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BRONCHIAL ASTHMA (BA)
• Most common chronic respiratory disease in children.
More common in children than adults
• Is a chronic episodic inflammatory obstructive lung
disease characterized by hyper-reactive airways
(patients have hyper-irritable airways which react to
• Primarily targets the bronchi and terminal bronchioles
• In it the airways go into bronchoconstriction/spasm.
• It results in a triad of:
1. intermittent and reversible airway constriction
2. Edema, inflammation with eosinophils and excess
3. bronchial smooth muscle cell hypertrophy
C/F of BA
In a classic asthmatic attack there is wheezing,
Complications of Bronchial Asthma
Chronic bronchitis or Emphysema
•most severe form of asthma severe acute
•severe bronchoconstriction that does not respond
easily to drugs.
•serious and requires hospitalization and may
severe cyanosis and death.
Extrinsic (atopic, allergic) Asthma 70% Intrinsic (non-atopic)Asthma 30%
Allergic type 1 hypersensitivity reaction induced by
exposure to extrinsic antigen/allergens e.g. food, pollen,
Usually family history present No personal history of allergy.
No family history of allergy.
Develop early in life Develops later in life
Sometimes extrinsic and intrinsic can co-exist in the same
Common among cigarette smokers and urban dwellers, age 40 to 65
Definition persistent productive cough (with sputum) for at least 3
consecutive months in at least 2 consecutive years
Can coexists with emphysema (Often, there are features of emphysema
Causative factor are:
– Cigarette smoking and pollutants.
– Genetic factors
Is abnormal permanent enlargement of the
airspaces distal to the terminal bronchioles
accompanied by destruction of their walls,
without obvious fibrosis.
Tends to coexist with chronic bronchitis
Types of emphysema:
– Centriacinar (centrilobular) : Occurs in
heavy smoker in association with chronic
– Panacinar: there is Alpha 1 antitrypsin
– Distal acinar /paraseptal
• Cough and wheezing. Respiratory acidosis
• Abnormal pulmonary function tests
■ Normal ■ Emphysema
Morphology: The lungs are pale, voluminous. Histology thinning
and destruction of alveolar walls creating large airspaces.
Centriacinar (centrilobular) emphysema
■ Occur in heavy smoker in association with chronic bronchitis
■ The central or proximal parts of the acini are affected, while distal
alveoli are spared
Panacinar (panlobular) emphysema
Cause: occurs in 1-anti-trypsin deficiency.
Uniform injury: Acini are uniformly
enlarged from the level of the respiratory
bronchiole to the terminal blind alveoli.
Distal acinar (paraseptal) emphysema
■ The proximal portion of the acinus is
normal but the distal part is dominantly
■ Sometimes forming multiple cyst-like
structures with spontaneous
Pathogenesis of Emphysema
Normally there is a balance between protease and anti protease
An imbalance between protease and antiprotease activity in the
Protease (e.g. elastase) is proteolytic enzymes that damages
alveolar elastic tissue. It is produced by neutrophils and
Smokers have increase in the numbers of alveolar macrophages
and neutrophils imbalance.
Note: Alpha 1 antitrypsin is an anti-protease. It is normally
present in the serum, in tissue fluids and in macrophages.
Deficiency panacinar emphysema.
■ The lungs are pale, voluminous.
■ Histologically: thinning and destruction of alveolar walls
creating large airspaces.
• Cough and wheezing. Respiratory
• Weight loss.
• Pulmonary function tests reveal
is chronic necrotizing inflammation and destruction of the bronchi and bronchioles leading to
abnormal permanent dilation of these airways.
most often involves the lower lobes of both lungs.
• fever and cough
• production of purulent foul smelling sputum,
• and recurrent pulmonary infection that may lead to lung abscess.
■ Airways are dilated airways up to four times of normal.
Morphology of Bronchiectasis
■ Usually affects lower lobes bilaterally.
■ Dilated airways up to four times of normal.
■ Acute and chronic inflammation
(neutrophils, lymphocytes, histiocytes and
■ Necrosis and ulceration in the wall of the
bronchi and bronchioles and fibrosis.
Pneumonia is defined as any infection of lung parenchyma
Portal of entry for most pneumonia is
Inhalation of air droplets
Aspiration of infected secretions or objects
Pneumonia can be acute or chronic
Histology: variable, can be:
acute fibrinopurulent alveolar exudate
chronic interstitial inflammation
CLASSIFICATION OF PNEUMONIA
■ occur in two extremes of life.
■ multiple small patches of
inflammation centered around
2. Lobar pneumonia:
• acute infection of a large portion of a
lobe or entire lobe (widespread
- Note: overlap of the two patterns often occur
Stages of pneumonia
There are 4 stages:
I. Congestion: lung is heavy, boggy and red. The alveoli are filled with fluid and bacteria.
II. Red hepatization: the lung is firm/solid, red and alveoli are filled with neutrophils, rbcs
(congestion) and fibrin.
III. Gray hepatization: the red cells are reduced but neutrophils and fibrin (fibrinopurulent/suppurative
exudate) are still present. The lung is still firm/solid but grey.
(hepatization = solidification = liver like consistency)
■ TB is a communicable granulomatous disease caused mainly by Mycobacterium
tuberculosis hominis (Koch bacillus) and occasionally by Mycobacterium tuberculosis
■ Primarily affects the lungs but other organs can also be infected.
■ Reservoir of infection is humans with active tuberculosis.
■ Characteristic lesion: epitheloid granuloma with central caseous necrosis.
■ Mycobacterium tuberculi are non-motile rod-shaped aerobic acid fast bacilli.
Reservoir of infection:
• humans with active tuberculosis.
• poverty, crowding, malnutrition, chronic debilitating illness,
elderly, people with AIDS, immunosuppression etc.
Route of transmission
• M. tuberculosis generally enters lung by inhalation (by
inhaling infected aerosols from the cough of a person with
active cavitatory TB).
• M. bovis generally enters by drinking unpasturized infected
cow's milk oropharyngeal & intestinal TB.
• Malaise, anorexia, weight loss, fever (low grade evening rise
of temperature) with chills and night sweats.
• Cough with sputum, hemoptysis etc.
• Extrapulmonary manifestations of tuberculosis depend on
the organ system involved.
• Localized secondary tuberculosis may be asymptomatic.
Cavitatory TB lung
Cavitatory tuberculosis with intracavitary
hemorrhage. Extensive necrosis with
cavitation, usually occurring in the upper
lung lobe .
Langhans Giant Cell
Diagnosis of TB
Ziehl-Neelsen stain shows red acid-fast
staining M. tuberculi.
Tubercle bacilli are acid fast:
Characteristically the bacilli stain red/pink with
Ziehl-Neelsen acid-fast stain and the glow with
fluorescent dye auramine O.
TB culture of the sputum or tissue is still the
most sensitive and specific, albeit slowest, way
to make the diagnosis. Culture is the gold
PCR testing allows for rapid diagnosis.
■ Most lung tumors are malignant.
■ Lungs are frequently the site of metastases.
■ Primary lung cancer is a common disease BUT metastatic tumors are more
common than the primary tumors.
■ The most common benign lesions are hamartomas.
Examples of Primary Lung Tumors
MALIGNANT EPITHELIAL TUMORS /BRONCHOGENIC CARCINOMA:
I. Non-Small Cell Lung Carcinoma
a) Squamous cell carcinoma: Strong association with smoking, poor prognosis, usually
central (perihilar) in location, can be well/ moderate/ poorly differentiated
b) Adenocarcinoma: do not have a clear link to smoking history, usually peripheral in location,
sometimes associated with pulmonary scars (scar carcinoma)
c) Large cell carcinoma: uncommon, strongly associated with smoking, very poor prognosis.
II. Small cell lung carcinoma: poorly differentiated highly malignant, aggressive neuroendocrine tumors.
Poor prognosis. Strongly associated with cigarette smoking. Central (perihilar), can be associated
with paraneoplastic syndrome. Microscopy small round blue cells.
III. Combine patterns
IV. Carcinoid tumor: well differentiated neuroendocrine tumor; not related to cigarette smoking. Tumor cells
produce serotonin and bradykinin carcinoid syndrome (flushing, wheezing, diarrhea etc.), can
also produce ectopic ACTH Cushing syndrome. Low malignancy, good prognosis (often resectable
MALIGNANT MESOTHELIAL TUMOR: malignant mesothelioma
OTHERS Miscellaneous malignant tumor e.g. Carcinosarcoma, Pulmonary blastoma, Melanoma,
Bronchogenic carcinoma is a malignant neoplasm
of the lung arising from the epithelium of the lung.
Most patients are 50-80 years.
For therapeutic purposes, bronchogenic carcinoma
are classified into:
1. Non- Small cell lung carcinoma (NSCC)
2. Small cell lung carcinoma (SCC)
Important to differentiated between the 2
because treatment are different.
For NSCC therapy:
•Surgical - the best chance for curing.
•Radiation – to control local disease.
•Chemotherapy – not effective.
•Chemotherapy - very effective, small cell
carcinomas are highly responsive to
SO: It is important to differentiated between the Non-small cell and small cell because treatment is different:
• Non- Small cell lung carcinoma (NSCC) surgery
• Small cell lung carcinoma (SCC) chemotherapy is very effective
Squamous cell carcinoma
■ strong association with smoking
■ Poor prognosis
■ SqCC arise in the central airways (centrally
located). So they appears as a hilar mass.
■ Tumor cells secrete a parathyroid hormone
(PTH)- like peptide hypercalcemia.
■ Histologically they are graded according to
degree of squamous differentiation:
• well-differentiated SqCC
• moderately differentiated SqCC
• poorly differentiated SqCC
■ They do not have a clear link to
■ They are classically peripheral tumors
arising from the peripheral airways and
■ The hallmark of adenocarcinomas is
the tendency to form glands that may
or may not produce mucin.
■ Peripheral adenocarcinomas are
sometimes associated with pulmonary
scars (from a previous pulmonary
inflammation/infection) and therefore is
also referred to as scar carcinoma.
■ Frequency: 10%
■ strongly associated with smoking
■ usually located peripherally.
■ poor prognosis.
Small cell carcinomas
■ SCLC are a poorly differentiated highly malignant
neuroendocrine tumors arising from
■ Highly malignant and aggressive tumor, poor
■ Strongly associated with cigarette smoking.
■ Centrally located perihilar mass.
■ Microscopically composed of small, round dark
■ Chemotherapy responsive
■ It may be associated with paraneoplastic
■ Carcinoid tumors of the lung are well differentiated
neuroendocrine tumor. They arise from the
neuroendocrine cells found in the bronchial epithelium.
■ These neoplasms account for 2% of all primary lung
cancers and are not related to cigarette smoking.
■ Can be central or peripheral in location
■ Composed of uniform cuboidal cells that have regular
round nuclei with few mitoses and little or no atypia.
■ Electron microscopy: dense-core neurosecretory
■ Tumor cells produce serotonin and bradykinin leading
to carcinoid syndrome (flushing, wheezing, diarrhea,
and cardiac valvular lesions).Tumor cells can also
produce ectopic ACTH leading to Cushing syndrome.
■ Can occur in patients with Multiple Endocrine
■ Low malignancy, Often resectable and curable.
■ Spreads by direct extension into adjacent tissues
Etiology of bronchogenic carcinoma
1. Tobacco smoking: cigarette smoking is linked to squamous cell carcinoma and small cell
carcinoma. The risk is 20 to 40 times greater among habitual heavy smokers. Passive
smoking increases the risk to approximately twice than non-smokers. The nonsmoker
who develops cancer of the lung usually adenocarcinoma.
3. Asbestos exposure bronchogenic carcinoma and mesothelioma.
4. Industrial exposure to nickel and chromates, coal, mustard gas, arsenic, iron etc.
5. Air pollution: may play a role e.g. indoor air pollution by radon.
6. Scarring: sometimes old infarcts, wounds, scar (from a previous pulmonary
inflammation/infection), granulomatous infections are associated with adenocarcinoma.
Clinical features of bronchogenic carcinoma
Can be silent or insidious lesions
Respiratory symptoms e.g. Cough, expectoration, hemoptysis, bronchial obstruction, lung collapse,
bronchiectasis, pneumonia, chest pain, pleural effusion etc.
Hoarseness, chest pain, superior vena cava syndrome, pericardial or pleural effusion.
Paraneoplastic syndrome: are extrapulmonary, remote effects of tumors. About 10% of lung cancers develop
paraneoplastic syndromes. In it the tumor cells produce various peptides/hormone lead to metabolic and
neuromuscular disturbances e.g.
Carcinoid tumors and small cell carcinomas may secrete ectopic ACTH Cushing's syndrome
small cell carcinomas may secrete ADH water retention and hyponatremia
squamous cell carcinomas may secrete PTH like peptide hypercalcemia.
■ Highly malignant tumor of mesothelial
cells lining the pleura
■ History of exposure to asbestos is
■ Treatment is largely ineffective and
prognosis extremely poor
Metastatic carcinoma of lung
■ Pulmonary Metastases are More
Common than Primary Lung Tumors
■ Typically multiple and circumscribed
nodules. Radiologically called
cannon ball metastases.
■ The common primary sites are the
breast, stomach, pancreas, and colon.