Respiratory System

Anatomy The respiratory system starts from the nose, mouth, larynx, trachea, and the two lungs.

Within the lungs, the bronchi transport air with oxygen to the alveoli on inspiration and carry waste gases (e.g. carbon dioxide) away on expiration. The acinus is the gas exchange unit of the lung and consists of branching respiratory bronchioles leading to clusters of alveoli. Alveoli are tiny air sacs lined by flattened epithelial cells and covered in capillaries where gas exchanges occur

The alveoli and capillaries have extremely thin walls and come into very close contact (the alveolar capillary membrane) so gases can rapidly diffuse between them. There are approximately 300 million alveoli in each lung for gas exchange with a total surface area of 40-80 meter square.

The lungs has two blood supplies: 1) the bronchial arteries which arise from the aorta and supply oxygenated blood to the bronchial walls. 2) The pulmonary arteries which deliver deoxygenated blood to the capillaries surrounding the alveoli

Symptoms 1) Cough 2) Sputum production 3) Hemoptysis 4) Chest pain 5) Breathlessness

Symptoms 1 )Cough: Is a forced expulsive maneuver against an initially closed glottis. Causing characteristic sound. Can be acute (less than 3 weeks) or chronic (more then 8 weeks) The most common cause is acute viral infections of the upper airway system

Cough (features) Prolonged wheezy coughing: asthma, COPD. Feeble non-explosive (bovine): lung cancer (paralysis of vocal cords), neuromsucular disease causing respiratory muscle weakness Moist cough: secretions from infection, bronchiectasis, chronic bronchitis. Noctunral cough: asthma

Cough (causes) Acute: Viral respiratory tract infection Bronchitis Chronic Gastroesophageal reflux disease (GERD) Asthma Post bronchial hyper-activity Rhinitis/sinusitis Cigarette smoking Drugs, ACE inhibitors Irritant dusts/fumes Lung tumors TB, Interstitial lung disease Bronchiectasis Acute: Viral respiratory tract infection Bronchitis Inhaled foreign body Inhalation of irritant dusts or fumes Pneumonia Acute extrinsic allergic alveolitis

Symptoms 2) sputum production Amount Colour Taste or smell Examples: COPD and chronic bronchitis: clear mucoid sputum if there is no infection Lower respiratory tract infection: yellowish sputum (presence of live neutrophils) Ashtma: yellowish sputum (eosinophils) Bronchiectasis: large volumes of purulent sputum varying with posture Pulmonary edema: watery sputum with a pink tinge

Symptoms 3) Hemoptysis Amount and appearance Duraion and frequency intermittent with recurrent infections over years: bronchiectasis Daily for a short periods (weeks) lung cancer, TB, abscess Single episodes with chest pain: pulmonary infarction.

Hemoptysis (causes) Infection: Bronchiectais, Tuberculosis, lung abscess, cystic fibrosis Tumours: Lung cancer, endobronchial metastasis, bronchial carcninoid. Vascular: Pulmonary infarction, arteriovenous malformation Vasculitis. Trauma Foreign body, iatrogenic

Hemoptysis (causes) Cardiac: Mitral Valve disease, acute left ventricular failure Hematological: Bleeding tendencies, anticoagulation

Symptoms 4) Chest pain: Pleural chest pain Chest wall pain Mediastinal chest pain

Pleural chest pain Is a sharp, stabbing pain and is intendified by inspiration or coughing caused by irritation of the parietal pleura. Causes: Infection: pneumonia, bronchiectasis Pneumothorax Pulmonary infarction Connective tissue disease

Chest wall pain Causes: Chornic cough/breathlessness Muscular pain Rib fractures Bony metastasis Thoracis shingles (herpes zoster)

Mediastinal chest pain Mediastinal chest pain is central, retrosternal and unrelated to respiration or cough. Causes: Massive pulmonary embolism Acute myocardial infarction Aortic dissection Infection, irritant dusts Eshophagitis Mediastinitis Lymphadenopathy

Symptoms 5) Breathlessness Shortness of breath, difficulty getting enough air. Mode of onset Minutes: pulmonary thromboembolism, pneumothorax, asthma, inhaled forein body Hours to days: pneumonia, asthma. Weeks to months: Anemia, Pleural effuion, neruomuscular disease. Months to years: COPD, pulmonary fibrosis, TB, Heart failure.

Breathlessness Causes: Non cardio-respiratory: Anemia, Obesity, Psychogenic, Metabolic acidosis. Cardiac: Heart failure, mitral valve disease, pericarditis, pericaridal effusion Respiratory: Foreign body, Ashtma, COPD, Bronchiectasis, Lung cancer, pulomnary fibrosis, Pneumonia, Tuberculosis, pulmonary thromboembolism, pulmonary hypertension, pneumothorax, kyphoscholiosis. Neumuscular disease.

Physical Examination of the respiratory system General Examination Examination of the thorax Respiratory rate Breathing pattern Inspection Accessory muscles Stridor Palpation Hoarseness Cyanosis Blood pressure Skin Appearances Percussion Hands Neck Ascultation Shape of chest

Physical Examination of the respiratory system General Examination Examination of the thorax Respiratory rate

Respiratory rate Average: 14 breath per minute Normal 12-20 breth per minute Tachypnea: Increased ventilatory drive: Fever Acute asthma, COPD exacerbation Reduced ventilatory capacity: Pneumonia, Pulmonary edema, interstitial lung disease. Decreased respiratory rate

Physical Examination of the respiratory system General Examination Examination of the thorax Respiratory rate Breathing pattern

Breathing Patterns Periodic breathing (Cheyne-Stokes respiration) Hyperventilation Anxiety/emotional stress Metabolic acidosis (Kussmaul respiration)

Physical Examination of the respiratory system General Examination Examination of the thorax Respiratory rate Breathing pattern Accessory muscles Stridor

Stridor A harsh, rasping or croaking inspiratory noise resulting from turbulent airflow in the upper airway, aggravated by coughing. Should always be investigated, can be an emergency Causes foreign body or tumour partially occluding larynx, trachea or main bronchus epiglottitis Air way edema

Physical Examination of the respiratory system General Examination Examination of the thorax Respiratory rate Breathing pattern Accessory muscles Stridor Hoarseness Cyanosis

Cyanosis Is a bluish discoloration of the skin and mucous membranes Can be Central of Peripheral

Physical Examination of the respiratory system General Examination Examination of the thorax Respiratory rate Breathing pattern Accessory muscles Stridor Hoarseness Cyanosis Blood pressure Skin Appearances Hands

Hands Clubbing (mild , moderate , gross ) Causes Familial Thoracic Non-Thoracic

Thoracic Non Thoracic Lung cancer Mesothelioma Pleural fibroma Esophageal cancer Thymoma Atrial myxoma IPF Bronchiectasis, lung abscess Empyema CF Bacterial Endocarditis Cyanotic congenital heart disease Lung AV malformation Non Thoracic Liver cirrhosis Celiac disease Ulcerative colitis Crohn’s disease

Hands Hypertrophic Pulmonary Osteoarthropathy (combination of clubbing and thickening of periosteum (connective tissue lining of the bones) and synovium) Discoloration of the finger and nails Tremor Fine tremor Coarse flapping tremor (asterixis)

Causes of flapping tremor Respiratory failure/ CO2 retention Liver failure Renal failure Electrolyte disturbance Hypoglycemia Hypokalemia Hypomagensemia Wilson’s disease CNS Intracerebral hemorrhage subdural hematoma subarachnoid hemorrhage cerebral ischemia cerebral lymphoma Drugs barbiturates alcohol sodium valproate phenytoin carbamazaepine metoclopramide gabapentin ceftazidime opioids

Physical Examination of the respiratory system General Examination Examination of the thorax Respiratory rate Breathing pattern Accessory muscles Stridor Hoarseness Cyanosis Blood pressure Skin Appearances Hands Neck

Neck JVP Neck Nodes

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