R E S P I R AT ORYPAT h O lO g Y

R E S P I R AT ORYPAT h O lO g Y

Rhinosinusitis Obstruction of sinus drainage into nasal cavity inflammation and pain over affected area(typically maxillary sinuses in adults A ). Most common acute cause is viral URI; maycause superimposed bacterial infection, most commonly S. pneumoniae, H. influenzae, and M. catarrhalis.

ARhinosinusitis. Coronal CT of the sinus shows bilateral maxillary sinusitis (yellow arrows) and unrelated nasal septal deviation (red arrow).

602seCtioN i i iRespi R at o R y R E S P I R AT ORYPAT h O lO g Y

Deep venous thrombosis

Predisposed by Virchow triad: Stasis Hypercoagulability (e.g., defect in coagulation cascade proteins, most commonly factor V Leiden) Endothelial damage (exposed collagen triggers clotting cascade)

Approximately 95% of pulmonary emboli arise from deep leg veins.Homan signdorsiflexion of foot calf pain. Use heparin for prevention and acutemanagement; use warfarin for long-term prevention of DVT recurrence.

Pulmonary emboli

A

V/Q mismatch hypoxemia respiratory alkalosis. Sudden-onset dyspnea, chest pain, tachypnea. May present as sudden death.Types: Fat, Air, Thrombus, Bacteria, Amniotic fluid, Tumor. Fat emboliassociated with long bone fractures and liposuction; classic triadof hypoxemia, neurologic abnormalities, and petechial rash.Amniotic fluid embolican lead to DIC, especially postpartum.

Pulmonary embolism. Note large embolus (arrows) in theGas embolinitrogen bubbles precipitate in ascending divers; treat with hyperbaric oxygen.

An embolus moves like a FAT BAT.CT pulmonary angiography is the imaging test of choice for a PE (look for filling defects) A B C .

B pulmonary artery.

C Pulmonary thromboembolus. Lines of Zahn are interdigitating areas of pink (platelets, fibrin) and red (RBCs)found only in thrombi formed before death. Help distinguish pre- and postmortem thrombi.

Obstructive lung diseases

Obstruction of air flow resulting in air trapping in the lungs. Airways close prematurely at highlung volumes RV and FVC. PFTs: FEV1, FVC FEV1/FVC ratio (hallmark), V/Qmismatch. Chronic, hypoxic pulmonary vasoconstriction can lead to cor pulmonale.

TYPE PAThOlOgY OThERChronic bronchitis(blue bloater)

A form of COPD along with emphysema. Hyperplasia of mucus-secreting glands in the bronchi Reid index (thickness of gland layer/total thickness of bronchial wall) > 50%.

Productive cough for > 3 months per year (not necessarily consecutive) for > 2 years. Disease of small airways.Findings: wheezing, crackles, cyanosis (early- onset hypoxemia due to shunting), late-onset dyspnea, CO2 retention. Emphysema (pink puffer, barrel- shaped chest)

Enlargement of air spaces, recoil, compliance, DLCO resulting from destruction of alveolar walls A .Two types: Centriacinarassociated with smoking B . Panacinarassociated with 1-antitrypsin deficiency.

elastase activity loss of elastic fibers lung compliance.Exhalation through pursed lips to airway pressure and prevent airway collapse during respiration.

Bby thin septa seen on left. There is relative preservation of alveoli on right.

Centriacinar emphysema. Gross specimen shows multiple air-space cavities lined by heavy black carbon deposits.

AsthmaBronchial hyperresponsiveness causes reversible bronchoconstriction. Smooth muscle hypertrophy, Curschmann spirals (shed epithelium forms mucus plugs), and Charcot-Can be triggered by viral URIs, allergens, and stress.Test with methacholine challenge. Findings: cough, wheezing, tachypnea,

Leyden crystals (formed from breakdown ofdyspnea, hypoxemia, I/E ratio, pulsus

eosinophils in sputum).paradoxus, mucus plugging.

BronchiectasisChronic necrotizing infection of bronchiAssociated with bronchial obstruction, poor

permanently dilated airways, purulentciliary motility (smoking), Kartagener

sputum, recurrent infections, hemoptysis.syndrome, cystic fibrosis, allergic

bronchopulmonary aspergillosis.

Restrictive lung disease Restricted lung expansion causes lung volumes ( FVC and TLC). PFTs: FEV1/FVC ratio 80%.

Types: Poor breathing mechanics (extrapulmonary, peripheral hypoventilation, normal A-a gradient): Poor muscular effortpolio, myasthenia gravis Poor structural apparatusscoliosis, morbid obesity Interstitial lung diseases (pulmonary diffusing capacity, A-a gradient): Acute respiratory distress syndrome (ARDS) Neonatal respiratory distress syndrome (hyaline membrane disease) Pneumoconioses (anthracosis, silicosis, asbestosis) Sarcoidosis: bilateral hilar lymphadenopathy, noncaseating granuloma; ACE and Ca2+ Idiopathic pulmonary fibrosis (repeated cycles of lung injury and wound healing with collagen deposition) Goodpasture syndrome Granulomatosis with polyangiitis (Wegener) Langerhans cell histiocytosis (eosinophilic granuloma) Hypersensitivity pneumonitis Drug toxicity (bleomycin, busulfan, amiodarone, methotrexate)

Hypersensitivity pneumonitis

Mixed type III/IV hypersensitivity reaction to environmental antigen dyspnea, cough, chest tightneass, headache. Often seen in farmers and those exposed to birds.

PneumoconiosesCoal workers pneumoconiosis, silicosis, and asbestosis risk of cor pulmonale and Caplan syndrome (rheumatoid arthritis and pneumoconioses with intrapulmonary nodules).

AsbestosisAssociated with shipbuilding, roofing, andAffects lower lobes.

Bplumbing. Ivory white, calcified pleuralAsbestos (ferruginous) bodies are golden-brown

plaques A are pathognomonic of asbestosfusiform rods resembling dumbbells B .

exposure, but are not precancerous. Associatedwith an incidence of bronchogenicAsbestos is from the roof (was common ininsulation), but affects the base (lower lobes).

carcinoma and mesothelioma.Silica and coal are from the base (earth), but

Asbestosis. Note white, calcified pleural plaquesaffect the roof (upper lobes).

A (arrows).

Coal workerspneumoconiosis

Prolonged coal dust exposure macrophages laden with carbon inflammation and fibrosis.Also known as black lung disease.

Affects upper lobes.Anthracosisasymptomatic condition found in many urban dwellers exposed to sooty air.

Silicosis Associated with foundries, sandblasting,and mines. Macrophages respond to silica and release fibrogenic factors, leading to fibrosis. It is thought that silica may disrupt phagolysosomes and impair macrophages, increasing susceptibility to TB. Also risk of bronchogenic carcinoma.

Affects upper lobes.Eggshell calcification of hilar lymph nodes.

Neonatal respiratory distress syndrome

Surfactant deficiency surface tension alveolar collapse. A lecithin:sphingomyelin ratio< 1.5 in amniotic fluid is predictive of neonatal respiratory distress syndrome. Persistently low O2 tension risk of PDA. Therapeutic supplemental O2 can result in retinopathy of prematurity and bronchopulmonary dysplasia.Risk factors: prematurity, maternal diabetes (due to fetal insulin), C-section delivery ( release of fetal glucocorticoids).Treatment: maternal steroids before birth; artificial surfactant for infant.

Acute respiratory distress syndrome

May be caused by trauma, sepsis, shock, gastric aspiration, uremia, acute pancreatitis, or amniotic fluid embolism. Diffuse alveolar damage alveolar capillary permeability protein-rich leakage into alveoli and noncardiogenic pulmonary edema (normal PCWP) A . Results in formation of intra-alveolar hyaline membrane B . Initial damage due to release of neutrophilic substances toxic to alveolar wall, activation of coagulation cascade, and oxygen-derived free

radicals.Acute respiratory distress syndrome. Near-completeABopacification of the lungs with obscured cardiomediastinal silhouette.

Acute respiratory distress syndrome. Note the alveolar fluid (clear, frothy) and thickened hyaline membranes (pink).

Obstructive vs. restrictive lung disease

NormalFEV1FVC = 80%

8 8

ObstructiveFEV1FVC < 80%

FEV1 FVC

RestrictiveFEV1FVC 80%

8

7 FEV1 FVC 7 7

6 6 6

Lung volume (L)5 5 5

4 4 4

3 3 3

FEV1 FVC

2 2 2

1 1 1

0 1 2 3 0

1 2 3 0

1 2 3Time (sec) Time (sec) Time (sec)

Note: Obstructive lung volumes > normal ( TLC, FRC, RV); restrictive lung volumes < normal. In both obstructive and restrictive, FEV1 and FVC are reduced. In obstructive, however, FEV1 is more dramatically reduced compared to FVC, resulting in a FEV1/FVC ratio.

Pulmonary hypertension

Normal pulmonary artery pressure = 1014 mmHg; pulmonary hypertension 25 mmHg at rest. Results in arteriosclerosis, medial hypertrophy, and intimal fibrosis of pulmonary arteries.Primarydue to an inactivating mutation in the BMPR2 gene (normally functions to inhibit vascular smooth muscle proliferation); poor prognosis.Secondarydue to COPD (destruction of lung parenchyma); mitral stenosis ( resistance pressure); recurrent thromboemboli ( cross-sectional area of pulmonary vascular bed); autoimmune disease (e.g., systemic sclerosis; inflammation intimal fibrosis medial hypertrophy); left-to-right shunt ( shear stress endothelial injury); sleep apnea or living at high altitude (hypoxic vasoconstriction).Course: severe respiratory distress cyanosis and RVH death from decompensated cor pulmonale.

Sleep apneaRepeated cessation of breathing > 10 seconds during sleep disrupted sleep daytimeTreatment: weight loss, CPAP, surgery. Hypoxia EPO release erythropoiesis.

somnolence. Normal Pao2 during the day. Nocturnal hypoxia systemic/pulmonaryhypertension, arrhythmias (atrial fibrillation/Obesity hypoventilation syndromeobesity(BMI 30 kg/m2) hypoventilation Pao2and Paco2 during waking hours.

flutter), and sudden death.

Central sleep apneano respiratory effort.Obstructive sleep apnearespiratory effort against airway obstruction. Associated with obesity, loud snoring.

Lungphysical findings

ABnORmAlITY BREATh SOUnDS PERCUSSIOn FREmITUS TRAChEAl DEVIATIOn

Pleural effusion Dull

Atelectasis (bronchial obstruction) Dull Toward side of lesion

Spontaneous pneumothorax Hyperresonant

Tension pneumothorax Hyperresonant Away from side of lesion

Consolidation (lobar pneumonia, pulmonary edema)Bronchial breath sounds; Dull late inspiratory crackles

Lung cancer Lung cancer is the leading cause of cancer death.Presentation: cough, hemoptysis, bronchial obstruction, wheezing, pneumonic coin lesion on x-ray film or noncalcified nodule on CT.In the lung, metastases (usually multiplelesions) are more common than 1 neoplasms. Most often from breast, colon, prostate, and bladder cancer.

carcinoid Excellent prognosis; metastasis ra Symptoms usually due to mass ef carcinoid syndrome (5-HT secrediarrhea, wheezing).Sites of metastases from lung canceradrenals, brain, bone (pathologic fracture), liver (jaundice, hepatomegaly).

SPHERE of complications: Superior vena cava syndrome Pancoast tumorHorner syndromeEndocrine (paraneoplastic)Recurrent laryngeal symptoms (hoarseness)Effusions (pleural or pericardial)All lung cancer types except bronchial carcinoid are associated with smoking.Squamous and Small cell carcinomas areSentral (central).

TYPE lOCATIOn ChARACTERISTICS hISTOlOgY

AdenocarcinomaPeripheral Most common lung cancer in nonsmokers andoverall (except for metastases). Activating mutations include k-ras, EGFR, and ALK. Associated with hypertrophic osteoarthropathy (clubbing).Bronchioloalveolar subtype (adenocarcinoma in Bronchioloalveolar subtype: situ): CXR often shows hazy infiltrates similar to grows along alveolar septa pneumonia; excellent prognosis. apparent thickeningof alveolar walls.

Squamous cell carcinomaCentralHilar mass arising from bronchus; Cavitation;Cigarettes; hyperCalcemia (produces PTHrP).Keratin pearls and intercellular bridges A .

Small cell (oat cell)carcinomaCentralUndifferentiated very aggressive.May produce ACTH, ADH, or Antibodies against presynaptic Ca2+ channels (Lambert-Eaton myasthenic syndrome). Amplification of myc oncogenes common. Inoperable; treat with chemotherapy.Neoplasm of neuroendocrine Kulchitsky cells small dark blue cells B .

Large cell carcinomaPeripheralHighly anaplastic undifferentiated tumor; poor prognosis. Less responsive to chemotherapy; removed surgically.Pleomorphic giant cells.

Bronchial tumorre.fect; occasionally tion flushing,Nests of neuroendocrine cells; chromogranin A .

BASquamous cell carcinoma. Note sheets of large, dysplastic squamous cells (arrows) surrounding dark, pink keratin pearls (lower right).

Small cell carcinoma. Sheets of dark purple tumor cellswith nuclear molding, high mitotic rate, necrosis, and salt and pepper neuroendocrine-type chromatin.

MesotheliomaMalignancy of the pleura associated with asbestosis. Results in hemorrhagic pleural effusions and pleural thickening.

Psammoma bodies seen on histology.

Pancoast tumor Carcinoma that occurs in apex of lung may affect cervical sympathetic plexus, causing Horner syndrome (ipsilateral ptosis, miosis, and anhidrosis), SVC syndrome, sensorimotordeficits, and hoarseness A .

APancoast tumor. Chest CT demonstrates mass (arrow) at the left lung apex.

Superior vena cava syndrome

An obstruction of the SVC that impairs blood drainage from the head (facial plethora), neck (jugular venous distention), and upper extremities (edema). Commonly caused by malignancy and thrombosis from indwelling catheters. Medical emergency. Can raise intracranial pressure (if obstruction severe) headaches, dizziness, and risk of aneurysm/rupture of intracranial arteries.

PneumoniaTYPE TYPICAl ORgAnISmS ChARACTERISTICSLobar S. pneumoniae most frequently, also Legionella, KlebsiellaBronchopneumonia S. pneumoniae, S. aureus, H. influenzae, Klebsiella

Intra-alveolar exudate consolidation; may involve entire lung A B .Acute inflammatory infiltrates from bronchioles into adjacent alveoli; patchy distribution involving 1 lobe C .Interstitial (atypical)pneumonia

Viruses (influenza, RSV, adenoviruses),Mycoplasma, Legionella, Chlamydia

Diffuse patchy inflammation localized to interstitial areas at alveolar walls; distribution involving 1 lobe D . Generally follows a more indolent course.

Lobar pneumonia. Dense right upper lobe consolida with branching air-bronchograms; sharp inferior marginrepresents the horizontal fissure.C Bronchopneumonia. Note neutrophils in the alveolar spaces.BA tion

Bronchopneumonia (left) and lobar pneumonia (right). Gross specimens show typical consolidation patterns. ,

DInterstitial pneumonia. Coarse bilateral reticular opacities, worse on the right.

Lung abscess

A

Localized collection of pus within parenchyma. Caused by: bronchial obstruction (e.g., cancer) or aspiration of oropharyngeal contents (especially in patients predisposed to loss of consciousness [e.g., alcoholics or epileptics]).

Air-fluid levels A often seen on CXR. Often due to S. aureus or anaerobes (Bacteroides, Fusobacterium, Peptostreptococcus).

Pleural effusions Excess accumulation of fluid between the two pleural layers A restricted lung expansion during inspiration.Transudate protein content. Due to CHF, nephrotic syndrome, or hepatic cirrhosis.Exudate protein content, cloudy. Due to malignancy, pneumonia, collagen vascular disease, trauma (occurs in states of vascular permeability). Must be drained in light of risk of infection.Lymphatic Also known as chylothorax. Due to thoracic duct injury from trauma, malignancy. Milky- appearing fluid; triglycerides.

APleural effusion. Blunting of the left costophrenic angle(arrow) due to fluid in the pleural space.

PneumothoraxAccumulation of air in the pleural space A . Unilateral chest pain and dyspnea, unilateral chest expansion, tactile fremitus, hyperresonance, diminished breath sounds, all on the affected side.Spontaneous pneumothoraxTension pneumothorax

Accumulation of air in the pleural space A . Occurs most frequently in tall, thin, young males because of rupture of apical blebs.

B .B Tension pneumothorax. Note the hyperlucent left lung field with low left hemidiaphragm (below the field of view)Usually occurs in setting of trauma or lung infection. Air is capable of entering pleural space but not exiting. Trachea deviates away from affected lung

A Pneumothorax. CT shows collapsed left lung.

and rightward mediastinal shift.