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Showing posts with the label Pulmunology

Microscopic structure of alveolar wall

From blood to air we have the following structures: 1) The capillary endothelium 2) A basement membrane and surrounding interstitial tissue  3) The pulmonary interstitium is most prominent in thicker portions of the alveolar septum. 4) Alveolar epithelium. The latter contains a continuous layer of two principal cell types: flattened, platelike type I pneumocytes covering 95% of the alveolar surface and rounded type II pneumocytes which produce pulmonary surfactant and are the main cell type involved in repair of alveolar epithelium in the wake of damage to type I pneumocytes.  The alveolar walls are not solid but are perforated by numerous pores of Kohn, which permit passage of bacteria and exudates between adjacent alveoli. Alveolar macrophages, mononuclear cells of phagocytic lineage, usually lie free within the alveolar space.  

hemoptysis - causes

Non-respiratory tract sources Nasopharyngeal source of bleeding - epistaxis Upper Gastrointestinal Bleeding - look out for melena Common Causes of respiratory tract bleeding Infection (60-70% of Hemoptysis) Acute Bronchitis (26% of Hemoptysis) - mucoid also Pneumonia (10% of Hemoptysis) Staphylococcus aureus Pseudomonas aeruginosa - foul smelling Tuberculosis (8% of Hemoptysis) Fungal organisms (e.g. Aspergillosis) - with a black component also Influenza Lung Cancer (23% of Hemoptysis) Hemoptysis is rarely due to metastases Less common causes of respiratory tract bleeding Cardiovascular causes Pulmonary venous Hypertension Congestive Heart Failure - frothy Severe Mitral Stenosis Pulmonary Embolism Arteriovenous malformation Pulmonary causes Bronchiectasis Airway trauma or foreign body (esp. children) Lung Abscess Goodpasture's Syndrome Wegener's Granulomatosis Lupus pneumonitis

Dexamethasone and asthma

Studies showed that a 2-day course of dexamethasone is as effective as a 5-day course of prednisolone in the treatment of mild to moderate asthma. Both drugs have the same bioavailability (fraction of an administered dose of unchanged drug that reaches the systemic circulation) but the half life of prednisolone varies between 8-24 hr while that of dexamethasone ranges between 32-72 hr.