Upper Respiratory Tract Infections

Burden of Upper respiratory tract infection (URI) Significant morbidity and direct health care costs Direct costs of $ 17 billion annually Excessive use of antibiotics a major issue Occasionally leads to fatal illness

Common cold - Definition The common cold is a viral infection upper respiratory tract, nose, and throat More than 100 viruses can cause a common cold signs and symptoms tend to vary greatly Preschool children are at greatest risk of frequent colds children average 8 per year, adults 3 Most people recover from a common cold a week or two

The Common Cold - Causes Etiologies Rhinoviruses 30 to 35% Coronaviruses about 10% Miscellaneous known viruses about 20% Influenza and adenovirus-30% Presumed undiscovered viruses up to 35% Group A streptococci 5% to 10% Parainfluenza was the first respiratory virus isolated (1955) Seasonal variation Rhinovirus early fall Coronavirus- winter

Transmission 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

Transmission through droplet dispersion (Courtesy-American Assoc Transmission through droplet dispersion (Courtesy-American Assoc. for the Advancement Of Science)

Molecular surface of a Human rhinovirus, showing protein spikes

Risk factors Cold viruses are almost always present in the environment But the following factors can increase your chances of getting a cold: Age Immunity Time of year

Clinical characteristics Incubation period 12-72 hours Nasal obstruction, drainage, sneezing, scratchy throat Median duration 1 week - but 25% can last 2 weeks Pharyngeal erythema is commoner with adenovirus than with rhino or coronavirus

Common Cold - Symptoms Common symptoms are Sometimes accompanied by sore throat runny nose nasal congestion sneezing Sometimes accompanied by conjunctivitis myalgias fatigue Sinusitis often present by CT scan; “rhinosinusitis” might be a better term

Common Cold - Complications Acute ear infection (otitis media) Wheezing Sinusitis Other secondary infections

The common cold

Diagnosis and treatment Main challenge is to distinguish between uncomplicated cold and streptococcal pharyngitis or bacterial sinusitis Marked exudate or pharyngeal erythema suggests Streptococcal infection Adenovirus Diphtheria Rapid antigen tests for group A streptococcus Rapid techniques for influenza, RSV, parainfluenza Treat with NSAIDs and whatever else your grandmother advises

A Rapid Strep Test kit

Acute sinusitis - Definition causes the cavities around your nasal passages to become inflamed and swollen With acute sinusitis, it may be difficult to breathe through the nose Acute sinusitis is most often caused by the common cold

Acute sinusitis - Causes Acute sinusitis can be caused by: Viral infection Bacterial infection Fungal infection Some health conditions can increase the risk of getting a sinus infection include: Allergies Nasal polyps or tumors Deviated nasal septum Tooth infection Other medical conditions

Acute bacterial sinusitis Epidemiological studies suggest 1 billion cases of viral rhinosinusitis occur annually in the US Of these 0.5 – 2 % are complicated by bacterial sinusitis Acute sinusitis typically starts with viral infection that paves the path for pathogenic bacteria The major pathogens are Streptococcus pneumoniae and Haemophilus influenzae Nose blowing generates high intranasal pressures that deposit bacteria into the sinus cavity More common in adults than in children

Acute bacterial sinusitis - Causes Community acquired bacterial sinusitis S. pneumoniae H. influenzae S. pyogenes Nosocomial sinusitis Seen in critically ill, mechanically ventilated S. aureus Pseudomonas aeruginosa Serratia marcescens Fungal

Bacterial sinusitis - Clinical features Sneezing Nasal discharge Facial pressure Fever Purulent drainage Headache Sinus imaging not routinely recommended

Chronic sinusitis Chronic sinusitis a common condition in which the cavities around nasal passages (sinuses) become inflamed and swollen for at least eight weeks, despite treatment attempts

Chronic sinusitis - Causes 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

Numerous microorganisms can be isolated from patients with chronic sinusitis Mixtures of aerobic and anaerobic bacteria are common The general conclusion at this time is that in most patients, no single microorganism can be assigned a pathogenic role

In some patients, however, P. aeruginosa or S In some patients, however, P. aeruginosa or S. aureus seems to be clearly pathogenic There are data suggesting roles for H. influenzae and Moraxella catarrhalis in children In these instances, especially in children, Streptococcus pneumoniae and Haemophilus influenzae may be important Numerous bacteria including gram-negative rods have been isolated with patients with post-operative sinusitis

Acute pharyngitis Inflammatory syndrome of the pharynx Most cases are viral Most important bacterial cause is Streptococcus pyogenes (15-20%) Presents with sore or scratchy throat In severe bacterial cases there may be odynophagia, fever, headache

Miscellaneous causes of pharyngitis Primary HIV infection Gonococcal infection Diphtheria Yersinia entercolitica (can have fulminant course) Mycoplasma pneumoniae Chlamydia pneumoniae

A case of strep throat

Severe Acute Respiratory 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 coronavirus (SARS-CoV) is causative of the syndrome

SARS: 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.

Croup Rhinorrhea, sore throat, mild cough, fever Parainfluenzae and influenza can be identified by nasopharyngeal swab Rapid tests are available Treat with vaporizers, nebulized adrenaline Systemic or nebulized corticosteroids in the severely sick The steeple sign as seen on an AP neck X-ray of a child with croup

Acute 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 parotitis Uncommon, but high morbidity and mortality Usually associated with some combination of dehydration, old age, malnutrition, and/or postoperative state S. aureus the usual pathogen

Otitis externa Acute, localized: often S. aureus, S. epidermidis or S. pyogenes Acute diffuse (swimmer’s ear): gram-negative rods, especially Ps. Aeruginosa ; Rx: topical quinolones Chronic: mainly with chronic otitis media Malignant: life-threatening infection in diabetics, elderly, immunecompromised

Malignant otitis externa Diabetes mellitus Pseudomonas aeruginosa Osteomyelitis of the temporal bone Involvement of vital structures at base of brain

Acute otitis media S. pneumoniae and H. influenzae the leading causes in all age groups (most H. flu is from non-typable strains and not “B”) Moraxella catarrhalis: 10% of cases Some cases may be viral (RSV, influenza, enteroviruses) Mycoplasma pneumoniae: inflammation of the tympanic membrane (“bullous myringitis”)

Acute 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

Diagnosis and treatment Presence of fluid in the middle ear AND Ear pain, drainage, hearing loss The fluid may take weeks to resolve Amoxicillin remains the drug of choice Beta-lactamase producing strains of H. influenza will need amoxicillin/clavulanic acid or cephalosporins

Otitis Media

Vesicular lesions Herpangina 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 Also think of Herpes simplex virus when you see vesicular lesions

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