CH9 - Respiratory Tract Pathology Flashcards
What is rhinitis?
Inflammation of the nasal mucosa;
What is the most common cause of rhinitis?
adenovirus
What does rhinitis present with?
sneezing, congestion, and runny nose (common cold)
What is allergic rhinitis?
a subtype of rhinitis due to a type I hypersensitivity reaction (e.g. to pollen)
What is allergic rhinitis characterized by?
an inflammatory infiltrate with eosinophils
What is allergic rhinitis characterized by?
associated with asthma and eczema
What is a nasal polyp?
Protrusion of edematous, inflamed nasal mucosa
What is a nasal polyp usually secondary to?
repealed bouts of rhinitis; also occurs in cystic fibrosis and aspirin - intolerant asthma
What is aspirin-intolerant asthma characterized by?
the triad of asthma, aspirin induced bronchospasms, and nasal polyps;
What is the incidence of asprin-intolerant asthma in asthmatic adults?
seen in 10% of asthmatic adults
What is angiofibroma?
Benign tumor of nasal mucosa composed of large blood vessels and fibrous tissue
In whom is angiofibroma classically seen?
in adolescent males
What does angiofibroma present with?
profuse epistaxis
What is nasopharyngeal carcinoma?
Malignant tumor of nasopharyngeal epithelium
What is nasopharyngeal carcinoma associated with?
EBV
Who is nasopharyngeal carcinoma classically seen in?
African children and Chinese adults
What happens in a biopsy of nasopharyngeal carcinoma?
usually reveals pleomorphic keratin-positive epithelial cells (poorly differentiated squamous cell carcinoma) in a background of lymphocytes
How does nasopharyngeal carcinoma often present?
with involvement of cervical lymph nodes
What is acute epiglottitis?
Inflammation of the epiglottis
What is the most common cause of acute epiglottitis?
H. influenzae type b especially in nonimmunized children
What does acute epiglottitis present with?
high fever, sore throat, drooling with dysphagia, muffled voice, and inspiratory stridor; risk of airway obstruction
What is laryngotracheobronchitis?
(croup) Inflammation of the upper airway
What is the most common cause of laryngotracheobronchitis?
parainfluenza virus
What does laryngotracheobronchitis present with?
a hoarse, (barking) cough and inspiratory stridor
What is a vocal cord nodule?
(singer?s nodule) nodule that arises on the true vocal cord
What is a vocal cord nodule due to?
excessive use of vocal cords, usually bilateral
What is a vocal cord nodule composed of?
degenerative (myxoid) connective tissue
How does a vocal cord nodule present?
with hoarseness; resolves with resting of voice
What is laryngeal papilloma?
Benign papillary tumor of the vocal cord
What is laryngeal papilloma due to?
HPV 6 and 11
What is usually the difference between papillomas in adults children?
Papilloma are usually single in adults and multiple in children.
What does laryngeal papilloma present with?
hoarseness
What is laryngeal carcinoma?
squamous cell carcinoma usually arising from the epithelial lining of the vocal cord
What are the risk factors for laryngeal carcinoma?
alcohol and tobacco; can rarely arise from a laryngeal papilloma
What does laryngeal carcinoma present with?
hoarseness; other signs include cough and stridor
What are some pulmonary infections?
Pneumonia, lobar pneumonia, bronchopneumonia, interstitial (atypical pneumonia), aspiration pneumonia, tuberculosis
What is pneumonia?
Infection of the lung parenchyma
When does pneumonia occur?
when normal defenses are impaired (e.g.. impaired cough reflex, damage to mucociliary escalator, or mucus plugging)
What are the clinical features of pneumonia?
include fever and chills, productive cough with yellow-green (pus) or rusty (bloody) sputum, tachypnea with pleuritic chest pain, decreased breath sounds, dullness to percussion, and elevated WBC count
How is the diagnosis for pneumonia made?
by chest x-ray, sputum gram stain and culture, and blood cultures.
What are the three patterns that are classically seen on chest x-ray for pneumonia?
lobar pneumonia, bronchopneumonia, and interstitial pneumonia.
What is lobar pneumonia?
Characterized by consolidation of an entire lobe of the lung
What are the most common causes for lobar pneumonia?
Usually bacterial; most common causes are Streptococcus pneumoniae (95%) and Klebsiella pneumoniae
What are the classic gross phases of lobar pneumonia?
1) Congestion, 2) red hepatization, 3) gray hepatization, 4) resolution
In lobar pneumonia what is the congestion due to?
congested vessels and edema
In lobar pneumonia what is red hepatization due to?
exudate, neutrophils, and hemorrhage tilling the alveolar air spaces, giving the normally spongy lung a solid consistency
In lobar pneumonia what is gray hepatization due to?
degradation of red cells within the exudate
What is bronchopneumonia?
Characterized by scattered patchy consolidation centered around bronchioles; often multifocal and bilateral
What is bronchopneumonia caused by?
a variety of bacterial organisms
What is interstitial (atypical) pneumonia characterized by?
diffuse interstitial infiltrates
How does interstitial (atypical) pneumonia present?
with relatively mild upper respiratory symptoms (minimal sputum and low fever); atypical presentation
What is interstitial (atypical) pneumonia caused by?
bacteria or viruses
What is the most common cause of community-acquired pneumonia?
Streptococcus pneumoniae
What is streptococcus pneumonia usually seen in?
middleaged adults and elderly
Who does Klebsiella pneumoniae affect?
malnourished and debilitated individuals, especially elderly in nursing homes, alcoholics, and diabetics (enteric flora that is aspirated).
What does Klebsiella pneumoniae result in?
Thick mucoid capsule results in gelatinous sputum (currant jelly); often complicated by abscess
What are the causes of bronchopneumonia?
Staphylococcus aureus, haemophilus influenzae, Pseudomonas aeruginosa, Moraxella calarrhalis, Legionella pnemnophila
What is the most common cause of secondary pneumonia?
Staphylococcus aureus
What is secondary pneumonia?
bacterial pneumonia superimposed on a viral upper respiratory tract infection
What is secondary pneumonia caused by staphylococcus aureus often complicated by?
abscess or emphyzema
Haemophilus influenzae is the most common cause of what type of pneumonia?
secondary pneumonia and pneumonia superimposed on COPD
How does haemophilus influenzae affect COPD?
It results in exacerbation of COPD?
What does pseudomonas aeruginosa cause?
Pneumonia in cystic fibrosis patients
What high yield association should be made with moraxella calarrhalis?
Community-acquired pneumonia and pneumonia super imposed on COPD (leads to exacerbation of COPD)
What high yield association should be made with Legionella pnemnophila?
Community-acquired pneumonia, pneumonia superimposed on COPD, or pneumonia in immunocompromised states;
How is Legionella pnemnophila transmitted?
from water source
How is Legionella pnemnophila best visualized?
Its an intracellular organism best visualized by silver stain
What is the most common cause of atypical pneumonia?
Mycoplasma pneumonia
What is the high yield association with mycoplasma pneumoniae?
Most common cause of atypical pneumonia, usually affects young adults (classically, military recruits or college students living in a dormitory).
What are the complications for mycoplasma pneumoniae?
they include autoimmune hemolytic anemia (IgM against I antigen on RBCs causes cold hemolytic anemia) and erythema multiforme. Not visibie on gram stain due to lack of cell wall
What is the second most common cause of atypical pneumonia in young adults?
Chlamydia pneumoniae
What is the most common cause of atypical pneumonia in infants?
Respiratory syncytial virus (RSV)
What causes atypical pneumonia with posttransplant immunosuppressive therapy?
Cytomegalovirus (CMV)
What does influenza virus cause?
atypical pneumonia in the elderly, immunocompromised, and those with preexisting lung disease
What does Influenza virus also increase the risk for?
superimposed S aureus or H influenzae bacterial pneumonia
What does coxiella burnetii cause?
atypical pneumonia with high fever (Q fever);
Who is coxiella burnetii seen in?
farmers and veterinarians
What happens to coxiella spores?
They are deposited on cattle by ticks or are present in cattle placentas
What is coxiella?
it is a rickettsial organism,
How is coxiella distinct from most rickettsiae?
because it (1) causes pneumonia, (2) does not require an arthropod vector for transmission (survives as highly heat-resistant endospores), and (3) does not produce a skin rash.
What is aspiration pneumonia seen in?
patients at risk for aspiration (e.g., alcoholics and comatose patients)
What is aspiration pneumonia most often due to?
anaerobic bacteria in the oropharynx (e.g., Bacteroides, Fusobacterium, and Peptococcus)
What does aspiration pneumonia classically result in?
a right lower lobe abscess
What is the anatomical difference between the right and left main stem bronchus?
branches at a less acute angle than the left.
What is tuberculosis due to?
inhalation of aerosolized mycobacterium tuberculosis
What arises with initial tuberculosis exposure?
Primary TB
What does primary TB result in?
focal, caseating necrosis in the lower lobe of the lung and hilar lymph nodes that undergoes fibrosis and calcification, forming a Ghon complex
What are generally the symptoms for primary TB?
Generally asymptomatic but leads to a positive PPD
What does secondary TB arise with?
reactivation of mycobacterium tuberculosis
What is reactivation of mycobacterium tuberculosis in secondary TB commonly due?
AIDS; may also be seen with aging
Where does secondary TB occur?
at apex of lung (high oxygen tension)
What does secondary TB form?
cavitary foci of caseous necrosis; may also lead to miliary pulmonary TB or tuberculous bronchopneumonia
What are the clinical features of secondary TB?
include fevers and night sweats, cough with hemoptysis, and weight loss.
What does biopsy in secondary TB reveal?
caseating granulomas, AFB stain reveals acid-fast bacilli
How might secondary TB spread?
Systemic spread often occurs and can involve any tissue; common sites include meninges (meningitis), cervical lymph nodes, kidneys (sterile pyuria), and lumbar vertebrae (Pott disease).
What is COPD?
Group of diseases characterized by airway obstruction; lung does not empty, and air is trapped.
What happens to the FVC and FEV in COPD?
Volume of air that can be forcefully expired is decreased (FVC), especially during the first second of expiration (FEV) results in decreased FEV:FVC ratio
What happens to total lung capacity in COPD and why?
Total lung capacity (TLC) is usually increased due to air trapping.
What happens in chronic bronchitis?
Chronic productive cough lasting at least 3 months over a minimum of 2 years; highly associated with smoking
What characterizes chronic bronchitis?
hypertrophy of bronchial mucinous glands
What does chronic bronchitis lead to?
increased thickness of mucus glands relative to overall bronchial wall thickness (Reid index increases to > 50%; normal is < 40%).
What are the clinical features for chronic bronchitis?
- Productive cough due to excessive mucus production 2. Cyanosis (blue bloaters) Mucus plugs trap carbon dioxide; increased PaCO2, and decreased PaO2
In chronic bronchitis what is there an increased risk of?
infection and cor pulmonale
What is emphysema?
Destruction of alveolar air sacs
What does emphysema result in?
Loss of elastic recoil and collapse of airways during exhalation results in obstruction and air trapping.
What is emphysema due to?
imbalance of proteases and antiproteases
What does inflammation in the lung normally lead to?
release of proteases by neutrophils and macrophages.
What neutralizes proteases?
A1-antitrypsin (A1AT)
In emphysema what leads to destruction of the alveolar air sac?
Excessive inflammation or lack of A1AT
What is the most common cause of emphysema?
Smoking
How does smoking lead to emphysema ?
- Pollutants in smoke lead to excessive inflammation and protease-mediated damage. 2. Results in centriacinar emphysema that is most severe in the upper lobes
AIAT deficiency relate to emphysema?
It is a rare cause of emphysema.
How does A1AT deficiency lead to emphysema?
- Lack of antiprotease leaves the air sacs vulnerable to protease-mediated damage. 2. Results in panacinar emphysema that is most severe in the lower lobes 3. Liver cirrhosis may also be present.
What is A1AT deficiency due to?
misfolding of the mutated protein
What happens to mutant A1AT?
it accumulates in the endoplasmic reticulum of hepatocytes, resulting in liver damage.