Transcript Infections of the Upper Respiratory Tract

Infections
of the
Upper Respiratory Tract
Cynthia L. Gibert, M.D.
Washington VA Medical Center
10/2/98
Upper Respiratory Infections
• Upper respiratory tract infections are the
most common human affliction.
• Major share of time lost from work and
school.
• Most common cause of antibiotic abuse.
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Upper Respiratory Infections
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Influenza
Epiglottitis
Sinusitis
The Common Cold
Influenza
• Virus isolated in 1933
• A major cause of morbidity and mortality
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Spanish Flu Pandemic of 1918
• Sept. - Nov. 1918
• 20-40 million deaths
• More Americans died than in the WWI,
WW2, Korea, Vietnam
• 1st case Camp Fuston, Kansas - 3/4/18
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Influenza A Pandemics
1918 - 1919
Spanish
H1N1
1957 - 1958
Asian
H2N2
1968 - 1969
Hong Kong
H3N2
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Influenza A
13 Hemagglutinin subtypes
9 Neuraminadase subtypes
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Epidemiologic Characteristics
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Pandemics
Epidemics
Endemic
Seasonal
Age
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Worldwide - antigenic shift
Local - antigenic drift
Sporadic
Winter months - abrupt
Infection: children > adults
Mortality: adults > children
Pathogenesis
• Virus replication: 24 - 72 hours
• Virus excretion: 3 - 7 days
• Antibodies to HA, NA subtypes
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Clinical Picture of Influenza
Chills
Fever
Myalgias
Cough
Coryza
Malaise
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Secondary Bacterial Pathogens
• S. pneumoniae
• H. influenzae
• S. aureus - Toxin Shock Syndrome
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Reye’s Syndrome
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Post influenza B
Encephalopathy
Hepatic dysfunction
Elevate NH3, LFTs, CPK
Influenza Vaccine
Trivalent vaccine
• A/Beijing/262/95-like (H1N1)
• A/Sydney/5/97-like (H3N2)
• B/Harbin/07/94
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Indications for Vaccine
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Elderly (age>65)
High-risk*
Household contacts
Health-care personnel
Pregnant women after 14th week
High-risk: institutionalized, chronic heart or lung disease, diabetes,
renal dysfunction, immunosuppressed, children on aspirin
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Influenza Vaccine
• Timing: October - Mid-November
• Duration of immunity:
start 1-2 weeks
end 4-6 months
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Diagnosis
• Viral culture - tissue culture
• Fluorescent-labeled murine monoclonal
Ab - shell viral cell culture - viral Ag
• PCR
• CF - at onset and 2 weeks
4-fold-rise in Ab titre
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Treatment of Influenza A
Amantadine or rimantadine within 48 hours
decreases fever and severity
• Use in elderly or high risk
• Hospitalized persons
• Healthy adults
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Prophylaxis of Influenza A
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Control of outbreaks in institutions
Adjunct to late vaccination
Immunodeficient - AIDS
Vaccine contraindicated
Home caregivers of high risk
Epiglottitis - Acute Supraglottitis
• A rapidly progressive and potentially
fatal disease that must be recognized
immediately.
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Epiglottitis
• Epidemiology:
– most common in children 3-7 yrs.
– decreased incidence because of Hib conjugate
vaccine-stable rate in adults
• Rate:
– 1 in 1000-2000 pediatric admissions
– 1 in 100,000 adult admissions
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Differential Diagnosis
of a Sore Throat
• Peritonsillar abscess
– sore throat, drooling, hoarseness, trismus, asymmetric tonsillar
enlargement
• Epiglottitis
– Children: high fever, toxic, drooling, absence of cough
– Adult: severe sore throat, dyshagia, fever
• Infectious mononucleosis
– tonsillar enlargement, exudative tonsillitis, pharyngeal inflammation,
lymphadenopathy, splenomegaly, maculopapular rashes, petechial
anathema
• Parapharyngeal space infection
– neck swelling after a sore throat
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Epiglottitis - Pathogenesis
• Haemophilus influenzae type b,
S. pneumoniae, S. aureus, H. influenzae
type non-b, H. parainfluenzae
• Inflammation and edema of the epiglottis,
arytenoids, arytenoepiglottic folds, subglottic
area
• Epiglottis pulled down into larynx and
occludes the airway
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Epiglottitis
Clinical Manifestations
• Abrupt onset - sore throat, fever, toxicity
dysphagia, drooling, stridor, chest wall
retractions
• Beefy-red epiglottis
• Inspiratory stridor and expiratory ronchi
• Adults: muffled voice, drooling
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Epiglottitis - Diagnosis
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Visualization of epiglottis - “cherry red”
Laternal neck x-rays: “thumb sign”
WBC count > 15,000 left shift
Blood cultures
Differential Diagnosis
• Viral croup - barking cough, less abrupt, less
toxic
• Bacterial tracheitis - S. aureus, H. influenzae,
Strept., diphtheria
• Aspiration of a foreign body
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Therapy
• Adequate airway - nasotracheal intubation
• Adults - close observation
• Antibiotics
– cefuroxime, ceftriaxone
– ampicillin resistance - up to 30%
– chloramphenicol
? Corticosteroids - reduce postintubation
inflammation
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Prevention
Rifampin - 20 mg/kg for 4 days
• All household contacts if children under 4
• Daycare and nursery school contacts
• Patient before discharge
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Sinusitis - Clinical Findings
• Viral URI, fever (50%), purulent nasal
discharge, swelling, facial pain worse on
percussion, headache, nasal obstruction,
loss of smell
• Children: facial pain, swelling, malodorous
breath (50%), cough (80%), nasal discharge
(76%), fever (63%), sore throat (23%)
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Specific Clinical Criteria
• Maxillary toothache, colored nasal discharge,
poor response to nasal decongestants,
abnormal transillumination, purulent
secretions, cough > 7 days
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Diagnosis
• Nasal swabs not helpful
• Transillumination of maxillary and frontal sinuses
• Sinus x-rays: air-fluid level, complete opacity,
mucosal thickening
• CT scan not indicated - unless chronic infection,
immunocompromised, suspected intracranial or
orbital complication
• Direct sinus aspiration
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Factors that
Predispose to Sinusitis
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Impaired mucociliary function
Obstruction of sinus ostia
Immune defects
Increased risk of microbial invasion
Microbial Causes of
Acute Maxillary Sinusitis
PREVALENCE MEAN (RANGE)
MICROBIAL AGENT (Bacteria)
Streptococcus pneumoniae
Haemophilus influenzae
(nonencapsulated)
S. pneumoniae and H. influenzae
Anaerobes (Bacteroides, Fusobacterium,
Peptostreptococcus, Veillonella)
Staphylococcus aureus
Streptococcus pyogenes
Branhamella (Moraxella) catarrhalis
Gram-negative bacteria
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Adults
(%)
31 (20-35)
21 (6-26)
Children
(%)
36
23
5 (1-9)
6 (0-10)
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4 (0-8)
2 (1-3)
2
9 (0-24)
-2
19
2
Microbial Causes of
Acute Maxillary Sinusitis
MICROBIAL AGENT
Viruses
Rhinovirus
Influenza virus
Parainfluenza virus
Adenovirus
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PREVALENCE MEAN (RANGE)
Adults
Children
(%)
(%)
15
5
3
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Decongestants
• Oxymetazoline HCL - TID for 48-72 hours
• Pseudoephedrine HCL - only if allergic
component
• Nasal steroids for 2-3 weeks
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Therapy
Empiric antibiotics for 10 days
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Amoxicillin/ampicillin
TMP/SMX
Cephalosporin - cefaclor, cefuroxime
Azithromycin, clarithromycin
Chronic Sinusitis
• Symptoms for > 3 months
Allergies, inadequately treated
• Aerobes and anaerobes
• ENT evaluation for endoscopy or CT
• Antibiotics for 3-4 weeks
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Caveat
• Frontal sinusitis with tenderness and
headache - thin barrier to CNS
• Treat 10-14 days
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Ethmoid and Sphenoid Sinusitis
• Ethmoid sinusitis: edema of eyelids, tearing,
retroorbital pain, proptosis
• Sphenoid sinusitis: intractable headache,
hypo/hyperesthesia of ophthalmic or
maxillary branches of trigeminal n. (30%)
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Cavernous Sinus Thrombosis
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Depressed mental status
Meningeal irritation
Ptosis, chemosis
Proptopsis
C.N. palsies - III, IV, VI
Intracranial Complications
of Sinusitis
Complication
• Meningitis
• Osteomyelitis
• Epidural abscess
• Subdural empyema
• Cerebral abscess
• Venous sinus thrombosis
• Cavernous sinus
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Clinical Signs
Headache, fever, stiff neck
lethargy, rapid death
Pott’s puffy tumor
Headache, fever
Headache, seizures
hemiplegia, rapid death
Convulsions, headache,
personality change
Picket-fence fever, rapid death
Orbital edema, ocular palsies
The Common Cold
• Hippocrates:
– rejected bleeding
• Pliny the Younger:
– kiss the hairy muzzle of a mouse
• Ben Franklin:
– not from exposure to cold/dampness;
– close contact
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Epidemiology
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65 million colds per year
150 million days of restricted activity
24 million medical visits
18 million days lost from work
22 million days missed from school
Virology
Over 200 viruses
Virus type
Andenoviruses
Coronaviruses
Influenza viruses
Parainfluenza viruses
Respiratory syncytial virus
Rhinoviruses
Enteroviruses
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Serotypes
41
2
3
4
1
100+
60+
Seasonal Variation
• May-Aug
• Sept-Dec
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• Jan-Feb
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• Mar-Apr
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Enteroviruses
Mycoplasma, Rhinoviruses,
Parainf. 1+2, RSV
Adenoviruses, Influenza,
Coronaviruses
Parainf. 3, Rhinoviruses
Transmission
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Direct contact with infected secretions
Hand - to - hand
Hand - to environmental surface - to hand
Spread by aerosoles
Pathogenesis
• Incubation period
1 - 4 days
• Begins in posterior pharynx
• Viral shedding
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days 3 - 4
Clinical Presentation
Dry, scratchy, sore throat
Sneezing, nasal stuffiness, rhinorrhea
Malaise, myalgia, headache
Hoarseness, cough, low grade fever
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Complications
• Bacterial superinfection
– Otitis media
– Sinusitis
– S. pneumoniae, H. influenzae, B. catarrhalis
• Guillain-Barre Syndrome
• Asthma attacks
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Management
• Throat culture, rapid Ag detection for
group A strep
• Diagnosis of influenza A, RSV
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Use of Antibiotics
• No benefit
• Do not reduce bacterial complications
• Emergence of resistant organisms
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Aspirin and Influenza
• Aspirin - prolonged excretion of
rhinoviruses, influenza virus
• Children - aspirin associated with Reye’s
syndrome
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Prevention
• Vaccines
– influenza A/B
– adenoviruses types 4,7
• Intranasal interferon
– rhinoviruses
– nasal obstruction, bloody discharge
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