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35 Cards in this Set
- Front
- Back
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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 |
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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 |
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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 |
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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 |
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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 |
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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 |
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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 |
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Diphtheria
Causative Agent |
– Corynebacterium diphtheria
– Variably shaped – Gram-positive – Non-spore forming – Certain strains produce diphtheria toxin (phage dependent) |
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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 |
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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 |
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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 |
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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 |
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Pinkeye
Symptoms |
• Increased tears and redness
• Swelling eyelids • Sensitivity to bright light • Large amounts of pus |
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Sinusitis
Symptoms |
• Pain and pressure
– Generally localized to involved sinus • Tenderness over sinus • Headache • Severe malaise |
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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 |
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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 |
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Earache and Sinus Infections
Causative Agents |
• Mycoplasma pneumoniae
• Streptococcus pyogenes • Staphylococcus aureus – One-third of cases of otitis media have viral etiology |
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Pinkeye
Pathogenesis |
• Few details known about pathogenesis of bacterial conjunctivitis
– Most likely from airborne respiratory droplets – Resist destruction by lysozyme |
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Sinusitis
Pathogenesis |
• Begins with infection of
nasopharynx • Spreads upwards to sinuses • Pathogenesis mechanism much like that of otitis media |
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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 |
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Pinkeye, Earache and Sinus Infections - Epidemiology
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– 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 |
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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 |
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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 |
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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 |
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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 |
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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 |
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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 |
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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 |
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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 |
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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 |
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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 |
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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 |
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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 |
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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 |
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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 |
