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Infections of the Upper Respiratory Tract

Infections of the Upper Respiratory Tract. Cynthia L. Gibert, M.D. Washington VA Medical Center. 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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Infections of the Upper Respiratory Tract

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  1. Infections of the Upper Respiratory Tract Cynthia L. Gibert, M.D. Washington VA Medical Center

  2. 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.

  3. Upper Respiratory Infections • Influenza • Epiglottitis • Sinusitis • The Common Cold

  4. Influenza • Virus isolated in 1933 • A major cause of morbidity and mortality

  5. 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

  6. Influenza A Pandemics 1918 - 1919 Spanish H1N1 1957 - 1958 Asian H2N2 1968 - 1969 Hong Kong H3N2

  7. Influenza A 13 Hemagglutinin subtypes 9 Neuraminadase subtypes

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

  9. Pathogenesis • Virus replication: 24 - 72 hours • Virus excretion: 3 - 7 days • Antibodies to HA, NA subtypes

  10. Clinical Picture of Influenza

  11. Secondary Bacterial Pathogens • S. pneumoniae • H. influenzae • S. aureus - Toxin Shock Syndrome

  12. Reye’s Syndrome • Post influenza B • Encephalopathy • Hepatic dysfunction • Elevate NH3, LFTs, CPK

  13. Influenza Vaccine Trivalent vaccine • A/Beijing/262/95-like (H1N1) • A/Sydney/5/97-like (H3N2) • B/Harbin/07/94

  14. 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

  15. Influenza Vaccine • Timing: October - Mid-November • Duration of immunity: start 1-2 weeks end 4-6 months

  16. 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

  17. Treatment of Influenza A Amantadine or rimantadine within 48 hours decreases fever and severity • Use in elderly or high risk • Hospitalized persons • Healthy adults

  18. Prophylaxis of Influenza A • Control of outbreaks in institutions • Adjunct to late vaccination • Immunodeficient - AIDS • Vaccine contraindicated • Home caregivers of high risk

  19. Epiglottitis - Acute Supraglottitis • A rapidly progressive and potentially fatal disease that must be recognized immediately.

  20. 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

  21. 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

  22. 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

  23. 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

  24. Epiglottitis - Diagnosis • Visualization of epiglottis - “cherry red” • Laternal neck x-rays: “thumb sign” • WBC count > 15,000 left shift • Blood cultures

  25. Differential Diagnosis • Viral croup - barking cough, less abrupt, less toxic • Bacterial tracheitis - S. aureus, H. influenzae, Strept., diphtheria • Aspiration of a foreign body

  26. Therapy • Adequate airway - nasotracheal intubation • Adults - close observation • Antibiotics • cefuroxime, ceftriaxone • ampicillin resistance - up to 30% • chloramphenicol ? Corticosteroids - reduce postintubation inflammation

  27. Prevention Rifampin - 20 mg/kg for 4 days • All household contacts if children under 4 • Daycare and nursery school contacts • Patient before discharge

  28. 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%)

  29. Specific Clinical Criteria • Maxillary toothache, colored nasal discharge, poor response to nasal decongestants, abnormal transillumination, purulent secretions, cough > 7 days

  30. 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

  31. Factors that Predispose to Sinusitis • Impaired mucociliary function • Obstruction of sinus ostia • Immune defects • Increased risk of microbial invasion

  32. 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

  33. 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

  34. Decongestants • Oxymetazoline HCL - TID for 48-72 hours • Pseudoephedrine HCL - only if allergic component • Nasal steroids for 2-3 weeks

  35. Therapy Empiric antibiotics for 10 days • Amoxicillin/ampicillin • TMP/SMX • Cephalosporin - cefaclor, cefuroxime • Azithromycin, clarithromycin

  36. Chronic Sinusitis • Symptoms for > 3 months Allergies, inadequately treated • Aerobes and anaerobes • ENT evaluation for endoscopy or CT • Antibiotics for 3-4 weeks

  37. Caveat • Frontal sinusitis with tenderness and headache - thin barrier to CNS • Treat 10-14 days

  38. 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%)

  39. Cavernous Sinus Thrombosis • Depressed mental status • Meningeal irritation • Ptosis, chemosis • Proptopsis • C.N. palsies - III, IV, VI

  40. Intracranial Complications of Sinusitis ComplicationClinical 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

  41. 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

  42. 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

  43. VirologyOver 200 viruses Virus type Serotypes Andenoviruses 41 Coronaviruses 2 Influenza viruses 3 Parainfluenza viruses 4 Respiratory syncytial virus 1 Rhinoviruses 100+ Enteroviruses 60+

  44. Seasonal Variation • May-Aug - Enteroviruses • Sept-Dec - Mycoplasma, Rhinoviruses, Parainf. 1+2, RSV • Jan-Feb - Adenoviruses, Influenza, Coronaviruses • Mar-Apr - Parainf. 3, Rhinoviruses

  45. Transmission • Direct contact with infected secretions • Hand - to - hand • Hand - to environmental surface - to hand • Spread by aerosoles

  46. Pathogenesis • Incubation period 1 - 4 days • Begins in posterior pharynx • Viral shedding days 3 - 4

  47. Clinical Presentation Dry, scratchy, sore throat Sneezing, nasal stuffiness, rhinorrhea Malaise, myalgia, headache Hoarseness, cough, low grade fever

  48. Complications • Bacterial superinfection • Otitis media • Sinusitis • S. pneumoniae, H. influenzae, B. catarrhalis • Guillain-Barre Syndrome • Asthma attacks

  49. Management • Throat culture, rapid Ag detection for group A strep • Diagnosis of influenza A, RSV

  50. Use of Antibiotics • No benefit • Do not reduce bacterial complications • Emergence of resistant organisms

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