Respiratory infections🦋

Question 1

What predisposing factors can cause pulmonary infections

Answer 1

• Decreased cough reflex
• Injury to cilia
• Decreased function of alveolar macrophages
• Edema/congestion
• Retention of secretions

Question 2

What’s the classification of pneumonia

Answer 2

• By clinical setting ( community/hospital acquired pneumonia)
• By organism ( mycoplasma, pneumococcal)
• By morphology ( lobar/broncho pneumonia)

Question 3

What type of pneumonia can affect the alveolar and what organism causes it

Answer 3

Bronchopneumonia ( streptococcus pneumoniae, haemophilus influenza, staphylococcus aureus) ( sometimes anaerobes and coliforms)

Lobar pneumonia ( streptococcus pneumoniae)( sometimes can be klebsiella/legionella)

Question 4

What pathogenic organisms can cause pneumonia that affects the interstitial/ interstitium.

Answer 4

Influenza virus

Mycoplasma pneumoniae

Question 5

How can the pathogen infect the person

Answer 5

By inhalation of air droplet’s
Aspiration of infected secretions/ objects
Hematogenous spread

Question 6

What is lobar pneumonia

How is lobar pneumonia usually acquired

Which group is most affected

Answer 6

It’s confluent consolidation involving a complete lung lobe

It’s community acquired

Young adults

Question 7

What is the pathogenesis of lobar pneumonia

Answer 7

It’s a classical acute inflammatory response where there is:
Exudation of fibrin rich fluid
Neutrophil infiltration 
Macrophage infiltration 
Resolution

Question 8

What’s the classical pathway of lobar pneumonia

Answer 8

Congestion
Red hepatization
Grey hepatization
Resolution

Question 9

What complications can arise from pneumonia

Answer 9

Organization (fibrous scarring)
Abscess
Bronchiectasis
Empyema (pus in pleural cavity)

Question 10

How does bronchopneumonia travel

Answer 10

Infection starts in airways and spreads to adjacent alveolar lung

Question 11

How does bronchopneumonia present in a chest X-ray

Answer 11

The consolidation is patchy

Question 12

How can bronchopneumonia arise

Answer 12

From a complication of viral infection (influenza)
From aspiration of gastric contents (infected with coliforms, anaerobes,staph)
Cardiac failure
COPD

Question 13

What complications can bronchopneumonia cause

Answer 13

Organization
Abscess
Bronchiectasis
Empyema

Question 14

Someone who is immunocompromised can acquire pneumonia from what (opportunistic pneumonia)

Answer 14

TB
Virus (CMV)
Bacteria(mycobacterium avium intracellulare)
Fungi( aspergillus,candida,pneumocystis)
Protozoa( cryptosporidia,toxoplasma)

Question 15

How can you diagnose pneumonia

Answer 15

Teamwork (physician,microbiologist,pathologist)
Broncho-alveolar lavage
Biopsy (where many stains will take place)

Question 16

What can cause someone to be immunosuppressed

Answer 16

If they have AIDS
Cancer patients
Transplant recipients

Question 17

What is a lung abscess

Symptoms of a lung abscess are

Answer 17

It’s a localized collection of pus, caused from central tissue destruction lined by granulation tissue/fibrosis in an attempt to heal. It’s tumor like

Chronic malaise and fever

Question 18

What organism can cause a lung abscess

What clinical ways can one result in a lung abscess

Answer 18

Staphylococcus,anaerobes,gram negatives

From an aspiration, following pneumonia,fungal infection,bronchiectasis,emboli

Question 19

What causes TB

A chronic infection of TB will be seen in which body sites

Answer 19

Mycobacterial infection

Lung,gut,kidneys,lymph nodes,skin

Question 20

Pathogenesis of TB involves what

Answer 20

Virulence of organism
Hypersensitivity and immunity
Tissue destruction and necrosis

Question 21

What is mycobacterial virulence (virulence of organism)

Answer 21

It’s related to the ability of the mycobacterium tb to resist phagocytosis and how the surface antigen stimulates the hosts tumour necrosis factor(TNF alpha) (resulting in fever and constitutional symptoms)

Question 22

What is immunity and hypersensitivity

Answer 22

Immunity is the T-cells response to organism and enhances macrophage ability to kill mycobacteria

Hypersensitivity type IV is the T-cell response which causes granulomatous inflammation,tissue necrosis and scarring

Question 23

What happens in primary TB

Answer 23

The inhaled organism is phagocytosed and carried to hilar lymph nodes.There is immune activation after some weeks leading to a granulomatous response in nodes where ghon focus are formed, but results in the killing of the organism

Question 24

What is secondary TB

Answer 24

This is where there is re-infection/reactivating of the disease (ghon complex)in a person who is immunocompromised/from old age. The disease initially remains localized in the apices of lung but can progress to spread by airways/ bloodstream leading to cavities and fibrosis

Question 25

Where can a ghon focus be found

What makes a ghon complex

Answer 25

In periphery of mid zone/ hilar lymph nodes

A ghon focus+ hilar lymph node

Question 26

What do we see in secondary TB

Answer 26

More caseous necrosis
Fibrosis
Cavitation (fibrocaseous cavities)

Question 27

What complications can secondary TB cause

Answer 27

Pleural effusion
TB pneumonia
Miliary TB can affect the lungs,kidneys,brain
Interstinal TB

Question 28

Why does TB reactivate

Answer 28

Because of decreased T-cell function as a result of
-age
-HIV/AIDS
-immunosuppressive therapy( steroids,cancer chemotherapy)
And because of reinfection at high dose/ with more virulent organism

Question 29

What different color sputum can you get as a result of pneumonia and what causes them

Answer 29

• pink/red/rusty looking it’s because of step pneumoniae
• green it’s because of pseudomonas
• if it’s foul smelling its an anaerobe bacteria
• if has a jelly consistency its klebsiella