micro chapter 21 (respiratory)
Pneumonia Anatomical diagnosis
--Inflammatory condition of the lung in which fluid fills the alveoli --Can be caused by a wide variety of microorganisms ---Must be able to avoid phagocytosis ---Or avoid killing once inside macrophages --Viral pneumonia is usually (but not always) milder than bacterial pneumonia --Fungi can also cause pneumonia
Pneumonia signs and symptoms
Begin with runny nose and congestion, headache, and fever Lung symptoms: chest pain, fever, cough, production of discolored sputum Patient appears pale and sickly due to pain and difficulty breathing Severity and speed of onset of symptoms depend on the etiologic agent
Hemagglutinin
Binds to host cell receptors of respiratory mucosa Contains antigen sites for antibody binding
whooping cause causative organism
Bordetella pertussis Small, gram-negative rod Able to attach to respiratory epithelium and produce 2 toxins: Pertussis toxin: causes massive mucus production Tracheal cytotoxin: causes direct destruction of ciliated cells
Neuraminidase
Breaks down protective mucus coating of the respiratory tract Assists viral budding and release Keeps viruses from sticking together Participates in host cell fusion
Over ---- kinds of virus can cause common cold
200
causative agent of common cold
99 serotypes of rhinovirus, coronavirus, and adenoviruses
Effusion
: buildup of fluid in the eustachian tubes
Whooping Cough - symptoms/phases
Catarrhal phase: Bacteria in the respiratory tract cause cold symptoms Paroxysmal phase: Uncontrollable coughing accompanied by a "whoop" sound Can result in broken blood vessels in the eyes, vomiting, or even hemorrhages in the brain Convalescent phase: Bacteria are decreasing, but ciliated epithelia have been damaged, requiring weeks to months of recovery
Diphtheria causative agent
Corynebacterium diphtheriae Non-endospore-forming, gram-positive, club-shaped bacterium Produces sore throat, lack of appetite, and low-grade fever Pseudomembrane forms on the tonsils or pharynx that can completely block respiration DTaP vaccine recommended for children with the Tdap booster for individuals 11 - 64 years
healthcare associated pneumonia
About 1% of hospitalized or institutionalized people develop pneumonia. Most often associated with mechanical ventilation via endotracheal or tracheostomy tube 30 - 50% mortality rate
Treatment of Tuberculosis
Active tuberculosis: 3 - 4 antibiotics for 6 months Latent tuberculosis: 1 antibiotic for 9 months Patient noncompliance leads to drug-resistant strains MDR-TB XDR-TB (Extensively drug resistant)
Sinusitis causative agents
Allergies, cold often initially then, Viruses Bacteria: *Most often normal biota Pathogenesis due to underlying infection, buildup of fluids which provides a rich bacterial medium, and the anatomy of the sinuses which can entrap bacteria and mucus Fungi: rare, but recognized when antibacterial drugs fail to alleviate symptoms
Tuberculosis
An ancient human disease: Found in mummies from the Stone Age, Ancient Egypt, and Peru Prevalent cause of disease historically - "Captain of the Men of Death," "The White Plague" Streptomycin reduced rates significantly Now a reemerging disease HIV epidemic MDR - Drug-resistant strains Nearly 1/3 of the world's population is infected Crowding
Mycoplasma pneumoniae; community-acquired pneumonia
Atypical pneumonia: symptoms do not resemble those of pneumococcal or other pneumonias - 'walking pneumonia' Lack a cell wall, irregularly shaped Transmitted by aerosol droplets among individuals in close quarters Diagnosis through ruling out other causes
Tubercles:
Granulomas containing a core of TB bacteria and enlarged macrophages surrounded by an outer wall made of fibroblasts, lymphocytes, and macrophages Can become necrotic caseous (cheese-like) lesions Lesions can become calcified
Influenza signs and symptoms
Headache, chills, dry cough, body aches, fever, stuffy nose, sore throat Extreme fatigue can last for a few days or weeks H1N1 "Swine flu": not all patients had a fever, many patients had gastrointestinal distress, or developed multiorgan system failure
prevention of whooping cough
High vaccination coverage has kept incidence low in the US - shock, encephalopathy, high fever may accompany vaccine Vaccine does not provide lifelong protection Immunity wanes a few years after childhood Increasing incidence in adult patients Disease can be passed to infants who are not yet fully immunized Organism may be evolving, and the current vaccine may not provide the best protection Rise in unvaccinated individuals
Transmission of RSV
Highly contagious and transmitted through droplet contact and fomites
Extrapulmonary tuberculosis
Organs most commonly involved: Regional lymph nodes Intestines Kidneys Long bones Genital tract Brain Meninges
Causative agents of hospital-associated pneumonia
Pseudomonas aeruginosa Acinetobacter baumannii Streptococcus pneumoniae Klebsiella pneumoniae Staphylococcus aureus (usually MRSA) Most cases are polymicrobial in origin
lower respiratory tract
Trachea, bronchi, bronchioles, alveoli
Transmission and epidemiology of tuberculosis
Transmission through fine droplets of respiratory mucus suspended in the air Epidemiological patterns vary with the living conditions of a community or area of the world TB is an infection of poverty Inadequate nutrition/crowded living conditions Debilitation of the immune system Poor access to medical care Lung damage Genetics
Treatment of Diphtheria
antitoxin, penicillin
cause/treatment/prevention of rev
cause: respiratory syntcical virus treatment: ribavirin in severe cases prevention: passive antibody
transmission of sinusitis
direct/indirect contact, endogenous
Antigenic ---- refers to minor changes in viral antigens and antigenic ---- is the result of gene swapping between different strains of the virus
drift shift
common cold transmission
droplet contact and indirect transmission
transmission of diphtheria
droplet contact, direct contact, indirect contact w/ contaminated fomites
transmission of phrangyitis
droplet contact, direct contact, opportunistic, all forms of contact
acute otitis media
ear infection, Another sequelae of the common cold. Viral infections can cause inflammation and buildup of fluid in the eustachian tubes Bacteria can migrate up the eustachian tubes, which increases the inflammatory response
In ------ tuberculosis, the lymph nodes, kidneys, long bones, and other organs can become involved.
extrapulmonary
True/False: The vaccine against influenza provides lifelong protection.
false
True/False: The vaccine against pertussis provides lifelong protection.
false
True/False: There is an effective vaccine available for the common cold
false
True/False: The lower respiratory tract is sterile. Remember the HMP.
false - lungs are not sterile
Legionella pneumophila
gram-negative, displays a variety of shapes First discovered after an American Legion convention in 1976 Widely distributed in aqueous environments Tap water, cooling towers, spas, ponds, other freshwater Opportunistic disease affecting elderly people; rarely seen in healthy children and adults
Patients requiring mechanical ventilation or who have tracheostomy tubes are more susceptible to ------- -associated pneumonia.
hospital
Second and third line defenses of respiratory tract
increased levels of cytokines and antimicrobial peptides, alveolar macrophages, secretory IgA
Alveoli can be found in the (upper/lower) respiratory tract
lower
Normal biota performs the important role of ------ in the upper respiratory tract.
microbial antagonism
Normal biota plays a significant role in
microbial antagonism
Upper respiratory tract infections
most common reason for doctor's visits and most common illness leading to missed work
mucus + cilia
mucociliary escalatortrap, push particles down into throat
Two anatomical methods for trapping bacteria in the respiratory tract are
mucous and cilia
Bacteria considered ------ can cause disease
normal biota S. . pyogenes, H. influenzae, S. pneumoniae, N. meningitidis, S. aureus
treatment of pharyngitis
penicillin, cephlaxin
Respiratory syncytial virus is most serious in -------
premature babies.
transmission of pertussis (whooping cough)
respiratory droplets
transmission of influenza
respiratory droplets, direct or indirect contact
causative organism of otitis media
streptococcus pnemoniae, haemophilus influenza
new data on ear infections suggest
that these infections are most often biofilm infections which are less susceptible to antibiotics
True/False: 1/3 of the world's population is infected with TB.
true
True/False: Organisms considered "normal biota" in the respiratory tract can cause serious disease
true
True/False: Sinusitis, otitis media, and pharyngitis can all be sequelae of the common cold.
true
True/False: There is an effective vaccine available for diphtheria.
true
The larynx is part of the (upper/lower) respiratory tract.
upper
Transmission of Tuberculosis
vehicle - airborne
Secondary (reactivation) tuberculosis
Bacteria remain dormant (latent) in the lungs for weeks, months, or years later Can become reactivated when immunity wanes Severe symptoms: violent coughing, greenish or bloody sputum, low-grade fever, anorexia, weight loss, fatigue, night sweats, and chest pain - "consumption" Untreated disease has a 60% mortality rate
Antigenic drift
Gradual changing of influenza antigens (antibody binding sites change) Results in decreased ability of host memory cells to recognize them
Histoplasma capsulatum
Darling's disease, Ohio Valley fever, spelunker's disease fungus Can be benign or severe, acute or chronic Most serious forms occur in AIDS patients Chronic pulmonary histoplasmosis: signs and symptoms similar to tuberculosis Endemic to all continents except Australia High prevalence in Ohio, Illinois, Missouri, Kentucky, Tennessee, Michigan, Georgia, and Arkansas
signs/symptoms of ear infections
Feeling of fullness or pain in the ear, loss of hearing Young children: irritability, trouble sleeping Infection can cause the eardrum to burst, and more serious infections can result
Primary Tuberculosis
Infectious dose: 10 bacteria Bacteria continue to grow inside alveolar macrophages
Respiratory Syncytial Virus (RSV)
Infects the respiratory tract and produces giant multinucleated cells Outbreaks occur around the world, peak incidence in winter and early spring Mortality highest among premature infants, those with congenital disease, or immunodeficiency
Pharyngitis signs and symptoms
Inflammation of the throat causing pain and swelling Inflammatory packets visible on the walls of the throat, difficulty swallowing, foul breath Viral: mild and leads to hoarseness Bacterial: more painful, often accompanied by fever, headache, and nausea
sinusitis (sinus infection)
Inflammatory condition of any of the four pairs of sinuses in the skull Patients suffering from a cold often also develop sinusitis - sequela.
Diagnosis of Tuberculosis
Mantoux test: shows evidence of delayed hypersensitivity after initial infection with TB Purified protein derivative is injected under the skin and observed for evidence of an induration (bleb) indicating delayed hypersensitivity Blood tests Acid-fast staining of sputum sample PCR methods Chest X-rays verify TB when other tests give indeterminate results
Prevention and treatment; Healthcare-Associated Pneumonia
Most causes are due to aspiration from the upper respiratory tract Elevation of patients' heads 45 degrees helps reduce aspiration of secretions Deep breathing and frequent coughing Proper care of ventilation and respiratory equipment Empiric antibiotic therapy should be started as soon as healthcare-associated pneumonia is suspected
Pneumocystitis (carnii) jiroveci
Most common pneumonia in AIDS patients Traditional antifungal drugs are ineffective against this organism
Treatment of ear infections
Most often, "watchful waiting" for 72 hours Tubes can help alleviate symptoms in recurrent infections
Upper respiratory tract
Mouth, nose, nasal cavity, sinuses, throat (pharynx), epiglottis, larynx
causative organism of tuberculosis
Mycobacterium tuberculosis Long, thin acid-fast rod, strict aerobe Generation time 15 - 20 hours, 6 weeks for colonies to appear Cord factor: lipid (waxy) component in the mycobacterial cell wall associated with virulent strains Makes the organism resistant to drying and disinfectants
Respiratory 1st line of defense
Nasal hairs, ciliated epithelium of trachea and bronchi, mucus, coughing, sneezing, swallowing
Respiratory Syncytial Virus signs/symptoms
Rhinitis, pharyngitis, otitis More serious infections: progress to bronchial tree and parenchyma, symptoms of *croup* and difficulty breathing
Untreated streptococcal infections can result in serious complications:
Scarlet fever Rheumatic fever Glomerulonephritis Necrotizing fasciitis: flesh eating
List and describe three sequelae of streptococcal pharyngitis.
Scarlet fever, glomerular nephtiris, necrotizing facitis
Diphtheria
Significant cause of morbidity and mortality for hundreds of years Immunization with the diphtheria toxoid has caused the number of cases to decline significantly Epidemics and smaller outbreaks have occurred due to a breakdown in immunity due to lack of vaccination
signs/symptoms/distinguishing features of sinusitis
Sinus pain, nasal congestion, pressure, headache or toothache * Discharge is opaque and can be yellow or green in color depending on etiology *
Streptococcus pneumoniae (pneumonia)
Small, gram-positive flattened coccus that appears in pairs Part of the normal biota of the respiratory tract Infection occurs when bacterium inhaled into the deep areas of the lung Capsule prevents phagocytosis Factors that enhance disease: old age, season, underlying viral respiratory disease, diabetes, chronic abuse of alcohol or narcotics Vaccine available
signs/symptoms of the common cold
Sneezing, scratchy throat, runny nose Generally not accompanied by fever Infection can predispose patients to secondary infections *Symptoms usually due to the immune response to the virus, not any particular virulence factors
prevention of influenza
Standard vaccine is 70 - 90% effective Consists of three different inactivated influenza strains that is updated annually - why? FluMist: contains three live, attenuated strains Scientists are continually researching emerging strains to attempt to prevent a pandemic
---------- is the bacterium responsible for 40% of all cases of community-acquired pneumonia.
Streptococcus pneumonia
Community-Acquired Pneumonia causative agent
Streptococcus pneumoniae accounts for 40% of community-acquired cases Viruses account for 30% Mycoplasma accounts for 20% 10% are caused by other organisms Legionella Haemophilus influenzae Histoplasma capsulatum Hantavirus
Pharyngitis causative organism
Streptococcus pyogenes: Gram-positive coccus that grows in chains, facultative anaerobe, produces capsules and slime layer
Antigenic shift
Swapping out of one of the strands of viral RNA with a gene or strand from another virus No recognition by host memory cells Often results in influenza pandemics