2.52k likes | 2.67k Views
Respiratory Exam 1. Flashcards. felton. microbiology. What is the most common infectious disease of humans?. The common cold Also, the leading cause of acute morbidity and of visits to a physician in the US Major cause of industrial and school absenteeism.
E N D
Respiratory Exam 1 Flashcards
felton microbiology
What is the most common infectious disease of humans? • The common cold • Also, the leading cause of acute morbidity and of visits to a physician in the US • Major cause of industrial and school absenteeism
What microorganism grows optimally at a temp lower than normal core body temp? • RHINOVIRUS • In tissue culture grow optimally at 33C, the temperature of the nasal mucosa of humans
Where does the rhinovirus multiply? • In the cytoplasm of host cells
What type of virus is the rhinovirus • Small, single stranded RNA virus • Related to poliovirus • Member of the family: picornaviruses
What types of viruses are coronaviruses? • Single stranded RNA viruses • Round or petal shaped projections around the viral capsid resembling a crown • Lipid envelopes are labile to ether or chloroform • SARS-CoV: caused by coronavirus
Respiratory syncytial virus • Infects infants and children more • Causes colds, bronchopneumonia, or bronchitis • Paramyxovirus • RNA, enveloped • Two antigenic types
Orthomyxoviruses • Influenza viruses • 3 antigenic types
Paramyxoviruses • Parainfluenza viruses • 4 antigenic types • Enveloped, SS RNA viruses • In kids, can cause severe diseases: • Croup, bronchitis, pneumonia • In adults: can cause adult respiratory diseases • Are one of the major causes of viral laryngitis and pharyngitis in adults
List the possible modes of transmission of a virus: • Direct contact with infectious secretions on skin and environmental surfaces • Large particles of respiratory secretions that are briefly transported in air • Infectious droplet nuclei suspended in air • Combination of these methods
How long is the incubation period for the common cold? 48-72 hours
What are the symptoms of the common cold? • Nasal discharge • Nasal obstruction • Sneezing • Sore or scratchy throat • Cough • Anorexia and slight fever may be present
What is sinusitis? • Acute, inflammatory affliction of one or more of the paranasal sinuses • Usually after: • Rhinitis • Dental extraction • Or in pts with predisposing factors such as: nasal polyps, deviation of the nasal septum, tumors, foreign bodies, trauma, abrupt change of pressure in the nasal passages, and conditions such as cystic fibrosis
What bacteria most commonly cause acute sinusitis? • Strep pneumoniae and H. influenzae
Things that can predispose you to purulent sinusitis • Nasal polyps • Deviation fo the nasal septum • Tumors • Foreign bodies • Trauma • Abrupt change of pressure in the nasal pasages • Cystic fibrosis
Type of bacteria more commonly associated with chronic sinusitis • Anaerobic bacteria • Often as a combined infection with aerobes
What is the pathogenesis of sinusitis? • Obstruction of the paranasal sinusal ostia impedes drainage • Infections impair the cilliary activity of the sinuses • Results in accumulation of mucous secretions • Mucus converted to mucopus by bacterial multiplication in the sinus cavities • The pus irritates the underlying mucosa causing further edema and aggravating the obstruction
When is sinusitis most prevalent? • Fall, winter, and spring
Clinical manifestations of sinusitis: • Facial pain • Purulent nasal discharge • Photophobia and tearing may be present
Diagnosis of sinusitis: • Can be made without radiographic exams when there is a hx of upper respiratory tract infection or allergic rhinitis, pain and tenderness over a sinus, and purulent discharge • Microbial etiology is determined by culture of an exudate or a rinse obtained by sinus puncture and aspiration • Cultures obtained from nasal pus or by rinsing of the nose are unreliable because of contamination with resident bacterial flora
Tx of sinusitis: • Responds well to antimicrobial therapy
Bacteria that causes mostly asymptomatic pharyngitis: • N. gonorrhoea • Occasional case of mild pharnygitis
Type of pharyngitis most commonly caused by adenoviruses • Pharyngoconjunctival fever • Usually more severe than the common cold • Temperature elevations persist for 5-6 days • MARKED sore throat • Distinguishing feature: • CONJUNCTIVITIS which occurs in 1/3 to ½ of cases • Follicular type • Bilateral • Cough, hoarseness, and substernal pain occur in acute respiratory disease [ARD] in military recruits.
Symptoms of pharyngitis with influenza: • Sore throat = major complaint • Coryza symptoms may be present • Temperature elevations are common in children and adults • Edema and erythema of the pharynx is NOT marked • NO pharyngeal exudates or painful exudate • Recovery in 3-4 days
Symptoms of pharyngitis with the common cold: • Mild to moderate pharyngitis discomfort, but not the primary complaint • Rhinorrhea and post-nasal discharge usually present • NO: • Severe pharyngeal pain or dysphagia • Pharyngeal and tonsillar exudates or painful lymphadenopathy
Adenoviruses can cause what 3 types of respiratory diseases? • Acute, febrile, self-limiting condition • Pharyngoconjunctival fever • Pertussis-like syndrome indistinguishable clinically from infection with Bordetella pertussis Adenoviruses are major etiologic agents of acute respiratory disease [ARD] and pharyngitis. Also indicated in pathogenesis of : epidemic keratoconjunctivitis, hemorrhagic cystitis, gastroenteritis, and rashes.
Symptoms of acute herpetic pharyngitis: • Primary infection may present as acute pharyngitis • Severe cases: inflammation and exudate may mimic full blown streptococcal pharyngitis • Vesicles and ulcers of the palate • Vesicles and ulcers on the labial and buccal mucosa when there is an assoc. gigivostomatitis
Characteristics of herpes simplex viruses: • Large DNA virus • Lipid containing capsids • Inactivated by ether • Will see: • eosinophilic intranuclear inclusion bodies in infected cells • Tend to produce latent infection • Role in recurrent fever blisters
What type of pharyngitis is caused by coxsackieviruses? • Herpangina • Small vesicles on soft palate, uvula, and anterior tonsillar pillars • Lesions rupture to become small, white ulcers • Mostly in kids: severe, febrile illness with marked sore throat with dysphagia
Cocksackieviruses • Picornaviruses • Can cause: • Aseptic meningitis • Myocarditis • Upper respiratory tract infections • Group A: • Types 2,4,5,6,8,10 can cause aherpangina • Type 10 is also associated with a summer febrile disease in children called acute lymphonodular pharyngitis
Symptoms of infectious mononucleosis: • Exudative tonsillitis or pharyngitis in about ½ the cases • Fever and cervical adenopathy usually present • Enlargement of spleen in ½ the cases
What does the presence of eosinophilic intranuclear inclusion bodies suggest? • Infection with herpes simplex virus
Symptoms of anaerobic pharyngitis: • Pharyngeal and tonsillar infection • Mix of anaerobic bacteria and spirochetes • Purulent exudate coats the membrane • May be a foul odor to the breath • With development of an abscess, pharyngeal pain is usually severe, dysphagia and low grade fever are common • Infection usually limited to one side, but when bilateral, partial obstruction of the pharynx occurs
Symptoms of streptococcal pharyngitis: • In severe cases: marked pharyngeal pain, dysphagia, and a temperatures of 39.4C or greater • Pharyngeal membrane is fiery red • A thick exudate covers the posterior pharynx & tonsilar area • Edema of uvula is often pronounced • Tender, enlarged cervical nodes • A leukocyte count of over 12,000/mm3 • Infection with S. pyogenes that produces erythrogenic toxin results in the characteristic erythemetous rash of scarlet fever.
Symptoms of DIPHTHERIA: • Low grade temperature elevation • Tonsillar or pharyngeal pseudomembrane varies from light to dark gray and is firmly attached to the tonsil and pharyngeal mucosa
Mycoplasma pneumoniae • Pharyngitis is usually mild with no distinguishing clinical features • M. pneumoniae characteristically causes bronchitis and primary atyptical pneumonia
What does the presence of exudate suggest? • Streptococcal pharyngitis • Vincent’s angina • Pharyngoconjunctival fever • Herpes simplex virus infection • Infectious mononucleosis
What does the presence of small vesicles or ulcers suggest? • Herpes simplex virus infection • Herpangina
What does the presence of exudate and small vesicles or ulcers suggest? • Herpes simplex virus infection • Will also see: eosinophilic intranuclear inclusion bodies
Medial displacement of one or both tonsils is seen with: • Peritonsillitis • Peritonsillar abscess
Type of agar that can be used to detect N. gonorrhoea: • Thayer-Martin agar
HOW is Vincent’s angina diagnosed? • Crystal violet stained smear of the pharyngeal or tonsillar exudate showing the presence of numerous fusobacteria and spirochetes
Medium used to detect DIPTHERIA: • Loeffler’s medium
Small, pleomorphic, gram negative rod that is nonmotile, nonsporulating, and usually capsulated: • H. influenzae • Aerobic or facultative • Requires • Iron protoporphrin compound [X factor] • Pyridine nucleotide [V factor]
What is the virulence of H. influenzae associated with? • Capsulation • 6 antigenic types [a-f] • Type b formerly accounted for almost all serious infection in humans • Vaccination has reduced the frequency of this disease in young children
Drugs used to treat respiratory airway infections caused by H. influenzae: • Chloramphenicol • Ampicillin • Penicillin G • Tetracycline • Sulfonamindes
Classic sites for localization of diptheria infection: • Larynx and pharynx
What microorganism causes whooping cough? • Bordetella pertussis • Small, ovoid • Nonmotile • Nonsporeforming • Gram NEGATIVE rod • Fastidious requirements for grouth • Phase I: virulent, encapsulated, piliated • produces several toxins • Phase IV: pleomorphic, noncapsulated, avirulent • ONLY PHASE I BACILLI ARE SUITABLE FOR THE PREPARATION OF VACCINES