<prompt> Answer this question truthfullyWhat is dyspnea, and how do you distinguish it from other conditions that cause shortness of breath?  <response>: <reason> The underlying causes of dyspnea are classified as acute causes and chronic causes based on the disease course. Different causes of dyspnea include pulmonary upper and lower airway, cardiovascular, central nervous system, toxic and metabolic, and systemic diseases.Diseases that cause shortness of breath have to be differentiated upon the following table To review the differential diagnosis of dyspnea and fever, click here.To review the differential diagnosis of dyspnea and chest pain, click here.To review the differential diagnosis of dyspnea and cough, click here.To review the differential diagnosis of dyspnea and jugular vein distention, click here.To review the differential diagnosis of dyspnea and cyanosis or clubbing, click here.To review the differential diagnosis of dyspnea and loss of consciousness or agitation, click here.To review the differential diagnosis of dyspnea with normal auscultation, click here.To review the differential diagnosis of dyspnea with stridor, click here.To review the differential diagnosis of dyspnea with wheezing, click here.To review the differential diagnosis of dyspnea with crackle, click here.To review the differential diagnosis of dyspnea with rhonchi, click here.To review the differential diagnosis of dyspnea, fever, and cough, click here.To review the differential diagnosis of dyspnea, fever, and chest pain, click here.To review the differential diagnosis of dyspnea, cough, and cyanosis or clubbing click here.To review the differential diagnosis of dyspnea, fever, chest pain, cough, and cyanosis or clubbing click here.Abbreviations: ABG arterial blood gas; ACE angiotensin converting enzyme; BMI body mass index; CBC complete blood count; CSF cerebrospinal fluid; CXR chest X-ray; DOE dyspnea on exercise; ECG electrocardiogram; FEF forced expiratory flow rate; FEV1 forced expiratory volume; FVC forced vital capacity; JVD jugular vein distention; MCV mean corpuscular volume; Plt platelet; RV residual volume; SIADH syndrome of inappropriate antidiuretic hormone; TSH thyroid stimulating hormone; Vt tidal volume; WBC white blood cell;Organ system Diseases Clinical manifestations Diagnosis Other features Symptoms Physical exam Loss of consciousness Agitation Weight loss Fever Chest pain Cough Orthopnea DOE Cyanosis Clubbing JVD Peripheral edema Auscultation CBC ABG Imaging Spirometry Gold standard Acute Dyspnea Respiratory system Head and Neck, Upper airway Angioedema - - - - - - - - - - Normal Normal O2, CO2 Normal NA Physical exam Generalized edema Anaphylaxis - - - - - - - - - - - Scattered wheezing Normal Normal Normal NA Vital sign Type 1 hypersensitivity Aspiration - - - - - - - - - Diminished breath sounds Normal Normal Atelectasis Vt, RV Bronchoscopy Choking Croup - - - - - - - - - Stridor WBC Normal Steeple sign Normal Physical exam Barking cough Epiglottitis - - - - - - - - - Stridor WBC Normal Thumb sign Normal Laryngoscopy Drooling Rhinosinusitis - - - - - - - - - - - Normal WBC Normal Air fluid level Normal Physical exam Headache Vocal cord dysfunction - - - - - - - - - - - - Stridor Normal Normal Normal FVC Laryngoscopy Choking sensation Chest and Pleura, Lower airway Asthma attack - - - - - - - - - Wheeze Eosinophil Respiratory alkalosis Normal FEV1, PEF Physical exam and Spirometry Chest pain Atelectasis - - - - - - - - - - - - Diminished breath sounds, Wheeze Normal O2, Normal CO2 Collapsed lung lobe, fissures displacement FVC Chest CT scan Surgical procedure, Aspiration, Mechanical ventilation Bronchitis - - - - - - - - - Rhonchi WBC Normal Normal Normal Physical exam Rhonchi relieved by cough Bronchospasm - - - - - - - - - Wheeze Normal O2, CO2 Normal Vt, RV Physical exam Allergic reaction Bronchiolitis - - - - - - - - - - Wheeze and Crackles WBC Normal Bronchovascular markings Vt Clinical assessment Respiratory syncytial virus RSV COPD exacerbation - - - - - - Wheeze, Rhonchi, and Crackles WBC, RBC Respiratory alkalosis Hyperexpansion FEV1 FVC Clinical assessment Acute exacerbations of chronic bronchitis AECB Lung carcinoma - - - - - - - - Wheeze and Crackles Normal Normal Mass lesion, hilar lymphadenopathy Vt, RV Bronchoscopy Paraneoplastic syndromes, such as SIADH and lambert-Eaton Pneumonia - - - - - - - - - Wheeze, Rhonchi, and Crackles WBC, neutrophilia Normal Lobar consolidation Normal Chest X-ray and CT Scan productive cough Pneumothorax - - - - - - - - - - - Diminished breath sounds Normal O2, CO2 Radiolucency without lung marking Vt CXR and Chest CT scan Tracheal deviation Pulmonary embolism - - - - - - - - - - - Normal Normal Respiratory alkalosis Normal Normal Pulmonary CT angiography Pleuritic chest pain Rib fractures flail chest - - - - - - - - - - Normal Normal Respiratory acidosis Fracture marks Normal Chest X-ray Pneumothorax Cardiovascular system Acute myocardial ischemia - - - - - - - - Normal Normal Normal Cardiac troponin I Nausea and vomiting, Positive pertinent risk factors, such as hypertension, diabetes, and smoking Acute heart failure - - - - - - S 3 Normal Respiratory alkalosis Cardiothoracic ratio Vt B-type natriuretic peptide BNP and N-terminal proBNP NT-proBNP Excessive sweating, high blood pressure Pericardial tamponade - - - - - - - - - - Muffled heart sounds Normal Normal Water bottle appearance enlarged heart Normal Echocardiography Fluid accumulation in pericardium Tachyarrhythmia - - - - - - - - - - - High pulse rate Normal Normal Normal ECG Palpitation Pulmonary edema - - Basal crackle Normal Respiratory alkalosis Bat wing pattern, air bronchograms Vt, RV Cardiac Catheterization Tachypnea Central nervous system Stroke - - - - - - - - - - - Normal Normal Normal Intracranial infarct or hemorrhage Normal Brain MRI Paralysis or paresthesia Encephalitis - - - - - - - - - Normal WBC, neutrophilia Normal Normal Normal CSF PCR Confusion Traumatic brain injury - - - - - - - - - - - Normal Normal Respiratory acidosis Intracerebral hemorrhage Normal Brain CT scan Lucid interval Toxic Metabolic Organophosphate poisoning - - - - - - - - - - Wheeze Normal O2, CO2 Normal Normal Blood test Salivation, Lacrimation, Emesis, Miosis Salicylate poisoning - - - - - - - - - - Normal Normal Metabolic acidosis, Respiratory alkalosis Normal Normal Blood test Vomiting, Tinnitus, Confusion, Hyperthermia Carbon monoxide poisoning - - - - - - - - Wheeze Carboxyhemoglobin O2, CO2 Normal NA Carboxyhemoglobin HbCO level Headache, Dizziness, Weakness, Vomiting, Confusion Diabetic ketoacidosis - - - - - - - - - - - Scattered wheeze, Kussmauls respiration WBC Metabolic acidosis Normal Normal Blood test acidosis, hyperglycemia, ketonemia Vomiting, Abdominal pain, Weakness, Confusion Systemic Panic attack - - - - - - - - - - - Normal Normal Normal Clinical assessment Severe anxiety Pregnancy - - - - - - - - - - - Normal WBC, RBC O2, CO2 Normal Vt, RV βhCG Missed period, Hyperemesis Sepsis - - - - - - - - - - - Normal WBC, neutrophilia O2, CO2 Normal Normal SIRS criteria Chills, Confusion Organ system Diseases Clinical manifestations Diagnosis Other features Symptoms Physical exam Loss of consciousness Agitation Weight loss Fever Chest pain Cough Orthopnea DOE Cyanosis Clubbing JVD Peripheral edema Auscultation CBC ABG Imaging Spirometry Gold standard Chronic Dyspnea Respiratory system Head and Neck, Upper airway Goiter - - - - - - - - - - - Normal Normal Normal Blood test TSH, T4 Weight gain Laryngeal adenocarcinoma - - - - - - - - - - - Stridor Normal O2, CO2 Retropharyngeal tissue thickness Normal Laryngoscopy Choking sensation Vocal cord paralysis - - - - - - - - - - - - Stridor Normal Normal Pharyngeal constrictor muscles thinning, uvular deviation Normal Laryngoscopy Choking sensation Tracheal stenosis - - - - - - - - - - Stridor, Stertorous Normal O2, CO2 Soft tissue thickening internal to normal-appearing tracheal cartilage Normal Bronchoscopy Respiratory distress Chest and Pleura, Lower airway Bronchial asthma - - - - - - - - Wheeze Eosinophil Respiratory alkalosis, Metabolic acidosis Pulmonary hyperinflation, Bronchial wall thickening FEV1 FVC Spirometry before and after bronchodilator Paroxysmal respiratory distress Bronchiectasis - - - - - - - Rhonchi, Wheezing, Crackles WBC, neutrophilia O2, CO2 Tram-track opacities FEV1 FVC High resolution computed tomography HRCT Chronic productive cough COPD - - - - - - Expiratory wheeze RBC Respiratory alkalosis, Metabolic acidosis Bronchovascular markings, Cardiomegaly FEV1 FVC Physical exam and Spirometry Heavy smoking history Emphysema - - - - - - - - - - Expiratory wheeze, Hyperinflation Normal Respiratory alkalosis, Metabolic acidosis Flattening of diaphragm, vertical heart FEV1 FVC Physical exam and Spirometry Barrel chest Pulmonary hypertension - - - - - - - - - - Accentuated S2 Normal Hypoxia and acidosis Enlarged pulmonary arteries Physiologic RV Cardiac catheterization Syncope, Ascites, Pleural effusion Interstitial lung disease - - - - - - - - Rhonchi, Wheezing, Crackles Normal O2, CO2 Peripheral pulmonary infiltrative opacification FEV1 FVC High resolution computed tomography HRCT Pneumoconiosis Sarcoidosis - - - - - - - - - - Crackles Normal O2, CO2 Hilar adenopathy FEV1 FVC High resolution computed tomography HRCT Hypercalcemia, high ACE Alveolitis - - - - - - - - - Basal crackle WBC, neutrophilia Normal Basal reticulonodular opacification FEV1 FVC High resolution computed tomography HRCT Dry cough Bronchiolitis obliterans - - - - - - - Expiratory wheeze WBC O2, CO2 Hyperinflation, Reticulonodular opacities FEV1 FVC Lung biopsy Complication of allogeneic hematopoietic stem cell transplantation Cystic fibrosis - - - - - - - - Rhonchi, Wheezing, Crackles Normal Metabolic alkalosis Thick-walled bronchiectasis FEF 75 FVC Sweat test Absent vas deferens Pleural effusion - - - - - - - - - - Egophony E-to-A change Normal Normal Blunting of the costophrenic and cardiophrenic angle Vt, RV Lights criteria Tactile fremitus, Asymmetrical chest expansion Pulmonary right-to-left shunt - - - - - - - - - Diminished breath sounds Normal O2, CO2, Respiratory acidosis Normal Vt, RV physiological Pulmonary CT angiography Chronic hypoxemia Diaphragmatic paralysis - - - - - - - - - - - - Normal Normal Normal Unilateral or bilateral diaphragmatic flattening Vt, RV anatomical CXR confirmed by fluoroscopic sniff test Respiratory insufficiency Tuberculosis - - - - - - - - Rhonchi, Wheezing, Crackles WBC O2, CO2 Patchy consolidation or poorly defined linear and nodular opacities Restrictive, obstructive, or mixed IFN-γ release assay IGRA Acid-fast staining Night sweat Cardiovascular system Constrictive pericarditis - - - - - - - - Muffled heart sounds Normal Normal Calcifications Normal Chest CT scan Syncope Restrictive cardiomyopathy - - - - - - - - - Normal Normal Normal Dilatation of the inferior vena cava and right atrium Normal Right ventricular biopsy Weight gain, Nausea Valvular heart disease - - - - - - - - - - Cardiac murmur Normal Normal Dilatation of heart chambers Normal Echocardiography Syncope, Palpitation Bradyarrhythmia - - - - - - - - - - - - Normal Normal Normal ECG Syncope, Palpitation Pericardial effusion - - - - - - - - - Muffled heart sounds Normal Normal Fluid density around the heart Normal M-mode and 2-dimensional Doppler echocardiography Hoarseness, Palpitation Coronary heart disease - - - - - - - - - Normal Normal O2 Normal Normal Cardiac troponin I Nausea, Lightheadedness, Sweating Intracardiac shunt - - - - - - - - - Cardiac continuous murmur Normal O2 Dilatation of heart chambers Normal Echocardiography Syncope, Palpitation Neuromuscular disease Amyotrophic lateral sclerosis - - - - - - - - - - - - Normal WBC Normal Normal Vt, RV Revised El Escorial criteria clinical Muscle weakness, Dysphagia Polymyositis dermatomyositis - - - - - - - - - - - Normal WBC Normal Normal Vt, RV Muscle biopsy Muscle weakness, Heliotrope Mitochondrial diseases - - - - - - - - - - - - Wheeze WBC, Plt Normal Normal Vt, RV Muscle biopsy Muscle pain Glycolytic enzyme defects e.g., McArdle - - - - - - - - - - - - Normal Normal Normal Vt, RV Muscle biopsy ragged red fibers Myoglobinuria, Muscle weakness Toxic Metabolic Metabolic acidosis - - - - - - - - - - - Normal Normal Metabolic acidosis, Respiratory alkalosis Normal Normal ABG Confusion, Vomiting Renal failure - - - - - - - - Normal RBC Metabolic acidosis Normal Normal Cr Nausea, Vomiting, Oliguria Systemic Anemia - - - - - - - - - - - Normal RBC O2 Normal Normal HGB, MCV Weakness, Fatigue Anxiety - - - - - - - - - Normal Normal Normal Psychological interview Sweating, Palpitation Ascites - - - - - - - - - - - - Normal Normal Normal Peritoneal fluid accumulation Vt, RV Abdominal ultrasound Abdominal distention Depression - - - - - - - - - - Normal Normal Normal Psychological interview Depressed mood, Fatigue Kyphoscoliosis - - - - - - - - - - - - Wheeze Normal Normal Deviated vertebral column Vt, RV anatomical Standing lateral spine radiograph Low back pain Obesity - - - - - - - - - - - - Normal Normal O2 Normal Vt, RV anatomical BMI Low stamina, Sweating Autoimmune Churg-Strauss syndrome - - - - - - - - - - - Scattered wheezing Normal Normal Areas of parenchymal opacification Vt, RV Biopsy Fatigue, Numbness Microscopic polyangiitis - - - - - - - - - - Scattered wheezing WBC O2, CO2 Normal Vt, RV Histological confirmation Skin lesions, Nerve damage Wegeners granulomatosis - - - - - - - - - - - Wheezing, Crackles RBC O2, CO2 Cavitate nodules, ground-glass opacity FEV1 FVC Biopsy demonstrating a granulomatous vasculitis Chronic rhinosinusitis Goodpastures disease - - - - - - - - - - - Bilateral coarse crepitations RBC, HGB, HCT Normal Like pulmonary edema Normal Kidney biopsy Hematuria, Hemoptysis 