Respiratory system- Disorders of the respiratory system

Types of respiratory disease

  • Infections- such as pneumonia

  • Obstructive disorders- disorder that obstruct airflow into and out of the lungs such as asthma, bronchitis and emphysema.

  • Restrictive disorders- conditions that limit normal expansion of the lungs such as pneumothorax, atelectasis, respiratory distress syndrome and cystic fibrosis

  • Cancers/ inhaled particles- alter the pulmonary functions.

General symptoms of respiratory diseases

  • Hypoxia- decreased levels of oxygen in the tissues

  • Hypoxemia- decreased levels of oxygen in arterial blood

  • Hypercapnia- increased levels of CO2 in the blood

  • Hypocapnia- decreased levels of CO2 in the blood

  • Dyspnea- difficulty breathing

  • Tachypnea- rapid rate of breathing

  • Cyanosis- bluish discolouration of skin and mucous membranes due to poor oxygenation of the blood

  • Haemoptysis- Blood in the sputum

Respiratory infections

Infections can occur in both the upper or lower respiratory tract.

organisms such as bacteria, viruses and fungi can cause these infections.

Common cold

Common pathogens - rhinovirus, parainfluenza virus, adenovirus and corona virus.

Tends to be a seasonal variation in peak incidence.

Entry is gained through nasal mucosa and surfaces of the eye.

Spread easily from person to person via respiratory secretions

Symptoms include;

  • Rhinitis- inflammation of nasal mucosa

  • Sinusitis- inflammation of sinus mucosa

  • Pharyngitis- inflammation of the pharynx and throat

  • Headache

  • Nasal discharge and congestion

Influenza

Respiratory tract infection that can effect either the upper or lower respiratory tract

3 distinct forms A,B,C- Ais the most common and causes serious illness

Highly transmissible respiratory pathogen

New genetic mutations cause new variants to spread constantly

Symptoms include;

  • Headache

  • Fever, chills

  • Muscle aches

  • Nasal discharge

  • Unproductive cough

  • Sore throat

Influenza can cause marked inflammation of the respiratory epithelum leading to acute tissue damage and loss of ciliated cells that protect respiratory passages from other organisms. - causing co-infection of the respiratory passages with bacteria- can cause viral pneumonia

Treatment;

  • Bed rest

  • Fluids

  • Keeping warm

  • Antiviral drugs

  • Influenza vaccine- has to be administered yearly to be effective and is only effective against some strains

Pneumonia

A condition that involves inflammation of lower lung structure such as the alveoli.

Can be caused by bacteria or viruses.

Severity of cases heightened due to antibiotic resistance

Different classifications of pneumonia according to the pathogen responsible

Potential pathogens

Typical;

  • streptococcus pneumoniae

  • hemophilus influenzae

  • mycobacterium catarrhalis

  • klebsiella pneumoniae

Atypical;

  • chlamydia pneumoniae

  • legionella pneumophila

  • mycoplasma pneumoniae

Viruses

Fungi

Manifestations

  • Inflammation and fluid accumulation in alveoli

  • White cell exudation- seen on radiographs

  • High fever

  • Chest pains

  • Chills

  • Malaise - fatigue

  • A degree of hypoxemia present

Obstructive respiratory disorder

Asthma

A condition characterised by reversible bronchospasm and chronic inflammation of airway passages

The incidence of asthma has been steadily increasing in recent years,

The exact etiology (cause) is uncertain however there appears to be a genetic predisposition to the development of the disorder.

A key component in asthma is the hyper reactivity of the airways in affected individuals.

People with asthma produce a large amount of the IgE antibody- attach to mast cells in many different tissues.

exposure to a trigger such as pollen will result in the allergen-binding mast cell-bound IgE- causing the release of inflammatory mediators such as histamine.

Potential triggers include;

  • Allergens, pollen, pet dander, fungi, dust mites

  • Cold air

  • Pollutants

  • Cigarette smoke

  • Strong emotions

  • Exercise

  • Respiratory tract infections.

Early phase asthma

It is characterised by marked constriction of bronchial airways (bronchospasm), edema of the airways, production of excess mucus.

The bronchospasm that occurs may be the result of the increased release of certain inflammatory mediators such as histamine, prostaglandins and bradykinin that, in the early stages of asthmatic response promote bronchoconstriction rather than inflammation.

Late phase asthma

This occurs several hours after the initial onset of symptoms and manifests mainly as ab inflammatory response. The primary mediators of inflammation during the asthmatic response are eosinophils (WBC). Subsequent infiltration of the airway tissues with WBC such as neutrophils and lymphocytes also contribute to the overall inflammatory response of the late phase asthma.

Manifestation of asthma (symptoms)

  • Coughing

  • Wheezing

  • Difficulty breathing

  • Rapid, shallow breathing

  • Increased respiratory rate (normal is 12-20)

  • Excess mucus production

  • Significant anxiety

Complication of asthmas

  • severe acute asthma (status asthmatics) - life threatening condition of prolonged bronchospasm that is often not responsive to drug therapy

  • Pneumothorax- can occur to the lung pressure increase resulting in extreme difficulty of expiration during a prolonged asthma attack

  • Respiratory failure- marked hypoxemia and acidosis might occur

Chronic obstructive pulmonary disease (COPD)

A name for lung conditions that cause breathing difficulty such as emphysema and chronic bronchitis.

Chronic bronchitis- long term inflammation of the branchial tubes which causes a persistent cough

Emphysema- damage to the alveoli in the lungs

is is characterised by destruction and permanent enlargement of terminal bronchiole and alveolar air sacs. loss of lung tissue causes a loss of tissue elasticity- this help keeps the airways open. this decreases surface area for gas exchange.

  • Leukocytes can digest and destroy the elastic walls of the alveoli

  • Excess release of protease enzymes such as trypsin from lung tissues

symptoms include

  • Tachypnea

  • Hypoxia/ cyanosis (end stages)

  • Barrel chest from prolonged expiration

  • Lack of purulent sputum

  • Can lead to respiratory failure

Restrictive respiratory disorders

Pneumothorax

  • The entry of air into the pleural cavity in which the lungs reside

  • With a pneumothorax the pleural cavity acts as a vaccum- this causes the lungs to collapse .

closed pneumothorax

  • Occurs when air leaks from the lungs into the pleural cavity

  • can be caused by lung cancer, rupture or a pulmonary disease

  • the increased pleural pressure prevents lung expansion during inspiration and the lung remains collapsed

Open pneumothorax( pen or communincating)

  • Usually involves a traumatic chest wound

  • Air enters the pleural cavity from the atmosphers

  • The lung collapses due to equilibriation of pressure within the pleural cavity with atmospheric pressure.

Tension pneumothorax

  • A condition in which there is a one-way movement of air but not out of the pleural cavity

  • may involve a hole or a wound to the pleural cavity that allows air to enter and the lung to collapse

  • upon expiration the hole/ opening closes- preventing the movement of air back out of the pleural cavity

  • life threatening condiron due to pressure in pleural cavity increasing

Manifestation of pneumothorax

  • Tachpnea, Dyspnea

  • chest pain

  • compression of thoracic blood vessel and heart

Treatment of pneumothorax

  • Removal of air from the pleural cavity with a needle or chest tube

  • Repair of trauma and closure of opening into pleural cavity