properly when exhale. This makes them inefficient at transferring oxygen into the blood, and in taking carbon dioxide out of the blood. 

Causes 

The main cause of emphysema is long- term exposure to airborne irritants, including: 

• Tobacco smoke 

• Marijuana smoke 

• Air pollution 

• Chemical fumes and dust 

Cigarette smoking is by far the most dangerous behaviour that causes people to develop emphysema, and it is also the most preventable cause. Other risk factors include a deficiency of an enzyme called α-1- antitrypsin, air pollution, airway reactivity, heredity, male sex and age. 

Symptoms 

Two of the key symptoms of emphysema are shortness of breath and a chronic cough appears in the early stages. A person with shortness of breath, or dyspnea, feels being unable to catch a breath may start only during physical exertion, but as the disease progresses, it can start to happen during rest, too. Emphysema and COPD develop over a number of years. In the later stages, the person may have: 

• Frequent lung infections, 

• Excess production of mucus, 

• Wheezing, 

• Reduced appetite and weight loss, 

• Fatigue, 

• Blue-tinged lips or fingernail beds, or cyanosis, due to a lack of oxygen, 

• Anxiety and depression, 

• Sleep problems, 

• Morning headaches due to a lack of oxygen, when breathing at night is difficult.
  
  
  
  

• Risk Factors 

Factors that increase risk of developing emphysema include: 

• Smoking: Emphysema is most likely to develop in cigarette smokers, but cigar and pipe smokers also are susceptible.The risk for all types of smokers increases with the number of years and amount of tobacco smoked. 

• Age: The lung damage that occurs in emphysema develops gradually; most people with tobacco-related emphysema begin to experience symptoms of the disease between the ages of 40 and 60. 

• Exposure to second-hand smoke: Second-hand smoke, also known as passive or environmental tobacco smoke, is smoke that you inadvertently inhale from someone else's cigarette, pipe or cigar. Being around second- hand smoke increases your risk of emphysema. 
• Occupational exposure to fumes or dust: Breathe fumes from certain chemicals or dust from grain, cotton, wood or mining products, are more likely to develop emphysema. This risk is even greater in cigarette smokers. 

^{Complications} 

People who have emphysema are also more likely to develop: 

• Collapsed lung (pneumothorax): A collapsed lung can be life-threatening in people who have severe emphysema, because the function of their lungs is already so compromised. This is uncommon but serious when it occurs. 

• Heart problems: Emphysema can increase the pressure in the arteries that connect the heart and lungs. This can cause a condition called corpulmonale, in which a section of the heart expands and weakens. 

• Large holes in the lungs: Some people with emphysema develop empty spaces in the lungs called bullae. They can be as large as half the lung. In addition to reducing the amount of space available for the lung to expand, giant bullae can increase your risk of pneumothorax. 

Treatment 

Medications used for treatment of emphysema are: 

Bronchodilator: Salmeterol, Albuterol, Metaproterenol, and Formoterol 

Anticholinergic: Ipratropium bromide and Tiotropium 

Steroids: Prednisone, Dexamethasone PDE4 inhibitors: Roflumilast 

Stop smoking: This recommendation for people with emphysema, quitting smoking may halt the progression of the disease and improve the function of the  lungs to some extent. Lung function deteriorates with age. In those susceptible to developing COPD, smoking can result in a five-fold deterioration of lung function. Smoking cessation may return lung function from this rapid deterioration to its normal rate after smoking is stopped. 

Antibiotics: These medications are often prescribed for people with emphysema who have increased shortness of breath. Even when the chest X-ray does not show pneumonia or evidence of infection, people treated with antibiotics tend to have shorter episodes of shortness of breath. It is suspected that infection may play a role in an acute bout of emphysema, even before the infection worsens into a pneumonia or acute bronchitis. 

Oxygen Therapy: As a patients' disease progresses, they may find it increasingly difficult to breathe on their own and may require supplemental oxygen. 

3. Bronchitis

Diksha Bhatla 01 Jan 1970

4. Bronchitis

Diksha Bhatla 01 Jan 1970

Bronchitis 

Bronchitis is an inflammation of the lining of the bronchial tubes, the airways that connect the trachea (windpipe) to the lungs. Bronchitis is more specifically when the lining of the bronchial tubes becomes inflamed or infected. People with bronchitis breathe less air and oxygen into their lungs; they also have heavy mucus or phlegm forming in their airways. 

Bronchitis can be acute or chronic. An acute medical condition occurs quickly and can cause severe symptoms, but it lasts only a short time (no longer than a few weeks). Acute bronchitis is most often caused by viruses that can infect the respiratory tract and attack the bronchial tubes. Infection by certain bacteria can also cause acute bronchitis. Most people have acute bronchitis at some point in their lives. Chronic bronchitis can be mild to severe and is longer lasting from several months to years. With chronic bronchitis, the bronchial tubes continue to be inflamed (red and swollen), irritated, and produce excessive mucus over time. The most common cause of chronic bronchitis is smoking. 

AcuteBronchitis 

Acute bronchitis is swelling and inflammation of the main air passages to the lungs. This swelling narrows the airways, making it harder to breath and causing other symptoms, such as a cough. 

Causes 

Acute bronchitis almost always follows a cold or flu-like infection. The infection is caused by viruses (influenza, parainfluenza, respiratory syncitial virus, rhinovirus and adenovirus). At first, it affects nose, sinuses, and throat. Then it spreads to the airways leading to lungs. Sometimes, bacteria (Mycoplasma, Streptococcus, Bordetella, Moraxella, Haemophilus and Chlamydia pneumoniae) also infect the airways. This is called a secondary infection. In addition, other agents such as tobacco smoke, chemicals and environmental air pollution may irritate the bronchi and cause acute bronchitis.

Symptoms 

The symptoms of acute bronchitis may include: 

• Chest discomfort. 

•Fatigue.
•Fever, usually low grade.
•Shortness of breath that gets worse with activity.
•Wheezing, in people with asthma.
•Even after acute bronchitis has cleared, a dry and nagging cough may remains for 1 to 4 weeks. 

In acute bronchitis, coughing usually lasts between 10 to 20 days. There are no specific tests for acute bronchitis. Certain tests may be required if there is recurrent or persistent cough that may suggest asthma or chronic bronchitis. Coughing for period of greater than four weeks may be due to whooping cough (pertussis).
Sputum tests: Sputum can be tested to see whooping cough (pertussis) or other illnesses that could be helped by antibiotics. Sputum can also be tested for signs of allergies.

• Chest X-ray
  • Spirometry
  • Pulse oximetry 

Treatment 

Treatment of acute bronchitis involves: 

Chronic Bronchitis 

Chronic bronchitis is a long-term, often irreversible respiratory illness. It is a chronic inflammatory condition in the lungs that causes the respiratory passages to be swollen and irritation increases the mucus production and damages the lungs.

Causes 

Bronchitis is considered "chronic" if symptoms continue for three months or longer. Bronchitis caused by allergies can also be classified as chronic bronchitis. There are many causes of chronic bronchitis, but the main cause is cigarette smoke. Many other inhaled irritants (for example, smog, industrial pollutants, toxic gases in the environment or workplace and solvents) can also result in chronic bronchitis. Viral and bacterial infections that result in acute bronchitis may lead to chronic bronchitis if people have repeated attack with infectious agents. 

Pathophysiology 

The disease is caused by an interaction between noxious inhaled agents and host factors, such as genetic predisposition or respiratory infections which cause injury or irritation to the respiratory epithelium of the walls and lumen of the bronchi and bronchioles. 

Symptoms 

•Bluish skin due to lack of oxygen (cyanosis).
•Breathing difficulty including wheezing and shortness of breath.
•Cough and sputum production are the most common symptoms; they usually last for at least 3 months and occur daily. The intensity of coughing and the amount and frequency of sputum production vary from patient to patient. Sputum may be clear, yellowish, greenish, or occasionally, blood-tinged.
•Fatigue.
•Fever may indicate a secondary viral or bacterial lung infection.
•Muscles around the ribs sink in as the child tries to breathe in (called intercostal retractions).
•Infant's nostrils get wide when breathing
•Rapid breathing (tachypnea).

Treatment

Medications used for treatment bronchitis are: 

Bronchodilator: Salmeterol, Albuterol, Metaproterenol and Formoterol 

Anticholinergic: Ipratropium bromide and Tiotropium 

Steroids: Presnisone, Dexamethasone PDE4 inhibitors: Roflumilast 

Antibiotics: Macrolides, Azithromycin sulfonamides, Tetracyclines, Trimetho-prim and Fluoroquinolones 

Vaccines: Patients with chronic bronchitis should receive a flu shot annually and pneumonia shot every five to seven years to prevent infections. 

Oxygen Therapy: As a patient's disease progresses, they may find it increasingly difficult to breathe on their own and may require supplemental oxygen. 

Surgery: Lung volume reduction surgery, during which small wedges of damaged lung tissue are removed, may be recommended for some patients with chronic bronchitis. 

Cough suppressants: Cough suppressants such as dextromethorphan may be helpful in reducing cough symptoms. 

Prevention 

The majority of instances of chronic bronchitis can be prevented by quit smoking and avoiding second-hand smoke. Flu and pneumococcal vaccines can help to prevent repeated infections that may lead to the disease. Certain industries (for example, chemical, textile, thermal etc.) and farm workers are often associated with air-borne chemicals and dust; avoiding air-borne chemicals and dust with appropriate masks may prevent or reduce the individual's chance of developing chronic bronchitis. 

5. Asthma

Diksha Bhatla 01 Jan 1970

ASTHMA 

Asthma is a chronic inflammatory disorder of the airways associated with variable (usually reversible) airflow obstruction and enhanced bronchial hyper responsiveness to a variety of stimuli. 

Causes 

Asthma is characterized by excessive sensitivity of the lungs to various stimuli. There is increasing evidence to suggest genetics play an important role in the etiology of the disease. Apparently, environmental factors interact with inherited factors to increase the risk of asthma. Environmental triggers range from viral infections and allergies, to irritating gases and particles in the air. Each person reacts differently to the factors that may trigger asthma. Physiological factors that may trigger or increase asthma symptoms include: 

• Viral upper respiratory infections.
• Heavy exercise.
• Untreated conditions such as rhinitis, sinusitis, and gastroesophageal reflux  (GERD).
• Drugs: NSAIDS such as aspirin.
• Ibuprofen, acetaminophen, naproxen sodium and Ketoprophen; statin drugs (cholesterol reducing medications) and other anti- inflammatory drugs. 

• Menstrual cycle/hormone changes.

Food Allergy:

Based upon causes, the asthma is divided into two types: 

a. Intrinsic asthma: Usually develop beyond age 40 and have many causes other than exposure to allergens. 

b. Extrinsic asthma: Most commonly develop in childhood and caused by exposure to definite allergens. 

Classification of Asthma 

1. Mild Intermittent Asthma: It occurs in people with daytime symptoms that occur no more frequently than twice a week and night-time symptoms that occur no more than twice a month. 

2. Mild Persistent Asthma: It is characterized by daytime symptoms that occur more than twice a week but less than once a day with night-time symptoms more frequent than twice a month. These people are asymptomatic but have abnormal pulmonary function tests. Exacerbations begin to limit their activity. 

3. Moderate Persistent Asthma: It occurs in people who have daytime symptoms every day and night-time symptoms more than once a week. 

4. Severe Persistent Asthma: It is characterized by continual daytime symptoms and frequent night-time symptoms. They experience limited physical activity and exacerbations are frequent. 

Pathophysiology 

The various common allergens are pollens, dust, mites, some food material and certain drugs which precipitate the asthmatic attack. The allergens upon exposure stimulate production of IgE which further bind to mast cells. Upon re-exposure to same allergen, the said allergens readily bind to IgE and result in degranulation of mast cell to release certain inflammatory mediators such as histamine, leukotriens, prostaglandins etc. With exposure to a trigger, a cascade of cellular responses cause:

1. Increased production of thick tenacious mucus with impaired mucocilary function. 

3. Bronchial smooth muscle contraction
4. These changes cause bronchial hyper responsiveness and obstruction. Airway obstruction increases resistance to air flow and decreases flow rates, including expiratory flow. 

6. Untreated inflammation can cause long term airway damage that is irreversible (airway remodelling).

Symptoms 

• Coughing, especially at night, during exercise or when laughing. 

• Chest tightness.
• Wheezing (a whistling or squeaky sound in chest when breathe, especially while exhaling).
• Any asthma symptom is serious and can become deadly if left untreated.
• Symptoms may be triggered by exposure to an allergen (such as ragweed, pollen and pet hair or dust mites), irritants in the air (such as smoke, chemical fumes or strong odours) or extreme weather conditions. 

Prevention and Treatment 

Prevention of exposure to known triggers is warranted. Hyposensitization may be beneficial if the asthma has an allergic mechanism, in such cases:

• Identify and avoid asthma triggers.
• Identify and treat attacks early and monitor breathing.
• Other measures include dust free house.
• Intake of selective type of food.
• Avoid exposure to extreme cold condition. 

• Get vaccinated for influenza and pneumonia.