Tuesday, October 17 (ellen)

Respiratory Pathologies Continued – Tuesday, October 17, 2006 Immuno background ~ GAMED – Igs in highest to lowest concentration in blood ~ IgM – non-specific, 1st response ~ IgA – secretory IgA in all secretions (tears, saliva, LU, gut, semen, vaginal fluid, breastmilk) ~ IgG – usually memory cells ~ IgE – allergies, parasites ~ IgD – surface receptors for basophils ~ omnipotent – turn into any cells ~ plueripotent – can divide into many different cell types ~ hypoclorhydria = decreased production of gastric acid by stomach ~ autoimmune disorder – antibodies against own parietal cells ~ can’t activate pepsinogen ~ means can’t break proteins which get sent to SI and may go into your cells ~ if similar to own tissues, B cells will make Ab to kill own proteins ~ Heparin is a vasodilator and helps clot ~ histamine is in charge of inflammation Pleural Effusion ~ excess fluid in the pleural space ~ normally, 10 to 20mL of fluid spread thinly over visceral and parietal pleurae ~ visceral covers LU ~ parietal under ribs ~ pleural effusions are classified as transudates or exudates ~ transudates – elevations in microvascular pressure or to decrease in oncotic pressure ~ caused by disturbances of hydrostatic or colloid osmotic pressure, not by inflammation ~ fluid that passes through a membrane which filters out much of the protein and cellular elements to yield a watery solution ~ accumulates in tissues outside blood vessels and can cause edema ~ exudates – pleural inflammation (pleurisy) with increased permeability of the pleural surface to fluid with protein ~ any fluid that filters from the circulatory system into lesions or areas of inflammation ~ composition varies but generally includes water and the dissolved solutes of the blood ~ fluid rich in protein and cellular elements ~ oozes out of blood vessels due to inflammation and is deposited nearby ~ altered permeability of blood vessels allow passage of large molecules and solid matter through walls Conditions Causing Transudates ~ heart failure – increases systemic venous and pulmonary capillary pressures ~ hypoalbuminemia – bilateral pleural effusions ~ ex: Kwashiorkor – protein deficiency

~ ascite fluid – can move from peritoneal space into pleural space through diaphragmatic defects or lymphatic channels ~ myxedema – usually transudates ~ seen in hypotheyroidism ~ post-parturition – small effusions, clear rapidly, usually only during the 1st 24 hrs ~ iatrogenic – doctor induced Conditions Causing Exudates ~ mycotic pleurisy – blastomycosis, coccidioidomycosis (West Coast), rare in primary histoplasmosis and cryptococcosis ~ parapneumoic effusion – visceral pleura overlying a pneumonia becomes inflamed ~ pulmonary embolism – pleural effusions in 30-50% of patients ~ metastatic neoplasms – m/c cause in persons > 60 yr ~ Hodgkin’s disease and non-Hodgkin’s lymphoma ~ malignant mesothelioma Pneumothorax ~ air/gas in pleural space ~ spontaneous – affects tall, thin men between 20-40yoa ~ cigarette and family history are contributing factors ~ secondary – complication of underlying pulmonary lung disease like asthma, CF, TB, COPD and whooping cough ~ traumatic – injury to chest ~ trauma may be penetrating or blunt Hemothorax & Chylothorax ~ hemothorax – d/t trauma and rarely after rupture of vessel in parietopleural adhesion ~ pleural blood often does not clot and may be easily drawn with needle ~ chylothorax – traumatic or neoplastic injury to thoracic duct ~ lipid content (neutrla fat and fatty acids) of pleural fluid is high ~ treatment is directed at underlying cause of ductal change Lung Abcess ~ A localized cavity with pus, resulting from necrosis of lung tissue, with surrounding pneumonitis ~ can be putrid (anaerobic bacteria) or non putrid (anaerobes or aerobes) ~ gangrene of the lung – more diffuse and extensive in which necrosis predominates ~ usually b/c of infected material from upper airway aspirated when patient is unconscious ~ causative organism usually anaerobes ~ single lung abscesses are most common ~ multiple abscesses usually unilateral ~ rupture of large abscess into bronchus or vigorous attempts at drainage may cause widespread bronchial dissemination of pus with diffuse pneumonia and condition resembling adult respiratory distress

Pleurisy ~ aka pleuritis ~ inflammation of pleura, usually producing an exudative pleural effusion and stabbing chest pain worsened by respiration and cough Pleurisy Etiology ~ underlying infection – pneumonia, infarction, TB ~ direct entry – infectious agent or irritating substance into pleural space (ex: ruptured esophagus, amebic empyema) ~ transport – infectious or noxious agent or neoplastic cells to pleura via blood or lymphatics ~ parietal pleural injury – like trauma, rib fracture, pleurodynia ~ asbestos-related pleural disease – in which asbestos particles reach the pleura by transversing the conducting airways and respiratory tissues Pleurisy Pathology ~ pleura becomes edematous and congested ~ cellular infiltration follows and fibrinous exudate develops on pleural surface ~ exudate my be reabsorbed or organized into fibrous tissue resulting in pleural adhesions ~ may see marked fibrous or even calcific thickening of pleura without previous acute pleurisy Lung Cancers ~ may be benign or malignant primary tumours or metastases from primary cancers or other organs and tissues ~ primary lung tumours include: bronchogenic carcinoma (m/c type of lung cancer), bronchial carcinoid, and number of rarer types ~ can have SI cells go to LU and get cancer there Bronchial Carcinoid ~ used to be called bronchial adenoma (adeno = gland) ~ benign or malignant ~ equal in both men and women ~ course is prolonged ~ can obstruct major bronchi ~ brisk bleeding from overlying mucous membrane often occurs ~ recurrent pneumonia (same LU zone) and localized pleural pain are common ~ metastases are uncommon Metastases and other Cancers ~ metastases to lungs are common from primary CA of breast, colon, prostate (top 3) ~ can also be from kidney, thuyroid, stomach, cervix, rectum, testis, bone, and melanoma ~ less common primary lung tumours include chondromatous harmatroma (benign), solitary lymphoma and sarcoma (malignant) ~ lungs are sometimes affected by multifocal lymphomas

Bronchogenic Carcinoma ~ a highly malignant primary lung tumour that accounts for most cases of lung cancer ~ poor prognosis ~ > 90% of all lung tumours ~ leading cause of cancer death among men (32%) and women (25%) ~ incidence rising in women ~ mc/ between 45-70 yoa Bronchogenic Carcinoma Etiology ~ primary cause – cigarette smoking ~ 87% of all LU cancers attributed to tobacco ~ dose-response relationship occurs in 3 most common types of bronchogenic carcinoma: ~ 1) squamous cell ~ 2) small cell ~ 3) adenocarcinoma ~ 15% men and 5% women ~ related to occupational agents: asbestos, radiation, arsenic, chromates, nickel, cloromethyl ethers and mustard gas ~ role of air pollution is uncertain ~ sometimes bronchogenic carcinomas associated with pulmonary scars ~ damage to DNA, oncogene activation, and stimulation by growth factors now thought to be of primary importance Bronchogenic CA – Pathology ~ four histologic types of are distinguished: ~ 1) squamous cell – larger bronchi, spread via direct extension & lymphatic metastasis ~ 2) undifferentiated small cell – assocatied with early hematogenous metastases ~ 3) undifferentiated large cell – usually spreading through bloodstream ~ 4) adenocarcinoma – commonly peripheral, often spreading through the bloodstream ~ usually spread via lymphatics ~ bronchioalveolar carcinoma – subtype of adenocarcinoma consolidates airspaces and often does not extend beyond the lungs ~ usually multifocal (ddx with other cancers) Bronchogenic CA – metastasis ~ hematogenous metastatic spread to liver, brain, adrenals, and bone ~ can occur early – symptoms may appear there before pulmonary symptoms Bronchogenic CA – Sequelae ~ small cell carcinomas – secrete ectopic ACTH (ex: Cushing’s syndrome) or ADH (water retention and hypoatremia) ~ ectopic – made somewhere where it’s not supposed to be ~ also associated with carcinoid syndrome (flushing, wheezing, diarrhea, and cardiac valvular lesions)

~ squamous cell carcinoma – secrete PTH-like substance  hypercalcemia ~ other endocrine syndrome with primary lung cancers include: ~ gynecomastia, hyperglycemia, thyrotoxicosis, skin pigmentation ~ may have hematologic disorders including thrombocytopenic purpura and leukemoid reaction Bening neoplasms ~ benign laryngeal neoplasms include: juvenile papillomas, hemangiomas, fibromas, chrondromas, myxomas, neurofibromas ~ may affect any part of larynx ~ removal restores voice, functional integrity of laryngeal sphincter, and airwa