Respiratory - Pathology

Question 1

Rhinosinusitis

• Definition
• Due to…
• Findings

Answer 1

• Definition
  
  • Obstruction of sinus drainage into nasal cavity Ž
  • –> inflammation and pain over affected area (typically maxillary sinuses in adults [A]).
• Due to…
  
  • Most common acute cause is viral URI
• Findings
  
  • May cause superimposed bacterial infection, most commonly S. pneumoniae, H. influenzae, and M. catarrhalis.

Question 2

Deep venous thrombosis

• Predisposed by…
• Most arise from…
• Homan sign
• Treatment

Answer 2

• Predisposed by Virchow triad:
  
  • Stasis
  • ƒƒHypercoagulability (e.g., defect in coagulation cascade proteins, most commonly factor V Leiden)
  • Endothelial damage (exposed collagen triggers clotting cascade)
• Approximately 95% of pulmonary emboli arise from deep leg veins.
• Homan sign
  
  • Dorsiflexion of foot Ž–> calf pain.
• Treatment
  
  • Use heparin for prevention and acute management
  • Use warfarin for long-term prevention of DVT recurrence.

Question 3

Pulmonary emboli (603)

• Due to…
• Findings
• Types
• Diagnosis

Answer 3

• Due to…
  
  • V/Q mismatch –> hypoxemia Ž–> respiratory alkalosis.
• Findings
  
  • Sudden-onset dyspnea, chest pain, tachypnea.
  • May present as sudden death.
• Types
  
  • Fat, Air, Thrombus, Bacteria, Amniotic fluid, Tumor.
    
    • An embolus moves like a FAT BAT
  • Fat emboli
    
    • Associated with long bone fractures and liposuction
    • Classic triad of hypoxemia, neurologic abnormalities, and petechial rash.
  • Amniotic fluid emboli
    
    • Can lead to DIC, especially postpartum.
  • Gas emboli
    
    • Nitrogen bubbles precipitate in ascending divers
    • Treat with hyperbaric oxygen.
• Diagnosis
  
  • CT pulmonary angiography is the imaging test of choice for a PE (look for filling defects) [A] [B] [C].

Question 4

Obstructive lung diseases

• Definition
• Findings
• PFTs

Answer 4

• Definition
  
  • Obstruction of air flow resulting in air trapping in the lungs.
• Findings
  
  • Airways close prematurely at high lung volumes Ž–> increased RV and decreased FVC.
  • Chronic, hypoxic pulmonary vasoconstriction can lead to cor pulmonale
• PFTs
  
  • Really decreased FEV1
  • Decreased FVC Ž–> decreased FEV1/FVC ratio (hallmark)
  • V/Q mismatch.

Question 5

Chronic bronchitis

• Type of disease
• Pathology
• Definition
• Findings

Answer 5

• Type of disease
  
  • Obstructive lung disease
• Pathology
  
  • A form of COPD along with emphysema.
  • Hyperplasia of mucus-secreting glands in the bronchi Ž
    
    • –> Reid index (thickness of gland layer/total thickness of bronchial wall) > 50%.
• Definition
  
  • AKA “blue bloater”
  • Productive cough for > 3 months per year (not necessarily consecutive) for > 2 years.
  • Disease of small airways.
• Findings
  
  • Wheezing, crackles, cyanosis (early-onset hypoxemia due to shunting), late-onset dyspnea, CO2 retention.

Question 6

Emphysema

• Type of disease
• Pathology
• Two types
• Definition
• Findings

Answer 6

• Type of disease
  
  • Obstructive lung disease
• Pathology
  
  • Enlargement of air spaces, decreased recoil, increased compliance, decreased DLCO resulting from destruction of alveolar walls [A].
• Two types
  
  • Centriacinar—associated with smoking [B].
  • Panacinar—associated with a1-antitrypsin deficiency.
• Definition
  
  • AKA “pink puffer,” barrelshaped chest
• Findings
  
  • Increased elastase activity –>Ž loss of elastic fibers Ž–>Ž increased lung compliance.
  • Exhalation through pursed lips to increases airway pressure and prevent airway collapse during respiration.

Question 7

Asthma

• Type of disease
• Pathology
• Due to…
• Diagnosis
• Findings

Answer 7

• Type of disease
  
  • Obstructive lung disease
• Pathology
  
  • Bronchial hyperresponsiveness causes reversible bronchoconstriction.
  • Smooth muscle hypertrophy, Curschmann spirals (shed epithelium forms mucus plugs), and Charcot-Leyden crystals (formed from breakdown of eosinophils in sputum).
• Due to…
  
  • Can be triggered by viral URIs, allergens, and stress.
• Diagnosis
  
  • Test with methacholine challenge.
• Findings
  
  • Cough, wheezing, tachypnea, dyspnea, hypoxemia, decreased I/E ratio, pulsus paradoxus, mucus plugging.

Question 8

Bronchiectasis

• Type of disease
• Pathology
• Associations

Answer 8

• Type of disease
  
  • Obstructive lung disease
• Pathology
  
  • Chronic necrotizing infection of bronchi Ž–> permanently dilated airways, purulent sputum, recurrent infections, hemoptysis.
• Associations
  
  • Associated with bronchial obstruction, poor ciliary motility (smoking), Kartagener syndrome, cystic fibrosis, allergic bronchopulmonary aspergillosis.

Question 9

Restrictive lung disease

• Definition
• PFTs
• Types
  
  • Poor breathing mechanics
  • Interstitial lung diseases

Answer 9

• Definition
  
  • Restricted lung expansion causes decreased lung volumes (decreased FVC and TLC).
• PFTs
  
  • FEV1/FVC ratio ≥ 80%.
• Types
  
  • Poor breathing mechanics (extrapulmonary, peripheral hypoventilation, normal A-a gradient):
    
    • Poor muscular effort—polio, myasthenia gravis
    • Poor structural apparatus—scoliosis, morbid obesity
  • Interstitial lung diseases (pulmonary decreased diffusing capacity, increased A-a gradient):
    
    • Acute respiratory distress syndrome (ARDS)
    • Neonatal respiratory distress syndrome (hyaline membrane disease)
    • Pneumoconioses (anthracosis, silicosis, asbestosis)
    • Sarcoidosis (bilateral hilar lymphadenopathy, noncaseating granuloma; increased ACE and Ca2+)
    • Idiopathic pulmonary fibrosis (repeated cycles of lung injury and wound healing with increased collagen deposition)
    • ƒƒGoodpasture syndrome
    • ƒƒGranulomatosis with polyangiitis (Wegener)
    • Langerhans cell histiocytosis (eosinophilic granuloma)
    • ƒƒHypersensitivity pneumonitis
    • ƒƒDrug toxicity (bleomycin, busulfan, amiodarone, methotrexate)

Question 10

Pneumo-

• Hypersensitivity pneumonitis
• Pneumoconioses

Answer 10

• Hypersensitivity pneumonitis
  
  • Mixed type III/IV hypersensitivity reaction to environmental antigen
    
    • –>Ž dyspnea, cough, chest tightness, headache.
  • Often seen in farmers and those exposed to birds.
• Pneumoconioses
  
  • Coal workers’ pneumoconiosis, silicosis, and asbestosis
  • Ž–> increased risk of cor pulmonale and Caplan syndrome (rheumatoid arthritis and pneumoconioses with intrapulmonary nodules).

Question 11

Asbestosis

• Type of disease
• Associations
• Findings

Answer 11

• Type of disease
  
  • Pneumoconiosis
• Associations
  
  • Associated with shipbuilding, roofing, and plumbing.
  • Associated with an increased incidence of bronchogenic carcinoma and mesothelioma
• Findings
  
  • “Ivory white,” calcified pleural plaques [A] are pathognomonic of asbestos exposure, but are not precancerous.
  • Affects lower lobes.
    
    • Asbestos is from the roof (was common in insulation), but affects the base (lower lobes).
    • Silica and coal are from the base (earth), but affect the roof (upper lobes).
  • ​Asbestos (ferruginous) bodies are golden-brown fusiform rods resembling dumbbells [B].

Question 12

Coal workers’ pneumoconiosis

• Type of disease
• Definition
• Findings
• Anthracosis

Answer 12

• Type of disease
  
  • Pneumoconiosis
• Definition
  
  • Prolonged coal dust exposure –>Ž macrophages laden with carbon –>Ž inflammation and fibrosis.
  • Also known as black lung disease.
• Findings
  
  • Affects upper lobes.
  • Asbestos is from the roof (was common in insulation), but affects the base (lower lobes).
  • Silica and coal are from the base (earth), but affect the roof (upper lobes).
• Anthracosis
  
  • Asymptomatic condition found in many urban dwellers exposed to sooty air.

Question 13

Silicosis

• Type of disease
• Associations
• Due to…
• Findings

Answer 13

• Type of disease
  
  • Pneumoconiosis
• Associations
  
  • Associated with foundries, sandblasting, and mines.
  • Also increases risk of bronchogenic carcinoma.
• Due to…
  
  • Macrophages respond to silica and release fibrogenic factors, leading to fibrosis.
  • It is thought that silica may disrupt phagolysosomes and impair macrophages, increasing susceptibility to TB.
• Findings
  
  • Affects upper lobes.
    
    • **Asbestos is from the roof (was common in insulation), but affects the base (lower lobes). **
    • Silica and coal are from the base (earth), but affect the roof (upper lobes).
  • “Eggshell” calcification of hilar lymph nodes.

Question 14

Neonatal respiratory distress syndrome

• Definition
• Associations
• Risk factors
• Treatment

Answer 14

• Definition
  
  • Surfactant deficiency Ž–> increased surface tension Ž–> alveolar collapse.
  • A lecithin : sphingomyelin ratio < 1.5 in amniotic fluid is predictive of neonatal respiratory distress syndrome.
• Associations
  
  • Persistently low O2 tension –>Ž risk of PDA.
  • Therapeutic supplemental O2 can result in retinopathy of prematurity and bronchopulmonary dysplasia.
• Risk factors
  
  • Prematurity, maternal diabetes (due to increased fetal insulin), C-section delivery (decreased release of fetal glucocorticoids).
• Treatment
  
  • Maternal steroids before birth
  • Artificial surfactant for infant.

Question 15

Acute respiratory distress syndrome

• Due to…
• Definition
• Findings

Answer 15

• Due to…
  
  • May be caused by trauma, sepsis, shock, gastric aspiration, uremia, acute pancreatitis, or amniotic fluid embolism.
• Definition
  
  • Diffuse alveolar damage Ž–> increased alveolar capillary permeability –>Ž protein-rich leakage into alveoli and noncardiogenic pulmonary edema (normal PCWP) [A].
  • Initial damage due to release of neutrophilic substances toxic to alveolar wall, activation of coagulation cascade, and oxygen-derived free radicals.
• Findings
  
  • Results in formation of intra-alveolar hyaline membrane [B].

Question 16

Obstructive vs. restrictive lung disease

• FEV1 / FVC
  
  • Normal
  • Obstructive
  • Restrictive
• Lung volumes
  
  • Obstructive
  • Restrictive

Answer 16

• FEV1 / FVC
  
  • Normal = 80%
  • Obstructive < 80%
    
    • FEV1 and FVC are reduced
    • FEV1 is more dramatically reduced compared to FVC
    • Results in a decreased FEV1/FVC ratio
  • Restrictive >/= 80%
    
    • FEV1 and FVC are reduced
• Lung volumes
  
  • Obstructive > normal (increased TLC, increased FRC, increased RV)
  • Restrictive < normal

Question 17

Pulmonary hypertension

• vs. normal pulmonary artery pressure
• Results in…
• Primary
• Secondary
• Course

Answer 17

• vs. normal pulmonary artery pressure
  
  • Normal pulmonary artery pressure = 10–14 mmHg
  • Pulmonary hypertension ≥ 25 mmHg at rest.
• Results in arteriosclerosis, medial hypertrophy, and intimal fibrosis of pulmonary arteries.
• Primary
  
  • Due to an inactivating mutation in the BMPR2 gene (normally functions to inhibit vascular smooth muscle proliferation)
  • Poor prognosis.
• Secondary due to…
  
  • COPD (destruction of lung parenchyma)
  • Mitral stenosis (increased resistance –>Ž increased pressure)
  • Recurrent thromboemboli (decreased cross-sectional area of pulmonary vascular bed)
  • Autoimmune disease (e.g., systemic sclerosis; inflammation –>Ž intimal fibrosis –>Ž medial hypertrophy)
  • Left-to-right shunt (increased shear stress –>Ž endothelial injury)
  • Sleep apnea or living at high altitude (hypoxic vasoconstriction).
• Course
  
  • Severe respiratory distress Ž–> cyanosis and RVH Ž–> death from decompensated cor pulmonale.

Question 18

Sleep apnea

• Definition
• Hypoxia Ž–>
• Nocturnal hypoxia Ž–>
• Central sleep apnea
• Obstructive sleep apnea
• Obesity hypoventilation syndrome
• Treatment

Answer 18

• Definition
  
  • Repeated cessation of breathing > 10 seconds during sleep –>Ž disrupted sleep –>Ž daytime somnolence.
  • Normal Pao2 during the day.
• Hypoxia Ž–>
  
  • Increased EPO release Ž–> increased erythropoiesis
• Nocturnal hypoxia Ž–>
  
  • Systemic/pulmonary hypertension, arrhythmias (atrial fibrillation/ flutter), and sudden death.
• Central sleep apnea
  
  • No respiratory effort.
• Obstructive sleep apnea
  
  • Respiratory effort against airway obstruction.
  • Associated with obesity, loud snoring.
• Obesity hypoventilation syndrome
  
  • Obesity (BMI ≥ 30 kg/m2) –>Ž hypoventilation Ž–> decreased Pao2 and –> decreased Paco2 during waking hours
• Treatment
  
  • Weight loss, CPAP, surgery.

Question 19

Lung—physical findings

• For each abnormality
  
  • Breath sounds (increased/decreased/other)
  • Percussion (dull/hyperresonant)
  • Fremitus (increased/decreased)
  • Tracheal deviation (toward/away/none)
• Pleural effusion
• Atelectasis (bronchial obstruction)
• Spontaneous pneumothorax
• Tension pneumothorax
• Consolidation (lobar pneumonia, pulmonary edema)

Answer 19

• Pleural effusion
  
  • Breath sounds: Decreased
  • Percussion: Dull
  • Fremitus: Decreased
  • Tracheal deviation: None
• Atelectasis (bronchial obstruction)
  
  • Breath sounds: Decreased
  • Percussion: Dull
  • Fremitus: Decreased
  • Tracheal deviation: Toward side of lesion
• Spontaneous pneumothorax
  
  • Breath sounds: Decreased
  • Percussion: Hyperresonant
  • Fremitus: Decreased
  • Tracheal deviation: None
• Tension pneumothorax
  
  • Breath sounds: Decreased
  • Percussion: Hyperresonant
  • Fremitus: Decreased
  • Tracheal deviation: Away from side of lesion
• Consolidation (lobar pneumonia, pulmonary edema)
  
  • Breath sounds: Bronchial breath sounds; late inspiratory crackles
  • Percussion: Dull
  • Fremitus: Increased
  • Tracheal deviation: None

Question 20

Lung cancer

• Epidemiology
• Findings
• Locations
• Complications
• Associations

Answer 20

• Epidemiology
  
  • Lung cancer is the leading cause of cancer death.
• Findings
  
  • Cough, hemoptysis, bronchial obstruction, wheezing, pneumonic “coin” lesion on x-ray film or noncalcified nodule on CT.
• Locations
  
  • In the lung, metastases (usually multiple lesions) are more common than 1° neoplasms.
  • Most often from breast, colon, prostate, and bladder cancer.
  • Sites of metastases from lung cancer—adrenals, brain, bone (pathologic fracture), liver (jaundice, hepatomegaly).
• SPHERE of complications:
  
  • Superior vena cava syndrome
  • Pancoast tumor
  • Horner syndrome
  • Endocrine (paraneoplastic)
  • Recurrent laryngeal symptoms (hoarseness)
  • Effusions (pleural or pericardial)
• Associations
  
  • All lung cancer types except bronchial carcinoid are associated with smoking.
  • Squamous and Small cell carcinomas are Sentral (central).

Question 21

Lung cancer:
Adenocarcinoma

• Location (central/peripheral)
• Characteristics
• Histology

Answer 21

• Location
  
  • Peripheral
• Characteristics
  
  • Most common lung cancer in nonsmokers and overall (except for metastases).
  • Activating mutations include k-ras, EGFR, and ALK.
  • Associated with hypertrophic osteoarthropathy (clubbing).
  • Bronchioloalveolar subtype (adenocarcinoma in situ): CXR often shows hazy infiltrates similar to pneumonia
  • Excellent prognosis.
• Histology
  
  • Bronchioloalveolar subtype: grows along alveolar septa Ž–> apparent “thickening” of alveolar walls.

Question 22

Lung cancer:
Squamous cell carcinoma

• Location (central/peripheral)
• Characteristics
• Histology

Answer 22

• Location
  
  • Central
• Characteristics
  
  • Hilar mass arising from bronchus
  • Cavitation
  • Cigarettes
  • HyperCalcemia (produces PTHrP).
• Histology
  
  • Keratin pearls and intercellular bridges [A].

Question 23

Lung cancer:
Small cell (oat cell) carcinoma

• Location (central/peripheral)
• Characteristics
• Histology

Answer 23

• Location
  
  • Central
• Characteristics
  
  • Undifferentiated Ž–> very aggressive.
  • May produce ACTH, ADH, or Antibodies against presynaptic Ca2+ channels (Lambert-Eaton myasthenic syndrome).
  • Amplification of myc oncogenes common.
  • Inoperable; treat with chemotherapy.
• Histology
  
  • Neoplasm of neuroendocrine Kulchitsky cells –>Ž small dark blue cells [B].

Question 24

Lung cancer:
Large cell carcinoma

• Location (central/peripheral)
• Characteristics
• Histology

Answer 24

• Location
  
  • Peripheral
• Characteristics
  
  • Highly anaplastic undifferentiated tumor
  • Poor prognosis.
  • Less responsive to chemotherapy
  • Removed surgically.
• Histology
  
  • Pleomorphic giant cells.

Question 25

Lung cancer: Bronchial carcinoid tumor * Characteristics * Histology

Answer 25

* Characteristics * Excellent prognosis * Metastasis rare. * Symptoms usually due to mass effect * Occasionally carcinoid syndrome (5-HT secretion --\>Ž flushing, diarrhea, wheezing). * Histology * Nests of neuroendocrine cells * Chromogranin A (+).

Question 26

Mesothelioma * Definition * Findings

Answer 26

* Definition * Malignancy of the pleura associated with asbestosis. * Findings * Results in hemorrhagic pleural effusions and pleural thickening. * Psammoma bodies seen on histology.

Question 27

Pancoast tumor

Answer 27

* Carcinoma that occurs in apex of lung may affect cervical sympathetic plexus * Causes Horner syndrome (ipsilateral ptosis, miosis, and anhidrosis), SVC syndrome, sensorimotor deficits, and hoarseness [A].

Question 28

Superior vena cava syndrome * Definition * Due to... * Findings

Answer 28

* Definition * An obstruction of the SVC that impairs blood drainage from the head (“facial plethora”), neck (jugular venous distention), and upper extremities (edema). * Medical emergency * Due to... * Commonly caused by malignancy and thrombosis from indwelling catheters. * Findings * Can raise intracranial pressure (if obstruction severe) --\>Ž headaches, dizziness, and increased risk of aneurysm/rupture of intracranial arteries.

Question 29

Pneumonia (611) * For each * Typical organisms * Characteristics * Lobar * Bronchopneumonia * Interstitial (atypical) pneumonia

Answer 29

* Lobar * _Typical organisms_: * S. pneumoniae most frequently * Also Legionella, Klebsiella * _Characteristics_: * Intra-alveolar exudate Ž--\> consolidation * May involve entire lung [A] [B]. * Bronchopneumonia * _Typical organisms_: * S. pneumoniae, S. aureus, H. influenzae, Klebsiella * _Characteristics_: * Acute inflammatory infiltrates from bronchioles into adjacent alveoli * Patchy distribution involving ≥ 1 lobe [C]. * Interstitial (atypical) pneumonia * _Typical organisms_: * Viruses (influenza, RSV, adenoviruses), Mycoplasma, Legionella, Chlamydia * _Characteristics_: * Diffuse patchy inflammation localized to interstitial areas at alveolar walls * Distribution involving ≥ 1 lobe [D]. * Generally follows a more indolent course.

Question 30

Lung abscess * Definition * Due to... * Findings

Answer 30

* Definition * Localized collection of pus within parenchyma. * Due to... * Bronchial obstruction (e.g., cancer) or aspiration of oropharyngeal contents (especially in patients predisposed to loss of consciousness [e.g., alcoholics or epileptics]). * Often due to S. aureus or anaerobes (Bacteroides, Fusobacterium, Peptostreptococcus). * Findings * Air-fluid levels [A] often seen on CXR.

Question 31

Pleural effusions * Definition * For each * Definition * Due to... * Transudate * Exudate * Lymphatic

Answer 31

* Definition * Excess accumulation of fluid between the two pleural layers [A] Ž--\> restricted lung expansion during inspiration. * Transudate  * Definition * Decreased protein content. * Due to CHF, nephrotic syndrome, or hepatic cirrhosis. * Exudate  * Definition * Increased protein content, cloudy. * Occurs in states of increased vascular permeability * Must be drained in light of risk of infection * Due to malignancy, pneumonia, collagen vascular disease, trauma * Lymphatic * Definition * Also known as chylothorax. * Milky-appearing fluid * Increased triglycerides * Due to thoracic duct injury from trauma, malignancy.

Question 32

Pneumothorax * Definition * Findings * Spontaneous pneumothorax * Tension pneumothorax

Answer 32

* Definition * Accumulation of air in the pleural space [A]. * Findings * Unilateral chest pain and dyspnea, unilateral chest expansion, decreased tactile fremitus, hyperresonance, diminished breath sounds, all on the affected side. * Spontaneous pneumothorax * Accumulation of air in the pleural space [A]. * Occurs most frequently in tall, thin, young males because of rupture of apical blebs. * Tension pneumothorax * Usually occurs in setting of trauma or lung infection. * Air is capable of entering pleural space but not exiting. * Trachea deviates away from affected lung [B].