10/2/98

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

• Influenza

• Epiglottitis

• Sinusitis

• The Common Cold

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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

• Pandemics Worldwide - antigenic shift• Epidemics Local - antigenic drift• Endemic Sporadic• Seasonal Winter months - abrupt• Age Infection: children > adults

Mortality: adults > children

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Pathogenesis

• Virus replication: 24 - 72 hours

• Virus excretion: 3 - 7 days

• Antibodies to HA, NA subtypes

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Clinical Picture of Influenza

0 1 2 3 4 5 6 7 8

Malaise

Coryza

Cough

Myalgias

Fever

Chills

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Secondary Bacterial Pathogens

• S. pneumoniae

• H. influenzae

• S. aureus - Toxin Shock Syndrome

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Reye’s Syndrome

• Post influenza B

• Encephalopathy

• Hepatic dysfunction

• Elevate NH3, LFTs, CPK

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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

• 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

• Control of outbreaks in institutions

• Adjunct to late vaccination

• Immunodeficient - AIDS

• Vaccine contraindicated

• Home caregivers of high risk

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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

• Visualization of epiglottis - “cherry red”

• Laternal neck x-rays: “thumb sign”

• WBC count > 15,000 left shift

• Blood cultures

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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

• Impaired mucociliary function

• Obstruction of sinus ostia

• Immune defects

• Increased risk of microbial invasion

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Microbial Causes of Acute Maxillary Sinusitis

PREVALENCE MEAN (RANGE)

Adults Children

MICROBIAL AGENT (Bacteria) (%) (%)

Streptococcus pneumoniae 31 (20-35) 36

Haemophilus influenzae 21 (6-26) 23

(nonencapsulated)

S. pneumoniae and H. influenzae 5 (1-9) --

Anaerobes (Bacteroides, Fusobacterium, 6 (0-10) --

Peptostreptococcus, Veillonella)

Staphylococcus aureus 4 (0-8) --

Streptococcus pyogenes 2 (1-3) 2

Branhamella (Moraxella) catarrhalis 2 19

Gram-negative bacteria 9 (0-24) 2

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Microbial Causes of Acute Maxillary Sinusitis

PREVALENCE MEAN (RANGE)

Adults Children

MICROBIAL AGENT (%) (%)

Viruses

Rhinovirus 15 --

Influenza virus 5 --

Parainfluenza virus 3 2

Adenovirus -- 2

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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

• Amoxicillin/ampicillin

• TMP/SMX

• Cephalosporin - cefaclor, cefuroxime

• Azithromycin, clarithromycin

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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

• Depressed mental status

• Meningeal irritation

• Ptosis, chemosis

• Proptopsis

• C.N. palsies - III, IV, VI

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Intracranial Complications of Sinusitis

Complication Clinical Signs• Meningitis Headache, fever, stiff neck

lethargy, rapid death• Osteomyelitis Pott’s puffy tumor• Epidural abscess Headache, fever• Subdural empyema Headache, seizures

hemiplegia, rapid death• Cerebral abscess Convulsions, headache,

personality change• Venous sinus thrombosis Picket-fence fever, rapid death• Cavernous sinus Orbital edema, ocular palsies

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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

• 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

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VirologyOver 200 viruses

Virus type SerotypesAndenoviruses 41

Coronaviruses 2

Influenza viruses 3

Parainfluenza viruses 4

Respiratory syncytial virus 1

Rhinoviruses 100+

Enteroviruses 60+

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Seasonal Variation

• May-Aug - Enteroviruses

• Sept-Dec - Mycoplasma, Rhinoviruses,

Parainf. 1+2, RSV

• Jan-Feb - Adenoviruses, Influenza, Coronaviruses

• Mar-Apr - Parainf. 3, Rhinoviruses

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Transmission

• Direct contact with infected secretions

• Hand - to - hand

• Hand - to environmental surface - to hand

• Spread by aerosoles

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Pathogenesis

• Incubation period 1 - 4 days

• Begins in posterior pharynx

• Viral shedding days 3 - 4

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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