Upper Respiratory Tract Infections

1. Upper Respiratory Tract Infections Divya Ahuja, M.D. November 2009

2. Burden of URI • Significant morbidity and direct health care costs • Direct costs of $ 17 billion annually • Occasionally leads to fatal illness • Excessive use of antibiotics a major issue

4. The Common Cold • Children average 8 per year, adults 3 • 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

5. Common Cold • Common symptoms are 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

6. The common cold

7. Transmission of rhinoviruses • Direct contact is the most efficient means of transmission: 40% to 90% recovery from hands. • Infectious droplet nuclei • Brief exposure (e.g., handshake) transmits in less than 10% of instances • Kissing does not seem to be a common mode of transmission.

8. 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

9. Diagnosis and treatment • Main challenge is to distinguish between uncomplicated cold and streptococcal pharyngitis or bacterial sinusitis • Good examination • 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

10. Acute bacterial sinusitis • Epidemiological studies suggest 1 billion cases of viral rhinosinusitis occur annually in the US • Of these0.5-2% are complicated by 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 • Nose blowing generates high intranasal pressures that deposit bacteria into the sinus cavity • More common in adults than in children

12. Paranasal sinuses

15. Waters view (left); Coronal CT

16. Sinusitis • 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

18. Clinical features • Clinical features • Sneezing • Nasal discharge • Facial pressure • Fever • Purulent drainage • Headache • Sinus imaging not routinely recommended

19. Acute sinusitis: complications • Maxillary: usually uncomplicated • Ethmoid: cavernous sinus thrombosis-serious • Frontal: osteomyelitis of frontal bone; cavernous sinus thrombosis; epidural, subdural, or intracerebral abscess; orbital extension • Sphenoid: Rare; extension to internal carotid artery, cavernous sinuses, pituitary, optic nerves; common misdiagnoses include ophthalmic migraine, aseptic meningitis, trigeminal neuralgia, cavernous sinus thrombosis

22. Case • BR 59 year old white female • Diplopia and left temporal headache • Thought to have temporal arteritis • Started on Prednisone 100mg once daily • Two months later developed cranial N palsies, headaches

26. Chronic sinusitis • The previous patient had an invasive aspergillus sinusitis as a result of chronic high dose steroid therapy, resulting in occlusion of carotid artery and invasion into the brain. She died in a month. • 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;

27. Spectrum of fungal sinusitis • Simple colonization • Sinus mycetoma (fungus ball) • Allergic fungal sinusitis • Acute (fulminant) invasive sinusitis (notably, rhinocerebral mucormycosis) • Chronic invasive fungal sinusitis

28. 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

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

30. 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”)

31. 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

33. 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

34. Otitis Media

36. 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

37. Acute 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

38. Pharyngoconjuntival 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

39. 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

40. Vincent’s angina and Quinsy • Vincent’s angina: anaerobic pharyngitis (exudate; foul odor to breath) • Ludwig’s angina- cellulitis of dental origin • Quinsy: peritonsillitis/peritonsillar abscess. Medial displacement of the tonsil; often spread of infection to carotid sheath

41. Diphtheria • fibrous pseudomembrane with necrotic epithelium and leukocytes

42. Diphtheria • Classic diphtheria (Corynebacteriumdiphtheriae): slow onset, then marked toxicity • Arcanobacteriumhemolyticum (formerly Cornyebacteriumhemolyticum): exudative pharyngitis in adolescents and young adults with diffuse, sometimes pruritic maculopapular rash on trunk and extremities

43. Miscellaneous causes of pharyngitis • Primary HIV infection • Gonococcal infection • Diphtheria • Yersiniaentercolitica (can have fulminant course) • Mycoplasmapneumoniae • Chlamydiapneumoniae

44. Treatment • Symptomatic • Penicillin for Strep throat • Macrolides for pen allergic patients • Add an anti-anaerobic agent for Vincent’s and Ludwig’s angina

45. Acute laryngotracheobronchitis (croup) • Children, most often in 2nd year • Parainfluenza virus type 1 most often in U.S.A. but other agents are Mycoplasma pneumoniae, H. influenza • Involvement of larynx and trachea: stridor, hoarseness, cough • Subglottic involvement: high-pitched vibratory sounds • Can lead to respiratory failure (2% get hospitalized)

46. 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

47. 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

48. 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

49. Deep fascial space infections of the 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)

50. Deep fascial space infections of 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