Pulm 3 Shea Flashcards
- Diffuse interstitial PNA in immunocompromised patients
- Characteristics of both fungus and protozoan parasite
- Transmission?
- # 1 cause of PNA in AIDS patients, leading cause of death in these patients
- Pneumocystis jiroveci
- Inhalation, does not cause disease in healthy patients
- Cup or boat shaped cysts in alveoli induces inflammatory response –> results in frothy, eosinophilic, edema fluid which blocks O2 exchange.
Pneumocystic jiroveci
- Sudden onset fever, cough, dyspnea, tachypnea
- Bilateral rales/rhonchi
- Chest x-ray reveals diffuse interstitial PNA
- Isolates to lungs only
Pneumocystic jiroveci
What type of stain is used to see the boat/ cup like appearance of pneumocystis jiroveci?
Silver Stain (GMS) for Cyst Organsims
A chronic, bacterial infectious disease caused by Mycobacterium
Tuberculosis
- TB is more common in which patients and which population?
- How is it treated?
- AIDS patiens
- Homeless population (crowding in small areas in the cold)
- Rod shaped bacterium w/ waxy capsule
- Acid fast
- Neither gram neg or gram pos
- DOES NOT stain w/ gram stain dyes
- Obligate aerobe
M. tuberculosis
M. tuberculosis has a cell wall which contains what?
Mycolic acid (a complex lipid) which is antiphagocytic
- Which organism stains “magenta?”
- What is the shape?
- TB on an acid fast stain
- Beaded rod
How is TB transmitted?
Person to person w/ respiratory aerosols
Where is the initial site of infection of TB?
Lungs
- Bacterial infection which is not acute
- Does not attract PMNs
- Not marked by acute purulent lesions
- Encapsulated bacteria form granulomas which contain stimulated macrophages, which transform into –> multi-nucleated giant cells w/ central caseous necrosis
TB
Why do we need to use 3 drugs to kill TB?
Because just one drug would not be enough to penetrate the necrosis
Where does the TB organism multiply in the lungs after being inhaled? Why?
In the alveoli, bc/ alveolar macrophages can’t kill it
Where does the initial infection of TB usually occur within the lungs?
Lower lobes
Consists of:
- peripheral parenchymal granuloma
- prominent infected draining mediastinal (hilar) lymph node w/ *caseous necrosis - looks like mozarella chz*
Ghon Complex associated w/ initial infection of TB
What part of the lungs is there higher oxygen levels?
Lower lobes
Grossly, is well circumscribed w/ central necrosis and later on the lesion is fibrotic and calcified
Healed, subpleural Ghon nodule
- How do patients w/ primary TB infection present clinically?
- Where is the organism?
- 90-95% (majority) are asymptomatic, lesion remains localized, heals w/ calcification that can be seen on CXR. (coin lesion)
- Calcified primary lesion within the caseous necrosis (organism visualized on AFB stain
The initial lesion enlarges rapidly and there is erosion of bronchi or bronchioles by the necrotic central liquefaction. Which 2 groups does this most often occur in?
(Primary TB typically does not remain limited and heal, it usually spreads to other parts of lungs)
Progressive Primary TB
- Children
- Immunosuppressed
Represents a reactivation of dormant primary infection
Secondary Infection of TB
(Reactivation)
- Bacteria spreads to apex of lungs
- Causes granulomatous PNAs
- Hemoptysis from erosion into pulmonary blood vessels
Secondary TB / Reactivation
What is the main complication of the Secondary Stage of TB?
Miliary Spread which is a result of tissue destruction and erosions
Multiple, small tuberculous granulomas in many organs which have well oxygenated sites
Miliary Spread
Where are the 4 oxygenated sites of miliary spread?
- If swallowed: GI tract (small intestines)
- Via eroded bloodstream: kidneys, brain, or bones
What are complications of miliary spread?
- contralateral PNA
- pleuritis w/ effusion
- pleural granulomas
- TB laryngitis
- intestinal TB (from swallowing)
- hemoptysis (from erosion of small pulm arteries in wall of cavity)
- Scrofula
- TB meningitis
- Osteoarthritis
- Lymphatic spread to the hilar lymph nodes w/ infection to the neck area causing enlarged supraclavicular lymph nodes
- Unilateral cervical adenitis (swollen non-tender nodes)
Scrofula (complication of Miliary Spread of TB)
Where does TB tend to go in the CNS?
Meninges (base of brainstem/pons)
- TB eroding the body of vertebrae, can involve the disc as well as the bone.
- A miliary form of TB
Pott’s disease
(vertebral osteoarthritis)
Expectorated acid-fast bacilli (TB) may cause infection of what?
Larynx, causing laryngitis
What is the initial diagnostic test for TB?
Acid-Fast Staining of sputum or other specimens
Slowest growing organism
Acid-fast bacilli (TB)
Where is a tuberculoma located?
Brainstem
What is the #1 cancer in men and #1 cause of death from cancer in the U.S.?
Carcinoma of the Lung
- Subtype of adenocarcinoma that grows along preexisting alveolar walls.
- Accounts for 1-5 % of all invasive lung tumors.
- Copious mucin in the sputum
- Grossly, may appear as a single peripheral nodule or coin lesion (over 50% of cases), multiplenodules or a diffuse infiltrate indisting-uishible from a lobar pneumonia.
Bronchioloalveolar Carcinoma
Which 3 cancers to 90% are centrally located?
- Squamous Cell Carcinoma
- Small Cell Carcinoma
- **Which cancer to 90% is peripherally located?
- often associated with scars which can result in puckering of the pleural.
- Slight association with smoking.
- Appear as irregular masses, which on cut section appear gray-white in color, soft and glistening, depending on the amount of mucus.
Adenocarcinoma
- Previously called “oat cell carcinoma”.
- A highly malignant epithelial tumor that exhibits neuroendocrine features.
- Accounts for 20% of all lung cancers and is strongly associated with cigarette smoking.
Small Cell Carcinoma
- Produces a variety of Paraneoplastic Syndromes, including Diabetes Insipidus, due to ADH production, ectopic ACTH (corticotropin) or Parathormone production.
Small Cell Carcinoma
- Usually appears as a perihilar (central) mass
- Extensive lymph node metastases.
- On cut section, it is soft and white, but with extensive hemorrhage and necrosis.
Small Cell Carcinoma
This type of lung cancer is the only tumor that is sensitive to radiotherapy.***
Small Cell Carcinoma
- Histologically, they consist of sheets of small, round, oval or spindle-shaped cells.
- The tumor cells display scant cytoplasm with finely granular nuclear chromatin.
- By EM (electron microscopy) many of the cells contain secretory neuroendocrine granules
Small Cell Carcinoma
- Diagnosis of exclusion in a poorly undifferentiated non-small cell carcinoma
- Does not show features of squamous or glandular differentiation.
- Cells are large and irregular and exhibit ample cytoplasm. The nuclei frequently show prominent nucleoli and vesicular chromatin.
Large Cell Carcinoma
- Where is the most common extranodal site/extranodal metastasis?
- 3 most common sites of metastatic disease
- Adrenal gland
- Brain, bone, liver
