sinusitis sinusitis is an extremely common part of the common cold syndrome rvs have been detected...
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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.