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35 Cards in this Set

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Streptococcal Pharyngitis
Symptoms
Characterized by
• Difficulty swallowing
• Fever
• Red throat with pus patches
• Enlarged tender lymph nodes – Localized to neck

– Most patients recover uneventfully in approximately a week
Streptococcal Pharyngitis
Causative Agent
– Streptococcus pyogenes
• Gram-positive
• Coccus in chains
• β hemolytic – Complete hemolysis of
red blood cells
• Commonly referred to as group A streptococcus
– Due to group A carbohydrate in cell wall
– Basis for identification from other organisms
Streptococcal Pharyngitis
Pathogenesis
– Causes a wide variety of illnesses
• Due to bacteria-producing enzymes and toxin that destroy cells
– Complications of infection can occur during acute illness
– Examples include scarlet fever and quinsy (peritonsilar abscess)
– Certain complications can develop late
• Acute glomerulonephritis
• Acute rheumatic fever
Streptococcal Pharyngitis
Epidemiology
– Spread readily by respiratory droplets
• Especially in range of 2 to 5 feet – Nasal organism spreads more effectively than
pharyngeal carriers
• Anal carriers not common
– Dangerous source of nosocomial infections

– Peak incidence occurs in winter or spring
• Highest in grade school children
Streptococcal Pharyngitis
Prevention
– No vaccine available
• New possibilities on horizon
– Adequate ventilation
– Avoid crowds
– Sore throats in presence of fever should be cultured (tested) for prompt treatment
Streptococcal Pharyngitis
Treatment
– Confirmed strep throat treated with 10 days of antibiotics
• Penicillin or erythromycin are drugs of choice
– Eliminates organisms in 90% of cases
Diptheria
Symptoms
-Usually begins with mild sore throat and slight fever,
fatigue and malaise and dramatic neck swelling
– Whitish membrane forms on tonsils, or in nasal cavity
– Most strains release diphtheria toxin
– Toxin is produced in low iron environments
Diphtheria
Causative Agent
– Corynebacterium diphtheria
– Variably shaped
– Gram-positive
– Non-spore forming
– Certain strains produce diphtheria toxin (phage dependent)
Diphtheria
Pathogenesis
– Little invasive ability
• Exotoxin released into bloodstream
– Results in damage to heart, nerves and kidneys

– Diphtheria toxin
• Released from bacteria in inactive form
• Cleaved into A and B chains
– B attaches to host cell membrane and enters through endocytosis
– A chain becomes active enzyme that inhibits proteins synthesis
– Small amount of enzyme inactivates large population of cells which explains potency
Diphtheria
Epidemiology
– Humans are primary reservoir
– Spread by air
• Acquired through inhalation

– Sources of infection include • Carriers who recovered from infection
• Asymptomatic cases
• People with active disease
• Contaminated fomites

– Bacterium can be carried in chronic skin ulcer
• Cutaneous diphtheria
Diphtheria
Prevention
– Disease results primarily from toxin absorption
• Not microbial invasion
– Prevention directed at immunization
• DPT - Neutralize toxin – Immunity wanes after
childhood
• Booster immunization should be given every 10 years
Diphtheria
Treatment
– Effectiveness depends on early antiserum treatment
• Delay in treatment may be fatal
– Antibiotics are given to eliminate bacteria
• Penicillin and erythromycin
• Stops transmission of disease
– No effect on absorbed toxin
– Even in presence of treatment 1 in 10 patients die
Pinkeye
Symptoms
• Increased tears and redness
• Swelling eyelids
• Sensitivity to bright light
• Large amounts of pus
Sinusitis
Symptoms
• Pain and pressure
– Generally localized to involved sinus
• Tenderness over sinus
• Headache
• Severe malaise
Earache (Otitis media)
Symptoms
• More common in young
children
• Extreme ear pain
• Mild fever
– Fever may even be absent
• Vomiting – Often at the height of ear
pain
• In many cases ear drum ruptures
– Trapped fluid drains to external ear canal
– Pain ends abruptly
Pinkeye, Earache and Sinus Infections
Causative Agent
– Haemophilus influenza
• Gram-negative bacillus
– Streptococcus pneumoniae
• Gram-positive diplococci
• A.k.a pneumococcus
– Both are most common cause of all three conditions
Earache and Sinus Infections
Causative Agents
• Mycoplasma pneumoniae
• Streptococcus pyogenes
• Staphylococcus aureus

– One-third of cases of otitis media have viral etiology
Pinkeye
Pathogenesis
• Few details known about pathogenesis of bacterial conjunctivitis
– Most likely from airborne respiratory droplets
– Resist destruction by lysozyme
Sinusitis
Pathogenesis
• Begins with infection of
nasopharynx
• Spreads upwards to sinuses
• Pathogenesis mechanism much like that of otitis media
Otitis media
Pathogenesis
• Often developing at the time of conjunctivitis diagnosis
• Begins with infection of nasal chamber and nasopharynx
– Infection moves to middle ear and damages ciliated cells in ear
• Ear drum often bursts
– Gives immediate relief of pain
Pinkeye, Earache and Sinus Infections - Epidemiology
– Carrier rates of H. influenza and S. pneumoniae can reach 80%
– Epidemics of pinkeye common among school children
• Generally in crowded environments – Otitis media very common in early childhood
• Older children develop immunity to H. influenza – Less common cause of earache after age five
– Sinusitis occurs in adults and older children
• Generally due to more developed sinuses
Pinkeye
Prevention and Treatment
• Prevention is directed towards
– Removal of infected individuals from school or day care – Hand washing – Avoid rubbing or touching eyes – Avoid sharing towels
• Treatment is achieved through eyedrops or ointments containing antibacterial medications
Otitis media
Prevention and Treatment
• Prevention is directed
towards
– Administration of influenza vaccine to infants in day care facilities during “flu” season
» Reduces incidences of earache
• Treatment includes
– Antibiotic therapy
» Amoxicillin
Sinusitis
Prevention and Treatment
• There are no proven preventative measures for sinusitis
• Treatment is directed at support care
– Decongestants and antihistamines are generally discouraged
» Ineffective and can be harmful
Common Cold
Symptoms
– Malaise
– Scratchy mild sore throat
– Runny nose
– Cough and hoarseness
– Nasal secretion
• Initially profuse and
watery
• Later, thick and purulent
• No fever
– Unless complicated with secondary infection
– Symptoms disappear in about a week
Common Cold
Causative Agent
– 30% to 50% caused by rhinovirus
• More than 100 serotypes of rhinovirus
• Member of picornavirus family
• Small
• Non-enveloped
• Single-stranded RNA genome
Common Cold
Pathogenesis
– Virus attaches to specific receptors on respiratory epithelial cells and multiplies in cells
– Injured cells cause inflammation which stimulates profuse nasal secretion, sneezing and tissue swelling
– Infection is halted by inflammatory response, interferon release and immune response
Common Cold
Epidemiology
– Humans are only source for cold virus
– Close contact with infected person or secretions
usually necessary for transmission
– Young children transmit cold virus easily
– NO reliable relationship between exposure to cold temperature and development of a cold
Common Cold
Prevention
– No vaccine
Common Cold
• Treatment
• Too many different types of rhinovirus
– Makes vaccination impractical
– Prevention directed at
• Hand washing
• Keeping hands away from face
• Avoiding crowds during times when colds are prevalent
Common Cold
Treatment
– Antibiotic therapy is ineffectual
– Certain antiviral medications show promise
• Must be taken at first onset of symptoms
– Treatment with over-the- counter medications may prolong duration due to inhibition of inflammation
Adenoviral Pharyngitis
Symptoms
Symptoms:
– Runny nose
– Fever
– Sore throat
• Often accompanied with pus
on the pharynx and tonsils
– Lymph nodes in neck enlarged and tender
– Certain strains of virus cause hemorrhagic conjunctivitis
– Mild cough is common with infection
• Cough may worsen; indication of complicating disease
– Infection usually resolves in 1 to 3 weeks
• With or without treatment
Adenoviral Pharyngitis
Causative Agent
– Adenovirus
• 45 types infect humans
• Non-enveloped
• Double-stranded DNA genome
• Remains infectious in environment for extended periods
• Transmitted easily on medical instruments
• Inactivated easily with heat and various disinfectants
Adenoviral Pharyngitis
Pathogenesis
– Virus infects epithelial cells
• Attaches to specific surface receptors
• Multiplies in cell nucleus
• Cells escape to epithelial surface
• Cell destruction initiates inflammation
– Different viruses affect different tissues
• Adenovirus type 4 causes sore throat and lymph
node enlargement
• Adenovirus type 8 causes extensive eye infection
Adenoviral Pharyngitis
Epidemiology
– Human is only source of infection
– Common among school children
• Usually sporadic; however, outbreaks do occur
• Most common in winter and spring
– Summer outbreaks linked to inadequately chlorinated
swimming pools

– Virus spread by respiratory droplets
– Epidemic spread promoted by high number of asymptomatic carriers
Adenoviral Pharyngitis
Prevention and Treatment
– Prevention is the same as the common cold
– There is no treatment
• Patients usually recover uneventfully
• Bacterial secondary infections may occur requiring antibiotics for treatment