Respiratory Tract Infections

Bronchiolitis

This is a lower respiratory tract infection which leads to the blockage of small airway in the lungs

– It can lead to significant respiratory distress, especially in children with other comorbidities such as prematurity, congenital heart disease or immunodeficiency.

– It is most seen in children younger than 2 and cases spike in autumn and winter

Cause:

Respiratory syncytial virus (most common), rhinovirus is second most common cause

Symptoms:

– General –> coryza, fever, irritability, poor feeding

– Dry cough

– Coryzal symptoms precede

– Wheeze and crackles on auscultation

– Respiratory distress –> chest wall recession, nasal flaring

– May experience pauses in breathing

Investigations:

– Usually made by clinical diagnosis

– Chest x-ray can be used to exclude pneumonia

– Immunofluorescence of nasopharyngeal secretions may show RSV, but this has little effect on management

Management:

– This is largely supportive and based on symptomatic management and most cases self-resolve

– Nutritional support, fluids, and oxygen therapy if low oxygen saturations

– If Apnoea (stop breathing), cyanosis, RR>70breaths/minute, SpO₂ <92% –> admit to hospital

Prevention:

– Palivizumab (monoclonal antibody), can be given to infants who are at high risk of severe infection. This includes children with underlying heart/lung disease and premature babies. 

Croup

This is an infection of the upper airway seen in infants and toddlers, known as laryngotracheobronchitis.

– Common infection particularly in the autumn months, affecting young children less than 3 years old

Cause:

Usually due to a virus –> parainfluenza virus in the most common cause

Symptoms:

–  Inspiratory Stridor and hoarseness

–  Barking cough (worsening during the night)

– Hoover’s sign: chest wall recession

– High fever, cold symptoms

Management:

As similar to epiglottis, it is first necessary to rule this out.

– If mild illness –> give oral dexamethasone (0.15mg/kg) and symptoms usually resolve in 28 hours

– If moderate, severe, or <6 months age or known upper airway abnormality –> admit to hospital and give oxygen and nebulised adrenaline

Acute epiglottitis

This refers to inflammation of the epiglottis, which is caused by bacteria Haemophilus Influenzae type B

– It needs to be recognised and treated quickly as it can lead to airway obstruction

– It usually presents in children, but Haemophilus Influenzae type B vaccination has meant that it is rare and now is increasingly more seen in adults

– When diagnosing do not examine the throat due to risk of airway obstruction

Symptoms:

– Rapid onset high fever and malaise

– Drooling of saliva

– Muffled voice –> due to very sore throat

– Inspiratory stridor (is a high-pitched sound due to turbulent air flow in the upper airway)

Diagnosis:

Clinical diagnosis after visualising throat, should only be done by senior

Management:

This is a medical emergency as there is a high risk of upper airway obstruction

– Secure airway with tube + fluids + antibiotics + give oxygen

Whooping cough

This is a condition which is caused by Bordetella Pertussis- a Gram-negative bacterium

– It is a notifiable disease, and so it is required by law to report it to government authorities

– Infants are immunised during the children, but this does not give lifelong protection

Symptoms:

These last 10-14 weeks and are more severe in infants

– 2-3 days of coryzal symptoms first

– Sudden coughing attacks with a distinctive inspiratory whoop, which is caused by forced inspiration against a closed glottis

– Coughing episodes which are followed by vomiting, increases the chance of diagnosis

– More frequent at night and following meals

– Complications include: rib fractures,  pneumothorax,  central cyanosis, subconjunctival haemorrhages and apnoea -> can lead to syncope and seizures

Diagnosis:

Patient must have an acute cough >2 weeks with one or more of following features:

i) Paroxysmal cough (during inspiration)

ii) Inspiratory whoop

iii) Post-tussive vomiting

iv) Apnoeic attacks in infants

Tests:

PCR and serology testing for antibodies

Management:

– If < 6months admit to hospital

– 1st line is oral macrolide (clarithromycin) if onset of cough is within previous 21 days

– Give prophylactic antibiotics to household contacts

– School exclusion for 48hours after starting antibiotics

Pneumonia

This is an acute lower respiratory tract infection which often occurs when normal defences are impaired

– The pathogen varies according to age, but S. Pneumonia is most like cause of bacterial pneumonia

Causes:

– Neonates –> Organisms from maternal genital tract (GBS, bacilli, gram -ve enterococci)

– Infants (<5 years) –> Respiratory viruses are most common, but bacterial infection also occurs

– Children (>5yrs) –> Strep pneumoniae (most common), mycoplasma and chlamydia

Symptoms:

Fever, cough, chest pain and lethargy

– Tachypnoea (most sensitive sign)

– Nasal flaring and recession (signs of respiratory distress)

– Decreased breath sounds, bronchial breathing, focal coarse crackles on auscultation

Diagnosis:

– Clinical diagnosis

– CXR –> Can be used to confirm diagnosis but cannot differentiate between viral and bacterial infection

– Sputum sample sent for culture to help determine antibiotic sensitivity

Management:

– 1st line is amoxicillin

– If mycoplasma or chlamydia pneumonia –> give macrolides