CHAPTER 21

DISEASES OF THE RESPIRATORY SYSTEM

FChapter Overview

Colds are among the most common diseases that affect humans. It seems that we never can avoid these pesky viruses no matter what we do. In addition, if our resistance is lowered due to stress, poor health, or lack of sleep, our chances of "catching" these viruses are greatly increased. Perhaps this is nature's way of trying to slow our hectic pace before more serious types of illnesses can catch up with us.

In this chapter we describe the important agents that cause upper respiratory infections as well as all those agents that affect the lower respiratory tract. The diseases of highest incidence or greatest importance are stressed; however, even those diseases that are rather uncommon, or perhaps occur elsewhere in the world, are presented to ensure a thorough survey of all those agents capable of affecting the respiratory system.

FChapter Objectives

  • List the components of the respiratory system and the normal microflora found there.
  • List the important bacteria that cause upper respiratory infections and describe the important epidemiologic and clinical aspects of the diseases they cause.
  • List the important viruses that cause upper respiratory infections and describe the important epidemiologic and clinical aspects of the diseases they cause.
  • List the important bacteria that cause lower respiratory infections and describe the important epidemiologic and clinical aspects of the diseases they cause.
  • List the important viruses that cause lower respiratory infections and describe the important epidemiologic and clinical aspects of the diseases they cause.
  • List the important fungi that cause lower respiratory infections and describe the important epidemiologic and clinical aspects of the diseases they cause.
  • List the important parasites that cause respiratory infections and describe the important epidemiologic and clinical aspects of the diseases they cause.
  1. Animations and videos – online
  2. NOVA’s Science Now website on the bird flu -
  3. Avian flu recent outbreaks timeline -
  4. Virtual Endocrine Centre 3D Medical Animations List site - Scroll down and click on Bronchitis to see a general video on this subject.

Web Destinations


  • CDC respiratory diseases web site

  • Medline Plus respiratory diseases web site

  • Medline Plus site about the common cold

  • American Lung Association site

  • Respiratory Syncytial Virus information center providing updates, links, and general information about RSV.

  • CDC SARS web site

  • World Health Organization SARS web site

Discussion Topics

  • Most adults are no longer maintaining their immunity level to diphtheria (few are receiving booster shots beyond high school or college). Is there a chance then, that diphtheria could exhibit a resurgence? Of what concern is the recent diphtheria outbreak in Russia to the rest of the world?
  • The BCG vaccine is used to prevent tuberculosis in many countries around the world. Should the United States consider using this vaccine as well? If not, why not?
  • Young children seem to be having increased problems with ear infections, which ultimately require the implantation of tubes. What are the problems that seem to create these infections, why has there been an increase, and what organisms are currently implicated?
  • Why was it so difficult to produce an effective, complication free vaccine against whooping cough? What problems have been documented concerning the current vaccine and what was done to compensate the victims of the old vaccine?
  • The BCG vaccine appears to provide immunity against tuberculosis and also seems to induce a cellular defense against certain cancerous tissues. What is the current status of effectiveness and use of this method of therapy?
  • Pneumocystis pneumonia was once a major cause of death for AIDS patients and patients who were immunocompromised. What is the current status of this disease and what methods of therapy are recommended for these patients?

FChapter Outline

I.Components of the Respiratory System

A.The upper respiratory tract

1.Nasal cavity

2.Nasal sinuses

3.Pharynx

4.Larynx

5.Trachea

6.Bronchi

7.Mucociliary escalator

B.The lower respiratory tract

1.Bronchioles

2.Alveoli

3.Pleura

C.The ears

1.Pinna

2.Auditory canal

3.Ceruminous glands

4.Tympanic membrane

5.Middle and inner ear

6.Mastoid area

D.Normal microflora of the respiratory system

II.Diseases of the Upper Respiratory System

A.Bacterial upper respiratory diseases

1.Pharyngitis and related infections

a.Streptococcal pharyngitis

b.Laryngitis and epiglottitis

c.Sinusitis

d.Bronchitis

2.Diphtheria

a.General features

b.Causative agent

c.The disease

d.Treatment and prevention

3.Ear infections

a. Otitis media

b. Otitis externa

B.Viral upper respiratory diseases

1.The common cold

a.Causative agents

1.Rhinoviruses

2.Coronaviruses

b.Transmission

c.Diagnosis and treatment

2.Parainfluenza

III.Diseases of the Lower Respiratory System

A.Bacterial lower respiratory diseases

1.Whooping cough (pertussis)

a.Incidence

b.Causative agent

c.The disease

1.Cararrhal stage

2.Paroxysmal stage

3.Convalescent stage

d.Diagnosis and treatment

e.Prevention

2.Classic pneumonia

a.Classification of pneumonias

1.Lobar pneumonia

2.Bronchial pneumonia

b.Transmission

c.The disease

d.Diagnosis, treatment, and prevention

3.Mycoplasma pneumonia

a.Primary atypical pneumonia

b.Walking pneumonia

c.Transmission

d.Diagnosis, treatment, and prevention

4.Legionnaire's disease

a.Basic features

b.Causative agent

c.Transmission

d.Pontiac fever

e.Diagnosis, treatment, and prevention

5.Tuberculosis

a.Incidence in the United States

b.Causative agents

c.The disease

1.Tubercles

2.Miliary tuberculosis

3.Disseminated tubercles

d.Diagnosis, treatment, and prevention

6.Psittacosis and ornithosis

a.Causative agent

b.Transmission

c.Diagnosis, treatment, and prevention

7.Q fever

a.Causative agent

b.Symptoms

c.Diagnosis and treatment

8.Nocardiosis

a.Causative agent

b.Symptoms

c. Diagnosis, treatment, and prevention

B.Viral lower respiratory diseases

1.Influenza

a.Incidence

b.Causative agent

c.Antigenic variation

1.Antigenic drift

2.Antigenic shift

3.Immune responses

d.The disease

e.Incidence and transmission

f.Diagnosis and treatment

g.Immunity and prevention

2.SARS (Severe Acute Respiratory Syndrome)

a.Incidence

b.Symptoms

c.Causative agent

d.Vaccine development

3.Respiratory syncytial virus infection

a.Syncytia

b.Viral pneumoniae

4.Hantavirus pulmonary syndrome

5.Acute respiratory disease

C.Fungal respiratory diseases

1.Coccidioidomycosis

a.Causative agent

b.Transmission, prevention, and treatment

2.Histoplasmosis

a.Causative agent

b.Transmission, prevention, and treatment

3.Cryptococcosis

a.Causative agent

b.Other characteristics

4.Pneumocystis pneumonia

a.Causative agent

b.Other characteristics

5.Aspergillosis

D.Parasitic Respiratory Disease

1.Causative agent

2.Other characteristics

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