PNEUMONIA Flashcards
Pneumonia
is an acute infection of the lung parenchyma.
Pneumonia Etiology
Pneumonia is more likely to occur when defense mechanisms become incompetent or are overwhelmed by the virulence or quantity of infectious agents.
Mechanisms that create a mechanical barrier to microorganisms
air filtration, epiglottis closure over the trachea, cough reflex, mucociliary escalator mechanism, and reflex bronchoconstriction
Immune defense mechanisms include
secretion of immunoglobulins A and G and alveolar macrophages.
Pneumonia is more likely to occur when defense mechanisms become
incompetent or are overwhelmed by the virulence or quantity of infectious agents.
Decreased consciousness
weakens the cough and epiglottal reflexes, which may allow aspiration of oropharyngeal contents into the lungs.
Tracheal intubation
bypasses normal filtration processes and interferes with the cough reflex and mucociliary escalator mechanism.
What changes that occur with aging also impair the mucociliary mechanism?
Air pollution, cigarette smoking, viral URIs, and normal changes that occur with aging can also impair the mucociliary mechanism.
Chronic diseases
can suppress the immune system’s ability to inhibit bacterial growth.
Risk Factors for Pneumonia
- Abdominal or thoracic surgery
- Age >65 yr
- Air pollution
- Altered consciousness: alcoholism, head injury, seizures, anesthesia, drug overdose, stroke
- Bed rest and prolonged immobility
- Chronic diseases: chronic lung and liver disease, diabetes mellitus, heart disease, cancer, chronic kidney disease
- Debilitating illness
- Exposure to bats, birds, rabbits, farm animals
- Immunosuppressive disease and/or therapy (corticosteroids, cancer chemotherapy, human immunodeficiency virus [HIV] infection, immunosuppressive therapy after organ transplant)
- Inhalation or aspiration of noxious substances
- Intestinal and gastric feedings via nasogastric or nasointestinal tubes
- IV drug use
- Malnutrition
- Recent antibiotic therapy
- Resident of a long-term care facility
- Smoking
- Tracheal intubation (endotracheal intubation, tracheostomy)
- Upper respiratory tract infection
Organisms that cause pneumonia reach the lung by three ways:
- Aspiration of normal flora from the nasopharynx or oropharynx. Many organisms that cause pneumonia are normal inhabitants of the pharynx in healthy adults.
- Inhalation of microbes present in the air. Examples include Mycoplasma pneumoniae and fungal pneumonias.
- Hematogenous spread from a primary infection elsewhere in the body. Examples are streptococci and Staphylococcus aureus from infective endocarditis.
Types of Pneumonia
community-acquired or hospital-acquired pneumonia.
Potential causes of pneumonia
Bacteria, viruses, Mycoplasma organisms, fungi, parasites, and chemicals
Organisms Causing Pneumonia -
Community-Acquired Pneumonia
- Streptococcus pneumoniae*
- Mycoplasma pneumoniae
- Haemophilus influenzae
- Respiratory viruses
- Chlamydophila pneumoniae
- Chlamydophila psittaci
- Coxiella burnettii
- Legionella pneumophila
- Oral anaerobes
- Moraxella catarrhalis
- Staphylococcus aureus
- Pseudomonas aeruginosa
- Enteric aerobic gram-negative bacteria (e.g., Klebsiella species)
- Fungi
- Mycobacterium tuberculosis
Organisms Causing Pneumonia
Hospital-Acquired Pneumonia
- Pseudomonas aeruginosa†
- Escherichia coli†
- Klebsiella pneumoniae†
- Acinetobacter species†
- Haemophilus influenzae
- Staphylococcus aureus
- Streptococcus pneumoniae
- Proteus species
- Enterobacter species
- Oral anaerobes
Community-acquired pneumonia (CAP)
is an acute infection of the lung occurring in patients who have not been hospitalized or resided in a long-term care facility within 14 days of the onset of symptoms.
(CAP) The decision to treat the patient at home or admit him or her to the hospital is based on several factors
patient’s age, vital signs, mental status, presence of co-morbid conditions, and current physiologic condition
Assessing Pneumonia Using CURB-65
may be used as a supplement to clinical judgment to determine the severity of pneumonia and if patients need to be hospitalized.
The CURB-65 scale - Identifying the Level of Risk
Patients receive 1 point for each of the following indicators:
- C: Confusion (compared to baseline)
- U: BUN >20 mg/dL
- R: Respiratory rate ≥30 breaths/min
- B: Systolic blood pressure <90 mm Hg or diastolic blood pressure ≤60 mm Hg
- 65: ≥Age 65 yr
CURB-65 scale - Scoring and Decision Making
0 Treat at home
1-2 Consider hospital admission
3 or more Hospital admission
4-5 Consider admission to intensive care unit
Empiric antibiotic therapy
the initiation of treatment before a definitive diagnosis or causative agent is confirmed, should be started as soon as CAP is suspected.
Hospital-acquired pneumonia (HAP)
pneumonia in a non intubated patient that begins 48 hours or longer after admission to hospital and was not present at the time of admission.
Ventilator-associated pneumonia (VAP)
type of HAP, refers to pneumonia that occurs more than 48 hours after endotracheal intubation.
Once the diagnosis of HAP or VAP is made treatment of pneumonia is initiated based on
known risk factors, early versus late onset, and probable organism. Antibiotic therapy can be adjusted once the results of sputum cultures identify the exact pathogen.
Both HAP and VAP are associated with
longer hospital stays, increased associated costs, sicker patients, and increased risk of morbidity and mortality.
A major problem in treating pneumonia today is
development of multidrug-resistant (MDR) organisms.
- methicillin-resistant Staphylococcus aureus and
- gram-negative bacilli.
Risk factors for development of multidrug-resistant MDR pneumonia include
advanced age, immunosuppression, history of antibiotic use, and prolonged mechanical ventilation.
MDR organisms also increase
the morbidity and mortality risks associated with pneumonia.
Aspiration pneumonia
the abnormal entry of material from the mouth or stomach into the trachea and lungs.
Conditions that increase the risk of aspiration
decreased level of consciousness (e.g., seizure, anesthesia, head injury, stroke, alcohol intake), difficulty swallowing, and insertion of nasogastric tubes with or without tube feeding.
The aspirated material (food, water, vomitus, or oropharyngeal secretions) triggers
an inflammatory response.
The most common form of aspiration pneumonia
primary bacterial infection
Until cultures are completed and results obtained, initial antibiotic therapy is based on
an assessment of probable causative organism, severity of illness, patient factors (e.g., malnutrition, current use of antibiotic therapy), and ability to treat common community-acquired organisms.
For patients who aspirate in hospitals, appropriate antibiotics should include
coverage for both gram-negative organisms and MRSA.
aspiration of acidic gastric contents causes
chemical (noninfectious) pneumonitis, which may not require antibiotic therapy.
However, secondary bacterial infection can occur 48 to 72 hours later.
Necrotizing pneumonia
rare complication of bacterial lung infection.
It is characterized by liquefaction and, in some situations, cavitation of lung tissue. Often occurs as a result (CAP)
Signs and symptoms of necrotizing pneumonia include
immediate respiratory insufficiency and/or failure, leukopenia, and bleeding into the airways. Lung abscesses commonly occur.
Treatment often includes long-term antibiotic therapy and possible surgery.
Opportunistic pneumonia
inflammation and infection of the lower respiratory tract in immunocompromised patients.
Individuals at risk for opportunistic pneumonia include
those with altered immune responses: severe protein-calorie malnutrition or immunodeficiencies (e.g., human immunodeficiency virus [HIV] infection) and those receiving radiation therapy, chemotherapy, and any immunosuppressive therapy, including long-term corticosteroid therapy.
P. jiroveci pneumonia (PJP)
symptoms of fever, tachypnea, tachycardia, dyspnea, nonproductive cough, and hypoxemia. The chest x-ray usually shows diffuse bilateral infiltrates. lungs have massive consolidation.
cytomegalovirus (CMV)
can cause viral pneumonia. asymptomatic or mild, but severe disease can occur in people with an impaired immune response
cytomegalovirus (CMV) treatment.
Antiviral medications (e.g., ganciclovir [Cytovene], foscarnet [Foscavir], cidofovir) and high-dose immunoglobulin are used for treatment.
pneumonia pathophysiologic changes
trigger an inflammatory response in the lungs w/ch attracts more neutrophils, edema of the airways occurs, and fluid leaks from the capillaries and tissues into alveoli. leading to hypoxia (e.g., tachypnea, dyspnea, tachycardia)
Consolidation
occurs when the normally air-filled alveoli become filled with fluid and debris. Mucus production also increases, which can potentially obstruct airflow and impair gas exchange even further.
symptoms of pneumonia
cough/may or may not be productive, fever, chills, dyspnea, tachypnea, and pleuritic chest pain. Sputum may appear green, yellow, or even rust colored (bloody).
Viral pneumonia may initially be seen as
influenza, with respiratory symptoms appearing and/or worsening 12 to 36 hours after onset.