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