Wk 8 - Terms; Diseases of the Lung Flashcards
What is the pathogenesis of SCLC?
Almost always develop in patients who smoke or recently smoked
What is the prognosis of SCLC?
exceptionally poor
Treatment for SCLC?
systemic treatment: chemotherapy and/or radiation
Risk factors for lung cancer?
-Smoking (most important factor - almost always case in SCLC)
-industrial hazards: radon, asbestos, etc.
-air. pollution
-radiation therapy
-genetic factors
-region of old pulmonary scars
What are the clinical features of SCLC?
a. Usually centrally located hilar or mediastinal tumours with rapid growth
b. Most small cell lung cancers have already metastasized to extra-pulmonary sites by the time they are diagnosed
What can be associated with SCLC?
Paraneoplastic syndromes
What are the three types of lung cancer?
Small Cell Lung Cancer
Non Small Cell Lung Cancer
(further divided into)
squamous cell carcinoma
adenocarcinoma
75% of adenocarcinomas are located where?
peripherally located
What is the most common lung cancer to occur in female patients?
adenocarcinoma
What is the most common lung cancer to occur in non-smoking patients?
adenocarcinoma
What are the clinical features of squamous cell carcinoma?
i. Usually centrally located tumours; tend to grow within lumen of bronchus causing airway obstruction
ii. May cavitate due to central necrosis
What is the most common lung cancer in male patient’s who smoke?
squamous cell carcinoma
What are the clinical presentations of lung cancer?
- 5% asymptomatic: routine chest x-ray (Mom’s)
- Local symptoms: cough, dyspnea, chest pain, hemoptysis
- Spread to adjacent thoracic structures:
o Hoarseness – recurrent laryngeal nerve compression
o Superior vena cava obstruction
o Horner’s syndrome – apical carcinoma/Pancoast tumour - Distant metastasis: brain, bone, adrenal gland, liver
- Non-specific symptoms: anorexia, fatigue, weight loss
- Paraneoplastic syndromes typically associated with SCLC
Define abscess
a localized collection of pus (i.e. an area of liquefactive necrosis in lung tissue).
Define acinus (acini)
in the lung the basic unit where gas exchange occurs; it includes respiratory bronchioles and its alveolar ducts and alveolar sacs; an acinus is supplied by a single terminal bronchiole
Define alveolus (alveoli)
literally means a small cell or cavity, it is the thin-walled sac-like terminal dilation of the acinus (respiratory bronchiole, alveolar ducts and alveolar sacs) across which gas transfer takes place across the alveolar-capillary membrane.
Define chronic obstructive pulmonary disease (COPD)
a nonspecific term that describes conditions in which there is airway obstruction and an increased resistance to airflow (resulting in a decreased forced expiratory volume). Includes bronchial asthma, chronic bronchitis and emphysema.
Define lung carcinoma
Four main subtypes: squamous cell carcinoma (25 - 40%), adenocarcinoma (25 - 40%), small cell undifferentiated carcinoma (20 - 25%), large cell undifferentiated carcinoma (10 - 15%). All are related to cigarette smoking; the leading cause of cancer deaths in Canadian men and women.
Define pleura
the membrane that covers the lungs and lines the walls of the pleural cavity
Define pneumonia
inflammation of the lung occurring secondary to infection
Define respiratory failure
the inability to maintain normal oxygen saturation of the blood and to remove carbon dioxide from the blood entering the lungs
Failure of ventilation, failure of perfusion, failure of gas exchange, or ventilation/perfusion mismatch
Define lobar pneumonia
bacterial pneumonia pattern in which an entire lobe or lung is involved
Define bronchopneumonia
bacterial pneumonia pattern in which the infection is patchy throughout lobe or lung
What are the basic functions of the respiratory tract?
oxygenation of blood and removal of carbon dioxide (waste products)
Define ventilation
involves the movement of air from the upper respiratory tract (e.g., trachea, bronchi, bronchioles) into the lower respiratory tract (e.g., alveolus)
Define perfusion
involves the movement of carbon dioxide-rich/oxygen-poor blood from the right side of the heart into the lung to the site of gas exchange, and the subsequent movement of oxygenated blood to the left side of the heart (and body)
Lung acinus is often used interchangeably with what?
lung alveolus/alveoli
Where is the site of gas exchange?
alveolar-capillary membrane
What is the alveolar-capillary membrane composed of?
it is comprised of pneumocytes, interstitial tissue, and endothelial cells surrounding capillaries
Infectious organisms can enter the lung how?
- Inhalation
- Aspiration
- Blood
- Direct inoculation (such as by surgery)
What factors determine if pneumonia infection will occur?
- Dose & virulence of the organism
- Host susceptibility:
o Impaired local defense mechanisms
Loss of cough reflex coma, anaesthesia, low LOC (ex: from alcohol consumption), neuromuscular disorders
Injury to the mucociliary apparatus (ex: damage to cilia from smoking)
Interference to alveolar macrophages
Accumulation of fluid or secretions within alveoli
o Impaired systemic defence mechanisms
Immunocompromised host
How is pneumonia diagnosed?
- Clinical presentation: cough, fever, chills, malaise, pain on inspiration
- Chest X-ray
- Bloodwork – increased WBC count in peripheral blood
- Microbiology studies – blood and sputum culture
Someone presents with cough, fever, chills, malaise, and pain on inspiration, what is the likely diagnosis?
pneumonia
When will a TB skin test test positive?
The TB skin test will be positive in the setting of prior infection, current infection, and prior immunization.
Describe a TB skin test
- Detects the presence of cellular immunity to an intracutaneous antigen
- Intradermal injection of a purified protein derivative of tuberculin
- Positive test of 10 mm or more induration at 48, 72, or 96 hrs
What are the four clinical setting classifications for pneumonia?
- community acquired pneumonia (CAP)
- hospital acquired (or nosocomial) pneumonia (HAP)
- aspiration pneumonia
- immunocompromised host
Describe hospital acquired pneumonia (HAP)
ii. Can be life threatening
iii. Especially:
1. Severe underlying disease
2. Immunosuppressed
3. Prolonged antibiotic therapy
4. Invasive access devices
5. ventilated
iv. Include:
1. Gram negative rods (E. Coli, pseudomonas aeruginosa
2. staphylococcus aureus
What are the most common etiological agents of community acquired pneumonia (CAP)?
i. Bacterial – Streptococcus pneumoniae – most common cause of CAP
ii. Also: (bacterial) Haemophilus influenzae
iii. Also: Atypical pneumonia syndrome (ex. mycoplasma)
List the three complications of pneumonia discussed
- Lung abscess
- Empyema
- Septicemia
Describe pulmonary tuberculosis
- Major cause of morbidity and mortality worldwide
- Causative organism is mycobacterium tuberculosis, an acid-fast bacillus
- Most cases of tuberculosis (TB) occur in developing countries
- TB flourishes in the setting of poverty, in crowded living conditions, in people with chronic debilitating diseases, and/or immunocompromise
When are patients infectious with TB bacilli?
When it can be demonstrated in lower respiratory tract sampling (e.g., sputum)
There is an increased incidence of what in tuberculosis?
multi-drug resistance
How is a diagnosis of lung cancer established?
- History and physical examination
- Imaging – chest x-ray & CT
- tissue diagnosis
What are the methods of tissue diagnosis used to establish a diagnosis of lung cancer?
o Sputum cytology (not sensitive)
o Bronchoscopy: brushing, washing, biopsy, transbronchial FNA
o Endoscopic ultrasound-guided transbronchial or transesophageal biopsy of mediastinal or hilar lymph nodes
o Transthoracic (percutaneous) biopsy
o Pleural fluid cytology
What is the treatment for NSCLC?
o Surgery – treatment of choice for early-stage NSCLC
o Chemotherapy & radiation – for advanced stage/unresectable NSCLC
o Targeted molecular therapy – for advanced stage/unresectable adenocarcinomas (at least for now…)
o Immunotherapy – for advanced stage/unresectable NSCLC (at least for now…)
Which cancer is the leading cause of cancer death in Canada?
Lung cancer
Someone presenting with cough, dyspnea, chest pain, hemoptysis, fatigue, and weight loss is likely to be diagnosed with what?
Lung cancer
