Week 5 - Respiratory Diseases + Symptoms

Define dyspnea

The subjective feeling of being short of breath, specifically at rest

Name the signs of dyspnea

• Nostril flaring

• Increased use of accessory muscles

• Sinking of skin within intercostal spaces

Explain 3 factors that affect dyspnea

• Cultural factors

• Context (occurring suddenly or overtime)

• Body position (lying down or standing up)

Define orthopnea

Dyspnea occurring when lying down due to the pressure that abdominal contents put on the diaphragm

Define eupnea

Normal breathing pattern (inspiration, expiration and pause) and rate (12-20 breaths/min)

Define tachypnea and list causes

Increased respiratory rate caused by exercise, anxiety and shock.

Define bradypnea and list causes

Decreased respiratory rate caused by sleep, drugs, head injury or stroke.

Define apnea and list causes

Absence of breathing caused by death, head injury or stroke.

Define hyperpnea

Normal breathing rate with increased respirations due to emotional stress or diabetic ketoacidosis.

Explain diabetic ketoacidosis

Extreme insulin deficiency that results in fat breakdown producing ketones that significantly drop blood pH.

Define Cheyne-Stokes breathing pattern and list causes

Gradual increased and decreased respiration with periods of apnea, caused by increased intracranial pressure, brain stem injury and actively dying.

Define Biot’s breathing pattern and list causes

Increased rate and deep respirations with short pauses between sets caused by CNS issues, spinal meningitis and head injuries.

Define Kussmaul’s breathing pattern and list causes

Tachypnea and hyperpnea caused by renal failure, metabolic or diabetic ketoacidosis.

Define apneustic and list causes

Prolonged inspiratory and shortened expiratory phase caused by brain stem lesions

Name the reverse equilibrium that maintains blood pH balance

CO₂ + H₂O <—> H₂CO₃ <—> H⁺ HCO₃^-

Define hypoventilation

Decreased ventilation in which there is inadequate CO₂ removal in relation to CO₂ production in metabolism.

List causes of hypoventilation

• Large airway obstruction

• Respiratory system depression

Explain how hypoventilation can lead to respiratory acidosis

• Decreased ventilation decreases CO₂ removal

• Increases partial pressure of CO₂ in the blood

• Increases hydrogen ions and carbonic acid production, decreasing blood pH

Define hypercapnia

Excess CO₂ in the blood in which CO₂ partial pressure increase above 44mmHg.

Define hyperventilation

Increased ventilation in which CO₂ removal exceeds CO₂ production in metabolism.

List causes of hyperventilation

• Severe anxiety

• Acute head injuries

• Pregnancy

Explain how hyperventilation can lead to respiratory alkalosis

• Increased ventilation increases CO₂ removal

• Decreases CO2 partial pressure in the blood

• Decreases hydrogen ions and carbonic acid production, increasing blood pH

Define hypocapnia

Reduced CO₂ in the blood in which the CO₂ partial pressure falls below 36mmHg.

Define a cough

An essential, protective reflex characterised by the explosive respiration that removes inhaled particles, accumulated mucus and foreign substances.

Explain the 2 types of coughs

• Acute - resolves after 2-4 weeks, caused by upper respiratory infections, chronic bronchitis and pneumonia

• Chronic - persists for over 4/8 weeks in children/adults, caused by colds, smoking, asthma and bronchitis.

Define pneumonia

Lung infection progression that causes fluid build-up in the lungs.

Define haemoptysis

Coughing up blood or bloody secretions

Explain characteristics of coughed blood in haemoptysis

• Bright red

• Alkaline

• Mixed with frothy sputum

Define haematemesis and explain how it differs from haemoptysis

Vomited blood which is dark in colour, has an acidic pH and mixed with food particles.

List causes of haemoptysis

• Infection

• Inflammation damaging bronchi or lung tissue

Define cyanosis

The blue discolouration of skin and mucous membranes due to increased concentration of deoxygenated haemoglobin.

Name and explain the 2 types of cyanosis

• Central - deoxygenation of haemoglobin in arterial blood, causing discolouration in buccal mucous membranes and lips

• Peripheral - reduced peripheral blood circulation causing discolouration in fingers and toes.

List the causes of cyanosis

• Decreased cardiac output

• Cold environments

• Anxiety

Name and explain the 2 diseases in which there is inadequate oxygenation but no cyanosis

• Sever anaemia - haemoglobin concentration is not high enough for there to be a high concentration of deoxygenated haemoglobin

• Carbon monoxide poisoning - bright red pigment when CO binds to haemoglobin

Name and explain the disease in which there is cyanosis present despite adequate oxygenation

Polycythemia in which more RBC’s leads to slower-moving viscous blood that extracts greater amounts of oxygen from tissues. This creates greater amounts of deoxygenated blood in which it is easier to reach high concentrations of deoxygenated haemoglobin.

Name the 3 types of pain

• Pleural pain

• Pulmonary pain

• Chest/rib pain

Explain pleural pain

Infection/inflammation of the pleura causes sharp stabbing pains when pleura is stretched during inspiration.

Name the breath sound that diagnosis pleural pain

Pleural friction rub

Explain pulmonary pain

Infection/inflammation in the airways that causes central chest pain

Explain chest/rib pain

Inflammation of costochondral junction that causes chest pain

Explain clubbing

The enlargement and rounding of the fingertips and nails due to poor oxygenation to the fingers.

Explain how abnormal sputum can be used for diagnosis

The colour and odour of sputum can be specific to certain pathogens.

Explain how abnormal sputum can be used for tracking effectiveness of therapies

Changes in the amount and consistency of sputum production over time.

Definitely asthma

An obstructive airway disease characterised by the chronic inflammation of the bronchi and bronchioles.

Name and explain the 2 types of asthma with examples

• Extrinsic asthma - hypersensitivity associated with a specific allergy, eg. Pollen and food

• Intrinsic asthma - hypersensitivity to specific stimuli, eg. Cold and exercise

Name the 3 components of asthma pathophysiology that cause airway obstruction

1. Airway inflammation

2. Mucous hypersecretion

3. Airway hyperresponsiveness

Name the type lining of airways

Pseudostratified ciliated columnar epithelium with goblet cells.

Name the 5 steps of cellular asthma pathophysiology

1. Initial immune response

2. Antigen entry to airways

3. Mast cell degranulation

4. Mediator effects

5. Late response

Explain the first step of cellular asthma pathophysiology: initial immune response

• Dendritic cells phagocytose the antigen and present it to T-helper 2 cells

• T-helper 2 cells interact with B cells to produce IgE antibodies against the antigen

• The IgE antibodies bind to the surface of mast cells

Explain the second step of cellular asthma pathophysiology: antigen entry to airways

The antigen enters the airways a second time and binds to the IgE antibodies on mast cells.

Explain the third step of cellular asthma pathophysiology: mast cell degranulation

Triggers mast cell degranulation, releasing mediators such as histamine, prostaglandins and cytokines.

Explain the fourth step of cellular asthma pathophysiology: mediator effects

• Mucous secretion by goblet cells, triggered by histamine and leukotrienes

• Smooth muscle constrictions

• Vascular fluid leak

Explain the fifth step of cellular asthma pathophysiology: late response

4-8 hours after the initial immune response, T-helper 2 cells recruit neutrophils, basophils and eosinophils which release mediators and cause epithelial damage.

Explain how the leukocytes recruited by T-helper 2 cells cause epithelial damage

• Impair mucociliary function in which mucous cannot be propelled out of the lungs, accumulating in the airways

• Injury to nerves and smooth muscle function

Explain epithelial desquamation and what occurs after

Epithelial shedding from damage, replaced by fibrous scar tissue that cannot undergo essential functions.

Explain how chronic asthma leads to uneven ventilation and perfusion

• Mucus accumulation and bronchospasms cause resistance to airflow in the airways

• This impairs expiration and traps air in the lungs causing alveolar hyperinflation

• This reduces the SA for gas exchange leading to uneven ventilation and perfusion

Explain how uneven ventilation can lead to respiratory failure

Uneven ventilation decreases the amount of alveolar ventilation, leading to respiratory failure.

Explain how uneven perfusion leads to respiratory failure

• Uneven perfusion decrease the amount of blood flowing to lungs

• This impairs gas exchange in which initially there is hypoxemia

• Hyperventilation occurs to increase oxygen however this decreases CO₂ levels and leads to alkalosis

• Eventually this causes hypoventilation to increase CO₂ levels, leading to hypercapnia and respiratory acidosis and therefore respiratory failure

List the common symptoms of asthma

• Coughing

• Wheezing on expiration

• Chest tightness

Explain asthma symptoms due to hypoxia

• Shortness of breath

• Tachypnea

• Tachycardia

• Increased use of accessory muscles for breathing

• Nasal flaring

Explain barrel chest

Rounded and large chest diameter due to hyperinflation in the lungs

Explain status asthmaticus

Life-threatening, severe asthma attack in which patients do not respond to emergency medications.