2/2/99

Pathology II

 

Fig 13-6-Possible effects of smoking on the lungs

·         Affect elastic ability

 

 

Emphysema

1.        centricular

2.        panacinar

3.        distal acinar

 

Incidence

·         50% of autopsies-many of these are asymptomatic

·         Cigarette smokers-most severe forms ages 50-80 yrs. Ventilatory defects appear earlier

 

Pathogenesis

·         excess protease/elastase

 

Morphology

·         histologically, thinning and destruction of alveolar walls-coalesce to create large airspaces

·         loss of elastic tissue results in collapse during expiration—chronic airflow problems

Fig

 

 

Clinical Course

·         insidious onset of dyspnea-steadily progressive

·         cough and wheeze w/underlying bronchitis

·         decrease FEV1-normal FVC = decrease FEV11/FVC ratio

·         “pink puffer”-predominately emphysemic

·         barrel chested, dyspneic w/prolonged expiration

·         gas exchange is normal until late in disease

·         dyspnea pulls adequate oxygenation = ”pink puffer”

·         “blue bloater”-emphysema w/chronic bronchitis

·         history of recurrent chest infections

·         less dyspnea, retain CARBON DIOXIDE, hypoxia w/cyanosis

·         tend to be obese

·         cor pulmonale plus edema plus cyanosis = “blue bloater”

·         death from COPD:

1. pulmonary failure
2. right heart failure (cor pulmonale)

 

Conditions Related to Emphysema (“misnomers”)

·         Compensatory emphysema-dilation of alveoli in response to loss of lung substance elsewhere

·         Senile emphysema-age related changes in lung causing overinflation.  No significant tissue destruction

·         Obstructive overinflation-lung expansion due to obstruction (e.g. tumor, foreign object)

·         Mediastinal (interstitial) emphysema-air escapes into connective tissue stroma of lung, mediastinum, or subcutaneous tissue.  Violent coughing (e.g. whooping cough w/ tearing of tissue), patients on respirator or perforating injury

 

Chronic Bronchitis

·         Cigarette smokers and urban dwellers in smoggy areas

·         Persistent productive cough for at least 3 months in at least 2 consecutive years—clinical definition

·         Forms of bronchitis:

·         Simple chronic bronchitis-productive cough, no obstruction

·         Chronic mucopuruloent bronchitis-pus in sputum form secondary infections

·         Chronic asthmatic bronchitis-hyperresponsive airways (difficult differential diagnosis from atopic asthma)

·         Chronic obstructive bronchitis-airflow obstruction

 

Basis of Airflow Obstruction in chronic bronchitis

1.        small airways disease-inflammation, fibrosis, and narrowing of bronchioles

2.        coexistent emphysema

·         b/w 5% and 15% of smokers develop COPD-initial presentation is bronchitis

 

Pathogenesis

·         hypersecretion of mucus

·         cigarette smoke and other pollutants

a)       induce hypersecretion of bronchial mucous glands

b)       cause hypertrophy of mucous glands

c)       lead to metaplastic formation of mucin-secreting goblet cells in surface bronchial epithelium

 

Morphology

·         enlargement of mucus-secreting glands

·         reid index-ratio of thickness of submucosal gland layer to bronchial wall

·         loss of ciliated epithelium

·         squamous

 

Clinical Course-variable

1.        prominent cough, production of sputum, and no ventilatory dysfunction

 

 

Bronchiectasis

·         permanent dilation of bronchi and bronchioles due to destruction of the supporting tissue, resulting from chronic necrotizing infections

·         secondary to infection or obstruction

·         cough, expectoration of copious purulent sputum

·         Dx:  appropriate history w/radiographic demonstration of bronchial dilation

·         Cystic fibrosous

 

 

Conditions that predispose:

1.        Bronchial obstruction-tumors, foreign bodies-localized region of bronchiectasis

2.        Congenital or hereditary conditions

a)       cystic fibrosis

b)       Immunodeficiency states esp. immunoglobulin deficiencies.  Increased susceptibility to repeated bacterial infections

c)       Kartagener’s syndrome-autosomal recessive disorder w/bronchiectassi and sterility in males.  Structural abnormality of cilia impair mucociliary clearance, leading to repeated infections

3.        Necrotizing or suppurative pneumonia-sequel to childhood pneumonia, complication measles, whooping cough, and influenza.  Less common in US w/ antibiotic use.

 

Clinical Course

·         Severe persistent cough w/expectoration of mucopurulent, sometimes fetid sputum

Fig 13-10

 

Restrictive Lung Disease

·         Reduced compliance-requiring more pressure to expand

·         Chronic changes tend to affect interstitial tissue-called interstitial lung disease

·         Fig 13-11

·         Signs and symptoms: 

·         Stiff lung-decrease compliance—dyspnea

·         Damage to alveolar epithelium and interstitial vasculature—abnormalities ventilation-perfusion ratio—hypoxia

·         Acute onset w/pulmonary edema and inflammation

·         Chronic onset-chronic inflammation and fibrosis

 

ACUTE RESTRICTIVE LUNG DISEASES

·         Usually due to damage of endothelium (rather than epithelium)-exposure to some toxin (often not identified)

·         Neutrophils (macrophages) are probably involved in mediating the injury

1. endotoxin triggers TNF
2. C5a up regulates adhesions
3. Neutrophils

 

 

More than 50% of cases are ARDS are associated /w following conditions

·         Table 12-1

·         Infection

·         Sepsis

·         Diffuse pulmonary infections:  Viral, Mycoplasma, and pneumocysists

·         Gastric aspiration

·         Physical injury

·         Mechanical trauma

 

·         Prognosis is grim, mortality is best is 50%, higher w/ sepsis

·         A lot of fibrosis if one survives

 

Chronic Restrictive Diseases

·         Table 13-2

·         Major categories of chronic interstitial lung disease w/ most common causes

1.        lung rxn:  alveolities, interstitial inflammation and diffuse fibrosis

a)       known etiology:  environmental agents:  asbestos, fumes, gases

b)       unknown etiology

·         collagen vascular disease:  scleroderma, RA, SLE

·         idiopathic

2.        lung response:  above plus granuloma formations—sarcoidosis

 

Idiopathic Pulmonary Fibrosis

·         unknown cause-diffuse interstitial fibrosis

·         AKA:  hamman-rich syndrome

·         males-30-50 y/o

·         unknown injurious agent cause alveoli’s and induce an immune response

 

Clinically

·         respiratory difficulty advancing to hypxemia and cyanosis

·         may lead to cor pulmonale and cardiac failure

·         progression is unpredictable

·         median survival is 5 years

 

Sacrcoidosis

·         multisystem disease of unknown cause characterized b y noncaseating granulomas

·         Dx: of exclusion-rule out other causes of granulomas (mycobacterial, fungal, berylliosis)

·         Bilateral hilar lymphadenopathy-major presenting feature (chest film)  “Potato Nodes”

·         Eye(iritis) and skin (erythema nodosum) involvement in ~25% of cases

·         Worldwide distribution

·         US 1-4/10,000

·         10x more prevalent in blacks

·         Schaumann bodies

·         Asteroid bodies

·         Mikulic’s syndrome—bilateral sacrcoidosis of parotid, submaxillary, sublingual glands

·         Fig 13-6

 

Clinical Course

·         Asymptomatic in many and detected on routine chest film

·         Symptomatic cases-respiratory symptoms )dyspnea, cough)

·         Constitutional signs-fever, fatigue, weight loss, anorexia, night sweats

·         Unpredictable clinical course-progressive chronically

·         Exacerbationsnd remission

·         Spontaneous remissions or due to corticosteroid use

·         Farmer’s lung-moldy hay (actinomycetes aspergillus)

·         Humidifier lung-cool mist humidifier (thermophilic actinomycetes)

·         Pigeon breeder’s lung

 

Diffuse Pumonary Hemorrhage Syndromes