Respiratory Tract Infections

Question 1

Name of the common flora of the upper respiratory tract

Answer 1

Viridans strep

Neisseria spp

Anaerobes

Candida spp

Strep pneumoniae

Strep pyogenes

Haemophilus influenzae

Psuedomonas

E. coli

Question 2

What defences are found in the respiratory system

Answer 2

Muco-ciliary clearance mechanism

Cough and sneeze reflex

Respiratory mucosal immune system

Question 3

Name some URTIs

Answer 3

Rhinitis

Pharyngitis

Epiglottitis

Laryngitis

Tracheitis

Sinusitis

Otitis media

Question 4

What is acute bronchitis, what symptoms does it cause

Answer 4

Inflammation of the medium sized airways

Occurs mainly in smokers

Symptoms: cough, fever, increased sputum, increased shortness of breath

Question 5

Name some pathogens that cause acute bronchitis

Answer 5

Viruses

S. pneumoniae

H. influenzae

M. catarrhalis

Question 6

Describe pneumonia

Answer 6

Inflammation of the lung parenchyma due to infection

Commonly have cellular exudate in alveolar spaces

Can be localised to particular lobe or may be diffuse and patchier (bronchopneumonia)

Have inflammatory response, exudation of firbin rich fluid, neutrophil and macrophage infiltration

Question 7

Name some types of pneumonia

Answer 7

Community acquired pneumonia

Nosocomial pneumonia

Aspiration pneumonia

Pneumonia in immunocompromised

Viral pneumonia

Question 8

Describe the causes of community acquired pneumonia

Answer 8

Commonest cause is Strep pneumoniae

Others include: Haemophilus influenzae, Moraxella catarrhalis, Klebsiella pneumoniae, Staph aureus

Atypical organisms - e.g. Mycoplasma pneumoniae, Chlamydia pneumoniae

Question 9

What is nosocomial pneumonia and what is it commonly caused by

Answer 9

Infection of the lower resp tract in hospitalised patients >48hrs after admission and was no incubating at time of admission

Can occur after recent hosptial admission

Important organisms: gram -ve bacteria, Staph aureus, MRSA

Question 10

What is aspiration pneumonia and what are the causative organisms

Answer 10

Aspiration of food, drink, saliva or vomitus leading to pneumonia

More likely in patients with altered level of consciousness

Oral flora and anaerobes are causative organisms

Question 11

Name some pathogens that cause immunocompromised pneumonia

Answer 11

Pneumocystis jirovecii

Cytomegalovirus

Fungal infections - candida spp, aspergillus spp

Question 12

What are the symptoms of pneumonia

Answer 12

Sputum - purulent, rust coloured or blood stained

Malaise

Nausea and/or vomiting

Cough

Pleuritic chest pain

Dyspnoea

Rigors

Question 13

What signs of pneumonia are found on examination

Answer 13

Pyrexia

Tachycardia

Tachypnoea

Cyanosis

Dullness to percussoin and tactile vocal fremitus

Bronchial breathing

Crackles

Question 14

What investigations can be done to test for pneumonia

Answer 14

FBC, U&E, CRP, ABG

CXR - usually reveals shadowing in at least one section of the lung field

Microbiology - sample and investigate. Look at: sputum sample, blood culture, broncho-alveolar lavage fluid, nose and throat swabs, urine, serum

Question 15

What score system is used to assess whether patient has pneumonia and how is it used

Answer 15

CURB 65 score - presence of two or more features is an indication for hospital treatment

C - new mental confusion

U - urea > 7mmol/L

R - resp rate >30/min

B - BP low

Age > 65

Question 16

How is pneumonia managed

Answer 16

Good oral fluid intake

Anti-pyretics - reduce fever and malaise

Analgesics for pleuritic pain

IV fluid and O2 for severe illness

Antibiotics depending on type of pneumonia

Question 17

What antibiotics are given for CAP

Answer 17

Target organism is pneumococcus -> amoxicillin

Mild-moderate - amoxicillin or doxycycline or erthyromycin/clarithromycin

Moderate-severe - hospital administration. Co-amoxiclav and clarithryomycin/doxycycline

Question 18

What antibiotics are given to treat nosocomial pneumonia

Answer 18

Likely to be due to gram -ve organism

E.g. IV co-amoxiclav

Question 19

What antibiotics are given to treat aspiration pneumonia

Answer 19

Co-amoxiclav

Question 20

What antibiotics are given to treat atypical causes of pneumonia

Answer 20

Do not respond to antibiotics that affect cell wall -> penicillin does not work

Give macrolides or tetracycline or any other antibiotics that targets something other than the cell wall

Question 21

What complications can occur with pneumonia

Answer 21

Pleural effusion

Empyema

Lung abscess formation

Question 22

What can cause a patient to fail to improve on treatment for a respiratory tract infection

Answer 22

Empyema/abscess

Proximal obstruction

Resistant organism

Not receiving or absorbing antibiotics

Immunosuppresion

Other diagnoses

Question 23

What viruses cause viral pneumonia

Answer 23

Influenza

Parainfluenza

Respiratory syncytial virus

Adenovirus

Question 24

Describe the stages of lobar pneumonia

Answer 24

Congestion - affected lung parenchyma is partially consolidated. Alveoli fill with exudate, bacteria and neutrophils

Red hepatization - lobe appears consolidated. Lungs hyperaemic. Alveoli fill with exudate rich in fibrin with leukocytes, bacteria and RBCs

Grey hepatization - lobe is grey with liver-like consistency. Greyish liquid drains if cut. Alveolar walls thick due to capillary congestion and oedema

Resolution - exudate drained via lymphatics and airways with gradual aeration of affected segment. Marcophages enter alveolar spaces and phagocytise leukocytes

Question 25

What are URTIs commonly caused by

Answer 25

URTIs are commonly caused by viruses, e.g. influenza, rhinovirus, parainfluenza