Adapted from Porth, C.M. 2011. Essentials of Pathophysiology, 3rd edn.
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Adapted from Porth, C.M. 2011. Essentials of Pathophysiology, 3rd edn.
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An infectious disease that primarily affects the lungs but can invade
other body systems as well. In tuberculosis, pulmonary infiltrates
accumulate, cavities develop, and masses of granulated tissue form
within the lungs. Tuberculosis may occur as an acute or a chronic
infection.
Pathophysiology: Tuberculosis results from exposure to Mycobacterium
tuberculosis and, sometimes, other strains of mycobacterium.
Transmission: an infected person coughs or sneezes, spreading infected
droplets.
Immune response: sends leukocytes, and inflammation results. After a
few days the leukocytes are replaced by macrophages.
Tubercle formation: macrophages that ingest the bacilli fuse to form
epithelioid cell tubercles, tiny nodules surrounded by lymphocytes.
Within the lesion, caseous necrosis develops and scar tissue
encapsulates the tubercle.
Dissemination: If the tubercles and inflamed nodules rupture, the
infection contaminates the surrounding tissue and may spread through
the blood and lymphatic circulation to distant sites.
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Hendler, C.B. 2002. Pathophysiology Made Incredibly Easy, 3rd edn.
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1. Inflammatory and Immune Process:
Fever and night sweats; malaise; weight
loss; adenopathy; productive cough
(lasting longer than 3 weeks);
haemoptysis; pleuritic chest pain.
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Development of neoplasm, usually within wall or epithelium
of bronchial tree. Most common types: squamous cell
carcinoma; small cell carcinoma; adenocarcinoma, and large
cell (anaplastic) carcinoma.
2. Pathophysiology: lung cancer most commonly results from
repeated tissue trauma from inhalation of irritants or
carcinogens. These substances include tobacco smoke, air
pollution, arsenic, asbestos, nickel and radon.
- Almost all lung cancers start in the epithelium. In normal
lungs, the epithelium lines protects the tissue below it.
However, when exposed to irritants or carcinogens, the
epithelium continually replaces itself until the cell develop
chromosomal changes and become dysplastic.
- Eventually, the dysplastic cells turn into neoplastic carcinoma
and start invading deeper tissues.
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Robinson, J.M. 2005. Pathophysiology: Just the facts.
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Hendler, C.B. 2002. Pathophysiology Made Incredibly Easy, 3rd edn.
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In children respiratory tract infections are common, an
d although they are troublesome, they usually are not
serious. Frequent infections occur because the immune
system of infants and small children has not been
exposed to many common pathogens.
2. Croup: is characterised by inspiratory stridor,
hoarseness and a barking cough. Although the
respiratory manifestations of croup often appear
suddenly, they usually are preceded by upper
respiratory infections that cause rhinorrhoea, coryza,
hoarseness, and low grade fever. In most children, the
manifestations of croup advances only to stridor and
slight dyspnoea before they begin to recover.
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Tuberculosis is transmitted through _____________ of
_______________ droplets.
______________ are the most frequent cause of respiratory
infection.
The common cold is a viral infection of the
_______________ respiratory tract.
The term ___________________ describes inflammation of
parenchymal structures of the lung, such as the alveoli and
the bronchioles.
The _____________ include squamous cell carcinomas,
adenocarcinoma, and large cell carcinoma.
How is lung cancer characterised?
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Hypoxemia:
Reduced oxygenation of arterial blood,
evidenced by reduced Pao2 of arterial blood
gases.
Can be caused by decreased oxygen content of
inspired gas, hypoventilation, diffusion
abnormalities, abnormal V/Q ratios, and
pulmonary right to left shunts.
Can lead to tissue hypoxia.
Can occur anywhere in the body.
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Cyanosis:
Bluish discolouration of skin and mucous membranes;
may be central or peripheral.
Central cyanosis: decreased oxygen saturation of
haemoglobin in arterial blood; best observed in buccal
mucous membranes and lips.
Peripheral cyanosis: slowed blood circulation of fingers
and toes; best visualised by examining nail bed area.
Caused by desaturation with oxygen or reduced
haemoglobin amounts (develops when 5 grams of
haemoglobin is desaturated, even if haemoglobin
counts are adequate or reduced).
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• Air entering through the airways inflates
the lung, and the negative pressure in
the pleural cavity keeps the lung from
collapsing. Disorders of lung inflation
are caused by conditions that obstruct
airways, cause lung compression, or
produce lung collapse.
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An accumulation of air in the pleural cavity that leads to partial or
complete lung collapse.
2. Classified as either traumatic or spontaneous.
3. Pathophysiology:
- Traumatic pneumothorax: a penetrating injury, such as a stab
wound, or impaled object, may cause traumatic pneumothorax.
- Open pneumothorax: results when atmospheric air flows directly
into the pleural cavity. As the lung pressure becomes positive, the
lungs collapses on the affected side, eventually resulting in hypoxia.
- Closed pneumothorax: occurs when air enters the pleural space from
within the lungs. This causes increased pleural pressure and
prevents expansion during inspiration.
- Spontaneous pneumothorax: is a type of closed pneumothorax. It is
more common in men and older patients with chronic pulmonary
disease.
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Hendler, C.B. 2002. Pathophysiology Made Incredibly Easy, 3rd edn
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Refers to an incomplete expansion of a lung or portion
of a lung.
2. Pathophysiology:
- Occurs when alveolar sacs or entire lung segments
expand incompletely, producing partial or complete
lung collapse.
- Removes certain lung regions from gas exchange,
allowing unoxygenated blood to pass unchanged
through these regions, resulting in hypoxia.
- May be chronic or acute; commonly occurs in patients
undergoing upper abdominal or thoracic surgery.
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Caused by conditions that limit expiratory
airflow. Bronchial asthma represents an acute
and reversible form of airway disease caused by
narrowing of airway disease caused by narrowing
of airways due to bronchospasm, inflammation,
and increased airway secretions.
• Airway disorders affect airway patency and
movement of atmospheric air into and out of the
gas exchange portion of the lung.
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A chronic reactive airway disorder that can present as an acute attack. It
causes episodic airway obstruction resulting from bronchospasm, increased
mucous secretion, and mucosal oedema.
Asthma is one type of Chronic obstructive pulmonary disease (COPD), a
long term pulmonary disease characterised by airflow resistance.
Pathophysiology:
In asthma, bronchial linings overreact to various stimuli, causing episodic
smooth-muscle spasms that severely constrict the airways.
Asthma can be described in two ways: extrinsic and intrinsic:
Extrinsic, or atopic, asthma is sensitive to specific external allergens , which
include pollen, animal dander, house dust or mould, and food additives
containing sulphites. Extrinsic asthma begins in childhood and is
commonly accompanied by other hereditary allergies, such as eczema and
allergic rhinitis.
Intrinsic, or nonatopic, asthma is a reaction to internal, nonallergenic
factors. Most episodes occur after a severe respiratory infection.
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Hendler, C.M. 2002. Pathophysiology Made Incredibly Easy, 3rd edn.
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Porth, C.M. 2011. Essentials of Pathophysiology, 3rd edn.
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A form of COPD, emphysema is the abnormal, permanent
enlargement of the acini accompanied by destruction of the
alveolar walls. Obstruction results from tissue changes,
rather than mucous production, which is the case in asthma
and chronic bronchitis.
2. Pathophysiology: Emphysema may be caused by a
deficiency of alpha1-protease inhibitor or by cigarette
smoking.
- In emphysema, recurrent inflammation is associated with
the release of proteolytic enzymes from lung cells. This
causes irreversible enlargement of the air spaces distal to the
terminal bronchioles.
- Enlargement of air spaces destroys the alveolar walls, which
results in a breakdown of elasticity and loss of fibrous and
muscle tissues, making the lungs less compliant.
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