Pathophysiology Flashcards
What is the most common cause of rhinitis?
Rhinovirus
What is the classic triad of aspirin-intolerant asthma?
asthma, aspirin-induced bronchospasms and nasal polyps
What are nasal polyps associated with in children and adults?
Children- CF
Adults- aspirin-intolerant asthma
What are the characteristics of a nasopharyngeal angiofibroma?
benign nasal mucosa tumor that is composed of large blood vessels and fibrous tissue
- classically seen in adolescent males
- presents with profuse epistaxis
What are the characteristics of nasopharyngeal carcinoma?
malignant tumor of nasopharyngeal epithelium, usually presents with cervical LAD
- associated with EBV, especially African kids and Chinese young adults
- Biopsy: pleomorphic keratin+ epithelial cells with lymphocytes
What is the presentation of acute epiglottitis and what is the most common cause?
Presents w fever, sore throat, dyphagia, muffled voice, inspiratory stridor
caused by H influenzae type b
Laryngotracheobronchitis (croup)
inflammation of upper airway, presents with hoarse cough and inspiratory stridor
-parainfluneza most common cause
vocal cord nodule
aka singer’s nodule, on true vocal cord due to overuse
composed of myxoid connective tissue
What are laryngeal papillomas associated with?
HPV 6 and 11 - usually single nodule in adults and multiple with kids
What are the three patterns of pneumonia on x-ray?
lobar pneumonia - consolidation of entire lobe
bronchopneumonia - scattered patchy consolidation around bronchioles; multifocal and bilateral
interstitial (atypical) pneumonia - diffuse interstitial infiltrates
What are the gross phases of lobar pneumonia?
- congestion - congested vessels and edema
- red hepatization - exudate, PMNs and RBCs fill alveolar air spaces -> solid consistency and red appearance
- Gray hepatization - degredation of RBCs within exudate
- Resolution -> type II pneumocytes help regenerate
What organisms usually cause lobar pneumonia?
strep pneumoniae, klebsiella (aspiration pneumonia)
What bacteria is associated with pneumonia in cystic fibrosis patients?
psuedomonas
What are the basic features of COPD?
lung can’t empty and air is trapped
-> decreased volume of air that can be forcefully expired is decreased, especially during 1st second –> FEV1:FVC Total lung capacity (TLC) is increased due to air trapping
Chronic bronchitis - clinical features
chronic productive cough lasting at least 3 months over at least 2 years due to excess mucus production
‘blue bloaters’ - Cyanosis - mucus prevents adequate diffusion -> low PaO2 and high PaCO2
What are the histological features of chronic bronchitis?
Hypertrophy of bronchial mucinous glands -> Reid index increases to > 50% (thickness of mucus glands/bronchial wall thickness)
What are complications of chronic bronchitis?
increased risk of infection and cor pulmonale (R heart failure)
What is the pathogenesis of emphysema?
Imbalance of proteases and antiproteases-> inflammation in lung leads to protease release by PMNs and macrophages and alpha1-antitrypsin (A1AT) neutralizes protease
–> too much inflammation (from smoking) or too little A1AT (A1AT deficiency) leads to destruction of alveolar air sacs
–>destruction of air sacs causes loss of elastic recoil and collapse of airways during exhalation, increased compliance and decreased diffusing capacity for CO
What usually causes centriacinar emphysema?
Smoking; most severe in upper lobes since smoke rises in lungs
Panacinar emphysema is usually caused by what?
alpha1-antitrypsin deficiency; most severe in lower lobes
Alpha1-antitrypsin deficiency
A1AT deficiency is due to misfolding of protein; can also accumulate in ER of hepatocytes and cause liver cirrhosis
Disease severity based on degree of deficiency
- PiM= normal allele; usually 2 copies: PiMM
- PiZ= mutated allele –> PiMZ heterozygotes usually asymptomatic with increase risk of emphysema, PiZZ homozygotes significant risk for panacinar emphysema and cirrhosis
Clinical features of emphysema
- ‘pink-puffer’ prolonged expiration with pursed lips
- weight loss, cough with minimal sputum
- ‘barrel-chest’ increased anterior-posterior diameter of chest
- –> INCREASED FRC (functional reserve capacity)
-CXR: hyperlucency of lung fields and flattening of diaphragm
Pathogenesis of asthma
Type I hypersensitivity
Allergen induce Th2 CD4+ cells in susceptible individuals *Th2 secretes: IL-4 (mediates class switch to IgE), IL-5 (attracts eosinophils) and IL-10 (stimulates Th2 cells and inhibits Th1 cells)
Reexposure to allergen -> IgE-crosslinking mediated activation of mast cells release
- –> histamine granules (1st phase) and generates leukotrienes C4, D4, and E4 -> bronchoconstriction, inflammation and edema
- –> Inflammation, especially major basic protein derived from eosinophils, damages cells and perpetuates bronchoconstriction (late phase)
What are the microscopic features of asthma?
Curschmann spirals: spiral-shaped mucus plugs
Charcot-Leyden crystals: eosinophil-derived crystals
What is bronchiectasis?
permanent dilation of bronchioles and bronchi; loss of airway tone results in air trapping
What are causes of bronchiectasis?
Necrotizing inflammation damages airway walls
Causes:
CF- mucus plug -> infection
Kartagener syndrome -> defect of dynein arm causes impaired ciliary movement
Tumor/ foreign body
Necrotizing infection
ABPA (Allergic bronchopulmonary aspergillosis; usually seen in asthma or CF)
What are the features and complications of bronchiectasis?
Features: cough, dyspnea, foul-smelling sputum
Complications: cor pulmonale, secondary amyloidosis
What are the general characteristics of restrictive lung diseases?
Restricted filling of lung –> decreased TLC and FEV1 and very decreased FVC –> FEV1/FVC > 80%
Commonly due to
- interstitial lung diseases –> DECREASED diffusing capacity of CO, INCREASED A-a gradient
-Poor breathing mechanics (obesity, scoliosis, myasthenia gravis) –> NORMAL A-a gradient
What is the pathogenesis of idiopathic pulmonary fibrosis
Likely related to cyclical lung injury and healing; TGF-beta from injured pneumocytes induces fibrosis
Thickening and stiffening of pulm. interstitium -> increased lung elastic recoil -> airway widening due to increased radial traction by surrounding fibrotic tissue –> decrease in airway resistance causes supernormal expiratory flow rates when corrected for lung volume