Respiratory Disorders MEDI 2006 PDF

1 MEDI 2006 Pathology for Medical Radiation Topic 5 RESPIRATORY DISORDERS Dr Jyothi Thalluri UniSA: Clinical and Health Sciences  Learning objec...

1 MEDI 2006 Pathology for Medical Radiation Topic 5 RESPIRATORY DISORDERS Dr Jyothi Thalluri UniSA: Clinical and Health Sciences  Learning objectives Gain knowledge and understanding of aetiology, pathogenesis, pathophysiology and clinical manifestations of: Obstructive, restrictive and malignant lung diseases COPD Asthma Pneumonia Lung cancer Differentiate between restrictive and obstructive lung diseases. Know what is atelectasis, bronchiectasis and pneumothorax. Understand etiology and pathogenesis of pulmonary embolism Topic 5a RESPIRATORY DISORDERS The respiratory system Microscopic anatomy of bronchi and alveoli Obstructive and Restrictive lung disorders Pickwick syndrome: severely overweight people fail to breathe rapidly enough or deeply enough, resulting in low blood oxygen levels and high blood carbon dioxide (CO2) levels Obstructive Lung Disease vs Restrictive Lung Disease 7  Obstructive processes A – Asthma B – Chronic Bronchitis C – Emphysema Porth “Pathophysiology: Concepts of Altered Health States”  COPD include: Emphysema Chronic bronchitis Most patients have a mix of emphysema and chronic bronchitis COPD is not curable, but treatment can slow the progress of the disease.  Pathogenesis emphysema Causes: Smoking Air pollution Hereditary (α1- antitrypsin deficiency) α1-antitrypsin (protein) inhibits the neutrophil elastase activity to protect the lungs' air sacs from damage when the immune system is doing work to protect the lungs. “Pathophysiology: Concepts of Altered Health States”. Emphysema (full of air) Close-up view. Normal alveoli are too small to be visible to the unaided eye. Merger of alveoli into larger air spaces makes them plainly visible in this specimen. Emphysema on chest X ray 44 sec: https://www.youtube.com/watch?v=oqciiDDDf2U  Types of emphysema Centri-acinar Proximal part of acini affected, distal alveoli spared Typical pattern in smokers Pan-acinar Acini uniformly enlarged Distal alveoli involved first Typical in α1-antitrypsin deficiency Kumar et al. ‘Robbin’ s Basic Pathology’  Alveolar elasticity lost ® Loss of elastic recoil ® air sac enlargement ® air trapping Lung permanently inflated Decreased FEV1 (1st symptom) Elastic tissue replaced with fibrous tissue changes in lung tissue distal to terminal bronchioles O2 diffusion decreased Co2 diffusion decreased (respiratory acidosis)  Clinical manifestations emphysema Dyspnoea Wheezing and cough usually a late symptom Accessory resp. muscle use ­ Barrel chest Hunched forward breathing Pursed lip breathing Weight loss http://www.nburge.com/phs/wp-content/uploads/2011/03/clip_image005.jpg “Pink puffer” (hypoxia at late stage) TLC ­, RV ­, FEV1 ¯  Diagnostic tests for emphysema Lung function tests A chest X-ray CT test Pulse oximetry  Chronic Bronchitis Hyper-secretion of mucus + chronic productive cough for at least 3 months of the year for at least 2 years in a row Obstruction caused by excessive mucus production which is not effectively cleared Initial disease in larger bronchi, later stages also small airway disease Causes Smoking Air pollution The relationship between emphysema and chronic bronchitis Most patients with COPD have a mixture of bronchial inflammation and alveolar destruction. Bronchitis  Blue bloater Pink puffer With cor pulmonale, blood can get backed up in the veins throughout your body, so peripheral edema develops. Due to the effects of gravity, fluid starts to pool in the lowest parts of your body. https://www.google.com/search?q=pink+puffer+blue+bloater&rls=com.microsoft:en-AU:IE-Address&tbm=isch&source=iu&ictx=1&fir=_71FlNh8Q3QgIM%253A%252ClWr- KxF_kejq1M%252C_&usg=AFrqEzc_Oxv1MiMCf8Zag9OpbacDQeqyVw&sa=X&ved=2ahUKEwjr0- bxy__cAhVPc3AKHVz4C_0Q9QEwAHoECAYQBA#imgrc=n6Y3OGQnuiB3mM:&spf=1534904245917 Blue bloaters (Chronic bronchitis) Pulmonary capillary bed is undamaged Reduced ventilation because increased obstruction = low O2 and high CO2 = cyanosis Increased obstruction = increased residual volume – bloating Pink puffers (Emphysema) Destruction of alveolar sacs = destruction of pulmonary capillary bed Blood cannot be oxygenated Hyper ventilation using neck and chest muscles to breath = pink complexion Clinical manifestations chronic bronchitis Cough Wheeze “blue bloater” (cyanosis) TLC may be ­ due to expiratory airflow limitation, RV ­, FEV1 ¯ Diagnosis Pulmonary function tests. Arterial blood gas Pulse oximetry Chest X-ray CT scan  Asthma is a chronic disease of the airways involves airway inflammation, intermittent airflow obstruction, and bronchial hyper-responsiveness. * Small bronchi and bronchioles with episodic airway obstruction and air trapping due to exaggerated bronchoconstriction and excessive mucus production. Etiological factors Environmental allergens Respiratory tract infections Certain food Exercise Tobacco/occupational exposure Types of asthma 1. Extrinsic or atopic: due to IgE immune responses to environmental antigens (Type 1 hypersensitivity) 2. Intrinsic or non-atopic: triggered by non-immune stimuli such as aspirin, psychological stress, exercise. The bronchi in asthma A. The normal bronchial lumen is wide; normal numbers of smooth muscle cells and mucous glands are present. B. In asthma, the lumen is narrow and contains a large amount of mucus; inflammatory cells are present; the mucus glands are larger and more numerous; and there are increased numbers of smooth muscle cells. Reversible component Bronchospasm and increased mucus production Irreversible component Airway remodelling Bronchial smooth muscle hypertrophy Mucus gland hyperplasia  Note: increased eosinophils http://medicinembbs.blogspot.com.au/2011/02/asthma-and-its-types.html  Clinical manifestations asthma Wheezing during attacks/chest tightness Dyspnoea/coughing Prolonged expiration Tachypnoea Tachycardia Respiratory acidosis at later stage with more severe obstruction.  ATELECTASIS Collapse of a PNEUMOTHORAX: a lung or part of a lung collapsed lung Kumar et al. ‘Robbin’ s Basic Pathology’ https://www.google.com/search?q=pneumothorax&source=lnms&tbm=isch&sa=X &ved=0ahUKEwj5_vTcov_cAhXVFogKHVyJDeMQ_AUICigB&biw=1920&bih=985#i  Bronchiectasis is a condition in which damage to the airways causes them to widen and become flabby and scarred. Usually is the result of an infection prevents the airways from clearing mucus. The airways slowly lose their ability to clear out mucus. So bacteria can grow that can lead to repeated, serious lung infections. Cor pulmonale: abnormal enlargement of the right side of the heart as a result of disease of the lungs or the pulmonary blood vessels.  Diagnostic tests for lung disorders Lung function tests using Spirometry Arterial blood gas analysis Blood tests. Chest X-ray CT scan  REFERENCES McConnell. “The Nature of Disease”. Chapter : “Diseases of the Respiratory system” Porth, Matfin. “Pathophysiology: Concepts of Altered Health States”.. Chapter: “Disorders of ventilation and gas exchange” Chapter: “Respiratory tract infections, neoplasms and childhood disorders”. Craft, Gordon, Tiziani. “Understanding Pathophysiology”. Chapter : “Alterations of pulmonary function across the life span” Kumar, Abbas, Aster. “Robbins Basic Pathology”. Chapter: “Lung”