Pathology of respiratory system

2. PATHOLOGY and MICROBIOLOGY II
P2M-85

3. Objectives:
 Reduction of pulmonary functions
 Signs and symptoms of pulmonary diseases
 Respiratory failure
 Obstructive pulmonary diseases

4. Reduction of Pulmonary Function
1. Inadequate blood flow to the lungs – hypoperfusion
2. Inadequate air flow to the alveoli – hypoventilation
3. Alveoli (The alveoli are where the lungs and the
blood exchange oxygen and carbon dioxide during
the process of breathing in and breathing out.
4. Oxygen breathed in from the air passes through the
alveoli and into the blood and travels to the tissues
throughout the body.)
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5. Hospital-acquired pneumonia (HAP),
or nosocomial pneumonia (NP)
 Pneumonia that develops 48 h or more after admission to a
hospital and does not include pneumonia that a patient had
contracted when admitted or before being admitted.
 Often, nosocomial infections are caused by multidrug-resistant
pathogens acquired via invasive procedures, excessive or improper
antibiotic use, and not following infection control and prevention
procedures.
 the most common is the bacterium Staphylococcus aureus.
 Other common pathogens like Escherichia coli, Enterococci,
and Candida normally found on the skin and mucous membranes.
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6. Types of Nosocomial Infections
 Bacterial infections. Bacteria are the most
common cause of nosocomial infections. Common
bacteria include E. coli and staph.
 Fungal infections. The most common fungi that
cause nosocomial infections are Candida (thrush)
and Aspergillus.
 Viral infections. Common nosocomial infections
caused by viruses are influenza (flu)
and respiratory synctial virus.

7. Symptoms
 Fever
 Burning sensation while urinating
 Cough
 Extreme tiredness or weakness
 Skin redness and soreness around a surgical or
needle wound
 Sweating
 Muscle soreness
 Nausea and vomiting

8. Treatment
 Antibiotics.
 Rest.
 Fluids.

9. Prevention
 Fully disinfecting skin and equipment
 Washing hands regularly
 Wearing protective equipment like face masks and gloves
 Regularly changing urinary catheters, and removing them
as soon as possible
 Removing hair near a surgical area
 Prescribing antibiotics only when needed

10. Signs and Symptoms of Respiratory
Disease
 Dyspnea – subjective sensation of uncomfortable
breathing, feeling “short of breath”
 Ranges from mild discomfort after exertion to extreme
difficulty breathing at rest.
 Tachypnea (rapid breathing)
 Hypopnea (shallow breathing)
 Hyperpnea (deep breathing),
 Apnea (absence of breathing).
 Breathing problems may occur in conditions affecting the
lungs alone or may be seen in association with more
generalized conditions, such as dehydration or infection
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11. Dyspnea cont.
 Due to:
Airway obstruction
Greater force needed to provide adequate
ventilation
Wheezing sound due to air being forced through
airways narrowed due to constriction or fluid
accumulation
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12. Signs of Dyspnea:
 Flaring nostrils(Nasal flaring occurs when
the nostrils widen while breathing. It is
often a sign of trouble breathing)
 Use of accessory muscles in breathing
 Retraction (pulling back) of intercostal
spaces
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13. CAUSES
 Asthma
 Anxiety
 pneumonia
 choking on or inhaling something that blocks breathing passageways
 allergic reactions
 Anemia (Anemia is a condition in which you lack enough healthy red blood cells to carry
adequate oxygen to your body's tissues)
 serious loss of blood, resulting in anemia
 exposure to dangerous levels of carbon monoxide
 heart failure
 hypotension which is low blood pressure
 pulmonary embolism, which is a blood clot in an artery to the lung
 collapsed lung

14. COUGH
 Attempt to clear the lower respiratory
passages by abrupt and forceful expulsion
of air
 Most common when fluid accumulates in
lower airways
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15. Cough may result from:
 Inflammation of lung tissue
 Increased fluid secretion in response to mucosal
irritation
Inhalation of irritants(Dust etc.)
Mucosal interruption – such as tumor invasion of
bronchial wall
 Excessive blood pressure in pulmonary capillaries
Pulmonary edema – excess fluid passes into
airways 15

16.  When cough can raise fluid into pharynx, the cough is
described as a productive cough, and the fluid is sputum.
Production of bloody sputum is called hemoptysis
Usually involves only a small amount of blood loss
Not threatening, but can indicate a serious pulmonary
disease
Tuberculosis, lung abscess, cancer, pulmonary
infarction.
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17.  If sputum is pus-filled, and infection of lung or airway is
indicated.
 Cough that does not produce sputum is called a dry,
nonproductive or hacking cough.
 Acute cough is one that resolves in 2-3 weeks from onset of
illness or treatment of underlying condition.
 Caused by
infections, allergIES, acute bronchitis, pneumonia,
congestive heart failure, pulmonary embolus, or
aspiration.
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18. Chronic Cough
 A chronic cough is one that persists for more
than 3 weeks.
 In nonsmokers, almost always due to asthma,
or gastroesophageal reflux disease Chronic
Cough is common.
 In smokers, chronic bronchitis is the most
common cause, although lung cancer should
be considered.
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19. Cyanosis
 When blood contains a large amount of unoxygenated
hemoglobin, it has a dark red-blue color which gives skin
a characteristic bluish appearance.
 Most cases arise as a result of reduced blood flow, which
allows hemoglobin to give up more of its oxygen to tissues-
peripheral cyanosis.
 Best seen in nail beds
 Due to cold environment, anxiety, etc.
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20.  Central cyanosis can be due to :
Abnormalities of the respiratory membrane
Mismatch between air flow and blood flow
Expressed as a ratio of change in ventilation (V) to perfusion
(Q) : V/Q ratio
 : V – ventilation – the air that reaches the alveoli. Q – perfusion – the blood that
reaches the alveoli via the capillaries.
 In persons with dark skin can be seen in the whites of the eye
and mucous membranes.
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21. In adults not evident until severe hypoxemia is present
Clinically observable when reduced hemoglobin levels
reach 5 g/ dl.
Severe anemia and carbon monoxide give inadequate
oxygenation of tissues.
Individuals with polycythemia may have cyanosis when
oxygenation is sufficient.
Polycythemia refers to an increase in the number of red
blood cells in the body
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22. Pain in Respiratory System
 Originates in pleurae, airways or chest wall
 Inflammation of the parietal pleura causes sharp
or stabbing pain when pleura stretches during
inspiration
Usually localized to an area of the chest wall,
where a pleural friction rub can be heard
Laughing or coughing makes pain worse
Common with pulmonary infarction due to
embolism (An embolism is a blocked artery
caused by a foreign body) 22

23.  Inflammation of trachea or bronchi produce a
central chest pain that is pronounced after
coughing
Must be differentiated from cardiac pain
 High blood pressure in the pulmonary
circulation can cause pain during exercise that
often mistaken for cardiac pain (angina
pectoris)
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24. Clubbing
 The selective enlargement of the end of a digit (finger or
toe).
 Usually painless
 Commonly associated with diseases that cause decreased
oxygenation
Lung cancer
Cystic fibrosis
Lung abscess
Congenital heart disease 24

25. 25

26. Respiratory Failure
 The inability of the lungs to sufficiently move
oxygen into the bloodstream and to clear it of
carbon dioxide.
 Can be acute:
Direct injury to the lungs, airways or chest wall
Indirect due to injury of another body system,
such as the brain or spinal cord.
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27. Chronic respiratory failure
 Due to progressive hypoventilation from airway
obstruction
 Respiratory failure always presents a serious threat
 Dyspnea always present, but may be difficult to detect
a change in a chronic patient
 Memory loss
 visual impairment
 drowsiness
 Headache due to increased intracranial pressure due to
cerebral vasodilation
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28. Two principal patterns:
1. Hypoxic Respiratory Failure:
when pO2 falls to or below 60 mm Hg
Typically seen in chronic bronchitis and emphysema, in
lung due to bacterial infection, or in lung collapse,
pulmonary hypertension, pulmonary embolism and
ARDS.
Initially, produces headache and nervous anxiety, soon
followed by a decline in
mental activity, and confusion. 28

29.  With a progressive lowering of pO2, more
widespread tissue damage and loss of
consciousness occurs.
 Renal hypoxia (i.e., decreased oxygen tension in
the kidney)
 Renal hypoxia can cause loss of homeostatic
balance and accumulation of wastes to complicate
the problem
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30. Hypoxic-Hypercapnic Respiratory
Failure
 When arterial pCO2 (normally 40 mm Hg) exceeds
45 mm HG, condition is called hypercapnia
 Most often, obstructive conditions produce this
form of respiratory failure, as can hypoventilation
from CNS problem, thoracic cage or
neuromuscular abnormalities
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31.  Attempts to compensate include
increased heart rate and vasodilation,
which produces warm, moist skin.
 CNS effects produce muscular tremors,
drowsiness and coma.
 Hypercapnia also produces acidosis.
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32. Obstructive Pulmonary Disease
 Characterized by airway obstruction that is worse
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.
 Many people have both chronic bronchitis and
emphysema, and together these are often called
chronic obstructive pulmonary disease - COPD
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33.  Major symptom of obstructive pulmonary
disease is dyspnea, and the unifying sign is
wheezing.
 Individuals have increased work of breathing, a
decreased forced expiratory volume.
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34. References
1- Bousquet J et al. Management of chronic respiratory and
allergic diseases in developing countries. Focus on sub-
Saharan Africa. Allergy, 2003, 58:265–283.
2- Enarson DA, Ait-Khaled N. Cultural barriers to asthma
management. Pediatric Pulmonology, 1999, 28:297–300
3- Masoli M et al. The global burden of asthma: executive
summary of the GINA Dissemination Committee Report.
Allergy, 2004, 59:469–478.

35. Outcomes:
 Students will be able to learn:
 Reduction of pulmonary functions
 Signs and symptoms of pulmonary diseases
 Respiratory failure
 Obstructive pulmonary diseases