Upper Respiratory Tract InfectionsUpper Respiratory Tract Infections

Charles S. Bryan, M.D.November 20, 2007

Burden of URIBurden of URI

Up to ½ of all symptomatic illness

Significant morbidity and direct health care costs

Occasionally leads to fatal illness

Excessive use of antibiotics a major issue

The Common ColdThe Common Cold

Children average 8 per year, adults 3 Rhinoviruses 30 to 35%; coronaviruses about

10%, miscellaneous known viruses about 20%, presumed undiscovered viruses up to 35%, group A streptococci 5% to 10%

Sinusitis often present by CT scan; “rhinosinusitis” might be a better term

The common coldThe common cold

Transmission of rhinovirusesTransmission of rhinoviruses Direct contact is the most efficient means of

transmission: 40% to 90% recovery from hands.

Brief exposure (e.g., handshake) transmits in less than 10% of instances

Kissing does not seem to be a common mode of transmission.

Severe acute respiratory Severe acute respiratory distress syndrome (SARS)distress syndrome (SARS)

Caused by a previously unrecognized coronavirus—genome has now been sequenced.

Clinical manifestations are similar to those of other acute respiratory illnesses—notably, influenza

Cases in U.S.—associated mainly with travel or as secondary contacts

SARS: CDC case definition (2003)SARS: CDC case definition (2003)

Respiratory illness of unknown etiology AND Measured temperature > 100.4 degrees F (38

degrees C) AND One or more clinical findings of respiratory illness

AND Travel within 10 days of onset of symptoms to an

area with documented or suspected cases OR close contact with a case

SARS: Case definition (2)SARS: Case definition (2)

Clinical findings of respiratory illness: cough, SOB, dyspnea, hypoxia, or radiographic findings of either pneumonia or ARDS

Travel includes certain areas (mainland China, Hong Kong, Hanoi, Singapore) and also airports with documented or suspected community transmission

SARS: Radiographic findingsSARS: Radiographic findings Early: a peripheral/pleural-based

opacity (ground-glass or consolidative) may be the only abnormality. Look especially at retrocardiac area.

Advanced: widespread opacification (ground-glass or consolidative) tending to affect the lower zones and often bilateral.

Pleural effusions, lymphadenopathy, and cavitation are not seen.

SARS: Hypothetical disease modelSARS: Hypothetical disease model((Emerg Infect DisEmerg Infect Dis 2003; 9: 1064-1069) 2003; 9: 1064-1069)

Phase 1: viral replication Phase 2: immune hyperactivity with cytokine

deregulation (hence, the theoretical justification for corticosteroid therapy)

Phase 3: Pulmonary destruction

Dr. Carlo Urbani (1956-2003)Dr. Carlo Urbani (1956-2003) 2/28/03: Recognized

SARS while examining a patient in Hanoi.

Identified outbreak and raises the alarm.

Stayed caring patients despite multiple illnesses in staff—sent wife and three children back to Italy

3/29/03: Died of SARS

Acute bacterial sinusitisAcute bacterial sinusitis Viral infection--> obstruction of ducts and

compromise of mucocilary blanket--> acute infection from virulent organisms (most often S. pneumoniae and H. influenzae)--> opportunistic pathogens

Complicates 0.5% of common URI More common in adults than in children

Paranasal sinusesParanasal sinuses

Waters view (left); Coronal CTWaters view (left); Coronal CT

Acute sinusitis: complications Acute sinusitis: complications

Maxillary: usually uncomplicated Ethmoid: cavernous sinus thrombosis

(40% mortality) Frontal: osteomyelitis of frontal bone;

cavernous sinus thrombosis; epidural, subdural, or intracerebral abscess; orbital extension

Acute sinusitis: complications (2)Acute sinusitis: complications (2)

Sphenoid: Rare, but usually misdiagnosed, with grave consequences; extension to internal carotid artery, cavernous sinuses, pituitary, optic nerves; common misdiagnoses include ophthalmic migraine, aseptic meningitis, trigeminal neuralgia, cavernous sinus thrombosis

Chronic sinusitisChronic sinusitis

Bacterial: Cultures show a variety of opportunistic pathogens including anaerobes but problem is mainly anatomic, not microbiologic

Fungal: suspect especially when a single sinus is involved; syndromes associated with nasal polyposis can have high morbidity

Spectrum of fungal sinusitisSpectrum of fungal sinusitis

Simple colonization Sinus mycetoma (fungus

ball) Allergic fungal sinusitis Acute (fulminant) invasive

sinusitis (notably, rhinocerebral mucormycosis)

Chronic invasive fungal sinusitis

Otitis externaOtitis externa Acute, localized: often S. aureus or S.

pyogenes Acute diffuse (swimmer’s ear): gram-

negative rods, especially Ps. aeruginosa Chronic: mainly with chronic otitis media Malignant: life-threatening infection in

diabetics; Pseudomonas aeruginosa

Otitis externaOtitis externa Acute, localized: often S. aureus

or S. pyogenes Acute diffuse (swimmer’s ear):

gram-negative rods, especially Ps. aeruginosa

Chronic: mainly with chronic otitis media

Malignant: life-threatening infection in diabetics; Pseudomonas aeruginosa

Malignant otitis externaMalignant otitis externa

Diabetes mellitus Pseudomonas

aeruginosa Osteomyelitis of

the temporal bone Involvement of

vital structures at base of brain

Acute otitis mediaAcute otitis media

S. pneumoniae and H. influenzae the leading causes in all age groups

Moraxella catarrhalis: ? emerging role Some case may be viral Mycoplasma pneumoniae:

inflammation of the tympanic membrane (“bullous myringitis”)

Acute otitis mediaAcute otitis media

Critical role of eustachian tube as conduit between nasopharynx, middle ear, and mastoid air cells

Children have shorter, wider eustachian tubes than adults

Chronic otitis media and mastoiditisChronic otitis media and mastoiditis

Prolonged middle ear effusions in patients with previous episodes of acute otitis media. Often “skin flora” or anaerobic organisms

Mastoiditis: Less common nowadays. formerly severe complications. Often anaerobic.

Acute pharyngitis: physical examAcute pharyngitis: physical exam

Viral: edema and hyperemia of tonsils and pharyngeal mucosa

Streptococcal: exudate and hemorrhage involving tonsils and pharyngeal walls

Epstein-Barr virus (infectious mono): may also cause exudate, with nasopharyngeal lymphoid hyperplasia

Acute pharyngitis: physical exam (2)Acute pharyngitis: physical exam (2)

Adenoviruses: exudate may sometimes be present

Herpes simplex virus and some coxsackie A infections: vesiculation and mucosal ulceration may be present

Diphtheria: fibrous pseudomembrane with necrotic epithelium and leukocytes

Pharyngoconjuntival feverPharyngoconjuntival fever

Adenoviral pharyngitis Pharyngeal erythema and exudate may

mimic streptococcal pharyngitis Conjunctivitis (follicular) present in

1/3 to 1/2 of cases; commonly unilateral but bilateral in 1/4 of cases

HerpanginaHerpangina

Uncommon Due to coxsackieviruss Small, 1-2 mm vesicles on the soft

palate, uvula, and anterior tonsillar pillars which rupture to form small white ulcers

Occurs mainly in children

Vincent’s angina and QuinsyVincent’s angina and Quinsy

Vincent’s angina: anaerobic pharyngitis (exudate; foul odor to breath)

Quinsy: peritonsillitis/peritonsillar abscess. Medial displacement of the tonsil; often spread of infection to carotid sheath

DiphtheriaDiphtheria

Classic diphtheria (Corynebacterium diphtheriae): slow onset, then marked toxicity

Arcanobacterium hemolyticum (formerly Cornyebacterium hemolyticum): exudative pharyngitis in adolescents and young adults with diffuse, sometimes pruritic maculopapular rash on trunk and extremities

Miscellaneous causes of pharyngitisMiscellaneous causes of pharyngitis

Primary HIV infection Gonococcal infection Diphtheria Yersinia entercolitica (can have

fulminant course) Mycoplasma pneumoniae Chlamydia pneumoniae

Acute laryngotracheobronchitis (croup)Acute laryngotracheobronchitis (croup) Children, most often in 2nd year Parainfluenza virus type 1 most often in U.S.A. but

other agents cause Involvement of larynx and trachea: stridor,

hoarseness, cough Subglottic involvement: high-pitched vibratory

sounds Can lead to respiratory failure (up to 12%)

Acute epiglottitisAcute epiglottitis A life-threatening

cellulitis of the epiglottis and adjacent structures

Onset usually sudden (as opposed to gradual onset of croup); drooling, dysphagia, sore throat

H. influenzae the usual pathogen both in children (the usual patients) and adults

Acute suppurative Acute suppurative parotitisparotitis

Uncommon, but high morbidity and mortality

Usually associated some combination of dehydration, old age, malnutrition, and/or postoperative state

S. aureus the usual pathogen

Deep fascial space infections of Deep fascial space infections of the head and neckthe head and neck

Several syndromes according to anatomic planes

Can complicate odontogenic or oropharyngeal infection

Ludwig’s angina: bilateral involvement of submandibular and sublingual spaces (brawny cellulitis at floor of mouth)

Deep fascial space infections of Deep fascial space infections of the head and neck (2)the head and neck (2)

Lemierre syndrome: suppurative thrombophlebitis of internal jugular vein (Fusobacterium necrophorum)

Retropharyngeal space infection: contiguous spread from lateral pharyngeal space or infected retropharyngeal lymph node; complications include rupture into airway, septic thrombosis of internal jugular vein