Flashcards in Respiratory pathology Deck (76)
What causes congenital pulmonary cysts?
Caused by premature separation of the embryonic foregut
Bronchiogenic cyst is .......
congenital pulmonary cyst, centrally located and may be connected to the bronchi/bronchioles. It is lined by ciliated bronchial epithelium. Single or multiple
* Rupture may cause hemoptysis or pneumothorax
Hypoplasia or missing of bronchial cartilage will cause ......
over inflation of the lung due to bronchial obstruction
Bacterial pneumonia occurs when .....
pulmonary defense mechanisms are compromised (decreased cough, macrophage phagocytic defect, pulmonary edema, bronchial injury etc...)
* Immunocompromised patients are at risk also
* It is caused by ???
* Clinical features?
Patchy consolidations of one or more lobes, usually in the bases (due to gravity)
* Caused by H. influenzae, staph aureus, Strep. pneumoniae, Pseudomonas or even fungi.
* Features: productive cough, fever, rales, chest pain. X-ray shows focal opacities
* Abscess, empyema, pericarditis, respiratory failure, bacteremia with metastasis of infection
What is the microscopic finding of bronchopneumonia?
purulent exudate dominated by neutrophils
Define lobar pneumonia
* Clinical features??
Infection by streptococcus pneumoniae which spreads throughout the lobe "With consolidation"
* Acute onset of fever, chills, watery sputum followed by rusty colored sputum (later), orthopnea, dyspnea, cyanosis
* Abscess, exudate, empyema, bacteremia, metastasis to liver, spleen, heart, joints, kideny and pericardium
Pneumoniae in alcoholics and diabetics are usually caused by .......
* The sputum resembles currant jelly
Red hepatization is ......
congestion of the lung with RBC, neutrophil and fibrin. Characteristic of lobar pneumonia
* It is followed by gray hepatization, when the RBC breakdown begin and and exudate accumulates
Why viral and mycoplasmal pneumonia are called "Atypical" pneumonia??
because they lack "Exudate" and the inflammation is found in the lung interstitium and alveolar septae (interstitial pneumonia)
* Viral pneumonia is more common in 2-3 years age
What are the causative agents for atypical pneumonia?
Influenza A & B virus, mycoplasma pneumoniae (common in crowded conditions), rhinovirus, and respiratory syncytial virus (RSV)
What is the most important clinical feature for atypical pneumonia?
* What is the gross pathology of the lesion?
* Uni or bilateral involvement in one or more lobes. Red blue and congested interstitium, but without consolidation (no exudate/pus), no pleural involvement
Pneumocystic carinii pneumonia is ......
* What are the symptoms
a fungal infection of the lungs. Common in immunocompromised patients, undernourished children, and oncology patients
* There is bilateral interstitial infiltrate on Xray. Also, fever, dyspnea, hypoxia
Define pulmonary abscess
* What are the clinical features?
* It is caused by ......
an area of inflammation with a central region of liquefactive necrosis
* There is fever, paroxysmal cough with foul smelling purulent or sanguineous sputum. Air fluid level is seen on Xray, dyspnea, chest pain
* Caused by aerobic and mouth anaerobes (like bacteroids, Fusobacterium, Peptostreptococcus)
What are the possible routes of infection for pneumonia?
1. Aspiration of gastric content & mouth flora
2. Inhalation of bacteria
5. Neoplasia with post obstructive pneumonia
1. What causes TB?
2. Where does reactivation of TB infection mostly occur??
1. Strict aerobic acid fast Mycobacterium tuberculosis
2. In the apex of the lung and renal cortex
Define Ghon complex
The presence of a calcified lesion in the lung and an associated lymph node shown on Xray in TB patients
Primary TB usually affects ......
the lower part of the upper lobe or the upper part of the lower lobe (subjacent to the pleura)
* There is caseous lesions with an ipsilateral caseous lymphnode which drains the affected parenchyma
What are the clinical features for patients with TB??
Mostly asymptomatic. Microphage phagocytosis of tubercle bacilli, then fusion to form epitheliod giant cells, ends with granuloma formation with central caseous necrosis. However, the bacteria survive in the granuloma for years to remit later
Define secondary TB
It is the reactivation of (not reinfection) of old TB. Usually in the areas of high O2 tension (lung apices)
* Only 10% of patients develop secondary infection
Define Miliary TB
spread of TB infection via blood or lymph.
* Systemic spread is possible after erosion of the pulmonary vein
Define COPD and what are its types
Increased resistance to airflow during inspiration and expiration due to obstruction
4. Chronic bronchitis
What could be the cause of emphysema?
destruction of the alveolar septae distal to the terminal bronchiole secondary to ischemia. There is ↑ in total lung capacity, ↑ residual volume, no fibrosis
* Associated with smoking and pollution
What are the two types of emphysema?
1. Centrilobular: affecting the central and proximal part of the lobule and sparing the peripheral alveoli. The lungs are not enlarged nor pale unless disease is advanced. Usually in the upper lobes
2. Panlobular: hyperinflation & pale lungs due to vessels destruction. There is high crepitance, and little inflammation, ↓ alpha-1 antitrypsin
What are the clinical features and complications of emphysema?
Dyspnea, cough, barrel chest, prolonged expiratory time, cor pulmonale (right heart failure), pink puffers (over ventilation), flattened diaphragm
* Complications include polycythemia, cor pulmonale, pneumothorax
* Due to pink puffers hyperventilation, there is less hypoxemia than blue bloaters (chronic bronchitis)
Chronic bronchitis means ......
persistent cough for at least 3 months for 2 consecutive years
* Cough can be productive or not, the sputum uninfected or purulent
* The lungs are hyperinflated with copious mucus plugging
What could be the causes for chronic bronchitis?
1. Chronic irritation: NO2 or SO2
2. Recurrent infections (don't cause it, but perpetuate it)
* The result is mucus plugging due to recurrent infections & irritations, which lead to blocking, inflammation, edema and fibrosis with smooth muscle atrophy. Also, metaplasia or dysplasia of the mucosa is common
What are the clinical features and complications for chronic bronchitis?
dyspnea, persistent productive cough, barrel chest, cyanosis.
* Cor pulmonale may occur due to hypoxia. Dysplasia of the epithelium may cause cancer
* Patients are called blue bloaters due to cyanosis. There is a severe ventilation:perfusion mismatch compared to emphysema
Define Extrinsic asthma (allergic, immune, atopic)
triggered by environmental factors. Spasm mediated by Type I (IgE) hypersensitivity.
* Histamine, leukotrienes, prostoglandin D2 and platelet activation all lead to airway constriction and increase vascular permeability.
* Serum IgE is elevated
* Can be confirmed by a positive skin test to the offending antigen
* Usually, there is a family history