Manifestations of respiratory system dysfunctions M. Tatár
Cardinal respiratory symptoms and signs cough sputum dyspnoea wheezing cyanosis chest pain
Disorders of lung mechanics
Disorders of the lung mechanics Airway obstruction –nasal cavity: nasal congestion –pharynx: collapse during sleep –larynx: suffocation –central aw: trachea: stridor main bronchi: dyspnoea, wheezing lobar bronchi: asymptomatic or minor dyspnoea –peripheral aw: dyspnoea Lung parenchyma ( compliance): dyspnoea Chest wall (abnormalities): dyspnoea Respiratory muscles (fatigue): dyspnoea
Disorders of airway defence mechanisms
Disorders of airways defence mechanisms Nasal cavity –sneezing –nasal discharge Airways –Cough: acute respiratory infections, foreign body aspiration, chronic bronchitis, chronic cough –Haemoptysis –Expectoration - Sputum mucoid (mainly macrophages) purulent (neutrophils) Pneumococcus - bloody or rust-colored Pseudomonas, Haemophilus - green sputum
Hyperplasia and hypertrophy of submucosal glands
Cough Physiologic reflex Pathologic reflex Acute cough Chronic cough –Rhinitis/sinusitis –Asthma –Gastroesophageal reflux disease
Disorders of gas exchange
PaO 2 PaCO 2 100% 70% chemoreceptors ventilatory drive hypoxemia hypercapnia hypoxemia normocapnia SaO 2
Disorders of gas exchange Respiratory insufficiency (failure) Hypoxemic –Decreased ventilation/perfusion ratio –Venous admixture (right-to-left intrapulmonary shunt) –Diffusion impairment Hypercapnic –Overall alveolar hypoventilation –Critical amount of the compartments with low V´/Q´ ratio + limits for hyperventilatory compensation
Hypoxemia Tachycardia, tachypnea, dyspnoea, mental confusion and irritability Secondary polycythemia ( hematocrit) Cyanosis threshold for central cyanosis is a capillary reduced haemoglobin content of 50 g/L !!! ancillary non-specific signs
Relation between SaO 2 and arterial Hb
Cyanosis Central –haemiglobin – methemoglobin, sulphhemoglobin – content of reduced haemoglobin Heart disorders – lung congestion Lung disorders –acute: pneumonia, lung oedema –chronic: COPD, severe lung fibrosis Peripheral –local perfusion disorders False –pigmentation (silver)
Central cyanosis
Hypercapnia Morning headaches Papilloedema, dilated conjunctival and superficial facial blood vessels CO 2 narcosis (rapid accumulation): anxiety may progress to delirium and somnolence
Disturbed regulation of breathing Cheyne-Stokes breathing Sleep apnoea Hyperventilation (tetany) Gasping Hypopnoea
Cheyne-Stokes breathing
Dyspnoea - breathlessness Air hunger, awareness of the act of breathing, chest tightness Sensations: shortness of breath, feeling puffed, inability to get enough air, suffocation Subject´s feelings – needs for increased ventilatory activity; mechanical rather than chemical disturbances Tachypnoea with either shallow or deep breathing Increased workload of respiratory muscles – normal gas exchange cannot be achieved without increased ventilatory effort
Pathophysiology of dyspnoea Hyperventilation – acute hypoxemia Relative hyperventilation - decreased ventilatory surface (atelectasis, pleural effusion, lung congestion, pneumothorax) Disordered lung mechanics (most frequent cause) - Upper airways stenosis - Increased airways resistance = obstruction of peripheral airways (asthma, COPD, heart failure) - Decreased muscle force (polyomyelitis, diaphragm paralysis, myasthenia gravis) - Limited chest movements (kyphoscoliosis) !!! acute or chronic state; rest or physical activity
Causes of dyspnoea Oxygen content in atmosphere Oxygen consumption during physical activity Lung function disorders Heart function disorders Decreased haemoglobin content (during exercise) Respiratory centre dysfunction (Cheyne-Stokes, acidosis) Stimulation of airway and lung nerve-endings (pneumonia, lung congestion) Obesity Emotive factors (chronic hyperventilatory syndrome) Brain disorders Metabolic disorders – hyperthyroidism
Systemic non-respiratory responses Fever Weakness, fatigue Decreased exercise tolerance Immunity: eosinophilia Weight loss: advanced disease Distant effects: finger clubbing and osteoarthropathy (periosteal overgrowth)
Primary respiratory disorders can significantly affect the function of other systems Most frequently CVS ( the lung is the recipient of the entire cardiac output through the lesser circulation ) Cor pulmonale: elevated jugular venous pulse, peripheral oedema Massive pulmonary embolism and tension pneumothorax circulatory shock: hypotension, weakness, pallor, cold sweat, oliguria, and develops impaired mentation Obstructive sleep apnoea syndrome: daytime sleepiness, right heart failure, systemic arterial hypertension