Obstructive Pulmonary

Disease

Characterized by airway obstruction that is increased

with expiration.

More force is required to expire a given volume of

air, or emptying of lungs is slowed, or both.

The most common obstructive diseases are asthma,

chronic bronchitis, and emphysema.

COPD

Asthma Emphysema

ChronicBronchitis

• Many people have both chronic bronchitis and

emphysema, and together these are often called

chronic obstructive pulmonary disease - COPD

• Major symptom of obstructive pulmonary disease

is dyspnea, and wheezing.

COPD

Asthma Emphysema

ChronicBronchitis

Clinical Diagnosis

Physiologic Diagnosis PathologicDiagnosis

1- Bronchial Asthma

• More intermittent and acute than COPD.

• It is a reversible disorder

• It occurs at all ages.

• Runs in families, so evidence genetics plays a role.

• Environmental factors interact with inherited

factors to increase the risk of asthma.

• Childhood exposure to high levels of allergens,

smoking and/or respiratory viruses increases chances

of developing asthma.

• Major events in acute asthma attack are

–bronchiolar constriction,

–mucus hyper-secretion

– inflammatory swelling.

Pathogenesis

• Smooth muscle spasm in bronchioles.

• Vascular congestion.

• Edema formation.

• Production of thick mucus.

• Impaired muco-ciliary function.

• Thickening of airway walls.

• Untreated, this can lead to airway damage that is

irreversible.

• Obstruction increases resistance to air flow and

decreases flow rates

• Impaired expiration causes hyperinflation of

alveoli, and increases the work of breathing

Clinical manifestations

• Dyspnea

• Sometimes, cough

• Wheezing

• Attacks may continue from few hours to days or

even weeks.

• During remission individual is asymptomatic and

pulmonary function tests are normal

2- Chronic Bronchitis

• Hyper-secretion of mucus and chronic productive

cough for at least 3 months of the year for at least

two consecutive years.

• Incidence may be increased up to 20 times in

persons who smoke and more in persons exposed

to air pollution.

Pathophysiology

• Inspired irritants result in inflammatory cell

infiltration into the bronchial wall.

• Causes bronchial edema and increases size and

number of mucus glands and goblet cells.

• Mucus is thick, and can’t be cleared because of

impaired ciliary function.

• Increases susceptibility to infection and injury

• Initially affects only larger bronchi, but eventually all

airways involved.

• Airways collapse in early expiration, blocked by mucus

leads to hypo-ventilation

• Hypoxemia

• Air trapping prevents respiratory muscles from functioning

efficiently (barrel chest).

Barrel Chest

Treatment

• Best treatment is PREVENTION.

• Stop smoking ------ halts progression of the disease

• Bronchodilators, expectorants, and chest physical

therapy.

• Acute attacks may require antibiotics, and steroids.

• Oxygen therapy may be required

3- Emphysema

• Abnormal, permanent enlargement of the gas-

exchange airways and destruction of the alveolar

walls.

• Obstruction results from changes in lung tissue

rather than mucus production and inflammation

(pathological changes).

• Major mechanism is loss of elastic recoil

• Major cause is smoking

• Other causes are air pollution and recurrent

respiratory infections

• Primary emphysema linked to an inherited

deficiency of the enzyme alpha 1- antitrypsin

which can affect lung tissue.

Normal Lung versus Emphysema

Normal Lung versus Emphysema

Pathophysiology

• Begins with the destruction of the alveolar septa, which

eliminates portions of the capillary bed, and increases

the volume of air in the alveolus.

• Continued alveolar loss and loss of elastic recoil

• Expiration becomes difficult, causing hyperexpansion

of the chest

• These are not effective in gas exchange and result in

hypoxia.

Clinical manifestations

• Dyspnea at rest

• Barrel chest

• Minimal wheezing

• Prolonged expiration

• Hypoventilation and hypoxia

Pursed Lip Breathing

Atelectasis

• Collapse or incomplete expansion of part or

all of the lung

• Types:

– Resorption (obstruction of airway).

– Compressive (pleural effusion or pneumothorax)

Bronchiectasis

Dilatation of bronchi and bronchioles secondary to

chronic inflammation

Associated conditions

Obstruction

Cystic fibrosis

Immotile cilia syndromes

Necrotizing pneumonia

Respiratory Failure

Respiratory Failure (RF)

• The inability of the lungs to adequately oxygenate the

blood and to clear it of carbon dioxide. RF could be :-

• Acute RF:

– Acute Respiratory Distress Syndrome (ARDS)

– Pulmonary embolism

– Direct injury to the lungs, airways or chest wall

– Indirect due to injury of another body system, as

brain.

• Chronic respiratory failure

–Due to progressive hypoventilation from

airway obstruction or restrictive disease

• Respiratory failure always presents with:-

– Dysnpea always present, but may be difficult to detect

a change in a chronic patient

– Since nervous tissue is highly oxygen-dependent ---

• Drowsiness, Memory and visual impairment,

• Headache due to increased intracranial

pressure due to cerebral vasodilatation

1- Hypoxic Respiratory Failure

2- Hypoxic-Hypercapnic Respiratory Failure

Two principal patterns:

1- Hypoxic Respiratory Failure:

Seen when pO2 {oxygen partial pressure} falls to

or below 60 mm Hg

Typically seen in:-

• chronic bronchitis and emphysema.

• lung consolidation due to bacterial infection (pneumonia).

• in lung collapse,

• pulmonary hypertension,

• pulmonary embolism and ARDS.

• With a progressive lowering of pO2, more

widespread tissue damage and loss of

consciousness can occur.

2- Hypoxic-Hypercapnic Respiratory Failure

• When arterial pCO2 {Carbon dioxide partial

pressure} (normally 40 mm Hg) exceeds 45 mm HG,

condition is called hypercapnia

• Most often caused by airway obstructive conditions,

and hypoventilation from CNS problem, thoracic

cage or neuromuscular abnormalities.

• Attempts to compensate include increased heart

rate and vasodilatation, which produces warm,

moist skin.

• CNS effects produce muscular tremors, drowsiness

and coma.

• Hypercapnia also produces acidosis.

ARDS

• Mortality in persons < 60 is 40%

• Those over 65 and immunocompromised still have

mortality over 60 %

• Most survivors have almost normal lung function 1 year

after acute illness.

Clinical manifestations:

• Symptoms developed progressively:

– Hyperventilation → respiratory alkalosis →

dyspnea and hypoxemia → metabolic acidosis →

respiratory acidosis → further hypoxemia →

hypotension, decreased cardiac output, death

Evaluation and Treatment

• Diagnosis based on physical examination, blood gases

and imaging

• Treatment is based on early detection, supportive

therapy and prevention of complications, esp. infection

• Often requires mechanical ventilation.

Tumors of the Lung

Carcinoma of the Lung

• 7% of all deaths

• More common in males than females

Causes

85-95% smoking

1% asbestos + smoking (estimate)

Rare arsenic, chromium, nickel,

Classification of Lung Carcinoma (Major Types)

• Squamous cell carcinoma 35%

• Adenocarcinoma 30%

• Small cell carcinoma 25%

• Large cell carcinoma 10%

Squamous cell carcinoma

• Frequency: 35%

• Smoking: X 25 (increased risk)

• Males > females

• Survival (5 years): 15 - 20%

• Arises in bronchial squamous metaplasia

• Centrally located

• May cavitate

Squamous cell carcinoma

Adenocarcinoma

• Frequency: 30%

• Smoking: X 3

(increased risk)

• Males < females

• Survival (5 years): 15 -

20%

• Peripheral

Bronchiolo-alveolar carcinoma

• Frequency: 2 %

• Smoking

• Males = females

• Survival (5 years): 25-40 %.

• Single or multiple tumor nodules

Small cell carcinoma

• Frequency: 25 %

• Smoking: 95% of patients

• Males >> females

• Survival (5 years): 1 - 5 %.

Small cell carcinoma

Large Cell Carcinoma

• Frequency: 10 %

– Gross picture: Peripheral lesion

• Microscopic

–Wastebasket group of tumors that do not fit the

criteria of a squamous cell carcinoma,

adenocarcinoma, or small cell carcinoma

– Prognosis: Similar to adenocarcinoma

Large Cell Carcinoma

Mesothelioma–Malignant tumor of mesothelial cells

– Highly malignant neoplasm with short survival

–Most patients (70%) have an asbestos exposure

history

• Asbestos exposure also increases the risk of

pulmonary cancer

• Smoking is not related to mesothelioma