Transcript Respiratory System

Chapter 22
Infections of the Respiratory
System
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Clinical Science
• Diagnosis
– Anatomical
– Etiological
• Prognosis and
Treatment
• Types of infections
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Acute
Chronic
Persistent
Symptomatic
Asymptomatic
Local
Systemic
Primary
Secondary
mixed
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Clinical Science
• Progress of
Infections
– Incubation
– Prodromal
– Active
– convalescent
Figure 22.1
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Respiratory System
Figure 22.2
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Epiglottitis
• Haemophilus influenzae
– require components of blood
– capsule
• pathogenic strains
• resistant to phagocytosis
• resistant to complement lysis
– children most vulnerable
– vaccine
• Hib
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Streptococcal pharyngitis
• Streptococcus pyogenes
– group A beta-hemolytic streptococcus
• group A--type of polysaccharide antigen
• beta-hemolytic--type of hemolysis of blood agar
– clinical syndrome
• whitish exudate covering tonsils
• inflammation of pharynx
• fever
– identification of bacteria
• throat culture
• latex agglutination detect antigens
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Complications of S. pyogenes
• scarlet fever
– toxin kills cells
• septicemia
– spread in the bloodstream
• Rheumatic fever
– inflammation in organs/joints
– heart valve damage
– prevention if Strep throat is treated
• Acute poststreptococcal glomerulonephritis
– inflammation in glomeruli
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Diphtheria
• Diphtheria--Corynebacterium diptheriae
– Protein toxin
– Symptoms
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localized inflammatory response
membranous pharyngitis
difficulty in swallowing
swelling of lymph glands
– Vaccine
• acellular
• portion of DTP
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Anthrax
• Bacillus anthracis
• Toxins
– Edema factor (EF)
– Lethal factor (LF)
– Protective antigen (PA) macrophages
• Receptor
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The Common Cold
– Rhinoviruses
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25-50% of the colds
100+ serotypes
transmission by respiratory droplets
pathogenesis
– replication in epithelial cells
– stimulate kinins-secretions
– immune response clears virus
• restoration of epithelium--months
• treatment: symptoms only
– other viruses
• Coronaviruses (SARS)
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Pneumococcal pneumonia
• Streptococcus pneumoniae
– pneumococcus
• pathogenic strains--capsule
• 80 serotypes
– clinical syndrome
• difficult to recover from clinical samples
• inhaling respiratory droplets
• intense inflammation
– pneumonia
– treatment
• antibiotics
– prevention
• vaccine (Pneumovax)
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Other pneumonias
• Various bacteria
• S. aureus, H. influenzae, Klebsiella spp, E. coli, Proteus
spp.
– secondary infection after other disease
– Pathogenesis
• replication/inflammation in alveoli
• inflammation leading to fluid in lungs
• need healthy breathing to facilitate normal cleansing
– Treatment--antibiotic
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Atypical pneumonias
• Primary atypical pneumonia
– Mycoplasma pneumoniae
– no cell wall
• Chlamydial Pneumonia
– Chlamydia psitacci
– exposure to sick birds
• Q Fever
– Coxiella burnetii
– Rare, almost never causes death
• Legionellosis
– Legionella pneumophila
– natural and artificial water supplies
– multiplies intracellularly
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Pertussis
• Whooping cough
• Bordatella pertussis
– Pathogenesis
• replication of bacteria
• production of toxins
– Symptoms
• characteristic cough (whooping)
• cold symptoms
• vomiting (intense cough)
– vaccine
• acellular vaccine (DPT)
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Tuberculosis
• Mycobacterium tuberculosis
– pathogenesis
• inflammation and lesions of lung
tissue
• cellular immune (TC) response
• slow growth rate
– Symptoms
• varies
• primary lesions
• can spread to various tissues
– Treatment
• prolonged multiple antibiotics (6
months)
Figure 22.9
– Increase incidence (drug
resistance)
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Influenza (flu)
• Influenza virus types A, B, C
– Epidemiology
• annual epidemics and occasional pandemics
– antigenic drift and antigenic shift
– Symptoms
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virus inhaled
1-3 days after exposure
sudden onset of fever 102-104oF
malaise, headache, muscle ache, cough
– Treatment
• uncomplicated recovery in few weeks
• prevent secondary infections--pneumonia,
• immunization
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Bronchitis
• Croup
– Parainfluenza virus
– Symptoms
• loud, barking cough
• Bronchiolitis
– Respiratory syncytial virus
– Paramyxovirus
• Subtype B: asymptomatic strains
• Subtype A: predominate in most outbreaks
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Hantavirus Pulmonary Syndrome
• May 1993 outbreak
– Four corners area of Southwest US
– 70% victims died
• many healthy
• lung failure
– capillaries leaked-filling air space
Figure 22.12
– Identified virus
• Sin Nombre virus
• new strain of Hantavirus
– reservoir
• deer mice and other rodents
– isolates
• worldwide
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Fungal Infections
• Histoplasmosis
– Histoplasma
capsulatum
– dimorphic
– distribution
• worldwide
• certain areas
– 1% infected
become ill
Figure 22.13
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Fungal Infections
• Coccidioidomycosis
– semiarid climates
– spores inhaled into
alveoli
Figure 22.14
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Fungal infections
• Blastomycosis
– humans and animals
– clinical syndrome
• resembles tuberculosis
• distant organs--skin, bone, testes
• Pneumocystic pneumonia (PCP)
– AIDS associated
• rarely seen before 1980’s
• most common cause of death with AIDS
– cysts in lung
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