Respiratory Infections

Question 1

What are the differences between the upper and lower respiratory tracts in terms of normal flora?

Answer 1

The upper respiratory tract contains normal flora such as S. Aureus, S. Pneumoniae and Haemophilus
The lower respiratory tract is sterile and doesnt contain bacteria normally

Question 2

What defence do the alveoli themselves have to pathogens?

Answer 2

They contain IgA antibodies, complement and macrophages for killing pathogens

Question 3

What are some of the common pathogens in the different regions of URT infections?

Answer 3

Nasopharynx - Rhinovirus (common cause of cold)
Oropharynx - Group A steptococcus
Epiglottis - H.Influenzae
Larynx - S.Aureus

Question 4

What are the main differences between a common cold and influenza?

Answer 4

Influenza commonly has headache and temperature whereas cold does not
Influenza can also have general aches and pains and fatigue whereas this is less likely in cold
Influenza has exhaustion whereas cold does not

Question 5

What are the types of influenza and which commonly cause disease?

Answer 5

The common types are A, B and C and A and B cause the majority of disease

Question 6

How is a diagnosis of Influenza made?

Answer 6

Through throat swab

Question 7

What is the most common cause of bacterial pharangitis?

Answer 7

Streptococcus pyogenes

Question 8

What are the three common causes of otitis media?

Answer 8

Viruses, s. pneumoniae and s. aureus

Question 9

What is the cause of whooping cough?

Answer 9

Bordatella pertussis bacteria

Question 10

What factors predispose people to lower respiratory tract infections?

Answer 10

Alcoholism
COPD
Cystic fibrosis
Mechanical ventilation

Question 11

What are the two different types of pneumonia?

Answer 11

Acute pneumonia is either community or hospital aquired

Chronic pneumonia is either fungal or due to TB

Question 12

What are the signs and symptoms for typical pneumonia and atypical pneumonia?

Answer 12

Typical pneumonia:
-Fever
-Chest pain
-Purulent sputum
-CXR shows lobar consolidation
Atypical pneumonia:
-dyspnea
-cough
-systemic upset
-little sputum
-cxr shows diffuse shadowing

Question 13

What is the most common cause of community aquired pneumonia?

Answer 13

Streptococcus pneumoiae

Microinspiration of droplets whilst sleeping

Question 14

What are the four stages of classical lobular pneumonia?

Answer 14

Acute congestion capillary enlargement and neutrophil recruitment
Red hepatisation - red blood cells move into alveoli
Grey hepatisation - red cells broken down leaving exudate
Resolution

Question 15

What are typical organisms that cause COPD exacerbations?

Answer 15

H.Influenzae and S.Pneumoniae

Question 16

What are the common causes of atypical pneumonias and how are they treated?

Answer 16

Commonly caused by mycoplasma pneumoniae, also legionella pneumoniae
Can be from faulty air con
Can be treated with tetracyclines

Question 17

What are the clinical findings in atypical pneumonia?

Answer 17

Insidious onset with low grade fever
Non productive cough
Chest pain
Flu like symptoms
No signs of consolidation

Question 18

What is CURB65 and what score is severe?

Answer 18

C - Confusion new onset
U-Urea greater than 7mmol/L
R - resp rate of greater than 30
B - Blood pressure less than 90 systolic
Over 65
Scoring over 3 is severe

Question 19

What are the treamtent options for mild and severe pneumonia?

Answer 19

In mild pneumonia it is usually treated with amoxicillin or clarithromycin
In severe it is treated with benzylpenicillin or clarithromycin

Question 20

How do you treat early and late onset hospital aquired pneumonia?

Answer 20

Early onset (>5 days since hosp admission) you give co - amoxiclav
Late onset is treated with piperacillin

Question 21

What is the pathogenesis of TB?

Answer 21

Mycobacterium tuberculosis is inhaled
This is ingested by phagocytes but prevents the lysosome binding
This can remain dormant and then becomes reactivated and causes secondary TB
Release of cytokines from memory T cells cause cavitating lesions

Question 22

What is the treatment for TB?

Answer 22

triple therapy of isoniazid, pyrazinamide and rimfampicin