Pathology Flashcards
What are the characteristic cells of acute vs chronic inflammation?
Acute PMNs
Chronic Lymphocytes
What’s the composition of a granuloma?
Center has caseating necrosis with TB, this is surrounded by granulation tissue containing collagen, lymphocytes and macrophages. Outside is a peripheral cap with multi-nuclear giant cells and lymphocytes.
What’s a Ghon nodule?
Well circumscribed with central necrosis. It can later become fibrotic and calcified. Called a coin lesion.
What’s a Ghon complex?
Ghon nodule with peri-hilar LN iadenopathy
How do the majority of those infected with TB handle the infection?
Asymptomatic, lesion remains localized and calcified, seen on CXR as a coin lesion.
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What type of TB is typical of the immunocompromised and children?
Primary progressive TB leading to miliary spread.
What are the four stages of TB?
Primary-children and immunocompromised are symptomactic and others are asymptomatic and may have coin lesions visible on CXR.
Secondary (reactivation of latent TB) If the person becomes immunocompromised the bacteria may reactivate (due to weakening of the granuloma/tubercule) this can lead to confluence of these granulomas into cavities.
Cavitation- erosion of the lungs can allow for hematogenous dissemination into the blood steam. This is the infectious state where people “cough up a lung” hemoptysis.
Miliary-bacteria spread to well oxygenated sites. CONTRALATERAL PNEUMONIA Liver, kidneys, adrenal glands, spine (Potts), brain, GI (cough up and swallow), lymphatic spread (Scrofula)
What is Scrofula?
unilateral cervical adenitis
After primary TB infection resistance is mediated by which cells?
CD4+ and MO
What do TST use to test and what does a positive test indicated?
Purified protein derivative (PPD), postitve test is due to delayed hypersensitivity reaction. Prior infection.
10mm thick red raised spot=positive infection usually (follow up CXR)
5-9mm people known to be exposed by the BCG vaccine, or probably infected.
What is the anatomic and physiologic dead space in the lungs referring to?
The anatomic dead space is contained within structures of the conducting zone where gas exchange does not occur and includes alveoli that for whatever reason are hypoxic and not exchanging gas.
The physiologic dead space is a combination of these two areas.
You get to base-camp on Everest and The the barometric pressure is 400mmHg. The fraction of Nitrogen gas in the atmosphere is 80% and the PO2 of humidified tracheal air is 50mmHg. What’s the partial pressure of O2 in the humidified air assuming it accounts for the remaining 20% of atmospheric gas?
Using this value of PO2 how much diffusion is occurring across the alveoli into the pulmonary capilarys? What’s the value of the systemic PO2?
Px=(PB-PH2O) x F
Px= (400-50) x 0.2= 70mmHg
70-40 (mixed venous blood)= 30mmHg
Systemic PO2 70 mmHg because the alveolar will equilibrate with the capillaries
During exercise your VCO2 rises to 450mmHg. Assuming a constant PaCO2 of 40mmHg how would your ventilation rate change?
Increase to facilitate release of the CO2 accumulating in the tissues.
What are the four diseases of COPD
Chronic Bronchitis
Emphysema
Bronchial Asthma
Bronchiectasis
Define chronic bronchitis and its primary cause
Chronic cough min 3 months 2 consecutive yrs
primary cause smoking, secondary other inhaled garbage t
What is the pathology of Chronic Bronchitis?
Fibrous thickening of the walls of the bronchi and bronchiole, with lumenal obstruction due to thickened mucus
Bronchial mucous gland hypertrophy and hyperplasia, as well as, hyperplasia of goblet cells
Mucosa is infiltrated with lymphocytes, MO, and plasma cells
What type of metaplasia can take place in chronic bronchitis?
columnar epithelium becomes statified squamous epithelium
What problems are associated with the thickened mucous seem in those with chronic bronchitis?
prolonged coughing, purulent thick sputum, dyspnea
hypoxic while coughing leading to cyanosis (blue bloater)
What are some prominant clinical findings among patient with chronic bronchitis aside from a persistant cough?
pulmonary htn
Cor Pulmonale- result in venous stasis and cyanosis
Define emphysema and describe the type of person it affects.
Enlargement of the airspaces distal to the terminal bronchioles with destruction of alveolar walls
Chronic smokers or those with A1AT deficiency
Describe the pathogenesis of emphysema
Irritants in cigarette smoke promote the recruitment of inflammatory cells like PMNs, and MO during the phagocytic process. They release proteases (such as elastase which break down elastin; facilitates recoil of the lungs) that destroys alveolar walls causing enlargment of the alveolar spaces, aka Bullae formation. (parenchymal air filled spaces larger than 1 cm).
What are blebs in the lungs?
Subpleural air filled spaced formed by ruptured alveoli. These blebs can rupture into the pleural cavity causing a pneumothorax.
What are the two types of emphysema?
Centrilobar- marked by widening of the airspaces in the center of the lobule and involves predominantly the respiratory bronchioles, sparing the alveoli and seen primarily in the upper lobes. This type affects mostly smokers.
Panacinar-Involves all the airspace distal to the terminal bronchioles and involves the alveoli. Typically seen in those with A1AT deficiency, but may be caused by smoking.
What are the clinical features of emphysema?
Patients have compensatory tachypnea to make up for the reduced respiratory surface area. The chest is barrel-shaped and patients often hunch forward to engage their accessory muscles for respiration. No cough. Pink puffers. Flattened diaphragm on CXR.
