RESPIRATORY TRACT INFECTIONS:

Common Cold:

Describe the manifestations and etiology of the common cold

-It affects the upper respiratory tract

-Dryness or stuffiness affecting mainly the nasopharynx

-Excessive production of of nasal secretions & lacrimation

-Secretions are clear & watery

-Reddened & swollen mucous membranes

-Sore throat

-Hoarseness

-Headache

-Generalized malaise

-Chills, fever & exhaustion

RESPIRATORY TRACT INFECTIONS:

Common Cold: 

What is the common cold caused by?

What's the greatest source of spread?

What's the most common portal of entry?

caused by: rhinoviruses, parainfluenza viruses, respiratory syncytial viruses, coronaviruses & adenoviruses

 source of spread: fingers

portal of entry: nasal mucosa & conjunctival surface of the eyes

RESPIRATORY TRACT INFECTIONS:

Rhinosinusitis

-Inflammation of the nose and paranasal sinuses

-Most commonly caused by conditions that block sinus drainage through the narrow ostia

-Some specific conditions are: nasal polyps, barotrauma, swimming, diving, and abuse of nasal decongestants

-Most common cause is when and upper RT infection or allergic rhinitis narrow the ostia & obstructs the flow of mucus

 RESPIRATORY TRACT INFECTIONS:

Rhinosinusitis

Differentiate between the manifestations of acute and chronic rhinosinusitis:

ACUTE RHINOSINUSITIS

-Facial pain, headache, purulent nasal dishcharge

-Decreased sense of smell & fever

-Pain on bending

-Unilateral maxillary pain & pain in the teeth

-History of preceeding common cold & the presence of purulent rhinitis

-Bacterial: worsens after 5-6 days, persists >10 days

-Viral: resolves within 5-7 days without medical treatment

RESPIRATORY TRACT INFECTIONS:

Rhinosinusitis

Differentiate between the manifestations of acute and chronic rhinosinusitis:

CHRONIC RHINOSINUSITIS

-Nasal obstruction

-Sense of fullness in ears

-Postnasal drip

-Hoarseness

-Chronic cough

-Loss of taste and smell or unpleasant breath

-Sinus pain is often absent, & instead there are c/o dull, constant headache

-Reversible epithelial changes

-Irreversible mucosal changes

RESPIRATORY TRACT INFECTIONS:

Influenza

Describe the transmisison, incubation period & infectious period of Influenza.

Which type is most severe?

transmitted: aerosol or direct contact

incubation period: 1-4 days (average of 2 days)

infectious period: 1-5 days

most severe: type A

Pathogenesis of Influenza:

What are the three potential types of infections?

1) An uncomplicated upper respiratory infection (rhinotracheitis)

2) Viral pneumonia

3) Respiratory viral infection followed by a bacterial infection

Pathogenesis of Influenza:

What is the pathogenesis behind a runny nose?

Manifestations of Influenza

Abrupt onset of fever & chills, malaise, muscle aching, headache, profuse & watery nasal discharge, nonproductive cough & sore throat

Rapid onset of profound malaise

-Viral pneumonia occurs as a complication, as well as sinusitis, otis media, bronchitis & bacterial pneumonia

Is it an upper or lower respiratory tract problem?

Are they always caused by an infectious agent?

Inflammation of parenchymal structures of the lung, such as alveoli and bronchioles.

This would be a lower respiratory tract problem.

They are not always caused by an infectious agent

How are they classified?

-Typical pneumonias are caused by bacterial infections

-Atypical pneumonias are caused by viral & mycoplasm infections

RESPIRATORY TRACT INFECTIONS:

Pneumonias

Community acquired pneumonia is defined as:

An infection that begins outside the hospital or is diagnosed within 48 hours after admission to the hospital in a person who has not resided in a long term care facility for 14 days or more before admission.

Identify the microbe that is the single most common cause of community-acquired pneumonia

S. pneumoniae

Hospital acquired pneumonia:

-define

-people at risk

-microbes that cause it

-Also called nosocomial; defined as a lower respiratory tract infectin that was not present or incubation on admission to the hospital

-persons requiring mechanical ventilation, compromised immune function, chronic lung disease, airway instrumentation (intubation & tracheotomy) are persons at risk for this

-caused by Pseudomonas aeruginosa, S. aureus, Enterbacter species, Klebsiella species, Escherichia coli & Serratia

RESPIRATORY TRACT INFECTIONS:

Pneumonias

Why are hospital acquired pneumonias more difficult to treat?

Because the organisms responsible for this are different from those responsible for community-acquired pneumonia and many of them have acquired antibiotic resistance.

Acute Bacterial (typical) Pneumonia

What 3 conditions predispose someone to developing pneumonia?

1) Loss of cough reflex

2)Damage to the ciliated epithelium that lines the respiratory tract

3) Impaired immune defenses

Compare & contrast causes & signs and symptoms of S. pneumoniae & Legionnaire's disease

S. pneumoniae (Pneumococcal) Pneumonia:

cause

s/s

cause: S. pneumoniae

-It starts with attachment and colonization in the nasopharynx; depending on the age and health of the individual, it may spread to lower respiratory tract and signs and symptoms ensue

signs & symptoms: sudden onset, malaise, severe shaking chill & fever as high as 106 degrees; watery sputum, pleuritic pain, dry or productive cough; abnormal chest x-ray showing infiltrates in either a single lobe or may be diffuse; WBC count elevated to more than 10,000, breath sounds with crackles; elderly lose appetite & mental status deterioration

Compare & contrast causes & signs and symptoms of S. pneumoniae & Legionnaire's disease

Legionnaire's Disease

caused by?

signs and symptoms

cause: Legionella pneumophila

signs & symptoms: pneumonia, diarrhea, hyponatremia & confusion are characteristic of this; also, occurs 2-10 days after infection, chest x-ray indicating infiltrates, GI disturbances, diarrhea, hyponatremic, confusion, malaise, weakness, lethargy, fever >104, non productive cough, positive antigens in urine for L. pneumophila, CNS disturbances: arthralgias

Primary (atypical) Pneumonias:

Characteristics?

Most common Cause?

characteristics: patchy inflammatory changes in the lungs, largely confined to the alveolar septa & pulmonary interstitium

most common cause: Mycoplasma pneumoniae

-atypical means that there is a lack of lung consolidation/productive

Primary (atypical) Pneumonias:

Clinical course

Symptoms

clinical course: varies from a mild infection to a fatal outcome

symptoms: fever, headache, muscle aches & pains, dry hacking cough; when it gets severe there is alveolar necrosis and inflammation

The biggest cause of death from a single infectious agent!!!

What kind of settings does TB occur more commonly?

Why has the rate of this increased in recent years?

-People with HIV, persons born in foreign countries where there is a high incidence, residents of high risk congregate settings: jails, drug treatment facilities & homeless shelters

-The rate has increased in recent years due to antibiotic resistance.

Describe the route of transmission.

Cause: M. tuberculosis hominis

Transmission: through airborne route; When a person with active TB coughs or sneezes or talks, TB is spread by minute, invisible particles, also called droplet nuclei that are harbored in the respiratory secretions of persons with active TB. The droplet nuclei remain suspended in the air, circulating by air currents.

Pathogenesis

-Inhaled droplet passes bronchial tree & implants on the alveoli.

-Bacilli are surround & englufed by macrophages which initiates a cell mediated immune response that eventually contains the infection.

-Tubercle bacilli grows slowly, infected macrophages degrade the mycobacteria and present the antigen to T lymphocytes to increase concentration of lytic enzymes, which also damage lung tissue

-This process takes 2-3 weeks to become effective; it is during this time that the test becomes positive, indicating cell mediated hypersensitivity response

-A Ghon focus, which contains tubercle bacilli, modified macrophages & other immune cells, develops in persons with intact cell-mediated response

-Tubercle bacilli drain along lymph channels to tracheobronchial lymph nodes of affected lung

-The primary lung lesion with lymph node granulomas are called  Ghon complex

Differentiate between primary & secondary tuberculosis as to pathogenesis & manifestations:

Primary Tuberculosis

-Develops in previously unexposed and unsensitized persons, hence the name primary

-Persons with this do not have symptoms, do not have active disease and are not contagious

Primary Tuberculosis:

Identify the manifestations of primary TB in persons who are immunocompromised.

-they go on to develop progressive primary tuberculosis with continued destruction of lung tissue and spread to multiple sites in lung

-they are more likely to develop progressive TB

Secondary Tuberculosis

Represents what?

Occurs in situations of?

Signs and symptoms

Represents either reinfection from inhaled droplet nuclei or reactivation of a previously healed primary lesion

Occurs in situations of impaired host defenses

signs & symptoms: cough (due to smoking or cold--at first it's dry, but becomes productive with purulent, sometimes blood tinged sputum), low grade fevers, night sweats, easy fatigability, anorexia, weight loss; if advanced: dyspnea & orthopnea

Diagnosis of TB

TB skin test measures??

Is a positive TB life long?

Does a positive test indicate an active infection?

What does it indicate?

-TB skin test measures delayed hypersensitivity that follows exposure to the tubercle bacillus

-A positive TB is life long

-Just because the TB test is positive, it does not mean that there is an active infeciton, it just means that there has been exposure to the bacillus & that cell mediated immunity to the organism has developed

How is active pulmonary TB diagnosed?

Identify the cause & manifestations of fungal infections

Causes:

-Opportunistic infections caused by low virulence organisms which may cause localized or system infections in people who are immunocompromised.

-Deep seated infection caused by highly virulent dimorphic fungi--it invades tissue and causes systemic infection

-Histoplasma capsulatum, coccidioides immitis & Blastomyces dermatitidis

RESPIRATORY TRACT INFECTIONS:

Fungal Infections 

What fungal infections are seen in folks living in Missouri?

Where is it acquired?

-H. capsulatum, causes histoplasmosis

-Acquired by inhaling the fungal spores that are released from the dust or dirt from the infected areas

-Symptoms are similar to tuberculosis; the disease can take three forms:

1) Acute Primary disease: nodules of aggregates of machrophages w/engulfed microorganisms and manifestations of: mild, self-limited flu like symptoms

2) Chronic cavity disease: resembles secondary TB with manifestations of: productive cough, fever, night sweats & weight loss

 3) Disseminated disease: high fever, generalized lymph node enlargement, hepatosplenomegaly, muscle wasting, anemia, leukopenia & thrombocytopenia; meningitis often becomes a dominant feature of the disease

Serious?

Causes?

-It is serious because it is the leading cause of cancer deaths for men and women in the United States

-Causes: smoking, asbestos exposure, exposure to dusts containing arsenic, chromium nickel & vinyl chloride

CANCER OF THE LUNG

Bronchogenic Carcinoma: describe the incidence of the various types of bronchogenic carcinoma: Small cell v. Non small cell lung cancers

Small Cell Lung Cancers: strongly associated with cigarette smoking; highly malignant, infiltrate widely and disseminate early

Non-Small Cell Lung Cancers:

-Squamous cell carcinoma is found primarily in men and is related to smoking

-Adenocarcinoma is found in women and nonsmokers

-Large cell carcinoma tends to metastasize to distant sites early in the course.

CANCER OF THE LUNG

Manifestations of Bronchogenic Carcinoma

Earliest symptoms: chronic cough, shortness of breath, wheezing

When tumor invades mediastinum: hoarseness, difficulty swallowing, superior vena cava syndrome, dull intermittent, poorly localized retrosternal pain

When tumor invades the pleura: atelectasis & dyspnea; pain is persistent, localized and more severe

CANCER OF THE LUNG

What are the common sites of metastasis of bronchogenic carcinomas?

CANCER OF THE LUNG

Which type of lung cancer is especially known to cause paraneoplastic syndromes?

RESPIRATORY DISORDERS IN CHILDREN

Upper airway Infections:

RESPIRATORY DISORDERS IN CHILDREN

Upper airway Infections:

Viral Croup

-Characterized by inspiratory stridor, hoarseness and a barking cough

-Affects the larynx, trachea and bronchi

-Occurs in children from 3 months to 5 years and is usually preceded by upper respiratory infections that cause rhinorrhea, coryza, hoarsenss & a low grade fever

RESPIRATORY DISORDERS IN CHILDREN

Upper airway Infections:

Spasmodic Croup

-Similar to acute viral croup.

-It may have an allergic origin.

-It occurs at night and recurs with respiratory tract infections

RESPIRATORY DISORDERS IN CHILDREN

Upper airway Infections:

Epiglottitis

-Potentially fatal and is caused by a variety of bacteria

-Occurs in children 2-7 years old

-It can cause complete airway obstruction and can lead to death in a matter of hours if not treated adequately

-Manifestations: lethargy, chin forward, difficulty swallowing, muffled voice, drooling, fever, extreme anxiety, stridor, flaring of nares, pale and toxic appearance, moderate to severe respiratory distress

RESPIRATORY DISORDERS IN CHILDREN

Upper airway Infections:

Lower Airway Infections: ACUTE BRONCHIOLITIS

-Defined as a viral infection of the lower airways

-Caused by the respiratory syncytial virus

-Seen during the first two years of life with a peak from 3-6 months

-Manifestations: fever, diminished appetite, gradual development of respiratory distress, wheezy cough, dyspnea, irritability, trouble exhaling, hypoxemia, hypercapnia (in severe cases), cyanosis, pallor, listlessness, sudden dimunition or absence of breath