Diseases Of The Pulmonary Parenchyma, Pleura, Mediastinum & Pulmonary Circulation PDF

Diseases of the Pulmonary Parenchyma, Pleura, Mediastinum & Disease of Pulmonary Circulation GENERAL PATHOLOGY 3º Prof. Luis D’Marco, MD, MSc, PhD.  Obstructive Lung Diseases These diseases are a group of pulmonary disorders that result in dyspnea...

Diseases of the Pulmonary Parenchyma, Pleura, Mediastinum & Disease of Pulmonary Circulation GENERAL PATHOLOGY 3º Prof. Luis D’Marco, MD, MSc, PhD.  Obstructive Lung Diseases These diseases are a group of pulmonary disorders that result in dyspnea characterized by an obstructive pattern of expiratory airflow limitation on spirometry. These include chronic obstructive pulmonary disease (COPD), asthma, cystic fibrosis (CF), bronchiectasis, and bronchiolar disorders. In some cases, these disorders overlap clinically. The symptoms of wheezing and sputum production, chronic airway-centered inflammation and episodic periods of temporarily worsened clinical status, known as exacerbations. Classification of obstructive lung diseases Features of Obstructive Lung Disease  Asthma Is a chronic inflammatory disorder of the airways, in which many cells and cellular elements play a role. Chronic inflammation is associated with airway hyper-responsiveness that leads to recurrent episodes of wheezing, breathlessness, chest tightness and coughing (night and in the early morning). These episodes are usually associated with widespread but variable airflow obstruction within the lung that is often reversible. The prevalence of asthma increased steadily over the latter part of the last century. Asthma affects all age groups, it is one of the most common and long- term respiratory conditions in terms of global years lived with disability.  Pathology Underlying chronic airway inflammation is a major pathogenic feature of asthma. Patients have higher numbers of activated inflammatory cells within the airway wall and the epithelium (eosinophils, mast cells, macrophages, and T lymphocytes), which produce (cytokines, leukotrienes, and bradykinins). Airway inflammation in asthma is typified by a type 2 helper T-cell response to inflammation, but some patients with severe asthma exhibit neutrophilic airway inflammation. The hallmark of asthma is airway hyperresponsiveness—a tendency of the airway’s smooth muscle to constrict in response to levels of inhaled allergens or irritants. Inhaled allergens provoke airway mast cell degranulation by binding to and cross-linking IgE on the mast cell surface. Mucus in the large airways & thickening of the airway smooth muscle layer of a patient with asthma  Clinical Presentation Major symptoms are wheezing, episodic dyspnea, chest tightness, and cough. The clinical manifestations vary widely, from mild intermittent symptoms to catastrophic attacks resulting in asphyxiation and death. Although wheezing is not a pathognomonic feature of asthma, in the setting of a compatible clinical picture, asthma is the most common diagnosis. Often symptoms worsen at night or in the morning. Other associated symptoms are sputum production and chest pain or tightness. Patients may exhibit only one or a combination of symptoms, such as chronic cough only (cough-variant asthma). Wheezing may occur several minutes after exercise (exercise-induced bronchoconstriction).  How to make a diagnosis of asthma no question about spirometry ; only clinical symptoms Compatible clinical history plus either/or: FEV1 ≥ 12% (and 200 mL) increase following administration of a bronchodilator/trial of glucocorticoids. Greater confidence is gained if the increase is >15% and >400 mL >20% diurnal variation on ≥3 days in a week for 2 weeks on PEF diary FEV1 ≥15% decrease after 6 mins of exercise *FEV1 = forced expiratory volume in 1 sec; PEF = peak expiratory flow Management approach in adults based on asthma control ICS = inhaled corticosteroids (glucocorticoids) How to use a metered-dose inhaler  Management of mild to moderate exacerbations & acute severe depend of o2 saturation and clinical manifestation Doubling the dose of inhaled glucocorticoids does not prevent an impending exacerbation. Short courses of ‘rescue’ glucocorticoids (prednisolone 30–60 mg daily) are therefore often required to regain control. Tapering of the dose to withdraw treatment is not necessary unless glucocorticoid has been given for more than 3 weeks.  Chronic obstructive pulmonary disease Although in the past COPD was defined by the presence of either emphysema (a pathologic enlargement of the distal air spaces) or chronic bronchitis (a clinical syndrome characterized by the presence of cough and sputum production for at least 3 months in each of 2 consecutive years), the current definition is based on the presence of airflow limitation and not on the presence of these entities. Both emphysema and chronic bronchitis may occur with or without the simultaneous presence of expiratory airflow limitation, and therefore these entities overlap with but are not synonymous with COPD. The current definition of COPD highlights the presence of persistent, reproducible expiratory airflow limitation and emphasizes the progressive nature of COPD and the presence of abnormal inflammation in the lungs and airways. Chronic obstructive pulmonary disease decrease of lumen higher mucus and higher thickness infla cells The pulmonary and systemic features of chronic obstructive pulmonary disease COPD : systemic repercusion Mechanisms of cigarette smoke-induced inflammation and oxidant injury last lecture Modified Medical Research Council (MRC) dyspnoea scale  Anterior-posterior (left) and lateral (right) chest radiographs anterio post view lateral hyper inflation with increase of the lung diameter Changes caused by severe COPD, including hyperinflation, increased anterior-posterior diameter, flattened diaphragms, and enlarged pulmonary arteries  CT scan shows paraseptal distribution of emphysema emhysema patient boulas emphysematosas  The pathology of emphysema Emphysematous lung showing gross loss of the normal surface area available Normal lung for gas exchange  The pathology of emphysema Emphysema with enlargement of distal air spaces Centrilobular emphysema surrounded by normal lung  Chronic obstructive pulmonary disease Model of annual decline in FEV1 with accelerated decline in susceptible smokers. Spirometric classification of COPD severity based on post- bronchodilator FEV1 When smoking is stopped, the subsequent loss is similar to that in healthy non-smokers. (FEV1 = forced expiratory volume in 1 second) acute bronchospasm = not oral but IV corticoids Algorithms for the treatment  Pneumonia Is an acute respiratory illness associated with a radiological pulmonary shadowing that may be segmental, lobar or multilobar. The context in which pneumonia develops is highly suggestive of the likely organism(s) involved. Pneumonias are usually classified as community- or hospital-acquired, or those occurring in immunocompromised hosts. ‘Lobar pneumonia’ is an Rx and pathological term referring to homogeneous consolidation of 1 or more lobes, cab be associated pleural inflammation. Bronchopneumonia is more patchy alveolar consolidation associated with bronchial and bronchiolar inflammation, 1 or both lower lobes.  Community-acquired pneumonia CAP Studies suggest that an estimated 5–11/1000 adults suffer from CAP each year, accounting for around 5–12% of all lower respiratory tract infections. CAP may affect all age groups but is particularly common at the extremes of age. Most cases are spread by droplet infection, and while CAP may occur in previously healthy individuals, several factors may impair the effectiveness of local defenses and predispose to CAP. Streptococcus pneumoniae remains the most common infecting agent, and thereafter the likelihood that other organisms may be involved depends on the age of the patient and the clinical context.  Community-acquired pneumonia Organisms causing community-acquired Factors that predispose to pneumonia pneumonia  Clinical features Pneumonia, particularly lobar, usually presents as an acute illness. Systemic features, such as fever, rigors and malaise. The appetite is invariably lost and headache are frequently reported. Pulmonary symptoms include cough, which at first is characteristically short, painful and dry, but later is accompanied by the expectoration of mucopurulent sputum. Rust-coloured sputum may be produced by patients with Strep. Pneumoniae infection and the occasional patient may report haemoptysis  Hospital-acquired pneumonia HAP or nosocomial pneumonia refers to a new episode of pneumonia occurring at least 2 days after admission to the hospital. It is the second most common HAI and the leading cause of HAI-associated death. The elderly are particularly at risk, as are patients in intensive care units, especially ventilated adquired pneumonia when mechanically ventilated; here, the term VAP is applied. HCAP refers to the development of pneumonia in a person who has spent at least 2 hemo dialysis days in hospital within the last 90 days, or has attended an HD unit, or received intravenous antibiotics, or been resident in a nursing home or other long-term care facility. hospital-acquired infection (HAI); ventilator-associated pneumonia (VAP); Health-care-associated pneumonia (HCAP) Factors predisposing to hospital-acquired pneumonia  Clinical features Clinical examination should first focus on the respiratory and pulse rates, blood pressure and an assessment of the mental state, as these are important in forming a judgement as to severity of the illness  Pneumonia of the right middle lobe A Posteroanterior view: consolidation in the right middle lobe with characteristic opacification beneath the horizontal fissure and loss of normal contrast between the right heart border and lung. B Lateral view: consolidation confined to the anteriorly situated middle lobe. Investigations in community-acquired pneumonia  Tuberculosis Features of primary tuberculosis TB is caused by Mycobacterium tuberculosis, which is part of a complex of organisms including M. bovis and M. africanum. The resurgence in TB is observed over the latter part of the last century has finally halted and notification of TB has fallen by around 1.5% per year since 2000. all lung affected An estimated 9.6 million new cases were recorded in 2014, with the majority presenting in the world’s poorest nations. In the same year, 1.5 million men, women and children died of TB, and TB continues to rank alongside HIV as a leading cause of death worldwide. Typical changes of tuberculosis difuse R and L compromised Systemic presentations of extrapulmonary tuberculosis TBC: Diagnosis & Treatment  Pulmonary Vascular Diseases Is a broad term for any disease that affects the blood vessels of the lungs. These diseases are a heterogeneous group of disorders with multiple causes, but most can be categorized as diseases of: Pulmonary embolism Pulmonary hypertension. Some pulmonary vascular diseases, such as idiopathic pulmonary arterial hypertension (PAH), directly affect the pulmonary vessels, whereas other forms of pulmonary vascular disorders are compensatory responses to elevation of pulmonary venous pressure or recurrent hypoxia due to chronic heart and lung diseases.  Pulmonary Vascular Diseases lot of blood there The normal pulm. vasculature is a high-flow, low-resistance system with a very high capacitance that can accept the entire output of the RV with only slight increases in pressure. The RV in health is well adapted to the pulmonary circulation and matches the cardiac output of the LV. increase resistance in the pulmonary artery after load increase However, the RV is unable to tolerate large increases in afterload, which occur acutely in the setting of pulmonary thromboembolism and more subacutely or chronically in pulmonary hypertension. RV function is important in the clinical manifestations, diagnosis, treatment, and prognosis of pulmonary vascular diseases.  Pulmonary hypertension Normal pulmonary arterial pressure (PAP) in healthy adults at rest is about 25/10 mmHg with a mean PAP (mPAP) of 14.3 mmHg ± 3.0 mmHg. mPAP