Viral Respiratory Tract Infections

Question 1

Pathogenesis of Common Cold

Answer 1

Caused by Rhinovirus
Infection of ciliated and non ciliated nasal epithelial cells - non-specific host inflammatory response - Bradykinnin IL1,6,8, TNF-A

Bradykinin - sore throat
Other inflammatory molecules - vasodilation and serum transudation - nasal obstruction and Rhinorrhea - leads to cough

Stimulation of cholinergic pathway - nasal mucus secretion and Reactive airway disease - cough

Infection of lower respiratory tract - cough

Question 2

Acute Respiratory Infections (ARI) Symptoms

Answer 2

Rhinitis, sore throat, Headache, Malaise, Myalgias, Cough, Fever, Tracheal tenderness, Wheezing, Stridor, Rales, Hypoxia, Cyanosis

Question 3

Pathogenesis of Common Cold (other viruses)

laryngitis, bronchitis, croup, bronchiolitis, pneumonia

Answer 3

Infection of epithelial cell - cell to cell spread - necrosis and denudation of ciliated epithelial cells - cell infiltration and inflammation - edema and mucus secretion

Question 4

Viral Pharyngitis

Answer 4

Direct viral cellular damage and Non specific host inflammatory response –> potent stimulation of pain nerve endings

Question 5

Transmission

Answer 5

Through virus contaminated hands

fomites, droplets, possibly aerosols

Question 6

Immunity

Answer 6

Many viruses induce long lasting immunity (not paramyxovirus). However, viral polymerase has poor proof reading leading to mutation and antigenic drift

Question 7

How to differentiate between viral pharyngitis and bacterial pharyngitis

Answer 7

Viral - associated with rhinitis, no pharyngeal exudate

Bacterial - with exudate, no nasal symptoms

In children under three pharyngitis is mostly kids

Question 8

MUMPS

Answer 8

Paramyxoviridae
(-)ssRNA

Highly infectious, early winter, school-aged children
Parotid glands Infected not epithelial cells
Complication -orchitis

Question 9

Mumps treatment and immunity

Answer 9

CMI and Humoral - lifelong

Vaccine