2 Viral And Chlamydial Respiratory Infections Flashcards
Infections of the nasal cavity and pharynx are generally referred to as…
Upper respiratory tract infections (URI)
Acute respiratory diseases are more severe in…
Children
Hallmark signs of a URI
Nasal discharge/obstruction
Sneezing, cough, malaise, throat discomfort
2-4 days incubation
Fever, or other indications of a constitutional infection are uncommon in these cases - typically benign, transitory, and self-limited
Most common etiologic cause of acute respiratory diseases?
Viral infections
Most common viral causes of URI
RHINOVIRUSES - 25-50%
Coronaviruses - 10%
Adenoviruses (and other unknown viruses) - 30-40%
Rhinoviruses are better transmitted by _____ than by ______
By touch than by cough
Don’t shake hands!!!
Wash hands, clean toys at daycare
Why did the FDA say not to use Zicam anymore (2009)?
Intranasal zinc remedy, can lead to permanent loss of sense of smell
Treatment for URIs
Supportive, symptomatic relief only
Abx will not alter course of disease with these agents and it is best to avoid prescribing them in these cases
__________ infections are predictably hyperendemic in winter months
Rhinovirus
The greatest incidence of rhinovirus infections is in …
Children and young adults
Are colds caused by exposure to cold temps?
No, you idiot
Experimental data suggests that simple exposure to cold temps does not DIRECTLY induce disease
How is rhinovirus transmitted?
By aerosol and fomites and direct contact
Hands are a major vector
Treatment of Rhinovirus
Primarily symptomatic relief
B/c hands are the major vector, hand washing and disinfection of objects are best means of control
Don’t use Zicam. Just don’t. You’ll lose your sense of smell
Possible pharmacological treatment for rhinovirus
Picovir (Pleconaril) - inhibits virus infective process by binding in rhinovirus virion canyon
Not yet approved for mass use in US
But many viruses cause colds and are not susceptible to pleconaril, so limited usefulness
Skeletal muscle weakness/paralysis syndrome similar to poliomyelitis, non-polio enters viruses and West Nile virus
Acute Flaccid Myelitis (viral etiology suspected, not yet proven)
What are the three types of influenza?
A, B, and C, defined by nucleocapsid proteins
Influenza type that is most problematic
Type A
Type B also causes epidemics and type C is the least pathogenic
How are different subtypes of influenza categorized/labeled?
Based on envelope proteins
H hemagglutinin (viral attachment)
N neuraminidase (viral penetration and release from infected cells)
Nomenclature: Type / Location / Year / Isolation # / Antigenic type
Ex: “A/HongKong/68/H2N1”, “A/Spanish/18/HswN1”
Clinical manifestations of influenza
Short incubation (1-2 days)
Very abrupt onset of symptoms
Respiratory tract entry
SSx - FEVER, aches, chills, cough, sometimes severe
Persists for about 1 week, with long convalescence (1-2 weeks)
Viral destruction of respiratory tract ciliated epithelium (mucociliary escalators system) sets stage for complication
In flu patients, return of fever after it went away usually indicates…
Possible secondary pneumonia (most common way it kills)
Pulmonary complications of influenza
Primary influenza viral PNA
Secondary bacterial PNA
• Strep pneumo
•Staph aureus
• H flu type B (if unvaccinated)
Two other categories of non-pulmonary complications of influenza
Reye’s syndrome
• Associated with many viral infections
• Acute, sometimes catastrophic systemic disorder —> edematous encephalitis and fatty alteration of liver
Guillain-Barré syndrome
• Demyelination disease, insult unclear
• Associated with 1976 swine flue vaccine
Reye’s syndrome is primarily observed in …
Children aged 6 months - 15 years with influenza
What is important to keep in mind with regards to Guillain-Barre and the flu vaccine?
Influenza vaccination may induce GBS but bear in mind the estimated risk is 10x higher after a natural infection with the virus
