pathology

Question 1

what is pneumonia?

Answer 1

• infection involving the distal airspaces, usually with inflammatory exudation
• fluid filled spaces lead to consolidation

Question 2

what is community acquired pneumoina?

Answer 2

getting it by clinical setting

Question 3

what organisms cause pneumonia?

Answer 3

• mycoplasma

- pneumococcal

Question 4

what morphology classes pneumonia?

Answer 4

• lobar pneumonia

- bronchopneumonia

Question 5

what is lobar pneumonia?

Answer 5

• confluent consolidatio involving a compete lung lobe
• casued by streptococcus pneumoniae
• can be seen with other organisms eg klebsiella, legionella

Question 6

who gets lobar pneumonia?

Answer 6

• community acquired

- otherwise healthy young adults

Question 7

what is the pathology of lobar pneumoina?

Answer 7

• acute inflammatory response
• exudation of fibrin-rich fluid
• neutrophil infiltration
• macrophage infiltration
• resolution
• antibodies lead to opsonisation and phagocytosis of bacteria

Question 8

what are the complications of lobar pneumonia?

Answer 8

• organisation (fibrous scarring)
• abscess
• bronchiectasis
• empyema

Question 9

what in bronchopneumonia?

Answer 9

• infection starting in the airways and spreading to adjacent alveolar lung
• most often seen in the context of pre-existing disease eg COPD, cardiac failure, complication of viral infection and aspiration of gastric contents

Question 10

what organisms are involved in bronchopneumoina?

Answer 10

• strep. pnuemoniae, haemophilus influenza, staphylococcus, anaerobes, coliforms

Question 11

what organisms are seen in aspiration?

Answer 11

• staph
• anaerobes
• coliforms

Question 12

what are the complications of bronchopneumoina?

Answer 12

• organisatoin
• abscess
• beonchiectasis
• empyema

Question 13

what is a lung abscess?

Answer 13

• localised collection of pus
• tumour-like
• chronic malaise and fever
• context = aspiration

Question 14

what is bronchiectasis?

Answer 14

• abnormal fixed dilation of the bronchi
• usually due to fibrous scarring following infection eg pneumoina, TB, CF
• also seen with chronic obstruction (tumour)
• dilated airways accumulate purulent secretions

Question 15

what is tuberculosis?

Answer 15

• mycobacterial infection
• chronic infection in many site eg lungs, gut, kidneys etc
• pathology is charactersed by delayed type IV hypersensitivity (granulomas with necrosis)

Question 16

what organisms are associated with TB?

Answer 16

• M. tuberculosis/M. bovis
• others cause atypical infections in immunocompromised hosts. pathogenicity due to ability to avoid phagocytosis and to stimulate a host T cell response

Question 17

what is immunity and hypersensitivity of TB?

Answer 17

• T-cell response to organism enhances macrophage ability to kill mycobacteria - this ability constitutes immunity
• T-cell response causes granulomatous inflammation, tissue necrosis and scarring, this is hypersensitivity type IV
• commonly both processes occur together

Question 18

what is the pathology of primary TB?

Answer 18

• first exposure and up to 5 years afterwards
• inhaled organism phagocytosed and carried to hilar lymph nodes. immune activation leads to granulomatous response in nodes, usually with killing of organism
• in a few cases infection is overwhelming and spreads

Question 19

what is the pathology of secondary TB?

Answer 19

• reinfection or reactivation of disease in a person with some immunity
• disease tends to initially remain localise as, often in apices of lung
• can progress to spread by airways and/or bloodstream

Question 20

what tissue changes occur in primary TB?

Answer 20

• small focus (ghon focus) in periohery of mid zone of lung

- large hilar nodes (granulomatous)

Question 21

what are the tissue changes in secondary TB?

Answer 21

• fibrosing and cavitating apical lesion (cancer important differential diagnosis)

Question 22

why does disease reactivate?

Answer 22

• decreased T-cell function due to age, coincident disease (HIV), immunosuppressive therapy (steroid, cancer chemotherapy)
• reinfection at high dose or with more virulent organism

Question 23

what is the pulmonary interstitial?

Answer 23

• thin-elastic rich connective component containing capillary blood vessels
• alveolar lining calles (types 1&2)

Question 24

what is interstitial lung disease?

Answer 24

• early stage = alveolitits
• late stage = fibrosis
• clinical effects due to hypoxia and cardiac fail

Question 25

what are the causes of interstitial lung diseases?

Answer 25

- environmental eg minerals, drugs, radiation, postARDS | - idiopathic

Question 26

what biopsys can you carry out for interstitial lung disease?

Answer 26

- transbronchial biopsy = special forceps used at bronchoscopy - thoracoscopic biospy = more invasive but more reliable and generates far more tissue

Question 27

what is idiopathic pulmonary fibrosis?

Answer 27

- progressive interstitial fibrosis of unknown cause - variable associated inflammation - finger clubbing

Question 28

what is the pathology of idiopathic pulmonary fibrosis?

Answer 28

- sub-pleural and basal fibrosis - inflammatory component variable - terminally lung structure replaced by dilated spaces surrounded by fibrous walls - as it progressises you get bigger white spaces and gas exchange gets worse and lungs cant expant because they have shrunk due to the fibrosis (honeycombing)

Question 29

what is extrinsic allergic alveolitis (hypersensitivity pneumonitis)?

Answer 29

chronic inflammatory disease = small airways, interstitium, occasional granulomas allergic origin = type 3 hypersensitivity, type 4 hypersensitivity

Question 30

what are the causes of EAA?

Answer 30

- thermophilic bacteria - farmers lung - avian proteins - bird fanciers lung - fungi - malt workers lung precipitins (antibodies) can often be detected in the serum , unusual cases come to a biopsy

Question 31

what is sarcoidosis?

Answer 31

- multi system granulomatous disorder of unknown cause - pulmonary involvement is common but it isnt a lung disease - most cases mild and self-limiting

Question 32

what are some manifestations of sarcoidosis?

Answer 32

- uveitis - erythema nodosum - lymphadenopathy - hypercalcaemina

Question 33

what is pneumoconiosis?

Answer 33

- lung disease caused by mineral dust exposure - asbestosis - coal workers lung - silicosis (silica)

Question 34

what is asbestos associate with?

Answer 34

- parietal pleural plaques - interstitial fibrosis (asbestosis) - bronchial carcinoma - mesothelioma - straight (amphibole) asbestos highly dangerous