Lower Respiratory Tract Infections

Question 1

What is Bronchiolitis?

Answer 1

Viral infection of the medium airways in young children causing inflammation and secretion build up. Most commonly occurs during the winter in infants/toddlers < 2 years and 90% are <9months

Question 2

What are risk factors for complicated bronchiolitis?

Answer 2

<6 months

Underlying medical conditions such as bronchopulmonary dysplasia, congenital heart disease or cystic fibrosis

Question 3

What are the clinical features of bronchiolitis?

Answer 3

Coryzal symptoms preceding cough 
Fever
Tachypnoea
Wheeze
Inspiratory crackles
Apnoea 
Dry cough
Intercostal recession sometimes with cyanosis 
Reduced feeding 
Oxygen requirement

Question 4

What are the common causes of bronchiolitis?

Answer 4

RSV
Mycoplasma
Parainfluenza and influenza 
Adenovirus
Coronavirus
Metapneumovirus
Can sometimes be a secondary bacterial infection in severe cases

Question 5

What investigations should be done in a child suspected of having bronchiolitis?

Answer 5

CXR to rule out pneumonia
Blood gases
Sats
Immunofluorescence of nasopharyngeal secretions (NPA – nasopharyngeal aspirate)

Question 6

When should a child with bronchiolitis be admitted and how should a child with bronchiolitis be managed?

Answer 6

Admit if: respiratory distress e.g. grunting, Sats<92% on air or RR >70, apnoea or central cyanosis.
Consider admitting if inadequate feeds (50-75% of normal), clinical dehydration or RR >60.

Give supportive care such as fluids and humidified oxygen +/- mechanical ventilation
Condition usually peaks at day 5-7 of infection
Nasogastric feeds if required
Suction if excessive upper airway secretions

Palivizumab – monoclonal antibody given to those at risk of RSV such as premature infants, those with lung or heart abnormalities and immunocompromised infants.

Question 7

What is a viral induced wheeze?

Answer 7

A child too young to be diagnosed with asthma who develop a wheeze when suffering from a viral infection but has no wheeze symptoms in-between viral infections. Peak is around 2 years and resolves by 5.

Question 8

What are the clinical features of a viral induced wheeze?

Answer 8

Coryzal prodrome
Dry cough
Hyperinflated 
Diffuse wheeze 
No crepitations 
Difficulty breathing

Question 9

What casues viral induced wheeze?

Answer 9

Rhinovirus most common 
RSV
Parainfluenza and influenza 
Adenovirus
Coronavirus
Metapneumovirus
Passive smoking (prolongs symptoms)

Question 10

How should children with viral induced wheeze be managed?

Answer 10

Happy wheezers – no treatment necessary
If distressed or have high work of breathing, then treatment should be trial of salbutamol via spacer inhaler
Next Montelukast or Ipratropium bromide
Nutrition and hydration if needed

Question 11

What are the long term implications of viral induced wheeze?

Answer 11

Children eventually grow out of it but if recurrent may consider 4-8 weeks trial of inhaled steroid or montelukast
If chronic consider Cystic fibrosis, TB, foreign body or asthma

Question 12

How should a mild/moderate acute wheeze in a child be managed?

Answer 12

Mild/moderate – sats >92%, RR <30 in over 5s and <40 under 5s, no/minimal accessor muscle use, feeding well or talking normally and wheeze only audible via stethoscope.

10 puffs of salbutamol via inhaler or nebulised salbutamol (2.5mg/5mg), reassess every 30 minutes, if not improving consider ipratropium bromide or steroids.

Question 13

How should a severe acute wheeze in a child be managed?

Answer 13

Severe
Sats <92%, RR >30 in over 5s and >49 in under 5s, use of accessory muscles, too breathless to feed or talk and audible wheeze.

High flow oxygen, nebulised salbutamol, and ipratropium bromide
Oral steroids
Continuous reassessment over 30minutes
Consider IV salbutamol, magnesium sulphate or aminophylline

Question 14

What are the clinical features of a community acquired pneumonia?

Answer 14

Malaise Poor feeding 
Respiratory distress – tachypnoea 
Tachypnoea and high fever
Wet cough 
Cyanosis 
Intercostal recession and accessory muscle use 
Older children like adults – pleuritic pain, crackles +/- wheeze and bronchial breathing 
Crepitations 
Reduced air entry

Question 15

How should a suspected community acquired pneumonia be investigated?

Answer 15

CXR
FBC
Sputum cultures

Question 16

What commonly causes community acquired Pneumonia?

Answer 16

Viral > bacterial
New-born – GBS, gram negative enterococci and bacilli
Infants and young children – RSV most common virus and Strep Pneumoniae are most common bacterial. Also, Haemophilus influenzae, pertussis, chlamydia and staph aureus.
Children > 5yrs – strep pneumoniae, Mycoplasma pneumoniae and chlamydia pneumoniae

Question 17

How can you distinguish between a viral and bacterial pneumonia?

Answer 17

Bacterial 
>2 years 
Mostly >38.5 degrees
Onset abrupt and toxic + No prodrome
No others ill in family 

Features
Unilateral signs 
Pleuritic chest
Wet and productive cough 
No wheeze 

Viral 
<2 years 
Mostly <38.5 degrees
Onset gradual with coryza 
Yes with URTI/rash/conjunctivitis
Bilateral signs

Features
Rash and myalgia
Dry cough
Wheeze

Question 18

How should a child with pneumonia be managed?

Answer 18

Admit if O2 < 92% or in respiratory distress
Those with moderate symptoms can be sent home as usually viral and nothing we can do
If bacterial or severe: amoxicillin is 1st line otherwise co-amoxiclav (if associated with H.influenza), azithromycin or clarithromycin for 5-7 days (if mycoplasma or chlamydia).

If moderate or severe (recession and cyanosis) then IV Cefuroxime and PO erythromicin

Note children do not swallow sputum until they are 8 years old

Question 19

When should you suspected TB in children?

Answer 19

Suspect if: Overseas contacts, odd CXR and anorexia. Diagnosis via Tuberculin test or interferon gamma blood test or 3x sputum test (Ziehl-Neelsen stain)

Question 20

What is whooping cough?

Answer 20

LRTI caused by Bordetella pertussis (gram negative). Low mortality rate usually due to secondary pneumonia but severe in young children. Significant morbidity in infants under 2.

Question 21

How is pertussis transmitted and what is the incubation period?

Answer 21

Transmitted by aerosol droplet with an incubation period of 3-12 days.

Question 22

How long is someone with pertussis infective for?

Answer 22

Infectious from 6 days after exposure to 3 weeks after onset of symptoms.

Question 23

How long does the pertussis vaccine last for?

Answer 23

Vaccine only lasts 6 years so cannot be eradicated.

Question 24

Describe the 3 phases of whooping cough and its clinical features

Answer 24

3 Phases
Catarrhal phase – 2-3 days of coryza
Paroxysmal phase – from 10-100-day cough with apnoea, bouts of coughing ending in vomiting, cough followed by whoop (due to inspiration against closed glottis), worse at night or after feeds.
Convalescent phase – chronic cough that lasts for 4 weeks

Often coinfection with RSV
Common in infants and adultescents over 14
Absolute lymphocytosis
Incubation period is 10-14 days

Question 25

What investigations should be done in suspected pertussis?

Answer 25

PCR via nasal swab
CXR

Diagnostic criteria
Suspected in those with a 14-day cough and one of the following: paroxysmal cough, inspiratory whoop (uncommon in young children), post-tussive vomiting and undiagnosed apnoeic attacks in young infants.

Question 26

What complications can occur form pertussis?

Answer 26

100-day cough and pneumonia 
Coughing may lead to petechiae
Seizures
Inguinal hernias 
Conjunctival, retina and CNS bleeds (rare)
Bronchiectasis

Question 27

How is pertussis managed?

Answer 27

NOTIFIABLE DISEASE
Admit if < 6 months
Macrolide such as Clarithromycin and antibiotic prophylaxis for household contacts

Prevention – Vaccination but not always effective, 30% of cases come from fully vaccinated children.

Vaccinating mother during pregnancy very important - offered at 20-32 weeks