Upper Respiratory Tract Infections

Definition

Inflammation of the respiratory mucosa from the nose to the lower respiratory tree, not including the alveoli.

Laryngitis & Epiglottitis

Laryngitis is swelling and irritation (inflammation) of the voice box (larynx) that is usually associated with hoarseness or loss of voice-Haemophilus influenzae & Streptococcus pneumoniae, could be fungal and viral.Epiglottitis- Inflammation of the cartilage that covers the trachea (windpipe)-Haemophilus influenzae, Streptococcus pneumoniae or Streptococcus pyogenes.

Otitis (URT)Otitis media- general term for infection or inflammation of the ear-fluid/exudates/pus/in the middle ear due to Haemophilus influenzae, Streptococcus pneumoniae or Streptococcus pyogenes.

OTITIS MEDIA, MASTOIDITIS, AND SINUSITIS

Middle ear, mastoid cavity, and sinuses are connected to the nasopharynx.

Sinuses and eustachian tubes have ciliated epithelial cells.◦ A virus initially invades the ciliated epithelium.◦ This destroys the ciliated cells, allowing bacteria to

invade.Mastoiditis is uncommon but very dangerous. Mastoid

cavity is close to the nervous system and large blood vessels.

Sinusitis- Inflammation of the sinuses and nasal passages, upper respiratory tract infection, the most common three causative agents are Streptococcus pneumoniae, Haemophilus influenzae and Moraxella catarrhalis

Categories

Acute Rhinosinusitis Acute Pharyngitis Acute Bronchitis

Differential Diagnosis

Influenza Pneumonia Tuberculosis Asthma

Anatomy of Sinuses

Acute Rhinosinusitis (Viral) Common Symptoms: Nasal discharge, nasal congestion, facial pressure, cough, fever, muscle aches, joint pains, sore throat with hoarseness.

Symptoms resolve in 10-14 days

Common in fall, winter and spring.

Treatment: Symptomatic

Acute Bacterial Sinusitis

Causative agents are usually the normal inhabitants of the respiratory tract.

Common agents: Streptococcus pneumoniae Nontypeable Haemophilus

Influenzae Moraxella Catarrhalis

Signs and Symptoms

Feeling of fullness and pressure over the involved sinuses, nasal congestion and purulent nasal discharge. Other associated symptoms: Sore throat, malaise, low grade fever, headache, toothache, cough > 1 week duration. Symptoms may last for more than 10-14 days.

Diagnosis

Based on clinical signs and symptoms Physical Exam: Palpate over the sinuses, look for structural abnormalities like DNS. X-ray sinuses: not usually needed but may show cloudiness and air fluid levels Limited coronal CT are more sensitive to inflammatory changes and bone destruction

Ethmoid Sinusitis

Coronal computed tomographic scan showing ethmoidal polyps. Ethmoid opacity is total as a result of nasal polyps, with a secondary fluid level in the left maxillary antrum.

Treatment About 2/3rd of patients will improve without treatment in 2 weeks.

Antibiotics: Reserved for patients who have symptoms for more than 10 days or who experience worsening symptoms.

OTC decongestant nasal sprays should be discouraged for use more than 5 days

Supportive therapy: Humidification, analgesics, antihistaminics

a) Amoxicillin (500mg TID) OR b) TMP/SMX ( one DS for 10 days).

c) Alternative antibiotics: High dose amoxi/clavunate, Flouroquinolones, macrolides

Antibiotics

Acute Pharyngitis

Fewer than 25% of patients with sore throat have true pharyngitis. Primarily seen in 5-18 years old. Common in adult women.

EtiologyA) Viral: Most common. Rhinovirus (most common). Symptoms usually last for 3-5 days.

B) Bacterial: Group A beta hemolytic streptococcus (GABHS).

Early detection can prevent complications like

acute rheumatic fever and post streptococcal GN.

Signs and Symptoms

Absence of Cough Fever Sore throat Malaise Rhinorrhoea Classic triad of GABHS: High fever, tonsillar exhudates and ant. cervical lymphadenopathy.

NO COUGH

Diagnosis

Physical Exam: Tonsillar exhudates, anterior cervical LAD Rapid strep: Throat swab. Sensitivity of 80% and specificity of 95%.

Throat Cultures: Not required usually.

Needed only when suspicion is high and rapid strep is negative.

Exhudates

Management

A) Symptomatic: Saline gargles, analgesics, cool-mist humidification and throat lozenges.

B) Antibiotics: a) Benzathine Pn-G 1.2 million units IM x 1OR Pn V orally for 10 days b) For Pn allergic pts: Erythromycin 500mg QID x 10 days OR Azithro 500 mg Qdaily x 3 days.

PHARYNGITIS A variety of bacteria can cause infection in the pharynx.

A classic infection is strep throat. Caused by Streptococcus pyogenes

Contains M proteins which inhibits phagocytosis

Produces pyrogenic toxins which cause the symptoms seen with pharyngitis

Group A streptococci can cause abscesses on the tonsils.

S. pyogenes can cause scarlet fever and toxic shock syndrome.

Streptococcal Pharyngitis-reddened adenoids -side of the throat (URT Bacterial Diseases)

50

SCARLET FEVER

Caused by Group A streptococciUsually seen in children under age of 18 yearsSymptoms usually begin with appearance of a rash.

Tiny bumps on the chest and abdomenCan spread over the entire body

Appears redder in armpits and groinRash lasts 2-5 days

..SCARLET FEVER

Symptoms can also include:Very sore throat with yellow or white papulesFever of 101˚F or higherLymphadenopathy in neckHeadache, body aches, and nauseaA variety of antibiotic therapies is available

DIPHTHERIA

Caused by the toxin produced by Corynebacterium diphtheriae

A potent inhibitor of protein synthesisIt is a localized infection.

Presents as severe pharyngitisCan be accompanied by plaque-like pseudomembrane in the throat

Microbiology: A Clinical Approach © Garland Science

…DIPHTHERIA

© Visuals Unlimited

Corynebacterium diphtheriae

….DIPHTHERIA

Toxemia can make diphtheria life threatening.

Can involve multiple organ systemsCan cause acute myocarditis

Diphtheria is transmitted by:Droplet aerosol.Direct contact with skin.Fomites (to a lesser degree).

…DIPHTHERIA:Vaccination

Vaccination against diphtheria- Infection is rare when vaccination is in place.Diphtheria still occurs frequently in some parts of the world, particularly where conditions do not permit vaccination.Toxin neutralization (exotoxin) is the most important.

Must be done as quickly as possible Antitoxin can only neutralize free toxin.

Pathogen elimination is also important.Corynebacterium diphtheriae is sensitive to many antibiotics

…DIPHTHERIA:PathogenesisLocal effects include epithelial cell necrosis and

inflammation.Pseudomembrane is composed of a mixture of

fibrin, leukocytes, cell debris.◦Size varies from small and localized to

extensive◦An extensive membrane can cover the trachea.

Incubation takes two to four days.Disease usually presents as pharyngitis or

tonsillitis with fever, sore throat, and malaise.Pseudomembrane can develop on tonsils, uvula,

soft palate, or pharyngeal walls.◦May extend downward toward larynx and

trachea.

VIRAL INFECTIONS OF THE UPPER RESPIRATORY TRACT (URT)

RHINOVIRUS INFECTION -There are several hundred serotypes of rhinovirus.

Fewer than half have been characterized.50% that have are all picornaviruses.Extremely small, non-enveloped, single-stranded RNA viruses

Optimum temperature for picornavirus growth is 33˚C.

The temperature in the nasopharynx

Acute Bronchitis

Inflammation of the bronchial respiratory mucosa leading to productive cough.

Acute Bronchitis

Etiology: A)Viral B) Bacterial (Bordetella

pertussis, Mycoplasma pneumoniae, and Chlamydia pneumoniae)

Diagnosis: Clinical

S/S: Productive cough, rarely fever or tachypnea.

Treatment

A) Symptomatic

B) If cough persists for more than 10 days:

Azithro x 5 days OR

Clarithro x 7 days

Non specific URI’sCommon ColdEtiology: Rhinovirus

Adenovirus RSV Parainfluenza EnterovirusesDiagnosis: ClinicalTreatment: Adequate fluid intake, rest,

humidified air, and over-the-counter analgesics and antipyretics.

Influenza

Etiology: Influenza A & BSymptoms: Fever, myalgias, headache, rhinitis, malaise, nonproductive cough, sore throatDiagnosis: Influenza A &B antigen testingTreatment: Supportive care, oseltamivir, amantidine

5. PERTUSSIS (WHOOPING COUGH)

Spread by airborne droplets from patients in the early stages.Highly contagious

Infects 80-100% of exposed susceptible individuals.Spreads rapidly in schools, hospitals, offices, and homes – just about anywhere.

….PERTUSSIS

Caused by Bordetella pertussisGram-negative coccobacillusDoes not survive in the environmentReservoir is humans.

Symptoms can be similar to those of a cold.

Infected adults often spread the infection to schools and nurseries.

…PERTUSSIS Mortality is highest in infants and children

under 1 year old. Immunization against pertussis started in the

1940s. Continues today as part of DTaP vaccination

Pertussis appears to be making a comeback. Epidemics are occurring every 3-5 years. Greatest numbers of infections are among 10-20

year-olds. People who were not immunized

Shows a relationship between lack of vaccination and infection

..PERTUSSIS: Pathogenesis Bordetella pertussis has an affinity for

ciliated bronchial epithelium. After attaching, it produces a tracheal

toxin. Immobilizes and progressively destroys the

ciliated cells. Causes persistent coughing

Caused by the inability to move the mucus that builds up

Pertussis does not invade cells of the respiratory tract or deeper tissues.

Incubation period is 7 to 10 days.

..PERTUSSIS: PathogenesisInfection has three stages:

Persistent perfuse and mucoid rhinorrhea (runny nose) May have sneezing, malaise, and anorexiaMost communicable during this stage

Complication of pertussis can lead to superinfection with Streptococcus pneumonia.

PERTUSSIS: Pathogenesis

Most common complications of pertussis are:

Superinfection with Streptococcus pneumonia.Convulsions.Subconjunctival and cerebral bleeding and anoxia.

.. PERTUSSIS: Treatment

Antibiotics can be used in the early stages.

Limits the spread of infection.Once the paroxysmal stage is reached, therapy is only supportive.Vaccination is the best option.

Questions?