cystic fibrosis

-excessive secretion of viscous mucus by the exocrine glands
-effects pancreas and digestive system
-cused by defective gene in the middle of chromosome 7
-radiographically: irregular thickening of linear markings

hyaline membrane disease

-aka idiopathic respiratory distress syndrome (IRDS)
-common respiratory distress of newborns, primarily premature
-caused by lack of surfactant in immature lungs
-hypoxia and distress apparent within 6 hrs of birth
radiographically:  pronounced underairation, fine granular appearance of pulmonary parenchyma associated with air bronchograms

croup

-viral infection  of oung children, produces inflammatory obstructive swelling localized in subglottic portion of trachea
-edema causes inpiratorry stridor/barking cough
-radiographically: hourglass shaped narrowing of the subglottic airway

epiglottitis

-commonly caused by haemophilus influenzae in children
-causes thickening of epiglottic tissue and surrounding pharangeal structures
-occurrence has decreased due to immunizations
-radiographically: lateral; round thickening of epiglottic shadow gives it the configuration
/ size of adult thumb

pneumonia

-inflmmation of the lungs most commonly caused by bacteria and viruses
-produces 3 radiographic patterns: alveolar/air-space pneumonia, bronchopneumonia, interstitial pneumonia, aspiration pneumonia

alveolar / air-space pneumonia

-usually pneumococcal infection, creates pus and fluids that fill the alveoli and they appear solid or radiopaque
-if airways are not infected it creates bronchogram; the airways can be seen in the infected lung space
-radiographically: consolidation of lung parenchyma w/ little involvement of the airways produces the characterisitc air bronchogram sign

bronchopneumonia

-typically a staphlococcal infection
-originates in the bronchi or bronchiolar mucosa and spreads tp alveoli
-radiograhically: air bronchogram is absent

interstitial pneumonia

-typically viral and mycoplasmal (fungal) infections
-mainly involves the walls of the alveoli and the interstitital supporting structures of the lung
-radiographically: linear or reticular pattern; seen on end thickened interstitium may appear as multiple small nodular densities.
-left untreated may cause "honeycomb lung" in CT images

aspiration pneumonia

-caused by aspirating esophageal or gastric contents into the lung
-radiographically: causes multiple alveolar densities w/ the posterior segments of the upper and lower lobes commonly affected

tuberculosis

-caused by mycobacterium tuberculosis
-mainly spread by droplets in the air
-3-6 wk incubation period
-skin test won be positive until 2-10wks after infection

primary TB

-traditionallly children & young adults
-infiltrate may be seen as lobar/segmental air-space consolidation, usually homogeneous, dense, and well defined
-lordotic view for apicies
-enlargement of hilar or mediastinal lymph nodes is common
-plural effusion (unilateral) is common in adults

miliary TB

-refers to dissemination of th disease by way of the blood stream
-radigraphically: produces innumberable fine discrete nodules (granulomas) distributed uniformly throughout the lungs
- if no response to therapy may break down into multiple necrotic cavities or a single large abscess filled with caseous material

secondary TB

-seen mostly in adults, reactivation of previous infection or reifection
-necrosis and liquefaction commonly lead to the development of tuberculous cavities
-radiography:  most comonly affects the upper lobes/ apical and psterior segemnts

COPD

includes several conditions in which chronic obstruction of the airways leads to an ineffective exchange of respiratory gases and makes breathing difficult
-chronic bronchitis
-emphysema
-asthma

chronic bronchitis

-excessive tracheobronchial mucus production, leading to obstruction of small airways
-chronnic inflammation of the bronchi= severe coughing w/ production of sputum
-90% of cases are associated with ciggarette smoking
-radiographically: 1/2 of cases show no changes, "dirty chest" is common (general increase in brochovascular markings)

emphysema

obstructive and destructive change in small airways, leads to dramatic increase in volume of air in lungs
-associated with heave smoking; chronic bronchitis is a predisposing factor
-radiographically: pulmonary overinflation, alterations in pulmonary vasculature, bulae formation
-pulmonary overinflation: flattening of the domes of the diaphragm
-lateral view: increase in size and lucency of retrosternal airspace

asthma

-widespread narrowing of the airways as a result of exposure to stimuli ( common allergens)
-dust, pollen, mold, animal dander, foods, heat/cold
-radiographically: during attack, bronchial narrowing and difficulty in expiration lead to increased volume of the hyperlucent lungs with flattening of the hemidiaphragms and increase in the retrosternal airspace

bronchogenic carcinoma

-primary carcinoma of the lung
-arises from the mucosa of the broncial tree
-linked to smoking/ inhaling of cancer causeing agents (carcinogens; pollution, exhaust gases, industrial fumes)
-common types: squamous carcinoma, adenocarcinoma, bronchiolar (alveolar cell) carcinoma
-Radiographically: broad spectrum of abnormlties that depend on the site of tumor and relationship tp bronchial tree.

squamous carcinoma

most common, typically arises in the major bronchial tree

adenocarcinoma

usually arisee in th periphery of the lung

bronchiolar ( alveolar cell) carcinoma

least common

pulmonary embolism

-most common lung pathology of hospitalized pts, may be fatal
-asymptomatic in 80% of cases
-difficult to diagnose even w/ symptoms
-95%+ of embolisms arise from deep bein thrombosis in lower extremities
-Radiographically: w/o infaction = normal chest, w/ infarction = area of lung consolidation
-radionuclide scan or ventilation-perfusion (v/q) considered most effective screening, but is being replaced by high res CT

atelectasis

-a condition where there is diminished air within the lung associated w/ reduced lung volume
-caused by bronchial obsruction due to neoplasm, foreign body, or mucous plug
-radiographically:  local increase in density caused by airless lung; varies from thin platelike streaks to lobar collapse

adult respiratory distress syndrome (ARDS)

-severe, unexpected, life-threatening acute respiratory distress that develops in pts who have a variety of medical/surgical disorders but no major underlying lung disease.
-lung structures break down w/ massive leakage of cells & fluid into the interstitial and aveloar spaces
-hypoxia and sever respiratory impairment results
-common in pts w/ non-thoracic trauma who develop hypotention ans shock; often called "shock-lung"
-radiographically:  patchy, ill defined areas of alveolar consolidation scattered throughout both lungs

other causes of ARDS

-severe pulmonary infection
-aspiration
-inhalation of toxins and irritants
-drug over dose

pneumothorax

-the presence of air in the pleural cavity, resultingin a partial or complete collapse of the lung
-radiographically: appears ad hyper lucent area, in which lung markings are absent
-CXR shold be taken upright
-both inspiration and expiration views used to identify small pnuemos

causes of pneumothorax

-rupture of a subpleural bella
-spontaneous event in an otherwise health young afult
-trauma (stabbing, gunshot, fractured rib)
-latrogentic causes (after lung biopsy or introduction of chest tube)
-complication of neonatal hyaline membrane disease

pleural effusion

-the accumulation of fluid in the pleural space
-a non specific finding caused by a variety of pathological processes
-can result from abd disease ( recent surgery, ascities, subphrenic abscess, pancreatitis)
-radiographically: -blunting of angle between diaphragm and rib cage w/ upward concave border of fluid level
-small effusions best seen on lat posteriorly; best seen  lat decub affected side down
-large amounts of fluid  = homogeneous opaque density (whiteness)