Major lung diseases are often caused by inhalation of irritants, infectious agents, or carcinogens. The lungs can be affected by diseases in other parts of the respiratory tract or body. Common lung diseases include infections like pneumonia, occupational diseases like black lung, and chronic conditions like COPD, lung cancer, and asthma. Loss of lung tissue cannot be recovered, so prevention and treatment of lung disease is important.

1. DiseasesDiseases
of theof the
RespiRatoRRespiRatoR
y systemy system

3. Major Determinants of Disease
• Diseases of one lung compartment tend to affect the
others
• The lungs are open to the environment, exposing them
to infectious agents, allergens, irritants, & carcinogens
• Most lung disease is caused by inhalation of material;
the most common exception is autoimmune lung disease
• Lost pulmonary membrane is not recoverable
• Smoking is a major cause of lung disease
• The heart & lungs are a functional unit; lung disease
usually affects the heart; & heart disease usually affects
the lungs

4. UppeR RespiRatoRyUppeR RespiRatoRy
infectionsinfections
• Allergic rhinitis
– “hay fever”
– nasal mucosal edema
– nasal discharge
– sneezing
– allergic conjunctivitis
• “Colds”
– transmitted through respiratory droplets
– clear nasal discharge
– low grade fever
– if nasal discharge becomes colorful, it is an indication of secondary bacterial
infection
• Acute pharyngitis
– “sore throat”
– usually viral
– bacterial infections more serious
– red, swollen tonsils

5. caRcinoma of thecaRcinoma of the
LaRynxLaRynx
• Common
• Mostly in male smokers
over 40
• Alcohol abuse
increases the risk
• Presents with
– hoarseness
– pain
– cough
– dysphagia
– hemoptysis

6. ateLectasisateLectasis
• Collapse of a lung or part of
a lung
• Resorption
– bronchial obstruction
– air below obstruction
completely absorbed
– obstructions are
• mucous plug
• asthma
• bronchitis
• tumors
• Compression
– pressure exerted from
pleural space or upward
pressure on diaphragm
• Contraction
– scars cause constriction &
collapse
– TB

7. asthmaasthma
• Chronic inflammatory disease of small bronchi &
bronchioles
• Triggered by inhaled irritants & classified by irritant
• Allergic
• Occupational
• Exercise-induced
• Infectious
• Others
– drug reactions
– emotional stress
– severe air pollution
• Hyperplastic mucous glands in bronchi, hypertrophied
smooth muscle, edema, & marked inflammation

8. chRonic obstRUctivechRonic obstRUctive
pULmonaRy Disease (copD)pULmonaRy Disease (copD)
• Related diseases
• Chronic bronchial
outflow obstruction
• Overlapping features

10. emphysemaemphysema
• Destruction of
alveolar walls,
alveoli merge to
form large air
spaces
• Loss of surface
area affects
diffusion
• 90% of cases
are smokers

11. chRonic bRonchitischRonic bRonchitis
• Chronic cough that produces
sputum for 3 consecutive
months 2 years in a row
• Primary cause is cigarette
smoking
• Chronic inflammation of
bronchi
• Simple chronic bronchitis
• Chronic asthmatic bronchitis
• Hereditary
• Shortness of breath
• Wheezing & coughing
• Weight loss
• Barrel-chested

12. • Cigarette smoke
irritates lung &
causes inflammation
• Inflammatory cells
release digestive
enzymes
• These enzymes
normally inhibited by
alpha-1 antitrypsin
• AAT inhibited by
smoke & so enzymes
digest lung tissue

13. BronchiectasisBronchiectasis
• Marked, permanent dilation of small bronchi
• Destruction of smooth muscle & elastic
supporting tissue
• Must have obstruction & infection
– obstruction causes mucus retention
– infection damages bronchial walls which causes
excess mucus production
• Not a primary condition
• Typically involves lower lobes
• Persistent cough

14. restrictive Lungrestrictive Lung
DiseaseDisease
• Chronic inflammation
making lungs stiff &
inelastic
• Affects diffusion
• Scar tissue accumulates
in the interstitium
• Mostly cause is unknown
• Equal decline in FEV1 &
FVC
• Usually presents with
shortness of breath
• Can lead to pulmonary
HTN

15. interstitiaL FiBrosisinterstitiaL FiBrosis
without granuLomatouswithout granuLomatous
inFLammationinFLammation• Usually middle-aged
men at time of
diagnosis
• Shortness of breath;
may progress to cor
pulmonale, hypoxia
• Pneumoconioses
– black lung disease
– silicosis
• most common
chronic occupational
disease
– asbestosis
• mesothelioma

16. interstitiaL FiBrosis withinterstitiaL FiBrosis with
granuLomatousgranuLomatous
inFLammationinFLammation
• Sarcoidosis
– cause unknown
– affects many
tissues but
mostly lungs
– present with
shortness of
breath, cough,
chest pain,
hemoptysis

17. PuLmonary eDemaPuLmonary eDema
• Fluid in alveoli
• Increased BP in lung
– normal is 25/8 mmHg
with average at 15 mmHg
• Microvascular injury
– due to
• toxic fumes
• hot gases
• septicemia
• IV drug abuse
• Main symptom is SOB

18. PuLmonaryPuLmonary
thromBoemBoLismthromBoemBoLism
• About 50,000 deaths annually
• Mostly from DVT
• Inflammation predisposes you
to it
• Promoted by
– CHF
– pregnancy
– birth control pills
– prolonged bed rest
– metastatic cancer
– genetics
• Most associated with no
symptoms but some
– cause lung infarcts
– chest pain & dyspnea
– death

19. PuLmonaryPuLmonary
hyPertensionhyPertension
• Sustained systolic pressure over
30 mmHg or average in excess of
25 mmHg
• Vicious cycle
• Most common cause is increased
pulmonary vascular resistance
• Usually secondary to
– COPD
– heart disease
– collagen vascular diseases
– recurrent pulmonary
thromboemboli
• With R heart failure is cor
pulmonale
• Thickening of arteriolar walls
• SOB
– chest pain
– fatigue

20. aDuLt resPiratoryaDuLt resPiratory
Distress synDromeDistress synDrome
• ARDS
• Alveolar or pulmonary capillary
damage
• Pathogenesis
– injury to endothelium or alveoli
– neutrophils infiltrate
– protein-rich fluid exudes into alveolar
space
– SOB occurs with rapid breathing which
dries the fluid into a thick membrane
– stiffens lungs
– limits airflow & interferes with diffusion
– hypoxia
• 50% fatality
• Causes
– sepsis
– smoke inhalation
– near drowning
– O2 toxicity
– burns
– DIC
– fat embolism
– endotoxic shock

21. PneumoniaPneumonia
• Inflammation of the
lungs
• Usually caused by
bacteria
• 80,000 deaths/yr
• Alveolar pneumonia
– usually acute
– fill with inflammatory
exudate
– most common

22. • Bronchopneumonia
– patchy inflammation
– involves alveoli of more
than 1 lobe
– usually in basilar parts
• Lobar pneumonia
– consolidation of an
entire lobe
– almost always caused
by S. pneumoniae

23. InterstItIal PneumonIaInterstItIal PneumonIa
• Inflammation
in septa
• Diffuse &
bilateral
• Usually viral

24. • Etiology
– mostly bacterial
• S. pneumoniae
• Haemophilus
influenzae
• Staph
• E. coli
• Pseudomonas
• Pathogenesis
– inhalation of droplets,
aspiration of gastric
contents, blood-borne
spread
– those susceptible
include
• immune deficiency
• decreased cough reflex
• impaired cilia
• accumulated secretions
• pulmonary congestion

25. • Community-acquired
– acute pneumonia
– bronchopneumonia
– lobar pneumonia
– Legionnaire’s disease
– atypical pneumonia
• Mycoplasma
• Nosocomial
– Commonly S. aureus &
E.coli
– Seen in
• People with severe
disease
• Prolonged antibiotic
therapy
• People with internal
mechanical devices
• Aspiration
– Inflammatory reaction due
to corrosive effects
– Those who are comatose
or those with a stroke
– Hi mortality rate

26. • Seen mostly in the young & the elderly
• Hypoxia & death
• Bacterial
– high fever & chills
– purulent sputum
– increased neutrophils
– cough
– SOB
• Interstitial
– less severe
– increased lymphocytes
– cough
– SOB

27. lung abscesslung abscess
• Purulent inflammation
with tissue necrosis &
liquefaction
• Usually have several
types of bacteria with
anaerobic
• Most commonly due to
aspiration of gastric
contents
• Foul-smelling sputum

28. tuberculosIstuberculosIs
• Mycobacterium tuberculosis
• Chronic granulomatous inflammation with
caseous necrosis

29. Pathogenesis

32. • Affects about 2 billion worldwide
• Kills about 2 million/yr
• 2nd
only to AIDS
• Associated with poverty, crowding,
malnourishment, & chronic disease
• PPD

33. • Low-grade fever
• Night sweats
• Malaise
• Weight loss anorexia

34. Mycoses
• Histoplasmosis
• Coccidiomycosis
• Cryptococcus

36. Lung neopLasmsLung neopLasms
• Mostly due to metastasis
• Bronchogenic carcinoma is the most
common
– most common of all cancers
– #1 cancer death
– about 90% are cigarette smokers

37. Bronchogenic CarcinomaBronchogenic Carcinoma
• Mostly caused by cigarettes
– Direct relationship between incidence of cancer &
number of cigarettes smoked
– Direct relationship between precancerous changes in
bronchial mucosa & number of cigarettes smoked

39. • Small cell carcinoma
– 20% of cases
– arise from specialized
neuroendocrine cells of the
bronchus
– strongest relationship to
cigarettes
– aggressively malignant
• Squamous cell carcinoma
– 30% of cases
– bronchial epithelium that
has undergone metaplasia
– arises centrally
– most common in men who
smoke
– grows slower so better
prognosis
• Adenocarcinomas
– 30% of cases
– most well-differentiated
– somewhat better prognosis
– more peripheral in smaller
bronchi
– less associated with
smoking
• Large cell carcinoma
– 15% of cases
– poor prognosis
– metastasizes early

40. Bronchial Carcinoid Tumor
• 5% of lung cancers
• Arise from bronchial neuroendocrine cells
• Much less aggressive
• Grows slow

41. pneumothoraxpneumothorax
• Air in pleural space
• Causes atelectasis
• May occur spontaneously
• More frequent in people with emphysema who
have large blebs near pleura
• Traumatic penetration
• Can be fatal
• Tension pneumothorax
– air in but not out

42. pLeuraL effusionpLeuraL effusion
• Fluid in pleural space
• Transudate from CHF most common
• If blood, called hemothorax

43. pLeuritis
• Inflammation
• Pleurisy with each breath
• Mostly caused by pneumonia