Chapter 21 Flashcards
What structures make up the upper respiratory tract?
mouth, nose, naval cavity, sinuses, throat, epiglottis, larynx
What structures make up the lower respiratory tract?
trachea, bronci, bronchioles, lungs
Which nine bacterial genera are observed in the normal biota of the lungs?
Prevotella, Sphingomonas, Pseudomonas, Acinetobacter, Fusobacterium, Megasphaera, Veillonella, Staphylococcus, and Streptococcus
What is another name for the common cold?
Rhinitis
What are the symptoms of the common cold?
Sneezing, scratchy throat, runny nose
How many different viruses can cause a common cold?
Over 200 different kinds of viruses
What are the most common type of viruses to cause a common cold?
Rhinoviruses, coronaviruses, adenoviruses
When is the Respiratory Syncytial Virus (RSV) a problem?
When it causes serious respiratory symptoms in infants, elderly, and other immunocompromised people
What actually causes the symptoms associated with a cold?
The immune system’s response while fighting the virus
How are cold viruses transmitted?
Respiratory droplets, indirect transmission
What is the best way to prevent a common cold?
Frequent hand washing
What is sinusitis/sinus infection?
Inflammation of any of the four pairs of sinuses in the skull
What are the signs/symptoms of sinusitis?
Nasal congestion, pressure above the nose or in the forehead, headache, toothache, facial swelling and tenderness
What kind of sinusitis discharge is indicative of a bacterial infection?
Yellow or green discharge
What three general organisms are possible causes of sinusitis?
Viruses, bacteria, fungi
Which viruses are responsible for most cases of sinusitis?
Rhinoviruses, coronaviruses, adenoviruses
What underlying factors allow for bacteria to cause sinusitis?
Underlying infection, buildup of fluids, rich environment for bacterial multiplication, sinus anatomy
When is bacterial sinusitis considered to be chronic?
After an infection has lasted for at least 12 weeks
What treatment is prescribed for bacterial sinusitis?
Broad-spectrum antibiotics
Which genera of fungi are typically found in fungal sinusitis cases?
Aspergillus, Bipolaris, Mucor
How does acute otitis media occur?
Upper respiratory tract infections can lead to inflammation of the eustachian tubes, resulting in fluid buildup in the middle ear and bacterial multiplication
What is the term for the fluid built up during an ear infection?
effusion
What is chronic otitis media?
indefinite fluid buildup in the middle ear
What are the signs and symptoms of otitis media?
feeling of fullness or pain in the ear, loss of hearing
Which conditions can result from untreated otitis media?
Ruptured eardrum, pus buildup, mastoiditis, meningitis, intracranial abcess
What are the two most common causes of otitis media?
Streptococcus pneumoniae and Haemophilus influenzae
What are the characteristics of S. pneumoniae?
Pairs of elongated, gram-positive cocci joined end to end
What gram staining outcome is associated with H. influenzae?
Gram-negative
How can otitis media be prevented?
Vaccination against S. pneumoniae (PCV13 or Pneumovax)
How is otitis media treated?
Broad spectrum antibiotics for infants under 6 months; watchful waiting for all other cases; insertion of tubes in chronic/reoccurrHing cases
What is pharyngitis?
Inflammation of the throat, experienced as pain and swelling
Which causative agent causes mild pharyngitis, and which one causes more painful pharyngitis?
Viral agents cause more mild pharyngitis; bacterial agents cause more severe/painful meningitis
What are the clinical signs of pharyngitis?
Reddened mucosa, swollen tonsils, white packets of inflammatory products
What are the causative agents of pharyngitis?
Rhinoviruses, coronaviruses, adenoviruses, Streptococcus pyogenes, Fusobacterium necrophorum
What are characteristics of Streptococcus pyogenes?
Gram-positive, grows in chains, non-motile, forms capsules and slime layers, does not produce endospores
What complications can arise due to untreated pharyngitis caused by S. pyogenes?
Rheumatic fever, scarlet fever, glomerulonephritis
What is scarlet fever?
Results from pharyngitis caused by S. pyogenes bacteria that are infected by bacteriophages; bacteriophage gives bacteria the ability to produce erythrogenic toxin
What are the symptoms of scarlet fever?
sandpaper-like rash, high fever
What is rheumatic fever?
A condition caused by the immunologic cross-reaction between streptococcal M protein and heart muscle
What are the symptoms/signs of rheumatic fever?
heart valve damage, arthritis, appearance of nodules on bony surfaces just under the skin
What is glomerulonephritis?
Result of streptococcal proteins participating in the formation of antigen-antibody complexes, which deposit in the basement membrane of the glomeruli of the kidney
What are the signs and symptoms of glomerulonephritis?
Nephritis characterized by low urine output and hand/foot swelling; blood in urine; increased blood pressure; heart failure
What is the main virulence factor of Group A Streptococci?
Production of streptolysins
What is the role of erythrogenic toxin in scarlet fever?
To produce the bright red rash and induce fever
What is TNF?
Tumor necrosis factor
How is S. pyogenes transmitted?
Respiratory droplets and direct contact with mucus secretions
How are Group A Streptococci diagnosed?
Rapid tests based on antibodies to Group A streptococci
How can infections by S. pyogenes be prevented?
Good hand washing and other hygiene techniques
What is the antibiotic of choice to treat S. pyogenes?
Penicillin
What is the gram-staining result associated with Fusobacterium necrophorum?
Gram-negative
What is Lemierre’s syndrome?
An invasion of the bloodstream by Fusobacterium necrophorum following a peritonsillar abscess
How is Fusobacterium necrophorum treated?
Penicillin
Why has there been a lack of diphtheria cases in the last 50 years?
protection provided by immunization with the diphtheria toxoid
What is the causative agent of diphtheria?
An endoxtoxin produced by Corynebacterium diphtheriae
What are the characteristics of Corynebacterium diphtheriae?
Non-endospore forming, gram-negative, club-shaped
What are the symptoms of diphtheria?
Sore throat, lack of appetite, low-grade fever, pseudomembrane formation on the tonsils/larynx
What is another name for pertussis?
Whooping cough
What are the two distinct symptom phases of pertussis?
Catarrhal and paroxysmal stages
What is the catarrhal stage of pertussis?
Stage that begins after incubation period; characterized by cold symptoms, most notably a runny nose
What is the paroxysmal stage of pertussis?
Second stage of pertussis, characterized by severe and uncontrollable coughing
What is the causative agent of pertussis?
Bordetella pertussis
What are the characteristics of Bordetella pertussis?
Small, gram-negative, bacillus, aerobic, fastidious
What are filamentous hemagglutinin structures?
fibrous structures that B. pertussis bacteria use to adhere to the epithelial cells of the mouth and throat
What are the two most important exotoxins in pertussis?
Pertussis toxin and tracheal toxin
What is the role of pertussis toxin?
Trigger excessive amounts of cyclic AMP to accumulate in affected cells
What is the role of tracheal toxin?
Direct destruction of ciliated cells; renders cells incapable of clearing mucus and secretions
How is B. pertussis transmitted?
Respiratory droplets
How is pertussis diagnosed?
Symptom-based diagnosis; nasopharyngeal swab cultures and PCR testing can be done if needed
How can pertussis be prevented?
Vaccination with DTaP and booster with Tdap; administration of antibiotics to those exposed
What is the drug of choice to treat pertussis?
Azithromycin
What is Respiratory Syncytial Virus (RSV)?
A virus that infects that respiratory tract and produces giant, multi-nucleated cells (syncytia)
What are the characteristics of RSV?
member of paramyxovirus family; contains single-stranded, negative-sense RNA; enveloped
What are the symptoms/signs of RSV?
rhinitis, pharyngitis, otitis, coughing, wheezing, difficulty breathing, abnormal breathing sounds
How is RSV transmitted?
Droplet contact, fomite contamination
What techniques are used to diagnose RSV?
Direct and indirect immunofluorescence testing, ELISA testing, DNA probes
How is RSV prevented?
passive antibody treatment for at-risk children
How is RSV treated?
Ribavirin and passive antibody treatment
What are the signs/symptoms of influenza?
headache, chills, dry cough, body aches, fever, stuffy nose, sore throat, fatigue
What are the causative agents of influenza?
Influenza viruses A, B, and C
What family do the influenza viruses belong to?
Orthomyxoviridae
What are the two glycoproteins that make up the spikes of the influenza virus envelope?
hemagglutinin and neuraminidase
What is antigenic drift?
gradual changes in the amino acid composition of Influenza A virus antigens
What is antigenic shift?
major changes in the Influenza A virus due to recombination of viral strains from two different host species
How is influenza transmitted?
Inhalation of droplets and aerosols; fomite contamination
How is influenza diagnosed?
RT-PCR testing
How is influenza prevented?
Yearly flu vaccines
How is influenza treated?
Tamiflu (oseltamivir) and other antiviral drugs
What are the signs/symptoms of primary tuberculosis?
Tubercle formation; necrotic caseous lesions that heal by calcification, tuberculin reaction in the skin
Which organs, other than the lungs, can be involved in extra-pulmonary TB?
lymph nodes, intestines, kidneys, long bones, genital tract, brain, meninges
What are the signs/symptoms of secondary (reoccurring) TB?
expansion of tubercles filled with bacteria; cavity formation in the lungs; drainage into bronchial tubes and URT; violent coughing; green or bloody sputum; low-grade fever; anorexia; weight loss; fatigue; night sweats; chest pain
What is the causative agent of tuberculosis?
Mycobacterium tuberculosis
What are the characteristics of M. tuberculosis?
long and thin acid-fast rod, strict aerobe, cord factor style of growth
What characteristics of M. tuberculosis contribute to its virulence?
waxy surface, ability to stimulate a strong cell-mediated immune response
How is M. tuberculosis transmitted?
Fine droplets of respiratory mucus
What factors increase an individual’s susceptibility to TB?
inadequate nutrition, debilitation of immune system, poor access to medical care, lung damage, genetics
How is TB diagnosed?
Mantoux tuberculin skin test, IGRA blood test, PCR test
What vaccine is used to prevent TB in other countries (not the US)?
Bacille Calmette-Guerin vaccine
How is TB treated?
Use of isoniazid; potential for combination with additional antibiotics
What is the biggest issue with TB therapy?
Noncompliance from the patient?
What is Multidrug-resistant TB?
TB that is resistant to at least isoniazid and rifampin
What is extensively drug-resistant TB?
TB that is resistant to at least two other drugs in addition to isoniazid and rifampin
What is pneumonia?
inflammatory condition of the lung in which fluid fills the alveoli
Which types of organisms can cause pneumonia?
Viruses, bacteria, fungi
What are the two forms of pneumonia?
Community-Acquired Pneumonia (CAP) and Healthcare-Associated Pneumonia (HCAP)
What are typical symptoms of all pneumonias?
congestion, headache, fever, chest pain, cough, discolored sputum
What are the most common causative agents of CAP?
Rhinoviruses, influenza, Streptococcous pneumoniae
What is walking pneumonia?
Pneumonia that still allows you to carry out day-to-day activities
What are common causative agents of walking pneumonia?
haemophilus influenzae, Moraxella catarrhalis, Chlamydia pneumoniae, Mycoplasma pneumoniae
What is consolidation?
A condition in which pneumonia exudates, cells, and bacteria solidifies in the air spaces of the lungs
How can S. pneumoniae be prevented?
Vaccination with PCV13 or PPSV23
How is S. pneumoniae treated?
broad-spectrum cephalosporins
How is Mycoplasma pneumoniae diagnosed?
Serological or PCR tests
How is Mycoplasma pneumoniae transmitted?
aerosol droplets
What are the characteristics of Legionella pneumophila?
gram-negative; widely distributed in aqueous habitats; resistant to chlorine
What are the various signs/symptoms of Histoplasmosis?
aches, pains, coughing, fever, night sweats, weight loss
What is the causative agent of Histoplasmosis?
Histoplasma capsulatum fungus
How is Histoplasma capsulatum transmitted?
From the soil or environment to humans
How is H. capsulatum diagnosed?
appearance of “fish-eye” yeasts, urine antigen test
What is the treatment for H. capsulatum?
1-2 weeks of amphotericin, followed by several weeks of itraconazole
What is Pneumocystis pneumonia?
opportunistic pneumonia infection in AIDS patients caused by Pneumocystis jirovecii
What are the symptoms of Pneumocystis pneumonia?
cough, fever, shallow respiration, cyanosis
How is Pneumocystis pneumonia diagnosed?
Visualization of cysts in a sputum specimen
What is the treatment for Pneumocystis pneumonia?
trimethoprim-sulfamethoxazole
What are the most common causes of healthcare-associated pneumonias?
MRSA strains and gram-negative bacteria
What are the symptoms/signs of hantavirus pulmonary syndrome?
fever, chills, myalgia, headache, nausea, vomiting, diarrhea, cough, pulmonary edema, respiratory distress
How is hantavirus transmitted?
airborne dust contaminated with the feces, urine, or saliva of infected rodents
How is hantavirus diagnosed?
PCR testing, IgM detection
