Respiratory Medicine

Transcription

1 Respiratory Medicine This document is based on the handout from the Medicine for Finals course. The notes provided here summarise key aspects, focusing on areas that are popular in clinical examinations. They will complement more detailed descriptions and are not intended to be comprehensive. Overview of respiratory medicine Examination Carcinoma of bronchus Pleural effusions Loss of lung volume Chronic airflow obstruction Acute asthma in adults Restrictive ventilatory defects Examination- inspection for signs of Breathlessness at rest Anaemia Central cyanosis Clubbing Horner s SVC obstruction Weight loss, lymphadenopathy Clubbing: 4 signs Increased fluctuancy of nail bed Loss of angle Curvature of nail Drum stick appearance Due to periosteal reaction Pancoast syndrome T1 root lesion with Horner s syndrome Carcinoma of upper lobe Wasting of small muscles of hand (T1 motor- myotome) Pain felt in axilla (T1 sensory- dermatome) Dr R Clarke 1

2 Presenting the short case Dyspnoea, cyanosis (overall respiratory status) Clubbing lymphadenopathy (? signs of neoplasia) Trachea and apex (?evidence mediastinal shift) Localising signs Examination Most of the useful information is obtained prior to using stethoscope Trachea and expansion most important Chest expansion always reduced on the side of the lesion Trachea and apex beat give signs of mediastinal shift Localising signs Expansion most important Grip firmly with thumbs just off the skin Carcinoma of bronchus Usually presents late Though 30% thought resectable, only 5% actually cured Investigate carefully to prevent unnecessary surgery Investigations- C/I to surgery Sputum cytology Small cell disease Lung function FEV1< 1 litre Bronchoscopy Carinal disease LFT, liver bone and CT head scan?mri Distant spread Pleural aspiration and biopsy Malignant effusion Pleural effusions Expansion reduced Percussion reduced (stony dull) Trachea usually normal Air entry reduced TVF reduced Pleural exudates Carcinoma of bronchus Infection: lobar pneumonia and tuberculosis Pulmonary emboli Rheumatoid arthritis Question stop How do you tell the difference between an effusion and a collapse? Dr R Clarke 2

3 Effusion vs collapse Stony dull with an effusion (subtle distinction between very dull and dull!) May be an area of bronchial breathing above an effusion (but occasionally bronchial breathing with collapse-consolidation ) Most useful sign is the trachea- normal with most effusions, pushed away with massive effusion and shifted towards the affected side with a collapse The main source of confusion is the varying use of the term collapse. In lay parlance, a collapsed lung usually refers to a pneumothorax. By contrast, respiratory physicians use the term collapse to imply collapse of the lung due to an intrinsic lesion causing occlusion of the airway, with loss of aeration of the distal lung, which collapses. This might happen, for example, with an inhaled foreign body or a bronchial carcinoma occluding a bronchus. Loss of lung volume In loss of lung volume the trachea is deviated towards the affected side Pneumonectomy TB and old treatments for TB Unilateral fibrosis Collapse of a lobe Trachea deviated to left Collapse of left lung Heart displaced to left (Normally one third of heart shadow visible on right of spine) Rarely trachea pushed AWAY from side of lesion Massive pleural effusion Pneumothorax with TENSION Dr R Clarke 3

4 Airflow obstruction Asthma Chronic bronchitis Emphysema FEV1/FVC < 75% Acute asthma in adults British Thoracic Society Guidelines signs of severe asthma 5 life threatening features 4 signs of severe asthma Unable to complete sentences in one breath Respiratory rate > 25 Heart rate > 110 PFR < 50% predicted (or best) 5 life threatening features S silent chest H hypotension O one third PFR (of predicted or best) C cyanosis K konfusion Investigation If severe, only blood gases needed Examine to exclude pneumothorax If in doubt, portable CXR Once stabilised, check FBC, U+E etc Dehydration common Blood gas markers of severity Low ph Severe hypoxia (po2<8kpa) pco2 normal- beware!- or high Alveolar hypoventilation Increased respiratory drive Low pco2 normally results Dr R Clarke 4

5 Arterial pco2 Death Normal pco2 A low pco2 is expected Beware the normal pco2 Increasing severity of asthma attack Immediate treatment High dose oxygen High dose nebulised beta 2 agonists High dose IV hydrocortisone Write No sedation on treatment card Reassess every 15 minutes with PFR Severe or not improving Request early assessment of ITU staff Arrange ECG monitor Repeat nebuliser with ipratropium Consider slow IV aminophylline infusion (if not on oral theophyllines) Repeat PFR and blood gases Asthma deaths in hospital Failure to measure PFR Failure to measure blood gases Its fine, the pco2 is normal Failure to ventilate quickly Too much aminophylline, too few nebulisations Sedating the patient Dr R Clarke 5

6 Chronic airflow limitation Bronchitis and emphysema often co-exist Audible wheeze, low PFR Symmetrically reduced expansion Expiratory wheezes No crackles- unless infective exacerbation No clubbing- unless bronchiectasis or tumour Chronic bronchitis Cough plus sputum 3/12 for 2 years Goblet cell hypertrophy Mucus hypersecretion and plugging Small areas of collapse cause shunting Leads to hypoxia Disease of the airways Emphysema Dilatation distal to terminal bronchiole Destruction of alveolar walls Reduced transfer factor Loss of elasticity, increase in compliance Airways collapse early in expiration Disease of lung tissue Signs suggesting emphysema Pursed lips expiration ( self-peep ) Barrel chest Tracheal tug Hyper- resonance Reduced breath sounds Pink puffer Marked breathlessness po2 slightly reduced, pco2 normal Partial compensation for hypoxia by increased respiratory rate Thin No cor pulmonale Dr R Clarke 6

7 Blue bloater CO2 retention Pulmonary hypertension RV failure Secondary polycythaemia Hypoxic respiratory drive Exacerbation of COPD 24% oxygen and no sedation Nebulised salbutamol and ipratropium Antibiotics and physiotherapy Steroids often given Treat heart failure Restrictive defect FEV1 reduced FVC reduced Ratio normal or increased Transfer factor reduced if pulmonary cause Transfer factor normal if extra-pulmonary Pulmonary causes Sarcoidosis Systemic sclerosis Fibrosing alveolitis Rheumatoid lung Asbestosis And many others! Dr R Clarke 7