SinusitisSinusitis• Sinusitis is an extremely common part of the

common cold syndrome

• RVs have been detected in 50% of adult patients with sinusitis by RT-PCR of maxillary sinus brushings or nasal swabs

• Frequency of association of RV infection with sinusitis suggests that common cold could be considered a rhinosinusitis

Sinusitis

Signs and symptoms

• Patient may complain of a ‘feeling of fullness’ and pressure over the involved sinuses, nasal congestion, and purulent nasal discharge

• Other associated symptoms include sore throat, malaise, low grade fever, headache, toothache, and cough >1 weeks duration

• Symptoms may last 10 – 14 days

SinusitisDiagnosis • Based on clinical signs and symptoms

• Physical examination may reveal patient described symptoms – palpate over sinuses, observe for structural abnormalities such a deviated nasal septum

• Sinus radiographs may reveal cloudiness and air fluid levels

• Limited coronal CT are more sensitive to inflammatory changes and bone destruction

SinusitisManagement/Treatment• 2/3 of untreated patients will improve symptomatically

within 2 weeks

• Antibiotics may be appropriate in certain patients

• Supportive therapy such as humidification, antihistamines, analgesics, and/or vasoconstrictors may relieve congestion and fullness

• OTC decongestant sprays for use of more than 5 days duration should be discouraged

Pharyngitis• Fewer than 25% of patients with a sore throat have

true pharyngitis

• Primarily seen in 5 – 18 year old population, it is common in adult women

• Most common cause is viral; most common agent is rhinovirus; Self-limiting; usually lasts 3-4 days

• Group A, beta-hemolytic streptococcus is the primary bacterial pathogen in 1/3 cases

• Early detection reduces incidence of acute rheumatic fever and post streptococcal pharyngitis

Pharyngitis• Sore throat is the prominent symptom

• Erythema

• Swelling of the affected tissues• Exudates: inflammatory cells overlaying mucous membranes

• Low-grade fever, mild general symptoms

• Difficult to differentiate from streptococcal infection

Caused by the same viruses that cause common cold and Adenovirus, Enteroviruses and Influenza virus.

Viral Causes of Pharyngitis• Rhinoviruses• Adenoviruses• Coronaviruses• Epstein-Barr Virus• Herpes Simplex Virus• Parainfluenza Viruses• Respiratory Syncytial Virus• Influenza Viruses• Coxsackie Viruses

Adenoviruses

Adenoviruses51 serotypes

• Immunity correlates with the presence of type- specific neutralizing antibodies

• Endemic or epidemic, often during summer

• Incubation period 4-7 days

• Moderate to severe pharyngitis, sometimes exudative

• Fever and systemic symptoms

• Rhinitis and follicular conjunctivitis are common

Adenovirus51 serotypes

Pharyngo-conjunctival fever sporadic or epidemicassociation with swimming pools

Epidemic acute respiratory disease in military recruits pneumonia in 10-20%

Nosocomial transmission: epidemic keratoconjunctivitis

Pneumonia in immunocompromised patientsBMT recipients: mortality 60%

Pathogenesis

• Epithelial cells are the primary target.

• E1B and E4 proteins inhibit transport of host mRNA from the nucleus to the cytoplasm causing cell death

• The penton protein has been shown to be directly toxic to cells and it has been found in the blood of several fatal cases of adenoviurs pneumonia.

• Entry by the mouth, the nasopharynx or via the conjunctiva.

• The lower stereotypes (1,2,5 and 6) are ubiquitous particularly in young children

• Endemic spread takes place by the fecal oral route to new pools of susceptible infants and children.

• May be transmitted in swimming pools, via medical equipment (tonometer), and via respiratory droplets.

• Site of initial replication is commonly the oropharynx and spread is mostly local.

• Virermic spread is rare.

• Latency has been shown to be common among humans (in tonsils and adenoids)

Adenovirus Clinical Syndromes

• They infect the respiratory tract as well as the eye, gastrointestinal tract, urinary bladder, and the liver.

• On occasions, these viruses may cause

disease in other organs such as CNS and the pancreas.

• Most human disease is associated with only one-third of the serotypes.

• Many adenovirus infections are subclinical

Respiratory Disease• Endemic Adenovirus Respiratory Infections of

young children

- Represent 5% of the acute respiratory disease in children(<5y) most commonly as pharyngitis or

pharyngoconjunctival fever - Most common serotypes are 1,2,5 and 6 and occasionally 3, 4 and 7. - Responsible for 10% of the pneumonias of childhood. - Most patients recover but epidemics of adenovirus 7 have resulted in considerable mortality.

Acute Respiratory Disease• Primarily affects military recruits (types 4, 7 and

occasionally 3). • Frequently occurs under conditions of fatigue

and crowding.

• Characterized by fever, pharyngitis, cervical adenitis, cough, hoarseness and rhinitis.

• Some cases have had a fatal outcome

(pneumonia).

• Pertussis – like syndrome - It is associated with adenovirus type 5.

• Infections of the Eye - Acute follicular conjunctivitis types 3 and 7 but other types (1,2,4,6,9,10,15,17,20,22) have been incriminated.

-Epidemic Keratoconjunctivitis

- Types 8, 11, 19 and 37.

- Followed by corneal subepithelial infiltration which may persist for a long period but it

resolves completely with return of visual acuity

to normal.

- Outbreaks can be traced to eye clinics

where an instrument (Tonometer) or a solution

acts as a vehicle.

Viral Causes of Pharyngitis• Rhinoviruses• Adenoviruses• Coronaviruses• Epstein-Barr Virus• Herpes Simplex Virus• Parainfluenza Viruses• Respiratory Syncytial Virus• Influenza Viruses• Coxsackie Viruses

Viral Infections of the Lower Respiratory Tract

Laryngotracheo Bronchitis (Croup)

- An acute viral inflammation of larynx, trachea, and bronchi that is common in young children.

- It is often preceded by a "cold".

- Accompanied by pyrexia, hoarseness, croaking cough, stridor, restlessness (respiratory insufficiency).

- Can be fatal - i.e. life-threatening disease.

Acute BronchitisAcute Bronchitis• Inflammation of bronchi, accompanied by fever,

cough, wheezing and "noisy chest".

• Respiratory virus infection associated with cough– Influenza virus: 75%–93% of cases– Adenovirus: 45%–90%– RVs: 32%–60%– Coronaviruses: 10%–50%

• 40% of nonasthmatic patients with acute bronchitis had FEV1 80% of predicted

• Bronchial reactivity remained increased up to 5 weeks after an episode of acute bronchitis

Acute Bronchiolitis- Inflammation of terminal bronchioles in young children.

- Bronchiole diameter is larger during inspiration than during expiration and this leads to hyperinflation of air sacs distal to bronchiole.

- Complete plugging of bronchiole with air resorption

leads to collapse. These features can be seen on x-ray.

- These changes cause respiratory embarrassment and

can be life-threatening. - Clinically, there is fever, rapid respiration, exhausting

cough and wheezing.

Pneumonia & Bronchopneumonia - Acute respiratory disease accompanied by

fever, restlessness and cyanosis.

- Often not much clinical "consolidation".

- Again, can be life-threatening.

Causative Agents

• Paramyxoviruses

- Parainfluenza viruses

- Respiratory Syncytial Virus (RSV)

- Measles virus

• Influenza

• Coronaviruses

• Adenoviruses

• Enteroviruses

• Rhinoviruses

Parainfluenza Viruses

Pathogenesis and Pathology• Initially, the mucous membranes of the nose

and throat are involved.

• Obstruction of the paranasal sinuses and eustachian tubes may also occur.

• Many patients with mild disease may have limited involvement of the bronchi as well.

• In more extensive infections there is a tendency

for HPIV-1 and 2 to involve the larynx and upper tarchea, resulting in croup.

• Such infections may extend also to the lower trachea and bronchi, with accumulation of inspissated mucous and resultant atelectasis and pneumonia.

• When HPIV-3 produces severe disease, infection of the small air passage is likely with the development of bronchopneumonia, bronchiolitis, or bronchitis.

• Lower respiratory tract involvement also occurs commonly during primary HPIV-1 and 2 infection; about 25% of primary infections produce bronchitis or pneumonia.

• The mechanisms responsible for localization and severity of human parainfluenza viruses' disease are not known.

• Severe respiratory tract disease caused by HPIV1, 2, and 3 generally occurs in the first 3-5 years of life.

• Primary infections and reinfections occur and most persons have had primary infections before the age of 5 years.

Clinical Features

• Most infections are asymptomatic, especially in older children and adults.

• The incubation period is 2-6 days.

• Fever and a spectrum of respiratory infections are caused by HPIVs; rhinorrhea/rhinitis, pharyngitis, croup, bronchiolitis and pneumonia.

• In children, the most common type of illness consists of rhinitis, pharyngitis, and bronchitis, usually with fever.

• Severe acute laryngotracheobronchitis (Croup) is noted in only 2-3% of primary HP1V1 or 2 infections.

• When croup develops, the initial symptoms of rhinitis, pharyngitis, fever, and cough progress.

• After several days, subglottic region becomes narrower, the cough worsens and becomes brassy, “seallike”, or barking, with hoarseness and stridor.

• At this stage, most children recover uneventfully after 24-48 hours.

• In some children, however, air hunger develops, with cyanosis, sternal and intercostal retraction, and progressive airway obstruction.

• HP1V3 is an important cause of bronchiolitis in young infants and children below 2 years of age.

• When bronchiolitis or pneumonia develops, fever persists and the cough progresses and becomes somewhat productive.

• It is accompanied by wheezing, tachypnea, retraction, and in severe cases cyanosis.

• A combined bronchopneumonia-croup syndrome occurs in some patients.

• Rarely, parainfluenza viruses are associated with otitis media, parotitis, and aseptic meningitis.

• Prolonged (persistent) and particularly severe infections are known to occur in the immunocompromised

Respiratory Syncitial Virus

• RSV is the most important cause of viral lower respiratory tract disease in infants and children worldwide.

• RSV is also an important agent of disease in immunosuppressed adults and the elderly.

• RSV grows poorly in tissue culture and most experimental animals, does not shut off host macromolecular synthesis, and it is unstable.

• Consequently, research on RSV was impeded.

• RSV survives on surfaces for up to 6 hours and on gloves for less than 2 hours.

• The virus loses activity with freeze-thaw cycles, in acidic conditions and with treatment by disinfectants.

• Classified into two types, RSV-A and RSV-B, on the basis of variation in the G glycoprotein

• RSV utilizes ICAM-1 as its receptor.

Pathogenesis• RSV is transmitted via large droplets, through fomites

and via hands

• The mechanism of virus spread from upper to lower respiratory tract is assumed to be via the respiratory epithelium or through aspirated secretions.

• The virus is capable of cell-to-cell spread without emergence into the extracellular fluid.

• Viremia has not been described during infection of

normal infants and children

Pathogenesis• RSV causes the release of

– Interleukins– Leukotrienes– Chemokines

• This results in inflammation and tissue damage

• Presence of eosinophils and eosinophilic cationic protein in blood is associated with recurrent wheezing episodes post RSV infection

Pathogenesis• Bronchiolitis

– Virus induced necrosis of bronchiolar epithelium– Hypersecretion of mucous– Round cell infiltration and edema of the surrounding

submucosa• This leads to

– Formation of mucous plugs– Hyperinflation/collapse of distal airways

• Can also result in interstitial pneumonia• Infants are particulary at risk due to small size of

normal bronchioles

Pathology• Lower respiratory tract involvement (signs) usually

appear 1-3 days after the onset of illness (rhinorrhea)

• Inflammatory infiltration, edema, and excessive mucous production cause obstruction of small bronchioles, with either collapse or emphysema of distal portions of the airway.

• In those instances in which pneumonia occurs, the interalveolar walls thicken as a result of mononuclear cell infiltration, and the alveolar spaces may fill with fluid.

• There is usually a patchy appearance of these pathologic changes, even though disease may be widespread.

• Severe infections are observed in:

- Preterm infants (<35 weeks gestational age)

- Those with chronic lung disease

- Those with cyanotic congenital heart disease

- Immunocompromised hosts.