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Transcript
Approach to Dyspnoea Prof R Morar Introduction • Dyspnoea, breathlessness or inadequate breathing is accompanied by the sensations of running out of air and not being able to breathe fast or deeply enough • The sensations are similar to that of thirst or hunger (an unignorable feeling of needing something) Introduction • Various disease states can produce dyspnoea in different ways • Perception of dyspnoea can vary greatly among individuals • Assessment of dyspnoea must balance the concepts of physiologic work and ventilatory demand with the individual’s perception of breathlessness Descriptions for Dyspnoea in Different Conditions Rapid breathing Chronic heart failure Incomplete exhalation Asthma Shallow breathing Restrictive lung diseases Increased work/effort COPD, interstitial lung disease, neuromuscular disease, chest wall diseases Suffocation Chronic heart failure Air hunger COPD, chronic heart failure, sighing dyspnoea Tight chest Asthma Heavy Breathing Asthma Outline • Overview basic mechanisms of dyspnoea • Disease states • Clinical evaluation • Diagnostic work-up • Treatment Basic Mechanisms • The physiologic system that regulates ventilation is extraordinarily complex • Receptors in the airways, lung parenchyma, respiratory muscles and chemoreceptors provide sensory feedback via vagal, phrenic and intercostal nerves to the spinal cord, medulla and higher centres Basic Mechanisms Mechanoreceptors respiratory muscles Hypoxia carotid and aortic bodies Airflow airway and parenchymal receptors Changes in pCO2/pH medullary center Irritants airway and parenchymal receptors Medullary centre afferent input and efferent output Cortical function sense of effort Disease States • Abnormalities of cardiopulmonary function are most commonly associated with dyspnoea • Other organ systems dysfunction can also manifest dyspnoea Disease States • Pulmonary • Endocrine • Cardiovascular • Psychogenic • Upper Airway • Miscellaneous • CNS/peripheral • Renal • Hepatic • Anaemia • Sepsis • Obesity • Paediatric Disease States Pulmonary • Parenchymal lung disease - pneumonia, restrictive lung disease, metastatic • Airways disease - COPD, asthma • Pulmonary vascular disease - pulmonary embolic disease • Pleural - pneumothorax, pleural effusion • Pulmonary oedema • Gastroesophageal reflux disease with aspiration Disease States Cardiovascular • Congestive heart failure and pulmonary edema (anemia or pulmonary embolism) • Coronary artery disease - acute myocardial infarction • Arrhythmia • Pericarditis and pericardial effusion • Valvular disease - mitral stenosis or atrial septal defect Disease States Upper airway obstruction • Epiglottitis • Foreign body • Croup • Epstein-Barr virus Disease States Neuromuscular • Neuromuscular disease is a well known cause of dyspnoea • Amyotrophic lateral sclerosis • Disease of the peripheral nerves - Guillain-Barré • Neuromuscular junction - myasthenia gravis • Muscle disease - muscular dystrophies, polymyositis • Severe weight loss from malnutrition, malignancy or chronic disease (weak muscles) • Pain • Aspirin overdose or paracetamol overdose Disease States Renal • Renal disease leads to dyspnoea from acidosis, anemia and fluid/volume overload Disease States Hepatic • Chronic liver disease patients often complain of dyspnoea • Mechanism of dyspnoea obscure • One particular cause can be small arteriovenous shunts at the lung bases • This condition is classically associated with breathlessness and oxyhaemoglobin desaturation on assuming the upright position as when arising from bed in the morning (platypnoea) Disease States Endocrine • Hyperthyroidism, can be associated with dyspnoea – In this setting the sensation is probably related to the hypermetabolic state associated with thyroid over-activity – In the late stage dyspnoea can be associated with high-output cardiac failure • Metabolic acidosis e.g. diabetic ketoacidosis Disease States Miscellaneous • Anaemia • Sepsis • Obesity Disease States Miscellaneous Anaemia • Prominent cause of dyspnoea • Lower the haemoglobin more pronounced the dyspnoea • Especially in acute anaemia • Dyspnoea blunted in chronic anaemia Disease States Miscellaneous Sepsis • Early sepsis / bacteraemia associated with hyperventilation • Hyperventilation and dyspnoea may be presenting feature • Cause may be multifactorial (acidosis, tissue ischemia and lactic acidosis, direct effect on the brainstem respiratory centre and carotid bodies by various mediators) Disease States Miscellaneous Obesity • Unfit and increased effort • Coronary artery disease • Hypertension and left ventricular dysfunction • Restrictive lungs Disease States Paediatric • Bronchiolitis • Croup • Epiglottitis • Foreign body aspiration • Myocarditis • DKA Disease States Psychogenic • Panic attacks • Hyperventilation – Patients exhibit extreme anxiety with concurrent symptoms of hyperventilation including visual complaints, dizziness, near-syncope and perioral and finger tingling and numbness • Sighing dyspnoea – inability to take a deep satisfying breath at rest • Pain • Anxiety History • Determine onset, duration, and occurrence at rest or exertion • Activities and body positions that provoke dyspnoea • Occupational History Cardiorespiratory Symptoms • Chest pain - pleural or coronary disease), AMI • Pleuritic chest pain - pericarditis, pneumonia, pulmonary embolism, pneumothorax (pneumothorax - traumatic, decompression, spontaneous, catamenial), pleuritis and pleural effusion • Sudden shortness of breath at rest is suggestive of pulmonary embolism or pneumothorax • Cough - asthma, COPD, pneumonia, parenchymal lung disease • Change in the character of sputum – infection • Sore throat - epiglottitis History • Cardiac failure symptoms – Orthopnoea, PND, pedal oedema – Angina and IHD and LV dysfunction • Drugs - -blockers, eye drops or poisoning • Psychogenic - hyperventilation syndrome, anxiety • Smoking Severity Scale of Dyspnoea - ATS Grade Degree Characteristics 0 None Only with strenuous activity 1 Slight When hurrying on level ground or climbing a slight incline 2 Moderate Needs to walk more slowly than others of the same age or has to stop for breath when walking at own pace on level ground 3 Severe Stops for breath after 100 metres or after a few minutes 4 Very severe Housebound or dyspnoea when dressing or undressing Questions in Evaluation of Dyspnoea Question Probable Pathophysiology Associated only with exertion? Heart failure, restrictive or obstructive lung disease Associated with exertion and occurs at night? Cough and wheeze? Asthma or heart failure Associated with exertion, chest, arm or neck discomfort and concurrent nausea or sweating? Angina pectoris Worse when assuming upright position? Liver disease with arteriovenous shunts at the lung bases (platypnoea) Present in the lateral decubitus position? Unilateral lung or pleural disease (trepopnoea) Fast onset when supine, relieved by lateral or upright positioning? Bilateral phrenic nerve dysfunction Occurring within minutes or hours of becoming recumbent? Heart failure (orthopnoea) Clues to the Diagnosis of Dyspnoea Symptoms in the history Possible diagnosis Cough Asthma, COPD, pneumonia Severe sore throat Epiglottitis Pleuritic chest pain Pericarditis, pulmonary embolism, pneumothorax, pneumonia, pleural effusion Orthopnoea, nocturnal paroxysmal dyspnoea, oedema Congestive heart failure Tobacco use COPD, congestive heart failure, pulmonary embolism Indigestion Gastroesophageal reflux disease, aspiration Barking cough Croup Clinical Evaluation Examination • Organ systems mentioned, with meticulous attention to the respiratory and cardiovascular systems Disease States • Pulmonary • Endocrine • Cardiovascular • Psychogenic • Upper Airway • Miscellaneous • Nervous system • Renal • Hepatic • Anaemia • Sepsis • Obesity • Paediatric Examination General Appearance and Vital Signs • To determine the severity of dyspnoea, carefully observe respiratory effort and rate, use of accessory muscles, mental status, and ability to speak in full sentences • Pulsus paradoxus • Stridor • Temperature • Pulse rate, rhythm and character • BP Examination General Appearance and Vital Signs • Pallor • Clubbing • Cyanosis • Oedema • Mental status Examination Respiratory • Inspection • Palpate the chest for subcutaneous emphysema and crepitus • Hyperresonance and tracheal deviation • Stony dullness • Absent breath sounds • Bronchial breathing / amphoric breathing • Wheezes • Crackles Examination Cardiovascular • Displaced apex beat and character • Parasternal heave • An S3 gallop suggests a left ventricular systolic dysfunction in congestive heart failure • An S4 gallop suggests left ventricular dysfunction or ischemia • Loud P2 - pulmonary hypertension or cor pulmonale • Murmurs can be an indirect sign of congestive heart failure • Distant heart sounds can point to pericardial effusion and cardiac tamponade • Pericardial friction rub Examination Neck • Raised JVP - congestive heart failure, cardiac tamponade, cor pulmonale • Thyroid - congestive heart failure may result from hyperthyroidism or hypothyroidism • Auscultate for stridor Examination Abdominal Examination • Tender hepatomegaly and ascites • Hepatojugular reflux • Liver disease - cirrhosis • Renal disease - enlarged kidneys, uraemic frost, pallor and HT Examination Extremities • Deep venous thrombosis Neurological examination • • • • • Higher functions Motor - proximal weakness Neuromuscular disorders Muscle diseases Fasciculations Endocrine • Thyrotoxicosis or myxoedema Physical Examination Findings Findings Possible diagnosis Wheezing, pulsus paradoxus, accessory muscle use Acute asthma, COPD exacerbation Wheezing, barrel chest, decreased breath sounds COPD exacerbation Fever, crackles, increased fremitus Pneumonia Oedema, neck vein distension, S3 or S4 hepatojugular reflux, murmurs, crackles, hypertension, wheezing Congestive heart failure, pulmonary oedema Wheezing, friction rub, lower extremity swelling Pulmonary embolism Absent breath sounds, hyperresonance Pneumothorax Physical Examination Findings Findings Possible diagnosis Inspiratory stridor, wheezes, retractions Croup Stridor, drooling, fever Epiglottitis Stridor, wheezing, persistent pneumonia Foreign body aspiration Wheezing, flaring, intercostal retractions, apnea Bronchiolitis Sighing Hyperventilation Special Investigations • Chest x-ray PA and lateral – Lateral neck radiographs (stridor or upper airway obstruction) • ECG - ischemia, LVH, arrhythmia, troponin-T, enzymes • Spirometry - asthma or COPD • Full blood count - infection or anemia • d-Dimer - pulmonary embolism • V/Q scan and or spiral computed tomography, pulmonary angiography • Bilateral venous doppler Special Investigations • Pulse oximetry • Liver and kidney function tests • Thyroid functions • Full lung function tests • Echocardiogram • Formal exercise test Diagnostic Evaluation in Dyspnoea Possible diagnosis Radiography Pulse oximetry or spirometry Other tests Acute asthma, COPD exacerbation Hyperinflated lungs Decreased O2 sat, decreased PEFR and FEV1 - Pneumonia Infiltrates, effusion, consolidation Decreased or normal O2 sat Normal or high WCC Congestive heart failure Interstitial edema, effusion, cardiomegaly Decreased O2 sat LVH, ischemia, or arrhythmia on ECG; low Hb Pulmonary embolism Normal, atelectasis, pleural effusion, wedge-shaped density Decreased O2 sat RBBB on ECG; tachycardia Pneumothorax Lung atelectasis, mediastinal shift Decreased O2 sat - Diagnostic Evaluation in Dyspnoea Possible diagnosis Radiography Pulse oximetry or spirometry Other tests Croup Subglottic narrowing by PA plain film or CT Decreased or normal O2 sat - Epiglottitis Enlarged epiglottis Decreased or normal O2 sat High WCC Foreign body aspiration Visualized foreign body, air trapping, hyperinflation Decreased or normal O2 sat Normal or high WCC Bronchiolitis Hyperinflation, atelectasis Decreased or normal O2 sat Normal WCC; RSV swab Hyperventilation Normal Normal - Treatment • Depends on the specific diagnosis Acute problem • Upper airway obstruction or stridor - remove foreign body • Administer oxygen • Consider intubation if patient gasping, apnoeic, or non responsive, following advanced cardiac life support • Intravenous line access and start administration of fluids and drugs • Needle/tube thoracentesis in patients with tension pneumothorax • Administer nebulized bronchodilator if bronchospasm • Administer IV furosemide if pulmonary edema • Electrocardioversion if unstable arrhythmia Treatment • Treatment aimed at the underlying cause • Cardiac failure • Lung disease • Severe restrictive lung disease as manifested by pulmonary fibrosis or neuromuscular abnormality poses a particularly difficult problem • In these cases the complaint is often permanent and debilitating • The most effective treatment of dyspnoea in cases of far-advanced pulmonary fibrosis is single lung transplantation • In advanced emphysema lung volume reduction surgery has been tried to relieve dyspnoea by reducing FRC, which reduces the work of breathing by improving the mechanical function of the lungs and diaphragm Treatment • Opiates and benzodiazepines have been tried in intractable dyspnoea especially malignant disease • Anecdotal reports indicate some short-term value • Clinical trials failed to confirm long-term benefit • Some studies have demonstrated deleterious events When to Refer • Many patients with dyspnoea can be evaluated and treated without referral to a specialist • Unexplained dyspnoea after routine evaluation usually warrants referral • When full pulmonary function testing or echocardiography or cardiopulmonary exercise testing required warrants referral Medico-Legal Considerations • Acute dyspnoea can be associated with life-threatening diseases such as pulmonary embolism and myocardial infarction • Failure to promptly and accurately pursue these diagnoses in patients with unexplained dyspnoea can lead to untimely deaths and subsequent lawsuits Summary of Evaluation History and Examination Evidence of cardiopulmonary or other disease FBC, CXR, ECG, Spirometry Asthma, COPD, Chronic HF, cardiomegaly, HT, Anaemia U&E, Liver Function tests Liver or Renal Disease Full LFT’s, Echocardiogram Restrictive lung disease, valvular heart disease, LV dysfunction Exercise Test Occult coronary artery disease, asthma Conclusion An approach to dyspnoea requires: • • • • • • • Stepwise approach Beginning with a careful medical history Physical examination Appropriate investigations Specific diagnosis Treat condition Refer
