Chapter 9 Respiratory Tract Flashcards
at its core, what is pneumonia?
Infection of the lung parenchyma
What types of impairments to normal defense mechanisms can lead to pneumonia? 3
impaired cough reflex
Damage to mucociliary escalator
mucus plugging
What are 7 clinical features of pneumonia?
Fever chills tachypnea with pleuritic chest pain decreased breath sounds dullness to percussion elevated WBC
How is diagnosis of pneumonia made?
CXR, sputum gram stain and culture, and blood cultures
What are three typical patterns seen on xray in pneumonia?
Lobular pneumonia, bronchopneumonia, interstitial pneumonia
What is lobular pneumonia characterized by?
Consolidation of an entire lobe of the lung
What is usually the cause of lobular pneumonia? bacteria vs viral
Usually bacteria
What are the classic gross phases of lobular pneumonia? 4
1 Congestion- due to congested vessels and edema
2 Red Hepatization - due to exudate, neutrophils, and hemorrhage filling the alveolar air spaces, giving the normally spongy lung a solid consistency
3 Gray Hepatization - due to degradation of red cells within exudate
4 Resolution (regeneration from type II pneumocytes
What is Bronchopneumonia characterized by?
Scattered patchy consolidation centered around bronchioles; often multifocal and bilateral
What is Bronchopneumonia caused by? bacteria vs virus
variety of bacterial orga
What is interstitial (atypical) pneumonia characterized by?
diffuse interstitial infiltrates without major consolidation. Increased lung markings on CXR
How does Interstitial pneumonia present?
Presents with relatively mild upper respiratory symptoms (minimal sputum and low fever); ‘atypical’ presentation
What is interstitial pneumonia caused by? bacteria vs virus?
Caused by both bacteria and viruses
What are the two most common organisms that cause lobular pneumonia?
Streptococcus pneumoniae (95%) Klebsiella pneumoniae
What are the high yield associations for streptococcus pneumoniae in the setting of lobular pneumonia?
Most common cause of community acquired pneumonia and secondary pneumonia (bacterial pneumonia superimposed on a viral URI); usually seen in middle aged adults and the elderly
What are the high yield associations for klebsiella pneumoniae in the setting of lobular pneumonia?
Enteric flora that is aspirated; affects malnourished and debilitated individuals. especially elderly in nursing homes, alcoholics, and diabetics. Thick mucoid capsule results in gelatinous sputum (currant jelly); often complicated by abscess.
Name five organisms that cause bronchopneumonia?
Staph aureus Haemophilus influenzae P. Aeruginosa Moraxella catarrhalis legionella pneumophila
What are the high yield associations of staph aureus?
Most common cause of secondary pneumonia; often complicated by abscess or empyema
What are the high yield associations of haemophilus influenzae?
Common cause of secondary and pneumonia superimposed on COPD (leads to exacerbation of COPD)
What are the high yield associations of pseudomonas aeruginosa?
pneumonia in CF patients
What are the high yield associations of moraxella catarrhalis?
Community acquired pneumonia and pneumonia superimposed on COPD (leads to exacerbation of COPD)
What are the high yield associations of legionella pneumophila?
Community acquired pneumonia, pneumonia superimposed on COPD, or pneumonia in immunocompromised states; transmitted from water source, intracellular organism that is best visualized by a silver stain
What are six organisms that cause interstitial pneumonia?
Mycoplasma pneumoniae chlamydia pneumonia Respiratory syncytial virus (RSV) Cytomegalovirus (CMV) Influenza virus Coxiella burnetii
What are the high yield associations of mycoplasma pneumoniae?
Most common cause of atypical pneumonia, usually affects young adults (classically military recruits or college students living in a dormitory). Complications include autoimmune hemolytic anemia (IgM against I antigen on RBCs causes cold hemolytic anemia) and erythema multiforme. Not visible on gram stain due to lack of cell wall.
What are the high yield associations of chlamydia pneumonia?
second most common cause of atypical pneumonia in young adults
What are the high yield associations of respiratory syncytial virus?
most common cause of atypical pneumonia in infants
What are the high yield associations of influenza virus?
Atypical pneumonia in the elderly, immunocompromised, and those with preexisting lung disease. Also increases the risk for superimposed S aureus or H influenzae bacterial pneumonia
What are the high yield associations of Coxiella burnetii
Atypical pneumonia with high fever (Q fever, normally have low fevers); seen in farmers and veterinarians (Coxiella spores are deposited on cattle by ticks or are present in cattle placentas). Coxiella is a rickettsial organism, but it is distinct from most rickettsiae because it 1 causes pneumonia, 2 does not require arthropods vectors for transmission (survives as highly heat resistant endospores), and 3 does not produce skin rash.
What patients is aspiration pneumonia typically seen in?
patients with risk for aspiration (eg. alcoholics and comatose patients)
What is aspiration pneumonia often due to?
anaerobic bacteria in the oropharynx (eg. bacteroides, fusobacterium, and peptococcus)
What does aspiration pneumonia classically result in?
Right lower lobe abscess
What is TB due to?
Inhalation of aerosolized mycobacterium tuberculosis
What does primary TB arise from and what does it result in?
Initial exposure, results in focal, caseating necrosis in the lower lobe of the lung and hilar lymph nodes that undergoes fibrosis and calcification, forming a Ghon complex
Where is a ghon complex usually seen?
Subpleural or hilar lymph nodes
Is primary TB symptomatic? what effect does it have on a PPD?
Usually asymptomatic and causes a positive PPD
What causes secondary TB?
reactivation of Mycobacterium tuberculosis
What is reactivation commonly due to in TB?
AIDS; may also be seen with agin
Where does secondary TB occur at?
Apex of the lung (relatively poor lymphatic drainage and high oxygen tension)
What does secondary TB form?
cavitary foci of caseous necrosis; may also lead to miliary pulmonary TB or tuberculosis bronchopneumonia
What are the clinical features of secondary TB?
fevers and night sweats, cough with hemoptysis, and weight loss
What does biopsy reveal in secondary TB?
caseating granulomas; AFB stain reveals acid fast bacilli in cords.
What tissues can systemic spread of secondary TB affect? which are the most common?
can affect any tissue; common sites include meninges (menigitis), cervical lymph nodes, kidneys (sterile pyuria), and lumbar vertebrae (Pott Disease)
How does TB meningitis present?
Usually involves the base of the brain, so meningitis with granulomas in the base of the brain
What are COPD disease characterized by?
airway obstruction; lung does not empty air; and air is trapped.
Describe the changes in FVC, FEV1, FEV1:FVC, and TLC in COPD?
vFVC, vvFEV1, vFEV1:FVC, ^TLC
How is chronic bronchitis defined?
Chronic productive cough lasting at least 3 months over a minimum of 2 years\
What is chronic bronchitis highly associated with?
smoking
What is chronic bronchitis characterized by?
hypertrophy of bronchial mucinous glands (cough up buckets of mucus). leads to increased thickness of mucus glands relative to bronchial wall thickness (Reid index increases to >50%; normal is <40%)
What are the clinical features of Chronic Bronchitis?
productive cough due to excessive mucus production. cyanosis (‘blue bloaters’) - mucus plugs trap CO2; increase PaCO2 and decreased PaO2. Increased risk of infection and cor pulmonale.
What is cor pulmonale?
Diffuse hypoxia results in globally pulmonary vasoconstriction and leading to RV hypertrophy and eventually RV failure.
What happens in emphysema?
destruction of alveolar air sacs. Loss of elastic recoil and collapse of small airways during exhalation results in obstruction and air trapping
What is emphysema due to?
imbalance of proteases and antiproteases.
What leads to the imbalance in in proteases and antiproteases in ephysema?
1 inflammation in the lung normally leads to release of proteases by neutrophils and macrophages.
2 alph1-antitrypsin (A1AT, inhibited by cigarette smoke) neutralizes proteases
3 excessive inflammation or lack of A1AT leads to destruction of the alveolar air sacs
What is the most common cause of emphysema and why?
Smoking, pollutants in smoke lead to excessive inflammation and protease mediated damage.
What pattern of emphysema arises in smokers?
centriacinar emphysema that is most severe in the upper lobes